view2d_ops.c

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/*
 * $Id: view2d_ops.c 37246 2011-06-06 11:04:54Z nazgul $
 *
 * ***** 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 <math.h>

#include "MEM_guardedalloc.h"

#include "DNA_userdef_types.h"

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

#include "BKE_context.h"

#include "RNA_access.h"
#include "RNA_define.h"

#include "WM_api.h"
#include "WM_types.h"


#include "ED_screen.h"

#include "UI_view2d.h"

#include "PIL_time.h" /* USER_ZOOM_CONT */

static int view2d_poll(bContext *C)
{
        ARegion *ar= CTX_wm_region(C);

        return (ar != NULL) && (ar->v2d.flag & V2D_IS_INITIALISED);
}

/* ********************************************************* */
/* VIEW PANNING OPERATOR                                                                 */

/*      This group of operators come in several forms:
 *              1) Modal 'dragging' with MMB - where movement of mouse dictates amount to pan view by
 *              2) Scrollwheel 'steps' - rolling mousewheel by one step moves view by predefined amount
 *
 *      In order to make sure this works, each operator must define the following RNA-Operator Props:
 *              deltax, deltay  - define how much to move view by (relative to zoom-correction factor)
 */

/* ------------------ Shared 'core' stuff ---------------------- */
 
/* temp customdata for operator */
typedef struct v2dViewPanData {
        bScreen *sc;                    /* screen where view pan was initiated */
        ScrArea *sa;                    /* area where view pan was initiated */
        ARegion *ar;                    /* region where view pan was initiated */
        View2D *v2d;                    /* view2d we're operating in */
        
        float facx, facy;               /* amount to move view relative to zoom */
        
                /* options for version 1 */
        int startx, starty;             /* mouse x/y values in window when operator was initiated */
        int lastx, lasty;               /* previous x/y values of mouse in window */
        int invoke_event;               /* event starting pan, for modal exit */
        
        short in_scroller;              /* for MMB in scrollers (old feature in past, but now not that useful) */
} v2dViewPanData;
 
/* initialise panning customdata */
static int view_pan_init(bContext *C, wmOperator *op)
{
        ARegion *ar= CTX_wm_region(C);
        v2dViewPanData *vpd;
        View2D *v2d;
        float winx, winy;
        
        /* regions now have v2d-data by default, so check for region */
        if (ar == NULL)
                return 0;
                
        /* check if panning is allowed at all */
        v2d= &ar->v2d;
        if ((v2d->keepofs & V2D_LOCKOFS_X) && (v2d->keepofs & V2D_LOCKOFS_Y))
                return 0;
        
        /* set custom-data for operator */
        vpd= MEM_callocN(sizeof(v2dViewPanData), "v2dViewPanData");
        op->customdata= vpd;
        
        /* set pointers to owners */
        vpd->sc= CTX_wm_screen(C);
        vpd->sa= CTX_wm_area(C);
        vpd->v2d= v2d;
        vpd->ar = ar;
        
        /* calculate translation factor - based on size of view */
        winx= (float)(ar->winrct.xmax - ar->winrct.xmin + 1);
        winy= (float)(ar->winrct.ymax - ar->winrct.ymin + 1);
        vpd->facx= (v2d->cur.xmax - v2d->cur.xmin) / winx;
        vpd->facy= (v2d->cur.ymax - v2d->cur.ymin) / winy;
        
        return 1;
}

/* apply transform to view (i.e. adjust 'cur' rect) */
static void view_pan_apply(wmOperator *op)
{
        v2dViewPanData *vpd= op->customdata;
        View2D *v2d= vpd->v2d;
        float dx, dy;
        
        /* calculate amount to move view by */
        dx= vpd->facx * (float)RNA_int_get(op->ptr, "deltax");
        dy= vpd->facy * (float)RNA_int_get(op->ptr, "deltay");
        
        /* only move view on an axis if change is allowed */
        if ((v2d->keepofs & V2D_LOCKOFS_X)==0) {
                v2d->cur.xmin += dx;
                v2d->cur.xmax += dx;
        }
        if ((v2d->keepofs & V2D_LOCKOFS_Y)==0) {
                v2d->cur.ymin += dy;
                v2d->cur.ymax += dy;
        }
        
        /* validate that view is in valid configuration after this operation */
        UI_view2d_curRect_validate(v2d);
        
        /* request updates to be done... */
        ED_region_tag_redraw(vpd->ar);
        
        UI_view2d_sync(vpd->sc, vpd->sa, v2d, V2D_LOCK_COPY);
        
        /* exceptions */
        if (vpd->sa->spacetype==SPACE_OUTLINER) {
                /* don't rebuild full tree, since we're just changing our view */
                SpaceOops *soops= vpd->sa->spacedata.first;
                soops->storeflag |= SO_TREESTORE_REDRAW;
        }
}

/* cleanup temp customdata  */
static void view_pan_exit(wmOperator *op)
{
        if (op->customdata) {
                MEM_freeN(op->customdata);
                op->customdata= NULL;                           
        }
} 
 
/* ------------------ Modal Drag Version (1) ---------------------- */

/* for 'redo' only, with no user input */
static int view_pan_exec(bContext *C, wmOperator *op)
{
        if (!view_pan_init(C, op))
                return OPERATOR_CANCELLED;
        
        view_pan_apply(op);
        view_pan_exit(op);
        return OPERATOR_FINISHED;
}

/* set up modal operator and relevant settings */
static int view_pan_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
        wmWindow *window= CTX_wm_window(C);
        v2dViewPanData *vpd;
        View2D *v2d;
        
        /* set up customdata */
        if (!view_pan_init(C, op))
                return OPERATOR_PASS_THROUGH;
        
        vpd= op->customdata;
        v2d= vpd->v2d;
        
        /* set initial settings */
        vpd->startx= vpd->lastx= event->x;
        vpd->starty= vpd->lasty= event->y;
        vpd->invoke_event= event->type;
        
        if (event->type == MOUSEPAN) {
                RNA_int_set(op->ptr, "deltax", event->prevx - event->x);
                RNA_int_set(op->ptr, "deltay", event->prevy - event->y);
                
                view_pan_apply(op);
                view_pan_exit(op);
                return OPERATOR_FINISHED;
        }
        
        RNA_int_set(op->ptr, "deltax", 0);
        RNA_int_set(op->ptr, "deltay", 0);
        
        if (v2d->keepofs & V2D_LOCKOFS_X)
                WM_cursor_modal(window, BC_NS_SCROLLCURSOR);
        else if (v2d->keepofs & V2D_LOCKOFS_Y)
                WM_cursor_modal(window, BC_EW_SCROLLCURSOR);
        else
                WM_cursor_modal(window, BC_NSEW_SCROLLCURSOR);
        
        /* add temp handler */
        WM_event_add_modal_handler(C, op);

        return OPERATOR_RUNNING_MODAL;
}

/* handle user input - calculations of mouse-movement need to be done here, not in the apply callback! */
static int view_pan_modal(bContext *C, wmOperator *op, wmEvent *event)
{
        v2dViewPanData *vpd= op->customdata;
        
        /* execute the events */
        switch (event->type) {
                case MOUSEMOVE:
                {
                        /* calculate new delta transform, then store mouse-coordinates for next-time */
                        RNA_int_set(op->ptr, "deltax", (vpd->lastx - event->x));
                        RNA_int_set(op->ptr, "deltay", (vpd->lasty - event->y));
                        
