view2d.c

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/*
 * $Id: view2d.c 37615 2011-06-18 09:01:26Z campbellbarton $
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. 
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2008 Blender Foundation.
 * All rights reserved.
 * 
 * Contributor(s): Blender Foundation, Joshua Leung
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <float.h>
#include <limits.h>
#include <math.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_scene_types.h"
#include "DNA_userdef_types.h"

#include "BLI_blenlib.h"
#include "BLI_utildefines.h"

#include "BKE_context.h"
#include "BKE_screen.h"
#include "BKE_global.h"


#include "WM_api.h"

#include "BIF_gl.h"

#include "BLF_api.h"

#include "ED_anim_api.h"
#include "ED_screen.h"

#include "UI_interface.h"
#include "UI_view2d.h"

#include "interface_intern.h"

/* *********************************************************************** */

/* XXX still unresolved: scrolls hide/unhide vs region mask handling */
/* XXX there's V2D_SCROLL_HORIZONTAL_HIDE and V2D_SCROLL_HORIZONTAL_FULLR ... */

/* helper to allow scrollbars to dynamically hide
 *      - returns a copy of the scrollbar settings with the flags to display 
 *        horizontal/vertical scrollbars removed
 *      - input scroll value is the v2d->scroll var
 *      - hide flags are set per region at drawtime
 */
static int view2d_scroll_mapped(int scroll)
{
        if(scroll & V2D_SCROLL_HORIZONTAL_HIDE)
                scroll &= ~(V2D_SCROLL_HORIZONTAL);
        if(scroll & V2D_SCROLL_VERTICAL_HIDE)
                scroll &= ~(V2D_SCROLL_VERTICAL);
        return scroll;
}

/* called each time cur changes, to dynamically update masks */
static void view2d_masks(View2D *v2d)
{
        int scroll;
        
        /* mask - view frame */
        v2d->mask.xmin= v2d->mask.ymin= 0;
        v2d->mask.xmax= v2d->winx - 1;  /* -1 yes! masks are pixels */
        v2d->mask.ymax= v2d->winy - 1;

#if 0
        // XXX see above
        v2d->scroll &= ~(V2D_SCROLL_HORIZONTAL_HIDE|V2D_SCROLL_VERTICAL_HIDE);
        /* check size if: */
        if (v2d->scroll & V2D_SCROLL_HORIZONTAL)
                if(!(v2d->scroll & V2D_SCROLL_SCALE_HORIZONTAL))
                        if (v2d->tot.xmax-v2d->tot.xmin <= v2d->cur.xmax-v2d->cur.xmin)
                                v2d->scroll |= V2D_SCROLL_HORIZONTAL_HIDE;
        if (v2d->scroll & V2D_SCROLL_VERTICAL)
                if(!(v2d->scroll & V2D_SCROLL_SCALE_VERTICAL))
                        if (v2d->tot.ymax-v2d->tot.ymin <= v2d->cur.ymax-v2d->cur.ymin)
                                v2d->scroll |= V2D_SCROLL_VERTICAL_HIDE;
#endif
        scroll= view2d_scroll_mapped(v2d->scroll);
        
        /* scrollers shrink mask area, but should be based off regionsize 
         *      - they can only be on one to two edges of the region they define
         *      - if they overlap, they must not occupy the corners (which are reserved for other widgets)
         */
        if (scroll) {
                /* vertical scroller */
                if (scroll & V2D_SCROLL_LEFT) {
                        /* on left-hand edge of region */
                        v2d->vert= v2d->mask;
                        v2d->vert.xmax= V2D_SCROLL_WIDTH;
                        v2d->mask.xmin= v2d->vert.xmax + 1;
                }
                else if (scroll & V2D_SCROLL_RIGHT) {
                        /* on right-hand edge of region */
                        v2d->vert= v2d->mask;
                        v2d->vert.xmax++; /* one pixel extra... was leaving a minor gap... */
                        v2d->vert.xmin= v2d->vert.xmax - V2D_SCROLL_WIDTH;
                        v2d->mask.xmax= v2d->vert.xmin - 1;
                }
                
                /* horizontal scroller */
                if (scroll & (V2D_SCROLL_BOTTOM|V2D_SCROLL_BOTTOM_O)) {
                        /* on bottom edge of region (V2D_SCROLL_BOTTOM_O is outliner, the other is for standard) */
                        v2d->hor= v2d->mask;
                        v2d->hor.ymax= V2D_SCROLL_HEIGHT;
                        v2d->mask.ymin= v2d->hor.ymax + 1;
                }
                else if (scroll & V2D_SCROLL_TOP) {
                        /* on upper edge of region */
                        v2d->hor= v2d->mask;
                        v2d->hor.ymin= v2d->hor.ymax - V2D_SCROLL_HEIGHT;
                        v2d->mask.ymax= v2d->hor.ymin - 1;
                }
                
                /* adjust vertical scroller if there's a horizontal scroller, to leave corner free */
                if (scroll & V2D_SCROLL_VERTICAL) {
                        /* just set y min/max for vertical scroller to y min/max of mask as appropriate */
                        if (scroll & (V2D_SCROLL_BOTTOM|V2D_SCROLL_BOTTOM_O)) {
                                /* on bottom edge of region (V2D_SCROLL_BOTTOM_O is outliner, the other is for standard) */
                                v2d->vert.ymin= v2d->mask.ymin;
                        }
                        else if (scroll & V2D_SCROLL_TOP) {
                                /* on upper edge of region */
                                v2d->vert.ymax= v2d->mask.ymax;
                        }
                }
        }
        
}

/* Refresh and Validation */

/* Initialise all relevant View2D data (including view rects if first time) and/or refresh mask sizes after view resize
 *      - for some of these presets, it is expected that the region will have defined some
 *        additional settings necessary for the customisation of the 2D viewport to its requirements
 *      - this function should only be called from region init() callbacks, where it is expected that
 *        this is called before UI_view2d_size_update(), as this one checks that the rects are properly initialised. 
 */
void UI_view2d_region_reinit(View2D *v2d, short type, int winx, int winy)
{
        short tot_changed= 0, init= 0;
        uiStyle *style= U.uistyles.first;

        /* initialise data if there is a need for such */
        if ((v2d->flag & V2D_IS_INITIALISED) == 0) {
                /* set initialised flag so that View2D doesn't get reinitialised next time again */
                v2d->flag |= V2D_IS_INITIALISED;

                init= 1;
                
                /* see eView2D_CommonViewTypes in UI_view2d.h for available view presets */
                switch (type) {
                        /* 'standard view' - optimum setup for 'standard' view behaviour, that should be used new views as basis for their
                         *      own unique View2D settings, which should be used instead of this in most cases...
                         */
                        case V2D_COMMONVIEW_STANDARD:
                        {
                                /* for now, aspect ratio should be maintained, and zoom is clamped within sane default limits */
                                v2d->keepzoom= (V2D_KEEPASPECT|V2D_LIMITZOOM);
                                v2d->minzoom= 0.01f;
                                v2d->maxzoom= 1000.0f;
                                
                                /* tot rect and cur should be same size, and aligned using 'standard' OpenGL coordinates for now 
                                 *      - region can resize 'tot' later to fit other data
                                 *      - keeptot is only within bounds, as strict locking is not that critical
                                 *      - view is aligned for (0,0) -> (winx-1, winy-1) setup
                                 */
                                v2d->align= (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_NEG_Y);
                                v2d->keeptot= V2D_KEEPTOT_BOUNDS;
                                
                                v2d->tot.xmin= v2d->tot.ymin= 0.0f;
                                v2d->tot.xmax= (float)(winx - 1);
                                v2d->tot.ymax= (float)(winy - 1);
                                
                                v2d->cur= v2d->tot;
                                
                                /* scrollers - should we have these by default? */
                                // XXX for now, we don't override this, or set it either!
                        }
                                break;
                        
                        /* 'list/channel view' - zoom, aspect ratio, and alignment restrictions are set here */
                        case V2D_COMMONVIEW_LIST:
                        {
                                /* zoom + aspect ratio are locked */
                                v2d->keepzoom = (V2D_LOCKZOOM_X|V2D_LOCKZOOM_Y|V2D_LIMITZOOM|V2D_KEEPASPECT);
                                v2d->minzoom= v2d->maxzoom= 1.0f;
                                
                                /* tot rect has strictly regulated placement, and must only occur in +/- quadrant */
                                v2d->align = (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_POS_Y);
                                v2d->keeptot = V2D_KEEPTOT_STRICT;
                                tot_changed= 1;
                                
                                /* scroller settings are currently not set here... that is left for regions... */
                        }
                                break;
                                
                        /* 'stack view' - practically the same as list/channel view, except is located in the pos y half instead. 
                         *      zoom, aspect ratio, and alignment restrictions are set here */
                        case V2D_COMMONVIEW_STACK:
                        {
                                /* zoom + aspect ratio are locked */
                                v2d->keepzoom = (V2D_LOCKZOOM_X|V2D_LOCKZOOM_Y|V2D_LIMITZOOM|V2D_KEEPASPECT);
                                v2d->minzoom= v2d->maxzoom= 1.0f;
                                
                                /* tot rect has strictly regulated placement, and must only occur in +/+ quadrant */
                                v2d->align = (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_NEG_Y);
                                v2d->keeptot = V2D_KEEPTOT_STRICT;
                                tot_changed= 1;
                                
                                /* scroller settings are currently not set here... that is left for regions... */
                        }
                                break;
                                
                        /* 'header' regions - zoom, aspect ratio, alignment, and panning restrictions are set here */
                        case V2D_COMMONVIEW_HEADER:
                        {
                                /* zoom + aspect ratio are locked */
                                v2d->keepzoom = (V2D_LOCKZOOM_X|V2D_LOCKZOOM_Y|V2D_LIMITZOOM|V2D_KEEPASPECT);
                                v2d->minzoom= v2d->maxzoom= 1.0f;
                                v2d->min[0]= v2d->max[0]= (float)(winx-1);
                                v2d->min[1]= v2d->max[1]= (float)(winy-1);
                                
                                /* tot rect has strictly regulated placement, and must only occur in +/+ quadrant */
                                v2d->align = (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_NEG_Y);
                                v2d->keeptot = V2D_KEEPTOT_STRICT;
                                tot_changed= 1;
                                
                                /* panning in y-axis is prohibited */
                                v2d->keepofs= V2D_LOCKOFS_Y;
                                
                                /* absolutely no scrollers allowed */
                                v2d->scroll= 0;
                                
                        }
                                break;
                        
                        /* panels view, with horizontal/vertical align */
                        case V2D_COMMONVIEW_PANELS_UI:
                        {
                                float panelzoom= (style) ? style->panelzoom : 1.0f;
                                
                                /* for now, aspect ratio should be maintained, and zoom is clamped within sane default limits */
                                v2d->keepzoom= (V2D_KEEPASPECT|V2D_LIMITZOOM|V2D_KEEPZOOM);
                                v2d->minzoom= 0.5f;
                                v2d->maxzoom= 2.0f;
                                //tot_changed= 1;
                                
                                v2d->align= (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_POS_Y);
                                v2d->keeptot= V2D_KEEPTOT_BOUNDS;
                                
                                v2d->scroll |= (V2D_SCROLL_RIGHT|V2D_SCROLL_BOTTOM);
                                v2d->scroll |= V2D_SCROLL_HORIZONTAL_HIDE;
                                v2d->scroll &= ~V2D_SCROLL_VERTICAL_HIDE;

                                v2d->tot.xmin= 0.0f;
                                v2d->tot.xmax= winx;
                                
                                v2d->tot.ymax= 0.0f;
                                v2d->tot.ymin= -winy;
                                
                                v2d->cur.xmin= 0.0f;
                                /* bad workaround for keeping zoom level with scrollers */
                                v2d->cur.xmax= (winx - V2D_SCROLL_WIDTH)*panelzoom;
                                
                                v2d->cur.ymax= 0.0f;
                                v2d->cur.ymin= (-winy)*panelzoom;
                        }
                                break;
                                
                                /* other view types are completely defined using their own settings already */
                        default:
                                /* we don't do anything here, as settings should be fine, but just make sure that rect */
                                break;  
                }
        }
        
        /* store view size */
        v2d->winx= winx;
        v2d->winy= winy;
        
        /* set masks */
        view2d_masks(v2d);
        
        /* set 'tot' rect before setting cur? */
        if (tot_changed) 
                UI_view2d_totRect_set_resize(v2d, winx, winy, !init);
        else
                UI_view2d_curRect_validate_resize(v2d, !init);
}

/* Ensure View2D rects remain in a viable configuration 
 *      - cur is not allowed to be: larger than max, smaller than min, or outside of tot
 */
// XXX pre2.5 -> this used to be called  test_view2d()
void UI_view2d_curRect_validate_resize(View2D *v2d, int resize)
{
        float totwidth, totheight, curwidth, curheight, width, height;
        float winx, winy;
        rctf *cur, *tot;
        
        /* use mask as size of region that View2D resides in, as it takes into account scrollbars already  */
        winx= (float)(v2d->mask.xmax - v2d->mask.xmin + 1);
        winy= (float)(v2d->mask.ymax - v2d->mask.ymin + 1);
        
        /* get pointers to rcts for less typing */
        cur= &v2d->cur;
        tot= &v2d->tot;
        
        /* we must satisfy the following constraints (in decreasing order of importance):
         *      - alignment restrictions are respected
         *      - cur must not fall outside of tot
         *      - axis locks (zoom and offset) must be maintained
         *      - zoom must not be excessive (check either sizes or zoom values)
         *      - aspect ratio should be respected (NOTE: this is quite closely realted to zoom too)
         */
        
        /* Step 1: if keepzoom, adjust the sizes of the rects only
         *      - firstly, we calculate the sizes of the rects
         *      - curwidth and curheight are saved as reference... modify width and height values here
         */
        totwidth= tot->xmax - tot->xmin;
        totheight= tot->ymax - tot->ymin;
        curwidth= width= cur->xmax - cur->xmin;
        curheight= height= cur->ymax - cur->ymin;
        
        /* if zoom is locked, size on the appropriate axis is reset to mask size */
        if (v2d->keepzoom & V2D_LOCKZOOM_X)
                width= winx;
        if (v2d->keepzoom & V2D_LOCKZOOM_Y)
                height= winy;
                
        /* values used to divide, so make it safe 
         * NOTE: width and height must use FLT_MIN instead of 1, otherwise it is impossible to
         *              get enough resolution in Graph Editor for editing some curves
         */
        if(width < FLT_MIN) width= 1;
        if(height < FLT_MIN) height= 1;
        if(winx < 1) winx= 1;
        if(winy < 1) winy= 1;
        
        /* V2D_LIMITZOOM indicates that zoom level should be preserved when the window size changes */
        if (resize && (v2d->keepzoom & V2D_KEEPZOOM)) {
                float zoom, oldzoom;

                if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
                        zoom= winx / width;
                        oldzoom= v2d->oldwinx / curwidth;

                        if(oldzoom != zoom)
                                width *= zoom/oldzoom;
                }

                if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
                        zoom= winy / height;
                        oldzoom= v2d->oldwiny / curheight;

                        if(oldzoom != zoom)
                                height *= zoom/oldzoom;
                }
        }
        /* keepzoom (V2D_LIMITZOOM set), indicates that zoom level on each axis must not exceed limits 
         * NOTE: in general, it is not expected that the lock-zoom will be used in conjunction with this
         */
        else if (v2d->keepzoom & V2D_LIMITZOOM) {
                float zoom, fac;
                
                /* check if excessive zoom on x-axis */
                if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
                        zoom= winx / width;
                        if ((zoom < v2d->minzoom) || (zoom > v2d->maxzoom)) {
                                fac= (zoom < v2d->minzoom) ? (zoom / v2d->minzoom) : (zoom / v2d->maxzoom);
                                width *= fac;
                        }
                }
                
                /* check if excessive zoom on y-axis */
                if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
                        zoom= winy / height;
                        if ((zoom < v2d->minzoom) || (zoom > v2d->maxzoom)) {
                                fac= (zoom < v2d->minzoom) ? (zoom / v2d->minzoom) : (zoom / v2d->maxzoom);
                                height *= fac;
                        }
                }
        }
        else {
                /* make sure sizes don't exceed that of the min/max sizes (even though we're not doing zoom clamping) */
                CLAMP(width, v2d->min[0], v2d->max[0]);
                CLAMP(height, v2d->min[1], v2d->max[1]);
        }
        
        /* check if we should restore aspect ratio (if view size changed) */
        if (v2d->keepzoom & V2D_KEEPASPECT) {
                short do_x=0, do_y=0, do_cur, do_win;
                float curRatio, winRatio;
                
                /* when a window edge changes, the aspect ratio can't be used to
                 * find which is the best new 'cur' rect. thats why it stores 'old' 
                 */
                if (winx != v2d->oldwinx) do_x= 1;
                if (winy != v2d->oldwiny) do_y= 1;
                
                curRatio= height / width;
                winRatio= winy / winx;
                
                /* both sizes change (area/region maximised)  */
                if (do_x == do_y) {
                        if (do_x && do_y) {
                                /* here is 1,1 case, so all others must be 0,0 */
                                if (ABS(winx - v2d->oldwinx) > ABS(winy - v2d->oldwiny)) do_y= 0;
                                else do_x= 0;
                        }
                        else if (winRatio > 1.0f) do_x= 0; 
                        else do_x= 1;
                }
                do_cur= do_x;
                do_win= do_y;
                
                if (do_cur) {
                        if ((v2d->keeptot == V2D_KEEPTOT_STRICT) && (winx != v2d->oldwinx)) {
                                /* special exception for Outliner (and later channel-lists):
                                 *      - The view may be moved left to avoid contents being pushed out of view when view shrinks. 
                                 *      - The keeptot code will make sure cur->xmin will not be less than tot->xmin (which cannot be allowed)
                                 *      - width is not adjusted for changed ratios here...
                                 */
                                if (winx < v2d->oldwinx) {
                                        float temp = v2d->oldwinx - winx;
                                        
                                        cur->xmin -= temp;
                                        cur->xmax -= temp;
                                        
                                        /* width does not get modified, as keepaspect here is just set to make 
                                         * sure visible area adjusts to changing view shape! 
                                         */
                                }
                        }
                        else {
                                /* portrait window: correct for x */
                                width= height / winRatio;
                        }
                }
                else {
                        if ((v2d->keeptot == V2D_KEEPTOT_STRICT) && (winy != v2d->oldwiny)) {
                                /* special exception for Outliner (and later channel-lists):
                                 *      - Currently, no actions need to be taken here...
                                 */

                                if (winy < v2d->oldwiny) {
                                        float temp = v2d->oldwiny - winy;
                                        
                                        cur->ymin += temp;
                                        cur->ymax += temp;
                                }

                        }
                        else {
                                /* landscape window: correct for y */
                                height = width * winRatio;
                        }
                }
                
                /* store region size for next time */
                v2d->oldwinx= (short)winx; 
                v2d->oldwiny= (short)winy;
        }
        
        /* Step 2: apply new sizes to cur rect, but need to take into account alignment settings here... */
        if ((width != curwidth) || (height != curheight)) {
                float temp, dh;
                
                /* resize from centerpoint, unless otherwise specified */
                if (width != curwidth) {
                        if (v2d->keepofs & V2D_LOCKOFS_X) {
                                cur->xmax += width - (cur->xmax - cur->xmin);
                        }
                        else if (v2d->keepofs & V2D_KEEPOFS_X) {
                                if(v2d->align & V2D_ALIGN_NO_POS_X)
                                        cur->xmin -= width - (cur->xmax - cur->xmin);
                                else
                                        cur->xmax += width - (cur->xmax - cur->xmin);
                        }
                        else {
                                temp= (cur->xmax + cur->xmin) * 0.5f;
                                dh= width * 0.5f;
                                
                                cur->xmin = temp - dh;
                                cur->xmax = temp + dh;
                        }
                }
                if (height != curheight) {
                        if (v2d->keepofs & V2D_LOCKOFS_Y) {
                                cur->ymax += height - (cur->ymax - cur->ymin);
                        }
                        else if (v2d->keepofs & V2D_KEEPOFS_Y) {
                                if(v2d->align & V2D_ALIGN_NO_POS_Y)
                                        cur->ymin -= height - (cur->ymax - cur->ymin);
                                else
                                        cur->ymax += height - (cur->ymax - cur->ymin);
                        }
                        else {
                                temp= (cur->ymax + cur->ymin) * 0.5f;
                                dh= height * 0.5f;
                                