                        vpd->lastx= event->x;
                        vpd->lasty= event->y;
                        
                        view_pan_apply(op);
                }
                        break;
                        
                case LEFTMOUSE:
                        /* switch to zoom */
                        if (event->val==KM_PRESS) {
                                /* calculate overall delta mouse-movement for redo */
                                RNA_int_set(op->ptr, "deltax", (vpd->startx - vpd->lastx));
                                RNA_int_set(op->ptr, "deltay", (vpd->starty - vpd->lasty));
                                
                                view_pan_exit(op);
                                WM_cursor_restore(CTX_wm_window(C));
                                
                                WM_operator_name_call(C, "VIEW2D_OT_zoom", WM_OP_INVOKE_DEFAULT, NULL);
                                return OPERATOR_FINISHED;
                        }
                        
                default:
                        if (event->type == vpd->invoke_event || event->type==ESCKEY) {
                                if (event->val==KM_RELEASE) {
                                        /* calculate overall delta mouse-movement for redo */
                                        RNA_int_set(op->ptr, "deltax", (vpd->startx - vpd->lastx));
                                        RNA_int_set(op->ptr, "deltay", (vpd->starty - vpd->lasty));
                                        
                                        view_pan_exit(op);
                                        WM_cursor_restore(CTX_wm_window(C));
                                        
                                        return OPERATOR_FINISHED;
                                }
                        }
                        break;
        }

        return OPERATOR_RUNNING_MODAL;
}

static int view_pan_cancel(bContext *UNUSED(C), wmOperator *op)
{
        view_pan_exit(op);
        return OPERATOR_CANCELLED;
}

static void VIEW2D_OT_pan(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Pan View";
        ot->description= "Pan the view";
        ot->idname= "VIEW2D_OT_pan";
        
        /* api callbacks */
        ot->exec= view_pan_exec;
        ot->invoke= view_pan_invoke;
        ot->modal= view_pan_modal;
        ot->cancel= view_pan_cancel;
        
        /* operator is modal */
        ot->flag= OPTYPE_BLOCKING|OPTYPE_GRAB_POINTER;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
}

/* ------------------ Scrollwheel Versions (2) ---------------------- */

/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrollright_exec(bContext *C, wmOperator *op)
{
        v2dViewPanData *vpd;
        
        /* initialise default settings (and validate if ok to run) */
        if (!view_pan_init(C, op))
                return OPERATOR_PASS_THROUGH;
                
        /* also, check if can pan in horizontal axis */
        vpd= op->customdata;
        if (vpd->v2d->keepofs & V2D_LOCKOFS_X) {
                view_pan_exit(op);
                return OPERATOR_PASS_THROUGH;
        }
        
        /* set RNA-Props - only movement in positive x-direction */
        RNA_int_set(op->ptr, "deltax", 20);
        RNA_int_set(op->ptr, "deltay", 0);
        
        /* apply movement, then we're done */
        view_pan_apply(op);
        view_pan_exit(op);
        
        return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_right(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Scroll Right";
        ot->description= "Scroll the view right";
        ot->idname= "VIEW2D_OT_scroll_right";
        
        /* api callbacks */
        ot->exec= view_scrollright_exec;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
}



/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrollleft_exec(bContext *C, wmOperator *op)
{
        v2dViewPanData *vpd;
        
        /* initialise default settings (and validate if ok to run) */
        if (!view_pan_init(C, op))
                return OPERATOR_PASS_THROUGH;
                
        /* also, check if can pan in horizontal axis */
        vpd= op->customdata;
        if (vpd->v2d->keepofs & V2D_LOCKOFS_X) {
                view_pan_exit(op);
                return OPERATOR_PASS_THROUGH;
        }
        
        /* set RNA-Props - only movement in negative x-direction */
        RNA_int_set(op->ptr, "deltax", -20);
        RNA_int_set(op->ptr, "deltay", 0);
        
        /* apply movement, then we're done */
        view_pan_apply(op);
        view_pan_exit(op);
        
        return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_left(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Scroll Left";
        ot->description= "Scroll the view left";
        ot->idname= "VIEW2D_OT_scroll_left";
        
        /* api callbacks */
        ot->exec= view_scrollleft_exec;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
}


/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrolldown_exec(bContext *C, wmOperator *op)
{
        v2dViewPanData *vpd;
        
        /* initialise default settings (and validate if ok to run) */
        if (!view_pan_init(C, op))
                return OPERATOR_PASS_THROUGH;
                
        /* also, check if can pan in vertical axis */
        vpd= op->customdata;
        if (vpd->v2d->keepofs & V2D_LOCKOFS_Y) {
                view_pan_exit(op);
                return OPERATOR_PASS_THROUGH;
        }
        
        /* set RNA-Props */
        RNA_int_set(op->ptr, "deltax", 0);
        RNA_int_set(op->ptr, "deltay", -40);
        
        if(RNA_boolean_get(op->ptr, "page")) {
                ARegion *ar= CTX_wm_region(C);
                RNA_int_set(op->ptr, "deltay", ar->v2d.mask.ymin - ar->v2d.mask.ymax);
        }
        
        /* apply movement, then we're done */
        view_pan_apply(op);
        view_pan_exit(op);
        
        return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_down(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Scroll Down";
        ot->description= "Scroll the view down";
        ot->idname= "VIEW2D_OT_scroll_down";
        
        /* api callbacks */
        ot->exec= view_scrolldown_exec;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
        RNA_def_boolean(ot->srna, "page", 0, "Page", "Scroll down one page.");
}



/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrollup_exec(bContext *C, wmOperator *op)
{
        v2dViewPanData *vpd;
        
        /* initialise default settings (and validate if ok to run) */
        if (!view_pan_init(C, op))
                return OPERATOR_PASS_THROUGH;
                
        /* also, check if can pan in vertical axis */
        vpd= op->customdata;
        if (vpd->v2d->keepofs & V2D_LOCKOFS_Y) {
                view_pan_exit(op);
                return OPERATOR_PASS_THROUGH;
        }
        
        /* set RNA-Props */
        RNA_int_set(op->ptr, "deltax", 0);
        RNA_int_set(op->ptr, "deltay", 40);
        
        if(RNA_boolean_get(op->ptr, "page")) {
                ARegion *ar= CTX_wm_region(C);
                RNA_int_set(op->ptr, "deltay", ar->v2d.mask.ymax - ar->v2d.mask.ymin);
        }
        
        /* apply movement, then we're done */
        view_pan_apply(op);
        view_pan_exit(op);
        
        return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_up(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Scroll Up";
        ot->description= "Scroll the view up";
        ot->idname= "VIEW2D_OT_scroll_up";
        
        /* api callbacks */
        ot->exec= view_scrollup_exec;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
        RNA_def_boolean(ot->srna, "page", 0, "Page", "Scroll up one page.");
}

/* ********************************************************* */
/* SINGLE-STEP VIEW ZOOMING OPERATOR                                             */