                                cur->ymin = temp - dh;
                                cur->ymax = temp + dh;
                        }
                }
        }
        
        /* Step 3: adjust so that it doesn't fall outside of bounds of 'tot' */
        if (v2d->keeptot) {
                float temp, diff;
                
                /* recalculate extents of cur */
                curwidth= cur->xmax - cur->xmin;
                curheight= cur->ymax - cur->ymin;
                
                /* width */
                if ( (curwidth > totwidth) && !(v2d->keepzoom & (V2D_KEEPZOOM|V2D_LOCKZOOM_X|V2D_LIMITZOOM)) ) {
                        /* if zoom doesn't have to be maintained, just clamp edges */
                        if (cur->xmin < tot->xmin) cur->xmin= tot->xmin;
                        if (cur->xmax > tot->xmax) cur->xmax= tot->xmax;
                }
                else if (v2d->keeptot == V2D_KEEPTOT_STRICT) {
                        /* This is an exception for the outliner (and later channel-lists, headers) 
                         *      - must clamp within tot rect (absolutely no excuses)
                         *      --> therefore, cur->xmin must not be less than tot->xmin
                         */
                        if (cur->xmin < tot->xmin) {
                                /* move cur across so that it sits at minimum of tot */
                                temp= tot->xmin - cur->xmin;
                                
                                cur->xmin += temp;
                                cur->xmax += temp;
                        }
                        else if (cur->xmax > tot->xmax) {
                                /* - only offset by difference of cur-xmax and tot-xmax if that would not move 
                                 *      cur-xmin to lie past tot-xmin
                                 * - otherwise, simply shift to tot-xmin???
                                 */
                                temp= cur->xmax - tot->xmax;
                                
                                if ((cur->xmin - temp) < tot->xmin) {
                                        /* only offset by difference from cur-min and tot-min */
                                        temp= cur->xmin - tot->xmin;
                                        
                                        cur->xmin -= temp;
                                        cur->xmax -= temp;
                                }
                                else {
                                        cur->xmin -= temp;
                                        cur->xmax -= temp;
                                }
                        }
                }
                else {
                        /* This here occurs when:
                         *      - width too big, but maintaining zoom (i.e. widths cannot be changed)
                         *      - width is OK, but need to check if outside of boundaries
                         * 
                         * So, resolution is to just shift view by the gap between the extremities.
                         * We favour moving the 'minimum' across, as that's origin for most things
                         * (XXX - in the past, max was favoured... if there are bugs, swap!)
                         */
                        if ((cur->xmin < tot->xmin) && (cur->xmax > tot->xmax)) {
                                /* outside boundaries on both sides, so take middle-point of tot, and place in balanced way */
                                temp= (tot->xmax + tot->xmin) * 0.5f;
                                diff= curheight * 0.5f;
                                
                                cur->xmin= temp - diff;
                                cur->xmax= temp + diff;
                        }
                        else if (cur->xmin < tot->xmin) {
                                /* move cur across so that it sits at minimum of tot */
                                temp= tot->xmin - cur->xmin;
                                
                                cur->xmin += temp;
                                cur->xmax += temp;
                        }
                        else if (cur->xmax > tot->xmax) {
                                /* - only offset by difference of cur-xmax and tot-xmax if that would not move 
                                 *      cur-xmin to lie past tot-xmin
                                 * - otherwise, simply shift to tot-xmin???
                                 */
                                temp= cur->xmax - tot->xmax;
                                
                                if ((cur->xmin - temp) < tot->xmin) {
                                        /* only offset by difference from cur-min and tot-min */
                                        temp= cur->xmin - tot->xmin;
                                        
                                        cur->xmin -= temp;
                                        cur->xmax -= temp;
                                }
                                else {
                                        cur->xmin -= temp;
                                        cur->xmax -= temp;
                                }
                        }
                }
                
                /* height */
                if ( (curheight > totheight) && !(v2d->keepzoom & (V2D_KEEPZOOM|V2D_LOCKZOOM_Y|V2D_LIMITZOOM)) ) {
                        /* if zoom doesn't have to be maintained, just clamp edges */
                        if (cur->ymin < tot->ymin) cur->ymin= tot->ymin;
                        if (cur->ymax > tot->ymax) cur->ymax= tot->ymax;
                }
                else {
                        /* This here occurs when:
                         *      - height too big, but maintaining zoom (i.e. heights cannot be changed)
                         *      - height is OK, but need to check if outside of boundaries
                         * 
                         * So, resolution is to just shift view by the gap between the extremities.
                         * We favour moving the 'minimum' across, as that's origin for most things
                         */
                        if ((cur->ymin < tot->ymin) && (cur->ymax > tot->ymax)) {
                                /* outside boundaries on both sides, so take middle-point of tot, and place in balanced way */
                                temp= (tot->ymax + tot->ymin) * 0.5f;
                                diff= curheight * 0.5f;
                                
                                cur->ymin= temp - diff;
                                cur->ymax= temp + diff;
                        }
                        else if (cur->ymin < tot->ymin) {
                                /* there's still space remaining, so shift up */
                                temp= tot->ymin - cur->ymin;
                                
                                cur->ymin += temp;
                                cur->ymax += temp;
                        }
                        else if (cur->ymax > tot->ymax) {
                                /* there's still space remaining, so shift down */
                                temp= cur->ymax - tot->ymax;
                                
                                cur->ymin -= temp;
                                cur->ymax -= temp;
                        }
                }
        }
        
        /* Step 4: Make sure alignment restrictions are respected */
        if (v2d->align) {
                /* If alignment flags are set (but keeptot is not), they must still be respected, as although
                 * they don't specify any particular bounds to stay within, they do define ranges which are 
                 * invalid.
                 *
                 * Here, we only check to make sure that on each axis, the 'cur' rect doesn't stray into these 
                 * invalid zones, otherwise we offset.
                 */
                
                /* handle width - posx and negx flags are mutually exclusive, so watch out */
                if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
                        /* width is in negative-x half */
                        if (v2d->cur.xmax > 0) {
                                v2d->cur.xmin -= v2d->cur.xmax;
                                v2d->cur.xmax= 0.0f;
                        }
                }
                else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
                        /* width is in positive-x half */
                        if (v2d->cur.xmin < 0) {
                                v2d->cur.xmax -= v2d->cur.xmin;
                                v2d->cur.xmin = 0.0f;
                        }
                }
                
                /* handle height - posx and negx flags are mutually exclusive, so watch out */
                if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
                        /* height is in negative-y half */
                        if (v2d->cur.ymax > 0) {
                                v2d->cur.ymin -= v2d->cur.ymax;
                                v2d->cur.ymax = 0.0f;
                        }
                }
                else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
                        /* height is in positive-y half */
                        if (v2d->cur.ymin < 0) {
                                v2d->cur.ymax -= v2d->cur.ymin;
                                v2d->cur.ymin = 0.0f;
                        }
                }
        }
        
        /* set masks */
        view2d_masks(v2d);
}

void UI_view2d_curRect_validate(View2D *v2d)
{
        UI_view2d_curRect_validate_resize(v2d, 0);
}

/* ------------------ */

/* Called by menus to activate it, or by view2d operators to make sure 'related' views stay in synchrony */
void UI_view2d_sync(bScreen *screen, ScrArea *area, View2D *v2dcur, int flag)
{
        ScrArea *sa;
        ARegion *ar;
        
        /* don't continue if no view syncing to be done */
        if ((v2dcur->flag & (V2D_VIEWSYNC_SCREEN_TIME|V2D_VIEWSYNC_AREA_VERTICAL)) == 0)
                return;
                
        /* check if doing within area syncing (i.e. channels/vertical) */
        if ((v2dcur->flag & V2D_VIEWSYNC_AREA_VERTICAL) && (area)) {
                for (ar= area->regionbase.first; ar; ar= ar->next) {
                        /* don't operate on self */
                        if (v2dcur != &ar->v2d) {
                                /* only if view has vertical locks enabled */
                                if (ar->v2d.flag & V2D_VIEWSYNC_AREA_VERTICAL) {
                                        if (flag == V2D_LOCK_COPY) {
                                                /* other views with locks on must copy active */
                                                ar->v2d.cur.ymin= v2dcur->cur.ymin;
                                                ar->v2d.cur.ymax= v2dcur->cur.ymax;
                                        }
                                        else { /* V2D_LOCK_SET */
                                                /* active must copy others */
                                                v2dcur->cur.ymin= ar->v2d.cur.ymin;
                                                v2dcur->cur.ymax= ar->v2d.cur.ymax;
                                        }
                                        
                                        /* region possibly changed, so refresh */
                                        ED_region_tag_redraw(ar);
                                }
                        }
                }
        }
        
        /* check if doing whole screen syncing (i.e. time/horizontal) */
        if ((v2dcur->flag & V2D_VIEWSYNC_SCREEN_TIME) && (screen)) {
                for (sa= screen->areabase.first; sa; sa= sa->next) {
                        for (ar= sa->regionbase.first; ar; ar= ar->next) {
                                /* don't operate on self */
                                if (v2dcur != &ar->v2d) {
                                        /* only if view has horizontal locks enabled */
                                        if (ar->v2d.flag & V2D_VIEWSYNC_SCREEN_TIME) {
                                                if (flag == V2D_LOCK_COPY) {
                                                        /* other views with locks on must copy active */
                                                        ar->v2d.cur.xmin= v2dcur->cur.xmin;
                                                        ar->v2d.cur.xmax= v2dcur->cur.xmax;
                                                }
                                                else { /* V2D_LOCK_SET */
                                                        /* active must copy others */
                                                        v2dcur->cur.xmin= ar->v2d.cur.xmin;
                                                        v2dcur->cur.xmax= ar->v2d.cur.xmax;
                                                }
                                                
                                                /* region possibly changed, so refresh */
                                                ED_region_tag_redraw(ar);
                                        }
                                }
                        }
                }
        }
}


/* Restore 'cur' rect to standard orientation (i.e. optimal maximum view of tot) 
 * This does not take into account if zooming the view on an axis will improve the view (if allowed)
 */
void UI_view2d_curRect_reset (View2D *v2d)
{
        float width, height;
        