/*      This group of operators come in several forms:
 *              1) Scrollwheel 'steps' - rolling mousewheel by one step zooms view by predefined amount
 *              2) Scrollwheel 'steps' + alt + ctrl/shift - zooms view on one axis only (ctrl=x, shift=y)  // XXX this could be implemented...
 *              3) Pad +/- Keys - pressing each key moves the zooms the view by a predefined amount
 *
 *      In order to make sure this works, each operator must define the following RNA-Operator Props:
 *              zoomfacx, zoomfacy      - These two zoom factors allow for non-uniform scaling.
 *                                                        It is safe to scale by 0, as these factors are used to determine
 *                                                        amount to enlarge 'cur' by
 */

/* ------------------ 'Shared' stuff ------------------------ */

/* temp customdata for operator */
typedef struct v2dViewZoomData {
        View2D *v2d;                    /* view2d we're operating in */
        ARegion *ar;

        /* needed for continuous zoom */
        wmTimer *timer;
        double timer_lastdraw;

        int lastx, lasty;               /* previous x/y values of mouse in window */
        int invoke_event;               /* event type that invoked, for modal exits */
        float dx, dy;                   /* running tally of previous delta values (for obtaining final zoom) */
        float mx_2d, my_2d;             /* initial mouse location in v2d coords */
} v2dViewZoomData;


/* initialise panning customdata */
static int view_zoomdrag_init(bContext *C, wmOperator *op)
{
        ARegion *ar= CTX_wm_region(C);
        v2dViewZoomData *vzd;
        View2D *v2d;
        
        /* regions now have v2d-data by default, so check for region */
        if (ar == NULL)
                return 0;
        v2d= &ar->v2d;
        
        /* check that 2d-view is zoomable */
        if ((v2d->keepzoom & V2D_LOCKZOOM_X) && (v2d->keepzoom & V2D_LOCKZOOM_Y))
                return 0;
        
        /* set custom-data for operator */
        vzd= MEM_callocN(sizeof(v2dViewZoomData), "v2dViewZoomData");
        op->customdata= vzd;
        
        /* set pointers to owners */
        vzd->v2d= v2d;
        vzd->ar = ar;
        
        return 1;
}

/* check if step-zoom can be applied */
static int view_zoom_poll(bContext *C)
{
        ARegion *ar= CTX_wm_region(C);
        View2D *v2d;
        
        /* check if there's a region in context to work with */
        if (ar == NULL)
                return 0;
        v2d= &ar->v2d;
        
        /* check that 2d-view is zoomable */
        if ((v2d->keepzoom & V2D_LOCKZOOM_X) && (v2d->keepzoom & V2D_LOCKZOOM_Y))
                return 0;
                
        /* view is zoomable */
        return 1;
}
 
/* apply transform to view (i.e. adjust 'cur' rect) */
static void view_zoomstep_apply(bContext *C, wmOperator *op)
{
        v2dViewZoomData *vzd= op->customdata;
        ARegion *ar= CTX_wm_region(C);
        View2D *v2d= &ar->v2d;
        float dx, dy, facx, facy;
        
        /* calculate amount to move view by, ensuring symmetry so the
         * old zoom level is restored after zooming back the same amount 
         */
        facx= RNA_float_get(op->ptr, "zoomfacx");
        facy= RNA_float_get(op->ptr, "zoomfacy");

        if (facx >= 0.0f) {
                dx= (v2d->cur.xmax - v2d->cur.xmin) * facx;
                dy= (v2d->cur.ymax - v2d->cur.ymin) * facy;
        }
        else {
                dx= ((v2d->cur.xmax - v2d->cur.xmin)/(1.0f + 2.0f*facx)) * facx;
                dy= ((v2d->cur.ymax - v2d->cur.ymin)/(1.0f + 2.0f*facy)) * facy;
        }

        /* only resize view on an axis if change is allowed */
        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
                if (v2d->keepofs & V2D_LOCKOFS_X) {
                        v2d->cur.xmax -= 2*dx;
                }
                else if (v2d->keepofs & V2D_KEEPOFS_X) {
                        if (v2d->align & V2D_ALIGN_NO_POS_X)
                                v2d->cur.xmin += 2*dx;
                        else
                                v2d->cur.xmax -= 2*dx;
                }
                else {
                        if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                                float mval_fac = (vzd->mx_2d - v2d->cur.xmin) / (v2d->cur.xmax-v2d->cur.xmin);
                                float mval_faci = 1.0f - mval_fac;
                                float ofs= (mval_fac * dx) - (mval_faci * dx);
                                
                                v2d->cur.xmin += ofs + dx;
                                v2d->cur.xmax += ofs - dx;
                        }
                        else {
                                v2d->cur.xmin += dx;
                                v2d->cur.xmax -= dx;
                        }
                }
        }
        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
                if (v2d->keepofs & V2D_LOCKOFS_Y) {
                        v2d->cur.ymax -= 2*dy;
                }
                else if (v2d->keepofs & V2D_KEEPOFS_Y) {
                        if (v2d->align & V2D_ALIGN_NO_POS_Y)
                                v2d->cur.ymin += 2*dy;
                        else
                                v2d->cur.ymax -= 2*dy;
                }
                else {
                        if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                                float mval_fac = (vzd->my_2d - v2d->cur.ymin) / (v2d->cur.ymax-v2d->cur.ymin);
                                float mval_faci = 1.0f - mval_fac;
                                float ofs= (mval_fac * dy) - (mval_faci * dy);
                                
                                v2d->cur.ymin += ofs + dy;
                                v2d->cur.ymax += ofs - dy;
                        } 
                        else {
                                v2d->cur.ymin += dy;
                                v2d->cur.ymax -= dy;
                        }
                }
        }

        /* validate that view is in valid configuration after this operation */
        UI_view2d_curRect_validate(v2d);

        /* request updates to be done... */
        ED_region_tag_redraw(vzd->ar);
        UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
}

/* --------------- Individual Operators ------------------- */

/* cleanup temp customdata  */
static void view_zoomstep_exit(wmOperator *op)
{
        if (op->customdata) {
                MEM_freeN(op->customdata);
                op->customdata= NULL;                           
        }
}

/* this operator only needs this single callback, where it calls the view_zoom_*() methods */
static int view_zoomin_exec(bContext *C, wmOperator *op)
{
        /* check that there's an active region, as View2D data resides there */
        if (!view_zoom_poll(C))
                return OPERATOR_PASS_THROUGH;
        
        /* set RNA-Props - zooming in by uniform factor */
        RNA_float_set(op->ptr, "zoomfacx", 0.0375f);
        RNA_float_set(op->ptr, "zoomfacy", 0.0375f);
        
        /* apply movement, then we're done */
        view_zoomstep_apply(C, op);
        
        view_zoomstep_exit(op);
        
        return OPERATOR_FINISHED;
}

static int view_zoomin_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
        v2dViewZoomData *vzd;
        
        if (!view_zoomdrag_init(C, op))
                return OPERATOR_PASS_THROUGH;
        
        vzd= op->customdata;
        
        if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                ARegion *ar= CTX_wm_region(C);
                
                /* store initial mouse position (in view space) */
                UI_view2d_region_to_view(&ar->v2d, 
                                event->mval[0], event->mval[1],
                                &vzd->mx_2d, &vzd->my_2d);
        }
        
        return view_zoomin_exec(C, op);
}

static void VIEW2D_OT_zoom_in(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Zoom In";
        ot->description= "Zoom in the view";
        ot->idname= "VIEW2D_OT_zoom_in";
        
        /* api callbacks */
        ot->invoke= view_zoomin_invoke;
//      ot->exec= view_zoomin_exec;  // XXX, needs view_zoomdrag_init called first.
        ot->poll= view_zoom_poll;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_float(ot->srna, "zoomfacx", 0, -FLT_MAX, FLT_MAX, "Zoom Factor X", "", -FLT_MAX, FLT_MAX);
        RNA_def_float(ot->srna, "zoomfacy", 0, -FLT_MAX, FLT_MAX, "Zoom Factor Y", "", -FLT_MAX, FLT_MAX);
}
        
/* this operator only needs this single callback, where it callsthe view_zoom_*() methods */
static int view_zoomout_exec(bContext *C, wmOperator *op)
{
        /* check that there's an active region, as View2D data resides there */
        if (!view_zoom_poll(C))
                return OPERATOR_PASS_THROUGH;
        
        /* set RNA-Props - zooming in by uniform factor */
        RNA_float_set(op->ptr, "zoomfacx", -0.0375f);
        RNA_float_set(op->ptr, "zoomfacy", -0.0375f);
        
        /* apply movement, then we're done */
        view_zoomstep_apply(C, op);

        view_zoomstep_exit(op);
        
        return OPERATOR_FINISHED;
}

static int view_zoomout_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
        v2dViewZoomData *vzd;
        
        if (!view_zoomdrag_init(C, op))
                return OPERATOR_PASS_THROUGH;

        vzd= op->customdata;
        
        if(U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                ARegion *ar= CTX_wm_region(C);
                
                /* store initial mouse position (in view space) */
                UI_view2d_region_to_view(&ar->v2d, 
                                event->mval[0], event->mval[1],
                                &vzd->mx_2d, &vzd->my_2d);
        }
        
        return view_zoomout_exec(C, op);
}

static void VIEW2D_OT_zoom_out(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Zoom Out";
        ot->description= "Zoom out the view";
        ot->idname= "VIEW2D_OT_zoom_out";
        
        /* api callbacks */
        ot->invoke= view_zoomout_invoke;
//      ot->exec= view_zoomout_exec; // XXX, needs view_zoomdrag_init called first.
        ot->poll= view_zoom_poll;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_float(ot->srna, "zoomfacx", 0, -FLT_MAX, FLT_MAX, "Zoom Factor X", "", -FLT_MAX, FLT_MAX);
        RNA_def_float(ot->srna, "zoomfacy", 0, -FLT_MAX, FLT_MAX, "Zoom Factor Y", "", -FLT_MAX, FLT_MAX);
}

/* ********************************************************* */
/* DRAG-ZOOM OPERATOR                                                                    */

/*      MMB Drag - allows non-uniform scaling by dragging mouse
 *
 *      In order to make sure this works, each operator must define the following RNA-Operator Props:
 *              deltax, deltay  - amounts to add to each side of the 'cur' rect
 */

/* apply transform to view (i.e. adjust 'cur' rect) */
static void view_zoomdrag_apply(bContext *C, wmOperator *op)
{
        v2dViewZoomData *vzd= op->customdata;
        View2D *v2d= vzd->v2d;
        float dx, dy;
        
        /* get amount to move view by */
        dx= RNA_float_get(op->ptr, "deltax");
        dy= RNA_float_get(op->ptr, "deltay");

        /* continous zoom shouldn't move that fast... */
        if (U.viewzoom == USER_ZOOM_CONT) { // XXX store this setting as RNA prop?
                double time= PIL_check_seconds_timer();
                float time_step= (float)(time - vzd->timer_lastdraw);

                dx *= time_step * 0.5f;
                dy *= time_step * 0.5f;
                
                vzd->timer_lastdraw= time;
        }

        /* only move view on an axis if change is allowed */
        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
                if (v2d->keepofs & V2D_LOCKOFS_X) {
                        v2d->cur.xmax -= 2*dx;
                }
                else {
                        if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                                float mval_fac = (vzd->mx_2d - v2d->cur.xmin) / (v2d->cur.xmax-v2d->cur.xmin);
                                float mval_faci = 1.0f - mval_fac;
                                float ofs= (mval_fac * dx) - (mval_faci * dx);
                                
                                v2d->cur.xmin += ofs + dx;
                                v2d->cur.xmax += ofs - dx;
                        }
                        else {
                                v2d->cur.xmin += dx;
                                v2d->cur.xmax -= dx;
                        }
                }
        }
        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
                if (v2d->keepofs & V2D_LOCKOFS_Y) {
                        v2d->cur.ymax -= 2*dy;
                }
                else {
                        if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                                float mval_fac = (vzd->my_2d - v2d->cur.ymin) / (v2d->cur.ymax-v2d->cur.ymin);
                                float mval_faci = 1.0f - mval_fac;
                                float ofs= (mval_fac * dy) - (mval_faci * dy);
                                
                                v2d->cur.ymin += ofs + dy;
                                v2d->cur.ymax += ofs - dy;
                        }
                        else {
                                v2d->cur.ymin += dy;
                                v2d->cur.ymax -= dy;
                        }
                }
        }
        
        /* validate that view is in valid configuration after this operation */
        UI_view2d_curRect_validate(v2d);
        
        /* request updates to be done... */
        ED_region_tag_redraw(vzd->ar);
        UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
}

/* cleanup temp customdata  */
static void view_zoomdrag_exit(bContext *C, wmOperator *op)
{
        if (op->customdata) {
                v2dViewZoomData *vzd= op->customdata;
                
                if(vzd->timer)
                        WM_event_remove_timer(CTX_wm_manager(C), CTX_wm_window(C), vzd->timer);
                
                MEM_freeN(op->customdata);
                op->customdata= NULL;                           
        }
} 

static int view_zoomdrag_cancel(bContext *C, wmOperator *op)
{
        view_zoomdrag_exit(C, op);

        return OPERATOR_CANCELLED;
}

/* for 'redo' only, with no user input */
static int view_zoomdrag_exec(bContext *C, wmOperator *op)
{
        if (!view_zoomdrag_init(C, op))
                return OPERATOR_PASS_THROUGH;
        
        view_zoomdrag_apply(C, op);
        view_zoomdrag_exit(C, op);
        return OPERATOR_FINISHED;
}

/* set up modal operator and relevant settings */
static int view_zoomdrag_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
        wmWindow *window= CTX_wm_window(C);
        v2dViewZoomData *vzd;
        View2D *v2d;
        
        /* set up customdata */
        if (!view_zoomdrag_init(C, op))
                return OPERATOR_PASS_THROUGH;
        
        vzd= op->customdata;
        v2d= vzd->v2d;
        
        if (event->type == MOUSEZOOM) {
                float dx, dy, fac;
                
                vzd->lastx= event->prevx;
                vzd->lasty= event->prevy;
                
                /* As we have only 1D information (magnify value), feed both axes
                 * with magnify information that is stored in x axis 
                 */
                fac= 0.01f * (event->x - event->prevx);
                dx= fac * (v2d->cur.xmax - v2d->cur.xmin) / 10.0f;
                dy= fac * (v2d->cur.ymax - v2d->cur.ymin) / 10.0f;

                RNA_float_set(op->ptr, "deltax", dx);
                RNA_float_set(op->ptr, "deltay", dy);
                
                view_zoomdrag_apply(C, op);
                view_zoomdrag_exit(C, op);
                return OPERATOR_FINISHED;
        }       
        