        /* assume width and height of 'cur' rect by default, should be same size as mask */
        width= (float)(v2d->mask.xmax - v2d->mask.xmin + 1);
        height= (float)(v2d->mask.ymax - v2d->mask.ymin + 1);
        
        /* handle width - posx and negx flags are mutually exclusive, so watch out */
        if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
                /* width is in negative-x half */
                v2d->cur.xmin= (float)-width;
                v2d->cur.xmax= 0.0f;
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
                /* width is in positive-x half */
                v2d->cur.xmin= 0.0f;
                v2d->cur.xmax= (float)width;
        }
        else {
                /* width is centered around x==0 */
                const float dx= (float)width / 2.0f;
                
                v2d->cur.xmin= -dx;
                v2d->cur.xmax= dx;
        }
        
        /* handle height - posx and negx flags are mutually exclusive, so watch out */
        if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
                /* height is in negative-y half */
                v2d->cur.ymin= (float)-height;
                v2d->cur.ymax= 0.0f;
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
                /* height is in positive-y half */
                v2d->cur.ymin= 0.0f;
                v2d->cur.ymax= (float)height;
        }
        else {
                /* height is centered around y==0 */
                const float dy= (float)height / 2.0f;
                
                v2d->cur.ymin= -dy;
                v2d->cur.ymax= dy;
        }
}

/* ------------------ */

/* Change the size of the maximum viewable area (i.e. 'tot' rect) */
void UI_view2d_totRect_set_resize (View2D *v2d, int width, int height, int resize)
{
        int scroll= view2d_scroll_mapped(v2d->scroll);
        
        /* don't do anything if either value is 0 */
        width= abs(width);
        height= abs(height);
        
        /* hrumf! */
        /* XXX: there are work arounds for this in the panel and file browse code. */
        if(scroll & V2D_SCROLL_HORIZONTAL) 
                width -= V2D_SCROLL_WIDTH;
        if(scroll & V2D_SCROLL_VERTICAL) 
                height -= V2D_SCROLL_HEIGHT;
        
        if (ELEM3(0, v2d, width, height)) {
                if (G.f & G_DEBUG)
                        printf("Error: View2D totRect set exiting: v2d=%p width=%d height=%d \n", (void *)v2d, width, height); // XXX temp debug info
                return;
        }
        
        /* handle width - posx and negx flags are mutually exclusive, so watch out */
        if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
                /* width is in negative-x half */
                v2d->tot.xmin= (float)-width;
                v2d->tot.xmax= 0.0f;
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
                /* width is in positive-x half */
                v2d->tot.xmin= 0.0f;
                v2d->tot.xmax= (float)width;
        }
        else {
                /* width is centered around x==0 */
                const float dx= (float)width / 2.0f;
                
                v2d->tot.xmin= -dx;
                v2d->tot.xmax= dx;
        }
        
        /* handle height - posx and negx flags are mutually exclusive, so watch out */
        if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
                /* height is in negative-y half */
                v2d->tot.ymin= (float)-height;
                v2d->tot.ymax= 0.0f;
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
                /* height is in positive-y half */
                v2d->tot.ymin= 0.0f;
                v2d->tot.ymax= (float)height;
        }
        else {
                /* height is centered around y==0 */
                const float dy= (float)height / 2.0f;
                
                v2d->tot.ymin= -dy;
                v2d->tot.ymax= dy;
        }
        
        /* make sure that 'cur' rect is in a valid state as a result of these changes */
        UI_view2d_curRect_validate_resize(v2d, resize);
}

void UI_view2d_totRect_set(View2D *v2d, int width, int height)
{
        UI_view2d_totRect_set_resize(v2d, width, height, 0);
}

int UI_view2d_tab_set(View2D *v2d, int tab)
{
        float default_offset[2]= {0.0f, 0.0f};
        float *offset, *new_offset;
        int changed= 0;

        /* if tab changed, change offset */
        if(tab != v2d->tab_cur && v2d->tab_offset) {
                if(tab < v2d->tab_num)
                        offset= &v2d->tab_offset[tab*2];
                else
                        offset= default_offset;

                v2d->cur.xmax += offset[0] - v2d->cur.xmin;
                v2d->cur.xmin= offset[0];

                v2d->cur.ymin += offset[1] - v2d->cur.ymax;
                v2d->cur.ymax= offset[1];

                /* validation should happen in subsequent totRect_set */

                changed= 1;
        }

        /* resize array if needed */
        if(tab >= v2d->tab_num) {
                new_offset= MEM_callocN(sizeof(float)*(tab+1)*2, "view2d tab offset");

                if(v2d->tab_offset) {
                        memcpy(new_offset, v2d->tab_offset, sizeof(float)*v2d->tab_num*2);
                        MEM_freeN(v2d->tab_offset);
                }

                v2d->tab_offset= new_offset;
                v2d->tab_num= tab+1;
        }

        /* set current tab and offset */
        v2d->tab_cur= tab;
        v2d->tab_offset[2*tab+0]= v2d->cur.xmin;
        v2d->tab_offset[2*tab+1]= v2d->cur.ymax;

        return changed;
}

/* *********************************************************************** */
/* View Matrix Setup */

/* mapping function to ensure 'cur' draws extended over the area where sliders are */
static void view2d_map_cur_using_mask(View2D *v2d, rctf *curmasked)
{
        *curmasked= v2d->cur;
        
        if (view2d_scroll_mapped(v2d->scroll)) {
                float dx= (v2d->cur.xmax-v2d->cur.xmin)/((float)(v2d->mask.xmax-v2d->mask.xmin+1));
                float dy= (v2d->cur.ymax-v2d->cur.ymin)/((float)(v2d->mask.ymax-v2d->mask.ymin+1));
                
                if (v2d->mask.xmin != 0)
                        curmasked->xmin -= dx*(float)v2d->mask.xmin;
                if (v2d->mask.xmax+1 != v2d->winx)
                        curmasked->xmax += dx*(float)(v2d->winx - v2d->mask.xmax-1);
                
                if (v2d->mask.ymin != 0)
                        curmasked->ymin -= dy*(float)v2d->mask.ymin;
                if (v2d->mask.ymax+1 != v2d->winy)
                        curmasked->ymax += dy*(float)(v2d->winy - v2d->mask.ymax-1);
                
        }
}

/* Set view matrices to use 'cur' rect as viewing frame for View2D drawing */
void UI_view2d_view_ortho(View2D *v2d)
{
        rctf curmasked;
        float xofs, yofs;
        
        /* pixel offsets (-0.375f) are needed to get 1:1 correspondance with pixels for smooth UI drawing, 
         * but only applied where requsted
         */
        /* XXX brecht: instead of zero at least use a tiny offset, otherwise
         * pixel rounding is effectively random due to float inaccuracy */
        xofs= 0.001f*(v2d->cur.xmax - v2d->cur.xmin)/(v2d->mask.xmax - v2d->mask.xmin);
        yofs= 0.001f*(v2d->cur.ymax - v2d->cur.ymin)/(v2d->mask.ymax - v2d->mask.ymin);
        
        /* apply mask-based adjustments to cur rect (due to scrollers), to eliminate scaling artifacts */
        view2d_map_cur_using_mask(v2d, &curmasked);
        
        curmasked.xmin-= xofs; curmasked.xmax-=xofs;
        curmasked.ymin-= yofs; curmasked.ymax-=yofs;
        
        /* XXX ton: this flag set by outliner, for icons */
        if(v2d->flag & V2D_PIXELOFS_X) {
                curmasked.xmin= floorf(curmasked.xmin) - 0.001f;
                curmasked.xmax= floorf(curmasked.xmax) - 0.001f;
        }
        if(v2d->flag & V2D_PIXELOFS_Y) {
                curmasked.ymin= floorf(curmasked.ymin) - 0.001f;
                curmasked.ymax= floorf(curmasked.ymax) - 0.001f;
        }
        
        /* set matrix on all appropriate axes */
        wmOrtho2(curmasked.xmin-xofs, curmasked.xmax-xofs, curmasked.ymin-yofs, curmasked.ymax-yofs);

        /* XXX is this necessary? */
        glLoadIdentity();
}

/* Set view matrices to only use one axis of 'cur' only
 *      - xaxis         = if non-zero, only use cur x-axis, otherwise use cur-yaxis (mostly this will be used for x)
 */
void UI_view2d_view_orthoSpecial(ARegion *ar, View2D *v2d, short xaxis)
{
        rctf curmasked;
        float xofs, yofs;
        
        /* pixel offsets (-0.375f) are needed to get 1:1 correspondance with pixels for smooth UI drawing, 
         * but only applied where requsted
         */
        /* XXX temp (ton) */
        xofs= 0.0f; // (v2d->flag & V2D_PIXELOFS_X) ? 0.375f : 0.0f;
        yofs= 0.0f; // (v2d->flag & V2D_PIXELOFS_Y) ? 0.375f : 0.0f;
        
        /* apply mask-based adjustments to cur rect (due to scrollers), to eliminate scaling artifacts */
        view2d_map_cur_using_mask(v2d, &curmasked);
        
        /* only set matrix with 'cur' coordinates on relevant axes */
        if (xaxis)
                wmOrtho2(curmasked.xmin-xofs, curmasked.xmax-xofs, -yofs, ar->winy-yofs);
        else
                wmOrtho2(-xofs, ar->winx-xofs, curmasked.ymin-yofs, curmasked.ymax-yofs);
                
        /* XXX is this necessary? */
        glLoadIdentity();
} 


/* Restore view matrices after drawing */
void UI_view2d_view_restore(const bContext *C)
{
        ARegion *ar= CTX_wm_region(C);
        int width= ar->winrct.xmax-ar->winrct.xmin+1;
        int height= ar->winrct.ymax-ar->winrct.ymin+1;
        
        wmOrtho2(0.0f, (float)width, 0.0f, (float)height);
        glLoadIdentity();
        
        //      ED_region_pixelspace(CTX_wm_region(C));
}

/* *********************************************************************** */
/* Gridlines */

/* View2DGrid is typedef'd in UI_view2d.h */
struct View2DGrid {
        float dx, dy;                   /* stepsize (in pixels) between gridlines */
        float startx, starty;   /* initial coordinates to start drawing grid from */
        int powerx, powery;             /* step as power of 10 */
};

/* --------------- */

/* try to write step as a power of 10 */
static void step_to_grid(float *step, int *power, int unit)
{
        const float loga= (float)log10(*step);
        float rem;
        
        *power= (int)(loga);
        
        rem= loga - (*power);
        rem= (float)pow(10.0, rem);
        
        if (loga < 0.0f) {
                if (rem < 0.2f) rem= 0.2f;
                else if(rem < 0.5f) rem= 0.5f;
                else rem= 1.0f;
                
                *step= rem * (float)pow(10.0, (*power));
                
                /* for frames, we want 1.0 frame intervals only */
                if (unit == V2D_UNIT_FRAMES) {
                        rem = 1.0f;
                        *step = 2.0f; /* use 2 since there are grid lines drawn in between, this way to get 1 line per frane */
                }
                
                /* prevents printing 1.0 2.0 3.0 etc */
                if (rem == 1.0f) (*power)++;    
        }
        else {
                if (rem < 2.0f) rem= 2.0f;
                else if(rem < 5.0f) rem= 5.0f;
                else rem= 10.0f;
                
                *step= rem * (float)pow(10.0, (*power));
                
                (*power)++;
                /* prevents printing 1.0, 2.0, 3.0, etc. */
                if (rem == 10.0f) (*power)++;   
        }
}

/* Intialise settings necessary for drawing gridlines in a 2d-view 
 *      - Currently, will return pointer to View2DGrid struct that needs to 
 *        be freed with UI_view2d_grid_free()
 *      - Is used for scrollbar drawing too (for units drawing)
 *      - Units + clamping args will be checked, to make sure they are valid values that can be used
 *        so it is very possible that we won't return grid at all!
 *      
 *      - xunits,yunits = V2D_UNIT_*  grid steps in seconds or frames 
 *      - xclamp,yclamp = V2D_CLAMP_* only show whole-number intervals
 *      - winx                  = width of region we're drawing to, note: not used but keeping for completeness.
 *      - winy                  = height of region we're drawing into
 */
View2DGrid *UI_view2d_grid_calc(Scene *scene, View2D *v2d, short xunits, short xclamp, short yunits, short yclamp, int UNUSED(winx), int winy)
{

        View2DGrid *grid;
        float space, pixels, seconddiv;
        
        /* check that there are at least some workable args */
        if (ELEM(V2D_ARG_DUMMY, xunits, xclamp) && ELEM(V2D_ARG_DUMMY, yunits, yclamp))
                return NULL;
        
        /* grid here is allocated... */
        grid= MEM_callocN(sizeof(View2DGrid), "View2DGrid");
        
        /* rule: gridstep is minimal GRIDSTEP pixels */
        if (xunits == V2D_UNIT_SECONDS) {
                seconddiv= (float)(0.01 * FPS);
        }
        else {
                seconddiv= 1.0f;
        }
        
        /* calculate x-axis grid scale (only if both args are valid) */
        if (ELEM(V2D_ARG_DUMMY, xunits, xclamp) == 0) {
                space= v2d->cur.xmax - v2d->cur.xmin;
                pixels= (float)(v2d->mask.xmax - v2d->mask.xmin);
                
                if(pixels!=0.0f) {
                        grid->dx= (U.v2d_min_gridsize * space) / (seconddiv * pixels);
                        step_to_grid(&grid->dx, &grid->powerx, xunits);
                        grid->dx *= seconddiv;
                }
                
                if (xclamp == V2D_GRID_CLAMP) {
                        if (grid->dx < 0.1f) grid->dx= 0.1f;
                        grid->powerx-= 2;
                        if (grid->powerx < -2) grid->powerx= -2;
                }
        }
        
        /* calculate y-axis grid scale (only if both args are valid) */
        if (ELEM(V2D_ARG_DUMMY, yunits, yclamp) == 0) {
                space= v2d->cur.ymax - v2d->cur.ymin;
                pixels= (float)winy;
                
                grid->dy= U.v2d_min_gridsize * space / pixels;
                step_to_grid(&grid->dy, &grid->powery, yunits);
                
                if (yclamp == V2D_GRID_CLAMP) {
                        if (grid->dy < 1.0f) grid->dy= 1.0f;
                        if (grid->powery < 1) grid->powery= 1;
                }
        }
        
        /* calculate start position */
        if (ELEM(V2D_ARG_DUMMY, xunits, xclamp) == 0) {
                grid->startx= seconddiv*(v2d->cur.xmin/seconddiv - (float)fmod(v2d->cur.xmin/seconddiv, grid->dx/seconddiv));
                if (v2d->cur.xmin < 0.0f) grid->startx-= grid->dx;
        }
        else
                grid->startx= v2d->cur.xmin;
                
        if (ELEM(V2D_ARG_DUMMY, yunits, yclamp) == 0) {
                grid->starty= (v2d->cur.ymin - (float)fmod(v2d->cur.ymin, grid->dy));
                if (v2d->cur.ymin < 0.0f) grid->starty-= grid->dy;
        }
        else
                grid->starty= v2d->cur.ymin;
        
        return grid;
}

/* Draw gridlines in the given 2d-region */
void UI_view2d_grid_draw(View2D *v2d, View2DGrid *grid, int flag)
{
        float vec1[2], vec2[2];
        int a, step;
        
        /* check for grid first, as it may not exist */
        if (grid == NULL)
                return;
        
        /* vertical lines */
        if (flag & V2D_VERTICAL_LINES) {
                /* initialise initial settings */
                vec1[0]= vec2[0]= grid->startx;
                vec1[1]= grid->starty;
                vec2[1]= v2d->cur.ymax;
                
                /* minor gridlines */
                step= (v2d->mask.xmax - v2d->mask.xmin + 1) / U.v2d_min_gridsize;
                UI_ThemeColor(TH_GRID);
                
                for (a=0; a<step; a++) {
                        glBegin(GL_LINE_STRIP);
                                glVertex2fv(vec1); 
                                glVertex2fv(vec2);
                        glEnd();
                        
                        vec2[0]= vec1[0]+= grid->dx;
                }
                
                /* major gridlines */
                vec2[0]= vec1[0]-= 0.5f*grid->dx;
                UI_ThemeColorShade(TH_GRID, 16);
                
                step++;
                for (a=0; a<=step; a++) {
                        glBegin(GL_LINE_STRIP);
                                glVertex2fv(vec1); 
                                glVertex2fv(vec2);
                        glEnd();
                        
                        vec2[0]= vec1[0]-= grid->dx;
                }
        }
        
        /* horizontal lines */
        if (flag & V2D_HORIZONTAL_LINES) {
                /* only major gridlines */
                vec1[1]= vec2[1]= grid->starty;
                vec1[0]= grid->startx;
                vec2[0]= v2d->cur.xmax;
                
                step= (v2d->mask.ymax - v2d->mask.ymin + 1) / U.v2d_min_gridsize;
                
                UI_ThemeColor(TH_GRID);
                for (a=0; a<=step; a++) {
                        glBegin(GL_LINE_STRIP);
                                glVertex2fv(vec1); 
                                glVertex2fv(vec2);
                        glEnd();
                        
                        vec2[1]= vec1[1]+= grid->dy;
                }
                
                /* fine grid lines */
                vec2[1]= vec1[1]-= 0.5f*grid->dy;
                step++;
                
                if (flag & V2D_HORIZONTAL_FINELINES) { 
                        UI_ThemeColorShade(TH_GRID, 16);
                        for (a=0; a<step; a++) {
                                glBegin(GL_LINE_STRIP);
                                        glVertex2fv(vec1); 
                                        glVertex2fv(vec2);
                                glEnd();
                                
                                vec2[1]= vec1[1]-= grid->dy;
                        }
                }
        }
        
        /* Axes are drawn as darker lines */
        UI_ThemeColorShade(TH_GRID, -50);
        
        /* horizontal axis */
        if (flag & V2D_HORIZONTAL_AXIS) {
                vec1[0]= v2d->cur.xmin;
                vec2[0]= v2d->cur.xmax;
                vec1[1]= vec2[1]= 0.0f;
                
                glBegin(GL_LINE_STRIP);
                        glVertex2fv(vec1);
                        glVertex2fv(vec2);
                glEnd();
        }
        
        /* vertical axis */
        if (flag & V2D_VERTICAL_AXIS) {
                vec1[1]= v2d->cur.ymin;
                vec2[1]= v2d->cur.ymax;
                vec1[0]= vec2[0]= 0.0f;
                
                glBegin(GL_LINE_STRIP);
                        glVertex2fv(vec1); 
                        glVertex2fv(vec2);
                glEnd();
        }
}

/* Draw a constant grid in given 2d-region */
void UI_view2d_constant_grid_draw(View2D *v2d)
{
        float start, step= 25.0f;

        UI_ThemeColorShade(TH_BACK, -10);
        
        start= v2d->cur.xmin - (float)fmod(v2d->cur.xmin, step);
        
        glBegin(GL_LINES);
        for(; start<v2d->cur.xmax; start+=step) {
                glVertex2f(start, v2d->cur.ymin);
                glVertex2f(start, v2d->cur.ymax);
        }

        start= v2d->cur.ymin - (float)fmod(v2d->cur.ymin, step);
        for(; start<v2d->cur.ymax; start+=step) {
                glVertex2f(v2d->cur.xmin, start);
                glVertex2f(v2d->cur.xmax, start);
        }
        
        /* X and Y axis */
        UI_ThemeColorShade(TH_BACK, -18);
        glVertex2f(0.0f, v2d->cur.ymin);
        glVertex2f(0.0f, v2d->cur.ymax);
        glVertex2f(v2d->cur.xmin, 0.0f);
        glVertex2f(v2d->cur.xmax, 0.0f);
        
        glEnd();
}

/* the price we pay for not exposting structs :( */
void UI_view2d_grid_size(View2DGrid *grid, float *r_dx, float *r_dy)
{
        *r_dx= grid->dx;
        *r_dy= grid->dy;
}

/* free temporary memory used for drawing grid */
void UI_view2d_grid_free(View2DGrid *grid)
{
        /* only free if there's a grid */
        if (grid)
                MEM_freeN(grid);
}

/* *********************************************************************** */
/* Scrollers */