        /* set initial settings */
        vzd->lastx= event->x;
        vzd->lasty= event->y;
        RNA_float_set(op->ptr, "deltax", 0);
        RNA_float_set(op->ptr, "deltay", 0);
        
        /* for modal exit test */
        vzd->invoke_event= event->type;
        
        if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                ARegion *ar= CTX_wm_region(C);
                
                /* store initial mouse position (in view space) */
                UI_view2d_region_to_view(&ar->v2d, 
                                event->mval[0], event->mval[1],
                                &vzd->mx_2d, &vzd->my_2d);
        }

        if (v2d->keepofs & V2D_LOCKOFS_X)
                WM_cursor_modal(window, BC_NS_SCROLLCURSOR);
        else if (v2d->keepofs & V2D_LOCKOFS_Y)
                WM_cursor_modal(window, BC_EW_SCROLLCURSOR);
        else
                WM_cursor_modal(window, BC_NSEW_SCROLLCURSOR);
        
        /* add temp handler */
        WM_event_add_modal_handler(C, op);

        if (U.viewzoom == USER_ZOOM_CONT) {
                /* needs a timer to continue redrawing */
                vzd->timer= WM_event_add_timer(CTX_wm_manager(C), CTX_wm_window(C), TIMER, 0.01f);
                vzd->timer_lastdraw= PIL_check_seconds_timer();
        }

        return OPERATOR_RUNNING_MODAL;
}

/* handle user input - calculations of mouse-movement need to be done here, not in the apply callback! */
static int view_zoomdrag_modal(bContext *C, wmOperator *op, wmEvent *event)
{
        v2dViewZoomData *vzd= op->customdata;
        View2D *v2d= vzd->v2d;
        
        /* execute the events */
        if (event->type == TIMER && event->customdata == vzd->timer) {
                view_zoomdrag_apply(C, op);
        }
        else if(event->type == MOUSEMOVE) {
                float dx, dy;
                
                /* calculate new delta transform, based on zooming mode */
                if (U.viewzoom == USER_ZOOM_SCALE) {
                        /* 'scale' zooming */
                        float dist;
                        
                        /* x-axis transform */
                        dist = (v2d->mask.xmax - v2d->mask.xmin) / 2.0f;
                        dx= 1.0f - ((float)fabs(vzd->lastx - dist) + 2.0f) / ((float)fabs(event->x - dist) + 2.0f);
                        dx*= 0.5f * (v2d->cur.xmax - v2d->cur.xmin);
                        
                        /* y-axis transform */
                        dist = (v2d->mask.ymax - v2d->mask.ymin) / 2.0f;
                        dy= 1.0f - ((float)fabs(vzd->lasty - dist) + 2.0f) / ((float)fabs(event->y - dist) + 2.0f);
                        dy*= 0.5f * (v2d->cur.ymax - v2d->cur.ymin);
                }
                else {
                        /* 'continuous' or 'dolly' */
                        float fac;
                        
                        /* x-axis transform */
                        fac= 0.01f * (event->x - vzd->lastx);
                        dx= fac * (v2d->cur.xmax - v2d->cur.xmin);
                        
                        /* y-axis transform */
                        fac= 0.01f * (event->y - vzd->lasty);
                        dy= fac * (v2d->cur.ymax - v2d->cur.ymin);
#if 0
                        /* continous zoom shouldn't move that fast... */
                        if (U.viewzoom == USER_ZOOM_CONT) { // XXX store this setting as RNA prop?
                                double time= PIL_check_seconds_timer();
                                float time_step= (float)(time - vzd->timer_lastdraw);

                                dx /= (0.1f / time_step);
                                dy /= (0.1f / time_step);
                                
                                vzd->timer_lastdraw= time;
                        }
#endif
                }
                
                /* set transform amount, and add current deltas to stored total delta (for redo) */
                RNA_float_set(op->ptr, "deltax", dx);
                RNA_float_set(op->ptr, "deltay", dy);
                vzd->dx += dx;
                vzd->dy += dy;
                
                /* store mouse coordinates for next time, if not doing continuous zoom
                 *      - continuous zoom only depends on distance of mouse to starting point to determine rate of change
                 */
                if (U.viewzoom != USER_ZOOM_CONT) { // XXX store this setting as RNA prop?
                        vzd->lastx= event->x;
                        vzd->lasty= event->y;
                }
                
                /* apply zooming */
                view_zoomdrag_apply(C, op);
        } 
        else if (event->type == vzd->invoke_event || event->type==ESCKEY) {
                if (event->val == KM_RELEASE) {
                        
                        /* for redo, store the overall deltas - need to respect zoom-locks here... */
                        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0)
                                RNA_float_set(op->ptr, "deltax", vzd->dx);
                        else
                                RNA_float_set(op->ptr, "deltax", 0);
                                
                        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0)
                                RNA_float_set(op->ptr, "deltay", vzd->dy);
                        else
                                RNA_float_set(op->ptr, "deltay", 0);
                        
                        /* free customdata */
                        view_zoomdrag_exit(C, op);
                        WM_cursor_restore(CTX_wm_window(C));
                        
                        return OPERATOR_FINISHED;
                }
        }

        return OPERATOR_RUNNING_MODAL;
}

static void VIEW2D_OT_zoom(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Zoom 2D View";
        ot->description= "Zoom in/out the view";
        ot->idname= "VIEW2D_OT_zoom";
        
        /* api callbacks */
        ot->exec= view_zoomdrag_exec;
        ot->invoke= view_zoomdrag_invoke;
        ot->modal= view_zoomdrag_modal;
        ot->cancel= view_zoomdrag_cancel;
        
        ot->poll= view_zoom_poll;
        
        /* operator is repeatable */
        // ot->flag= OPTYPE_BLOCKING;
        
        /* rna - must keep these in sync with the other operators */
        RNA_def_float(ot->srna, "deltax", 0, -FLT_MAX, FLT_MAX, "Delta X", "", -FLT_MAX, FLT_MAX);
        RNA_def_float(ot->srna, "deltay", 0, -FLT_MAX, FLT_MAX, "Delta Y", "", -FLT_MAX, FLT_MAX);
}

/* ********************************************************* */
/* BORDER-ZOOM */

/* The user defines a rect using standard borderselect tools, and we use this rect to 
 * define the new zoom-level of the view in the following ways:
 *      1) LEFTMOUSE - zoom in to view
 *      2) RIGHTMOUSE - zoom out of view
 *
 * Currently, these key mappings are hardcoded, but it shouldn't be too important to
 * have custom keymappings for this...
 */
 
static int view_borderzoom_exec(bContext *C, wmOperator *op)
{
        ARegion *ar= CTX_wm_region(C);
        View2D *v2d= &ar->v2d;
        rctf rect;
        int gesture_mode;
        
        /* convert coordinates of rect to 'tot' rect coordinates */
        UI_view2d_region_to_view(v2d, RNA_int_get(op->ptr, "xmin"), RNA_int_get(op->ptr, "ymin"), &rect.xmin, &rect.ymin);
        UI_view2d_region_to_view(v2d, RNA_int_get(op->ptr, "xmax"), RNA_int_get(op->ptr, "ymax"), &rect.xmax, &rect.ymax);
        