/* View2DScrollers is typedef'd in UI_view2d.h 
 * WARNING: the start of this struct must not change, as view2d_ops.c uses this too. 
 *                 For now, we don't need to have a separate (internal) header for structs like this...
 */
struct View2DScrollers {
                /* focus bubbles */
        int vert_min, vert_max; /* vertical scrollbar */
        int hor_min, hor_max;   /* horizontal scrollbar */
        
        rcti hor, vert;                 /* exact size of slider backdrop */
        int horfull, vertfull;  /* set if sliders are full, we don't draw them */
        
        /* scales */
        View2DGrid *grid;               /* grid for coordinate drawing */
        short xunits, xclamp;   /* units and clamping options for x-axis */
        short yunits, yclamp;   /* units and clamping options for y-axis */
};

/* Calculate relevant scroller properties */
View2DScrollers *UI_view2d_scrollers_calc(const bContext *C, View2D *v2d, short xunits, short xclamp, short yunits, short yclamp)
{
        View2DScrollers *scrollers;
        rcti vert, hor;
        float fac1, fac2, totsize, scrollsize;
        int scroll= view2d_scroll_mapped(v2d->scroll);
        
        /* scrollers is allocated here... */
        scrollers= MEM_callocN(sizeof(View2DScrollers), "View2DScrollers");
        
        vert= v2d->vert;
        hor= v2d->hor;
        
        /* slider rects need to be smaller than region */
        hor.xmin+=4;
        hor.xmax-=4;
        if (scroll & V2D_SCROLL_BOTTOM)
                hor.ymin+=4;
        else
                hor.ymax-=4;
        
        if (scroll & V2D_SCROLL_LEFT)
                vert.xmin+=4;
        else
                vert.xmax-=4;
        vert.ymin+=4;
        vert.ymax-=4;
        
        CLAMP(vert.ymin, vert.ymin, vert.ymax-V2D_SCROLLER_HANDLE_SIZE);
        CLAMP(hor.xmin, hor.xmin, hor.xmax-V2D_SCROLLER_HANDLE_SIZE);
        
        /* store in scrollers, used for drawing */
        scrollers->vert= vert;
        scrollers->hor= hor;
        
        /* scroller 'buttons':
         *      - These should always remain within the visible region of the scrollbar
         *      - They represent the region of 'tot' that is visible in 'cur'
         */
        
        /* horizontal scrollers */
        if (scroll & V2D_SCROLL_HORIZONTAL) {
                /* scroller 'button' extents */
                totsize= v2d->tot.xmax - v2d->tot.xmin;
                scrollsize= (float)(hor.xmax - hor.xmin);
                if(totsize==0.0f) totsize = 1.0f; /* avoid divide by zero */
                
                fac1= (v2d->cur.xmin - v2d->tot.xmin) / totsize;
                if(fac1<=0.0f)
                        scrollers->hor_min= hor.xmin;
                else
                        scrollers->hor_min= (int)(hor.xmin + (fac1 * scrollsize));
                
                fac2= (v2d->cur.xmax - v2d->tot.xmin) / totsize;
                if(fac2>=1.0f)
                        scrollers->hor_max= hor.xmax;
                else
                        scrollers->hor_max= (int)(hor.xmin + (fac2 * scrollsize));
                
                /* prevent inverted sliders */
                if (scrollers->hor_min > scrollers->hor_max) 
                        scrollers->hor_min= scrollers->hor_max;
                /* prevent sliders from being too small, and disappearing */
                if ((scrollers->hor_max - scrollers->hor_min) < V2D_SCROLLER_HANDLE_SIZE) {
                        scrollers->hor_max= scrollers->hor_min + V2D_SCROLLER_HANDLE_SIZE;

                        CLAMP(scrollers->hor_max, hor.xmin+V2D_SCROLLER_HANDLE_SIZE, hor.xmax);
                        CLAMP(scrollers->hor_min, hor.xmin, hor.xmax-V2D_SCROLLER_HANDLE_SIZE);
                }
                
                /* check whether sliders can disappear due to the full-range being used */
                if(v2d->keeptot) {
                        if ((fac1 <= 0.0f) && (fac2 >= 1.0f)) { 
                                v2d->scroll |= V2D_SCROLL_HORIZONTAL_FULLR;
                                scrollers->horfull= 1;
                        }
                        else    
                                v2d->scroll &= ~V2D_SCROLL_HORIZONTAL_FULLR;
                }
        }
        
        /* vertical scrollers */
        if (scroll & V2D_SCROLL_VERTICAL) {
                /* scroller 'button' extents */
                totsize= v2d->tot.ymax - v2d->tot.ymin;
                scrollsize= (float)(vert.ymax - vert.ymin);
                if(totsize==0.0f) totsize = 1.0f; /* avoid divide by zero */
                
                fac1= (v2d->cur.ymin- v2d->tot.ymin) / totsize;
                if(fac1<=0.0f)
                        scrollers->vert_min= vert.ymin;
                else
                        scrollers->vert_min= (int)(vert.ymin + (fac1 * scrollsize));
                
                fac2= (v2d->cur.ymax - v2d->tot.ymin) / totsize;
                if(fac2>=1.0f)
                        scrollers->vert_max= vert.ymax;
                else
                        scrollers->vert_max= (int)(vert.ymin + (fac2 * scrollsize));
                
                /* prevent inverted sliders */
                if (scrollers->vert_min > scrollers->vert_max) 
                        scrollers->vert_min= scrollers->vert_max;
                /* prevent sliders from being too small, and disappearing */
                if ((scrollers->vert_max - scrollers->vert_min) < V2D_SCROLLER_HANDLE_SIZE) {
                        
                        scrollers->vert_max= scrollers->vert_min + V2D_SCROLLER_HANDLE_SIZE;
                        
                        CLAMP(scrollers->vert_max, vert.ymin+V2D_SCROLLER_HANDLE_SIZE, vert.ymax);
                        CLAMP(scrollers->vert_min, vert.ymin, vert.ymax-V2D_SCROLLER_HANDLE_SIZE);
                }

                /* check whether sliders can disappear due to the full-range being used */
                if(v2d->keeptot) {
                        if ((fac1 <= 0.0f) && (fac2 >= 1.0f)) { 
                                v2d->scroll |= V2D_SCROLL_VERTICAL_FULLR;
                                scrollers->vertfull= 1;
                        }
                        else    
                                v2d->scroll &= ~V2D_SCROLL_VERTICAL_FULLR;
                }
        }
        
        /* grid markings on scrollbars */
        if (scroll & (V2D_SCROLL_SCALE_HORIZONTAL|V2D_SCROLL_SCALE_VERTICAL)) {
                /* store clamping */
                scrollers->xclamp= xclamp;
                scrollers->xunits= xunits;
                scrollers->yclamp= yclamp;
                scrollers->yunits= yunits;
                
                scrollers->grid= UI_view2d_grid_calc(CTX_data_scene(C), v2d, xunits, xclamp, yunits, yclamp, (hor.xmax - hor.xmin), (vert.ymax - vert.ymin));
        }
        
        /* return scrollers */
        return scrollers;
}

/* Print scale marking along a time scrollbar */
static void scroll_printstr(Scene *scene, float x, float y, float val, int power, short unit, char dir)
{
        int len;
        char str[32];
        
        /* adjust the scale unit to work ok */
        if (dir == 'v') {
                /* here we bump up the power by factor of 10, as 
                 * rotation values (hence 'degrees') are divided by 10 to 
                 * be able to show the curves at the same time
                 */
                if (ELEM(unit, V2D_UNIT_DEGREES, V2D_UNIT_TIME)) {
                        power += 1;
                        val *= 10;
                }
        }
        
        /* get string to print */
        ANIM_timecode_string_from_frame(str, scene, power, (unit == V2D_UNIT_SECONDS), val);
        
        /* get length of string, and adjust printing location to fit it into the horizontal scrollbar */
        len= strlen(str);
        if (dir == 'h') {
                /* seconds/timecode display has slightly longer strings... */
                if (unit == V2D_UNIT_SECONDS)
                        x-= 3*len;
                else
                        x-= 4*len;
        }
        
        /* Add degree sympbol to end of string for vertical scrollbar? */
        if ((dir == 'v') && (unit == V2D_UNIT_DEGREES)) {
                str[len]= 186;
                str[len+1]= 0;
        }
        
        /* draw it */
        BLF_draw_default_ascii(x, y, 0.0f, str, sizeof(str)-1);
}

/* Draw scrollbars in the given 2d-region */
void UI_view2d_scrollers_draw(const bContext *C, View2D *v2d, View2DScrollers *vs)
{
        Scene *scene= CTX_data_scene(C);
        rcti vert, hor;
        int scroll= view2d_scroll_mapped(v2d->scroll);
        
        /* make copies of rects for less typing */
        vert= vs->vert;
        hor= vs->hor;
        
        /* horizontal scrollbar */
        if (scroll & V2D_SCROLL_HORIZONTAL) {
                /* only draw scrollbar when it doesn't fill the entire space */
                if(vs->horfull==0) {
                        bTheme *btheme= U.themes.first;
                        uiWidgetColors wcol= btheme->tui.wcol_scroll;
                        rcti slider;
                        int state;
                        
                        slider.xmin= vs->hor_min;
                        slider.xmax= vs->hor_max;
                        slider.ymin= hor.ymin;
                        slider.ymax= hor.ymax;
                        
                        state= (v2d->scroll_ui & V2D_SCROLL_H_ACTIVE)?UI_SCROLL_PRESSED:0;
                        
                        /* show zoom handles if:
                         *      - zooming on x-axis is allowed (no scroll otherwise)
                         *      - slider bubble is large enough (no overdraw confusion)
                         *      - scale is shown on the scroller 
                         *        (workaround to make sure that button windows don't show these, 
                         *              and only the time-grids with their zoomability can do so)
                         */
                        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0 && 
                                (v2d->scroll & V2D_SCROLL_SCALE_HORIZONTAL) &&
                                (slider.xmax - slider.xmin > V2D_SCROLLER_HANDLE_SIZE))
                        {
                                state |= UI_SCROLL_ARROWS;
                        }
                        
                        UI_ThemeColor(TH_BACK);
                        glRecti(v2d->hor.xmin, v2d->hor.ymin, v2d->hor.xmax, v2d->hor.ymax);
                        