        /* check if zooming in/out view */
        gesture_mode= RNA_int_get(op->ptr, "gesture_mode");
        
        if (gesture_mode == GESTURE_MODAL_IN) {
                /* zoom in: 
                 *      - 'cur' rect will be defined by the coordinates of the border region 
                 *      - just set the 'cur' rect to have the same coordinates as the border region
                 *        if zoom is allowed to be changed
                 */
                if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
                        v2d->cur.xmin= rect.xmin;
                        v2d->cur.xmax= rect.xmax;
                }
                if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
                        v2d->cur.ymin= rect.ymin;
                        v2d->cur.ymax= rect.ymax;
                }
        }
        else /* if (gesture_mode == GESTURE_MODAL_OUT) */ {
                /* zoom out:
                 *      - the current 'cur' rect coordinates are going to end upwhere the 'rect' ones are, 
                 *        but the 'cur' rect coordinates will need to be adjusted to take in more of the view
                 *      - calculate zoom factor, and adjust using center-point
                 */
                float zoom, center, size;
                
                // TODO: is this zoom factor calculation valid? It seems to produce same results everytime...
                if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
                        size= (v2d->cur.xmax - v2d->cur.xmin);
                        zoom= size / (rect.xmax - rect.xmin);
                        center= (v2d->cur.xmax + v2d->cur.xmin) * 0.5f;
                        
                        v2d->cur.xmin= center - (size * zoom);
                        v2d->cur.xmax= center + (size * zoom);
                }
                if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
                        size= (v2d->cur.ymax - v2d->cur.ymin);
                        zoom= size / (rect.ymax - rect.ymin);
                        center= (v2d->cur.ymax + v2d->cur.ymin) * 0.5f;
                        
                        v2d->cur.ymin= center - (size * zoom);
                        v2d->cur.ymax= center + (size * zoom);
                }
        }
        
        /* validate that view is in valid configuration after this operation */
        UI_view2d_curRect_validate(v2d);
        
        /* request updates to be done... */
        ED_region_tag_redraw(ar);
        UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
        
        return OPERATOR_FINISHED;
} 

static void VIEW2D_OT_zoom_border(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Zoom to Border";
        ot->description= "Zoom in the view to the nearest item contained in the border";
        ot->idname= "VIEW2D_OT_zoom_border";
        
        /* api callbacks */
        ot->invoke= WM_border_select_invoke;
        ot->exec= view_borderzoom_exec;
        ot->modal= WM_border_select_modal;
        ot->cancel= WM_border_select_cancel;
        
        ot->poll= view_zoom_poll;
        
        /* rna */
        RNA_def_int(ot->srna, "gesture_mode", 0, INT_MIN, INT_MAX, "Gesture Mode", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "xmin", 0, INT_MIN, INT_MAX, "X Min", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "xmax", 0, INT_MIN, INT_MAX, "X Max", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "ymin", 0, INT_MIN, INT_MAX, "Y Min", "", INT_MIN, INT_MAX);
        RNA_def_int(ot->srna, "ymax", 0, INT_MIN, INT_MAX, "Y Max", "", INT_MIN, INT_MAX);
}

/* ********************************************************* */
/* SCROLLERS */

/*      Scrollers should behave in the following ways, when clicked on with LMB (and dragged):
 *              1) 'Handles' on end of 'bubble' - when the axis that the scroller represents is zoomable, 
 *                      enlarge 'cur' rect on the relevant side 
 *              2) 'Bubble'/'bar' - just drag, and bar should move with mouse (view pans opposite)
 *
 *      In order to make sure this works, each operator must define the following RNA-Operator Props:
 *              deltax, deltay  - define how much to move view by (relative to zoom-correction factor)
 */

/* customdata for scroller-invoke data */
typedef struct v2dScrollerMove {
        View2D *v2d;                    /* View2D data that this operation affects */
        ARegion *ar;                    /* region that the scroller is in */
        
        short scroller;                 /* scroller that mouse is in ('h' or 'v') */
        short zone;                             /* -1 is min zoomer, 0 is bar, 1 is max zoomer */ // XXX find some way to provide visual feedback of this (active color?)
        
        float fac;                              /* view adjustment factor, based on size of region */
        float delta;                    /* amount moved by mouse on axis of interest */
        
        float scrollbarwidth;   /* width of the scrollbar itself, used for page up/down clicks */
        
        int lastx, lasty;               /* previous mouse coordinates (in screen coordinates) for determining movement */
} v2dScrollerMove;


/* View2DScrollers is typedef'd in UI_view2d.h 
 * This is a CUT DOWN VERSION of the 'real' version, which is defined in view2d.c, as we only need focus bubble info
 * WARNING: the start of this struct must not change, so that it stays in sync with the 'real' version
 *                 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 */
};

/* quick enum for vsm->zone (scroller handles) */
enum {
        SCROLLHANDLE_MIN= -1,
        SCROLLHANDLE_BAR,
        SCROLLHANDLE_MAX,
        SCROLLHANDLE_MIN_OUTSIDE,
        SCROLLHANDLE_MAX_OUTSIDE
} /*eV2DScrollerHandle_Zone*/;

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

/* check if mouse is within scroller handle 
 *      - mouse                 =       relevant mouse coordinate in region space
 *      - sc_min, sc_max        =       extents of scroller 'groove' (potential available space for scroller)
 *      - sh_min, sh_max        =       positions of scrollbar handles
 */
static short mouse_in_scroller_handle(int mouse, int sc_min, int sc_max, int sh_min, int sh_max)
{
        short in_min, in_max, in_bar, out_min, out_max, in_view=1;
        
        /* firstly, check if 
         *      - 'bubble' fills entire scroller 
         *      - 'bubble' completely out of view on either side 
         */
        if ((sh_min <= sc_min) && (sh_max >= sc_max)) in_view= 0;
        if (sh_min == sh_max) {
                if (sh_min <= sc_min) in_view= 0;
                if (sh_max >= sc_max) in_view= 0;
        }
        else {
                if (sh_max <= sc_min) in_view= 0;
                if (sh_min >= sc_max) in_view= 0;
        }
        
        
        if (in_view == 0) {
                return SCROLLHANDLE_BAR;
        }
        
        /* check if mouse is in or past either handle */
        // TODO: check if these extents are still valid or not
        in_max= ( (mouse >= (sh_max - V2D_SCROLLER_HANDLE_SIZE)) && (mouse <= (sh_max + V2D_SCROLLER_HANDLE_SIZE)) );
        in_min= ( (mouse <= (sh_min + V2D_SCROLLER_HANDLE_SIZE)) && (mouse >= (sh_min - V2D_SCROLLER_HANDLE_SIZE)) );
        in_bar= ( (mouse < (sh_max - V2D_SCROLLER_HANDLE_SIZE)) && (mouse > (sh_min + V2D_SCROLLER_HANDLE_SIZE)) );
        out_min= mouse < (sh_min - V2D_SCROLLER_HANDLE_SIZE);
        out_max= mouse > (sh_max + V2D_SCROLLER_HANDLE_SIZE);
        
        if (in_bar)
                return SCROLLHANDLE_BAR;
        else if (in_max)
                return SCROLLHANDLE_MAX;
        else if (in_min)
                return SCROLLHANDLE_MIN;
        else if (out_min)
                return SCROLLHANDLE_MIN_OUTSIDE;                          
        else if (out_max)
                return SCROLLHANDLE_MAX_OUTSIDE;
        
        /* unlikely to happen, though we just cover it in case */
        return SCROLLHANDLE_BAR;
} 

/* initialise customdata for scroller manipulation operator */
static void scroller_activate_init(bContext *C, wmOperator *op, wmEvent *event, short in_scroller)
{
        v2dScrollerMove *vsm;
        View2DScrollers *scrollers;
        ARegion *ar= CTX_wm_region(C);
        View2D *v2d= &ar->v2d;
        float mask_size;
        
        /* set custom-data for operator */
        vsm= MEM_callocN(sizeof(v2dScrollerMove), "v2dScrollerMove");
        op->customdata= vsm;
        
        /* set general data */
        vsm->v2d= v2d;
        vsm->ar= ar;
        vsm->scroller= in_scroller;
        
        /* store mouse-coordinates, and convert mouse/screen coordinates to region coordinates */
        vsm->lastx = event->x;
        vsm->lasty = event->y;
        
        /* 'zone' depends on where mouse is relative to bubble 
         *      - zooming must be allowed on this axis, otherwise, default to pan
         */
        scrollers= UI_view2d_scrollers_calc(C, v2d, V2D_ARG_DUMMY, V2D_ARG_DUMMY, V2D_ARG_DUMMY, V2D_ARG_DUMMY);
        if (in_scroller == 'h') {
                /* horizontal scroller - calculate adjustment factor first */
                mask_size= (float)(v2d->hor.xmax - v2d->hor.xmin);
                vsm->fac= (v2d->tot.xmax - v2d->tot.xmin) / mask_size;
                
                /* get 'zone' (i.e. which part of scroller is activated) */
                vsm->zone= mouse_in_scroller_handle(event->mval[0], v2d->hor.xmin, v2d->hor.xmax, scrollers->hor_min, scrollers->hor_max);
                
                if ((v2d->keepzoom & V2D_LOCKZOOM_X) && ELEM(vsm->zone, SCROLLHANDLE_MIN, SCROLLHANDLE_MAX)) {
                        /* default to scroll, as handles not usable */
                        vsm->zone= SCROLLHANDLE_BAR;
                }

                vsm->scrollbarwidth = scrollers->hor_max - scrollers->hor_min;
        }
        else {
                /* vertical scroller - calculate adjustment factor first */
                mask_size= (float)(v2d->vert.ymax - v2d->vert.ymin);
                vsm->fac= (v2d->tot.ymax - v2d->tot.ymin) / mask_size;
                
                /* get 'zone' (i.e. which part of scroller is activated) */
                vsm->zone= mouse_in_scroller_handle(event->mval[1], v2d->vert.ymin, v2d->vert.ymax, scrollers->vert_min, scrollers->vert_max);
                        
                if ((v2d->keepzoom & V2D_LOCKZOOM_Y) && ELEM(vsm->zone, SCROLLHANDLE_MIN, SCROLLHANDLE_MAX)) {
                        /* default to scroll, as handles not usable */
                        vsm->zone= SCROLLHANDLE_BAR;
                }
                
                vsm->scrollbarwidth = scrollers->vert_max - scrollers->vert_min;
        }
        
        UI_view2d_scrollers_free(scrollers);
        ED_region_tag_redraw(ar);
}

/* cleanup temp customdata  */
static void scroller_activate_exit(bContext *C, wmOperator *op)
{
        if (op->customdata) {
                v2dScrollerMove *vsm= op->customdata;

                vsm->v2d->scroll_ui &= ~(V2D_SCROLL_H_ACTIVE|V2D_SCROLL_V_ACTIVE);
                
                MEM_freeN(op->customdata);
                op->customdata= NULL;           
                
                ED_region_tag_redraw(CTX_wm_region(C));
        }
}

static int scroller_activate_cancel(bContext *C, wmOperator *op)
{
        scroller_activate_exit(C, op);

        return OPERATOR_CANCELLED;
}

/* apply transform to view (i.e. adjust 'cur' rect) */
static void scroller_activate_apply(bContext *C, wmOperator *op)
{
        v2dScrollerMove *vsm= op->customdata;
        View2D *v2d= vsm->v2d;
        float temp;
        
        /* calculate amount to move view by */
        temp= vsm->fac * vsm->delta;
        
        /* type of movement */
        switch (vsm->zone) {
                case SCROLLHANDLE_MIN:
                        /* only expand view on axis if zoom is allowed */
                        if ((vsm->scroller == 'h') && !(v2d->keepzoom & V2D_LOCKZOOM_X))
                                v2d->cur.xmin -= temp;
                        if ((vsm->scroller == 'v') && !(v2d->keepzoom & V2D_LOCKZOOM_Y))
                                v2d->cur.ymin -= temp;
                        break;
                        
                case SCROLLHANDLE_MAX:
                        
                        /* only expand view on axis if zoom is allowed */
                        if ((vsm->scroller == 'h') && !(v2d->keepzoom & V2D_LOCKZOOM_X))
                                v2d->cur.xmax += temp;
                        if ((vsm->scroller == 'v') && !(v2d->keepzoom & V2D_LOCKZOOM_Y))
                                v2d->cur.ymax += temp;
                        break;
                        
                case SCROLLHANDLE_MIN_OUTSIDE:
                case SCROLLHANDLE_MAX_OUTSIDE:
                case SCROLLHANDLE_BAR:
                default:
                        /* only move view on an axis if panning is allowed */
                        if ((vsm->scroller == 'h') && !(v2d->keepofs & V2D_LOCKOFS_X)) {
                                v2d->cur.xmin += temp;
                                v2d->cur.xmax += temp;
                        }
                        if ((vsm->scroller == 'v') && !(v2d->keepofs & V2D_LOCKOFS_Y)) {
                                v2d->cur.ymin += temp;
                                v2d->cur.ymax += temp;
                        }
                        break;
                        
        }
        
        /* validate that view is in valid configuration after this operation */
        UI_view2d_curRect_validate(v2d);
        
        /* request updates to be done... */
        ED_region_tag_redraw(vsm->ar);
        UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
}

/* handle user input for scrollers - calculations of mouse-movement need to be done here, not in the apply callback! */
static int scroller_activate_modal(bContext *C, wmOperator *op, wmEvent *event)
{
        v2dScrollerMove *vsm= op->customdata;
        
        /* execute the events */
        switch (event->type) {
                case MOUSEMOVE:
                {
                        /* calculate new delta transform, then store mouse-coordinates for next-time */
                        if (ELEM(vsm->zone, SCROLLHANDLE_BAR, SCROLLHANDLE_MAX)) {
                                /* if using bar (i.e. 'panning') or 'max' zoom widget */
                                switch (vsm->scroller) {
                                        case 'h': /* horizontal scroller - so only horizontal movement ('cur' moves opposite to mouse) */
                                                vsm->delta= (float)(event->x - vsm->lastx);
                                                break;
                                        case 'v': /* vertical scroller - so only vertical movement ('cur' moves opposite to mouse) */
                                                vsm->delta= (float)(event->y - vsm->lasty);
                                                break;
                                }
                        }
                        else if (vsm->zone == SCROLLHANDLE_MIN) {
                                /* using 'min' zoom widget */
                                switch (vsm->scroller) {
                                        case 'h': /* horizontal scroller - so only horizontal movement ('cur' moves with mouse) */
                                                vsm->delta= (float)(vsm->lastx - event->x);
                                                break;
                                        case 'v': /* vertical scroller - so only vertical movement ('cur' moves with to mouse) */
                                                vsm->delta= (float)(vsm->lasty - event->y);
                                                break;
                                }
                        }
                        