                        uiWidgetScrollDraw(&wcol, &hor, &slider, state);
                }
                
                /* scale indicators */
                if ((scroll & V2D_SCROLL_SCALE_HORIZONTAL) && (vs->grid)) {
                        View2DGrid *grid= vs->grid;
                        float fac, dfac, fac2, val;
                        
                        /* the numbers: convert grid->startx and -dx to scroll coordinates 
                         *      - fac is x-coordinate to draw to
                         *      - dfac is gap between scale markings
                         */
                        fac= (grid->startx - v2d->cur.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
                        fac= (float)hor.xmin + fac*(hor.xmax - hor.xmin);
                        
                        dfac= (grid->dx) / (v2d->cur.xmax - v2d->cur.xmin);
                        dfac= dfac * (hor.xmax - hor.xmin);
                        
                        /* set starting value, and text color */
                        UI_ThemeColor(TH_TEXT);
                        val= grid->startx;
                        
                        /* if we're clamping to whole numbers only, make sure entries won't be repeated */
                        if (vs->xclamp == V2D_GRID_CLAMP) {
                                while (grid->dx < 0.9999f) {
                                        grid->dx *= 2.0f;
                                        dfac *= 2.0f;
                                }
                        }
                        if (vs->xunits == V2D_UNIT_FRAMES)
                                grid->powerx= 1;
                        
                        /* draw numbers in the appropriate range */
                        if (dfac > 0.0f) {
                                float h= 2.0f+(float)(hor.ymin);
                                
                                for (; fac < hor.xmax-10; fac+=dfac, val+=grid->dx) {
                                        
                                        /* make prints look nicer for scrollers */
                                        if(fac < hor.xmin+10)
                                                continue;
                                        
                                        switch (vs->xunits) {                                                   
                                                case V2D_UNIT_FRAMES:           /* frames (as whole numbers)*/
                                                        scroll_printstr(scene, fac, h, val, grid->powerx, V2D_UNIT_FRAMES, 'h');
                                                        break;
                                                        
                                                case V2D_UNIT_FRAMESCALE:       /* frames (not always as whole numbers) */
                                                        scroll_printstr(scene, fac, h, val, grid->powerx, V2D_UNIT_FRAMESCALE, 'h');
                                                        break;
                                                
                                                case V2D_UNIT_SECONDS:          /* seconds */
                                                        fac2= val/(float)FPS;
                                                        scroll_printstr(scene, fac, h, fac2, grid->powerx, V2D_UNIT_SECONDS, 'h');
                                                        break;
                                                        
                                                case V2D_UNIT_SECONDSSEQ:       /* seconds with special calculations (only used for sequencer only) */
                                                {
                                                        float time;
                                                        
                                                        fac2= val/(float)FPS;
                                                        time= (float)floor(fac2);
                                                        fac2= fac2-time;
                                                        
                                                        scroll_printstr(scene, fac, h, time+(float)FPS*fac2/100.0f, grid->powerx, V2D_UNIT_SECONDSSEQ, 'h');
                                                }
                                                        break;
                                                        
                                                case V2D_UNIT_DEGREES:          /* Graph Editor for rotation Drivers */
                                                        /* HACK: although we're drawing horizontal, we make this draw as 'vertical', just to get degree signs */
                                                        scroll_printstr(scene, fac, h, val, grid->powerx, V2D_UNIT_DEGREES, 'v');
                                                        break;
                                        }
                                }
                        }
                }
        }
        
        /* vertical scrollbar */
        if (scroll & V2D_SCROLL_VERTICAL) {
                /* only draw scrollbar when it doesn't fill the entire space */
                if(vs->vertfull==0) {
                        bTheme *btheme= U.themes.first;
                        uiWidgetColors wcol= btheme->tui.wcol_scroll;
                        rcti slider;
                        int state;
                        
                        slider.xmin= vert.xmin;
                        slider.xmax= vert.xmax;
                        slider.ymin= vs->vert_min;
                        slider.ymax= vs->vert_max;
                        
                        state= (v2d->scroll_ui & V2D_SCROLL_V_ACTIVE)?UI_SCROLL_PRESSED:0;
                        
                        /* show zoom handles if:
                         *      - zooming on y-axis is allowed (no scroll otherwise)
                         *      - slider bubble is large enough (no overdraw confusion)
                         *      - scale is shown on the scroller 
                         *        (workaround to make sure that button windows don't show these, 
                         *              and only the time-grids with their zoomability can do so)
                         */
                        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0 && 
                                (v2d->scroll & V2D_SCROLL_SCALE_VERTICAL) &&
                                (slider.ymax - slider.ymin > V2D_SCROLLER_HANDLE_SIZE))
                        {
                                state |= UI_SCROLL_ARROWS;
                        }
                                
                        UI_ThemeColor(TH_BACK);
                        glRecti(v2d->vert.xmin, v2d->vert.ymin, v2d->vert.xmax, v2d->vert.ymax);
                        
                        uiWidgetScrollDraw(&wcol, &vert, &slider, state);
                }
                
                
                /* scale indiators */
                if ((scroll & V2D_SCROLL_SCALE_VERTICAL) && (vs->grid)) {
                        View2DGrid *grid= vs->grid;
                        float fac, dfac, val;
                        
                        /* the numbers: convert grid->starty and dy to scroll coordinates 
                         *      - fac is y-coordinate to draw to
                         *      - dfac is gap between scale markings
                         *      - these involve a correction for horizontal scrollbar
                         *        NOTE: it's assumed that that scrollbar is there if this is involved!
                         */
                        fac= (grid->starty- v2d->cur.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
                        fac= vert.ymin + fac*(vert.ymax - vert.ymin);
                        
                        dfac= (grid->dy) / (v2d->cur.ymax - v2d->cur.ymin);
                        dfac= dfac * (vert.ymax - vert.ymin);
                        
                        /* set starting value, and text color */
                        UI_ThemeColor(TH_TEXT);
                        val= grid->starty;
                        
                        /* if vertical clamping (to whole numbers) is used (i.e. in Sequencer), apply correction */
                        if (vs->yclamp == V2D_GRID_CLAMP)
                                fac += 0.5f * dfac;
                                
                        /* draw vertical steps */
                        if (dfac > 0.0f) {
                                
                                BLF_rotation_default(90.0f);
                                BLF_enable_default(BLF_ROTATION);

                                for (; fac < vert.ymax-10; fac+= dfac, val += grid->dy) {
                                        
                                        /* make prints look nicer for scrollers */
                                        if(fac < vert.ymin+10)
                                                continue;
                                        
                                        scroll_printstr(scene, (float)(vert.xmax)-2.0f, fac, val, grid->powery, vs->yunits, 'v');
                                }
                                
                                BLF_disable_default(BLF_ROTATION);
                        }
                }       
        }
        
}

/* free temporary memory used for drawing scrollers */
void UI_view2d_scrollers_free(View2DScrollers *scrollers)
{
        /* need to free grid as well... */
        if (scrollers->grid) MEM_freeN(scrollers->grid);
        MEM_freeN(scrollers);
}

/* *********************************************************************** */
/* List View Utilities */

/* Get the view-coordinates of the nominated cell 
 *      - columnwidth, rowheight        = size of each 'cell'
 *      - startx, starty                        = coordinates (in 'tot' rect space) that the list starts from
 *                                                        This should be (0,0) for most views. However, for those where the starting row was offsetted
 *                                                        (like for Animation Editor channel lists, to make the first entry more visible), these will be 
 *                                                        the min-coordinates of the first item.
 *      - column, row                           = the 2d-corodinates (in 2D-view / 'tot' rect space) the cell exists at
 *      - rect                                  = coordinates of the cell (passed as single var instead of 4 separate, as it's more useful this way)
 */
void UI_view2d_listview_cell_to_view(View2D *v2d, short columnwidth, short rowheight, float startx, float starty, int column, int row, rctf *rect)
{
        /* sanity checks */
        if ELEM(NULL, v2d, rect)
                return;
        if ((columnwidth <= 0) && (rowheight <= 0)) {
                rect->xmin= rect->xmax= 0.0f;
                rect->ymin= rect->ymax= 0.0f;
                return;
        }
        
        /* x-coordinates */
        rect->xmin= startx + (float)(columnwidth * column);
        rect->xmax= startx + (float)(columnwidth * (column + 1));
        
        if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
                /* simply negate the values for the coordinates if in negative half */
                rect->xmin = -rect->xmin;
                rect->xmax = -rect->xmax;
        }
        
        /* y-coordinates */
        rect->ymin= starty + (float)(rowheight * row);
        rect->ymax= starty + (float)(rowheight * (row + 1));
        
        if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
                /* simply negate the values for the coordinates if in negative half */
                rect->ymin = -rect->ymin;
                rect->ymax = -rect->ymax;
        }
}

/* Get the 'cell' (row, column) that the given 2D-view coordinates (i.e. in 'tot' rect space) lie in.
 *      - columnwidth, rowheight        = size of each 'cell'
 *      - startx, starty                        = coordinates (in 'tot' rect space) that the list starts from
 *                                                        This should be (0,0) for most views. However, for those where the starting row was offsetted
 *                                                        (like for Animation Editor channel lists, to make the first entry more visible), these will be 
 *                                                        the min-coordinates of the first item.
 *      - viewx, viewy                  = 2D-coordinates (in 2D-view / 'tot' rect space) to get the cell for
 *      - column, row                           = the 'coordinates' of the relevant 'cell'
 */
void UI_view2d_listview_view_to_cell(View2D *v2d, short columnwidth, short rowheight, float startx, float starty, 
                                                float viewx, float viewy, int *column, int *row)
{
        /* adjust view coordinates to be all positive ints, corrected for the start offset */
        const int x= (int)(floorf(fabsf(viewx) + 0.5f) - startx);
        const int y= (int)(floorf(fabsf(viewy) + 0.5f) - starty);
        
        /* sizes must not be negative */
        if ( (v2d == NULL) || ((columnwidth <= 0) && (rowheight <= 0)) ) {
                if (column) *column= 0;
                if (row) *row= 0;
                
                return;
        }
        
        /* get column */
        if ((column) && (columnwidth > 0))
                *column= x / columnwidth;
        else if (column)
                *column= 0;
        
        /* get row */
        if ((row) && (rowheight > 0))
                *row= y / rowheight;
        else if (row)
                *row= 0;
}

/* Get the 'extreme' (min/max) column and row indices which are visible within the 'cur' rect 
 *      - columnwidth, rowheight        = size of each 'cell'
 *      - startx, starty                        = coordinates that the list starts from, which should be (0,0) for most views
 *      - column/row_min/max            = the starting and ending column/row indices
 */
void UI_view2d_listview_visible_cells(View2D *v2d, short columnwidth, short rowheight, float startx, float starty, 
                                                int *column_min, int *column_max, int *row_min, int *row_max)
{
        /* using 'cur' rect coordinates, call the cell-getting function to get the cells for this */
        if (v2d) {
                /* min */
                UI_view2d_listview_view_to_cell(v2d, columnwidth, rowheight, startx, starty, 
                                        v2d->cur.xmin, v2d->cur.ymin, column_min, row_min);
                                        
                /* max*/
                UI_view2d_listview_view_to_cell(v2d, columnwidth, rowheight, startx, starty, 
                                        v2d->cur.xmax, v2d->cur.ymax, column_max, row_max);
        }
}

/* *********************************************************************** */
/* Coordinate Conversions */

/* Convert from screen/region space to 2d-View space 
 *      
 *      - x,y                   = coordinates to convert
 *      - viewx,viewy           = resultant coordinates
 */
void UI_view2d_region_to_view(View2D *v2d, int x, int y, float *viewx, float *viewy)
{
        float div, ofs;

        if (viewx) {
                div= (float)(v2d->mask.xmax - v2d->mask.xmin);
                ofs= (float)v2d->mask.xmin;
                
                *viewx= v2d->cur.xmin + (v2d->cur.xmax-v2d->cur.xmin) * ((float)x - ofs) / div;
        }

        if (viewy) {
                div= (float)(v2d->mask.ymax - v2d->mask.ymin);
                ofs= (float)v2d->mask.ymin;
                
                *viewy= v2d->cur.ymin + (v2d->cur.ymax - v2d->cur.ymin) * ((float)y - ofs) / div;
        }
}

/* Convert from 2d-View space to screen/region space
 *      - Coordinates are clamped to lie within bounds of region
 *
 *      - x,y                           = coordinates to convert
 *      - regionx,regiony       = resultant coordinates 
 */
void UI_view2d_view_to_region(View2D *v2d, float x, float y, int *regionx, int *regiony)
{
        /* set initial value in case coordinate lies outside of bounds */
        if (regionx)
                *regionx= V2D_IS_CLIPPED;
        if (regiony)
                *regiony= V2D_IS_CLIPPED;
        
        /* express given coordinates as proportional values */
        x= (x - v2d->cur.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
        y= (y - v2d->cur.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
        
        /* check if values are within bounds */
        if ((x>=0.0f) && (x<=1.0f) && (y>=0.0f) && (y<=1.0f)) {
                if (regionx)
                        *regionx= (int)(v2d->mask.xmin + x*(v2d->mask.xmax-v2d->mask.xmin));
                if (regiony)
                        *regiony= (int)(v2d->mask.ymin + y*(v2d->mask.ymax-v2d->mask.ymin));
        }
}

/* Convert from 2d-view space to screen/region space
 *      - Coordinates are NOT clamped to lie within bounds of region
 *
 *      - x,y                           = coordinates to convert
 *      - regionx,regiony       = resultant coordinates 
 */
void UI_view2d_to_region_no_clip(View2D *v2d, float x, float y, int *regionx, int *regiony)
{
        /* step 1: express given coordinates as proportional values */
        x= (x - v2d->cur.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
        y= (y - v2d->cur.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
        
        /* step 2: convert proportional distances to screen coordinates  */
        x= v2d->mask.xmin + x*(v2d->mask.xmax - v2d->mask.xmin);
        y= v2d->mask.ymin + y*(v2d->mask.ymax - v2d->mask.ymin);
        
        /* although we don't clamp to lie within region bounds, we must avoid exceeding size of ints */
        if (regionx) {
                if (x < INT_MIN) *regionx= INT_MIN;
                else if(x > INT_MAX) *regionx= INT_MAX;
                else *regionx= (int)x;
        }
        if (regiony) {
                if (y < INT_MIN) *regiony= INT_MIN;
                else if(y > INT_MAX) *regiony= INT_MAX;
                else *regiony= (int)y;
        }
}

/* *********************************************************************** */
/* Utilities */

/* View2D data by default resides in region, so get from region stored in context */
View2D *UI_view2d_fromcontext(const bContext *C)
{
        ScrArea *area= CTX_wm_area(C);
        ARegion *region= CTX_wm_region(C);

        if (area == NULL) return NULL;
        if (region == NULL) return NULL;
        return &(region->v2d);
}

/* same as above, but it returns regionwindow. Utility for pulldowns or buttons */
View2D *UI_view2d_fromcontext_rwin(const bContext *C)
{
        ScrArea *sa= CTX_wm_area(C);
        ARegion *region= CTX_wm_region(C);

        if (sa == NULL) return NULL;
        if (region == NULL) return NULL;
        if (region->regiontype!=RGN_TYPE_WINDOW) {
                ARegion *ar= BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
                return ar ? &(ar->v2d) : NULL;
        }
        return &(region->v2d);
}


/* Calculate the scale per-axis of the drawing-area
 *      - Is used to inverse correct drawing of icons, etc. that need to follow view 
 *        but not be affected by scale
 *
 *      - x,y   = scale on each axis
 */
void UI_view2d_getscale(View2D *v2d, float *x, float *y) 
{
        if (x) *x = (v2d->mask.xmax - v2d->mask.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
        if (y) *y = (v2d->mask.ymax - v2d->mask.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
}

/* Check if mouse is within scrollers
 *      - Returns appropriate code for match
 *              'h' = in horizontal scroller
 *              'v' = in vertical scroller
 *              0 = not in scroller
 *      
 *      - x,y   = mouse coordinates in screen (not region) space
 */
short UI_view2d_mouse_in_scrollers (const bContext *C, View2D *v2d, int x, int y)
{
        ARegion *ar= CTX_wm_region(C);
        int co[2];
        int scroll= view2d_scroll_mapped(v2d->scroll);
        
        /* clamp x,y to region-coordinates first */
        co[0]= x - ar->winrct.xmin;
        co[1]= y - ar->winrct.ymin;
        
        /* check if within scrollbars */
        if (scroll & V2D_SCROLL_HORIZONTAL) {
                if (IN_2D_HORIZ_SCROLL(v2d, co)) return 'h';
        }
        if (scroll & V2D_SCROLL_VERTICAL) {
                if (IN_2D_VERT_SCROLL(v2d, co)) return 'v';
        }       
        
        /* not found */
        return 0;
}

/* ******************* view2d text drawing cache ******************** */

/* assumes caches are used correctly, so for time being no local storage in v2d */
static ListBase strings= {NULL, NULL};

typedef struct View2DString {
        struct View2DString *next, *prev;
        union {
                unsigned char ub[4];
                int pack;
        } col;
        int mval[2];
        rcti rect;
} View2DString;


void UI_view2d_text_cache_add(View2D *v2d, float x, float y, const char *str, const char col[4])
{
        int mval[2];
        
        UI_view2d_view_to_region(v2d, x, y, mval, mval+1);
        
        if(mval[0]!=V2D_IS_CLIPPED && mval[1]!=V2D_IS_CLIPPED) {
                int len= strlen(str)+1;
                /* use calloc, rect has to be zeroe'd */
                View2DString *v2s= MEM_callocN(sizeof(View2DString)+len, "View2DString");
                char *v2s_str= (char *)(v2s+1);
                memcpy(v2s_str, str, len);

                BLI_addtail(&strings, v2s);
                v2s->col.pack= *((int *)col);
                v2s->mval[0]= mval[0];
                v2s->mval[1]= mval[1];
        }
}

/* no clip (yet) */
void UI_view2d_text_cache_rectf(View2D *v2d, rctf *rect, const char *str, const char col[4])
{
        int len= strlen(str)+1;
        View2DString *v2s= MEM_callocN(sizeof(View2DString)+len, "View2DString");
        char *v2s_str= (char *)(v2s+1);
        memcpy(v2s_str, str, len);

        UI_view2d_to_region_no_clip(v2d, rect->xmin, rect->ymin, &v2s->rect.xmin, &v2s->rect.ymin);
        UI_view2d_to_region_no_clip(v2d, rect->xmax, rect->ymax, &v2s->rect.xmax, &v2s->rect.ymax);

        v2s->col.pack= *((int *)col);
        v2s->mval[0]= v2s->rect.xmin;
        v2s->mval[1]= v2s->rect.ymin;

        BLI_addtail(&strings, v2s);
}


void UI_view2d_text_cache_draw(ARegion *ar)
{
        View2DString *v2s;
        int col_pack_prev= 0;
        
        // glMatrixMode(GL_PROJECTION);
        // glPushMatrix();
        // glMatrixMode(GL_MODELVIEW);
        // glPushMatrix();
        ED_region_pixelspace(ar);
        
        for(v2s= strings.first; v2s; v2s= v2s->next) {
                const char *str= (const char *)(v2s+1);
                int xofs=0, yofs;

                yofs= ceil( 0.5f*(v2s->rect.ymax - v2s->rect.ymin - BLF_height_default("28")));
                if(yofs<1) yofs= 1;

                if(col_pack_prev != v2s->col.pack) {
                        glColor3ubv(v2s->col.ub);
                        col_pack_prev= v2s->col.pack;
                }

                if(v2s->rect.xmin >= v2s->rect.xmax)
                        BLF_draw_default((float)v2s->mval[0]+xofs, (float)v2s->mval[1]+yofs, 0.0, str, 65535);
                else {
                        BLF_clipping_default(v2s->rect.xmin-4, v2s->rect.ymin-4, v2s->rect.xmax+4, v2s->rect.ymax+4);
                        BLF_enable_default(BLF_CLIPPING);
                        BLF_draw_default(v2s->rect.xmin+xofs, v2s->rect.ymin+yofs, 0.0f, str, 65535);
                        BLF_disable_default(BLF_CLIPPING);
                }
        }
        
        // glMatrixMode(GL_PROJECTION);
        // glPopMatrix();
        // glMatrixMode(GL_MODELVIEW);
        // glPopMatrix();
        
        if(strings.first) 
                BLI_freelistN(&strings);
}


/* ******************************************************** */