                        /* store previous coordinates */
                        vsm->lastx= event->x;
                        vsm->lasty= event->y;
                        
                        scroller_activate_apply(C, op);
                }
                        break;
                        
                case LEFTMOUSE:
                        if (event->val==KM_RELEASE) {
                                /* single-click was in empty space outside bubble, so scroll by 1 'page' */
                                if (ELEM(vsm->zone, SCROLLHANDLE_MIN_OUTSIDE, SCROLLHANDLE_MAX_OUTSIDE)) {
                                        if (vsm->zone == SCROLLHANDLE_MIN_OUTSIDE)
                                                vsm->delta = -vsm->scrollbarwidth * 0.8f;
                                        else if (vsm->zone == SCROLLHANDLE_MAX_OUTSIDE)
                                                vsm->delta = vsm->scrollbarwidth * 0.8f;
                                        
                                        scroller_activate_apply(C, op);
                                        scroller_activate_exit(C, op);
                                        return OPERATOR_FINISHED;
                                }
                                
                                /* otherwise, end the drag action  */
                                if (vsm->lastx || vsm->lasty) {
                                        scroller_activate_exit(C, op);
                                        return OPERATOR_FINISHED;
                                }
                        }
                        break;
        }

        return OPERATOR_RUNNING_MODAL;
}


/* a click (or click drag in progress) should have occurred, so check if it happened in scrollbar */
static int scroller_activate_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
        ARegion *ar= CTX_wm_region(C);
        View2D *v2d= &ar->v2d;
        short in_scroller= 0;
                
        /* check if mouse in scrollbars, if they're enabled */
        in_scroller= UI_view2d_mouse_in_scrollers(C, v2d, event->x, event->y);
        
        /* if in a scroller, init customdata then set modal handler which will catch mousedown to start doing useful stuff */
        if (in_scroller) {
                v2dScrollerMove *vsm;
                
                /* initialise customdata */
                scroller_activate_init(C, op, event, in_scroller);
                vsm= (v2dScrollerMove *)op->customdata;
                
                /* check if zoom zones are inappropriate (i.e. zoom widgets not shown), so cannot continue
                 * NOTE: see view2d.c for latest conditions, and keep this in sync with that
                 */
                if (ELEM(vsm->zone, SCROLLHANDLE_MIN, SCROLLHANDLE_MAX)) {
                        if ( ((vsm->scroller=='h') && (v2d->scroll & V2D_SCROLL_SCALE_HORIZONTAL)==0) ||
                                 ((vsm->scroller=='v') && (v2d->scroll & V2D_SCROLL_SCALE_VERTICAL)==0) )
                        {
                                /* switch to bar (i.e. no scaling gets handled) */
                                vsm->zone= SCROLLHANDLE_BAR;
                        }
                }
                
                /* check if zone is inappropriate (i.e. 'bar' but panning is banned), so cannot continue */
                if (vsm->zone == SCROLLHANDLE_BAR) {
                        if ( ((vsm->scroller=='h') && (v2d->keepofs & V2D_LOCKOFS_X)) ||
                                 ((vsm->scroller=='v') && (v2d->keepofs & V2D_LOCKOFS_Y)) )
                        {
                                /* free customdata initialised */
                                scroller_activate_exit(C, op);
                                
                                /* can't catch this event for ourselves, so let it go to someone else? */
                                return OPERATOR_PASS_THROUGH;
                        }                       
                }
                
                /* zone is also inappropriate if scroller is not visible... */
                if ( ((vsm->scroller=='h') && (v2d->scroll & (V2D_SCROLL_HORIZONTAL_HIDE|V2D_SCROLL_HORIZONTAL_FULLR))) ||
                         ((vsm->scroller=='v') && (v2d->scroll & (V2D_SCROLL_VERTICAL_HIDE|V2D_SCROLL_VERTICAL_FULLR))) )
                {
                        /* free customdata initialised */
                        scroller_activate_exit(C, op);
                                
                        /* can't catch this event for ourselves, so let it go to someone else? */
                        /* XXX note: if handlers use mask rect to clip input, input will fail for this case */
                        return OPERATOR_PASS_THROUGH;
                }
                
                /* activate the scroller */
                if (vsm->scroller=='h')
                        v2d->scroll_ui |= V2D_SCROLL_H_ACTIVE;
                else
                        v2d->scroll_ui |= V2D_SCROLL_V_ACTIVE;
                
                /* still ok, so can add */
                WM_event_add_modal_handler(C, op);
                return OPERATOR_RUNNING_MODAL;
        }
        else {
                /* not in scroller, so nothing happened... (pass through let's something else catch event) */
                return OPERATOR_PASS_THROUGH;
        }
}

/* LMB-Drag in Scrollers - not repeatable operator! */
static void VIEW2D_OT_scroller_activate(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Scroller Activate";
        ot->description= "Scroll view by mouse click and drag";
        ot->idname= "VIEW2D_OT_scroller_activate";

        /* flags */
        ot->flag= OPTYPE_BLOCKING;
        
        /* api callbacks */
        ot->invoke= scroller_activate_invoke;
        ot->modal= scroller_activate_modal;
        ot->cancel= scroller_activate_cancel;

        ot->poll= view2d_poll;
}

/* ********************************************************* */
/* RESET */

static int reset_exec(bContext *C, wmOperator *UNUSED(op))
{
        uiStyle *style= U.uistyles.first;
        ARegion *ar= CTX_wm_region(C);
        View2D *v2d= &ar->v2d;
        int winx, winy;

        /* zoom 1.0 */
        winx= (float)(v2d->mask.xmax - v2d->mask.xmin + 1);
        winy= (float)(v2d->mask.ymax - v2d->mask.ymin + 1);

        v2d->cur.xmax= v2d->cur.xmin + winx;
        v2d->cur.ymax= v2d->cur.ymin + winy;
        
        /* align */
        if (v2d->align) {
                /* 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)) {
                        v2d->cur.xmax= 0.0f;
                        v2d->cur.xmin= -winx*style->panelzoom;
                }
                else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
                        v2d->cur.xmax= winx*style->panelzoom;
                        v2d->cur.xmin= 0.0f;
                }

                /* - 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)) {
                        v2d->cur.ymax= 0.0f;
                        v2d->cur.ymin= -winy*style->panelzoom;
                }
                else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
                        v2d->cur.ymax= winy*style->panelzoom;
                        v2d->cur.ymin= 0.0f;
                }
        }

        /* validate that view is in valid configuration after this operation */
        UI_view2d_curRect_validate(v2d);
        
        /* request updates to be done... */
        ED_region_tag_redraw(ar);
        UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
        
        return OPERATOR_FINISHED;
}
 
static void VIEW2D_OT_reset(wmOperatorType *ot)
{
        /* identifiers */
        ot->name= "Reset View";
        ot->description= "Reset the view";
        ot->idname= "VIEW2D_OT_reset";
        
        /* api callbacks */
        ot->exec= reset_exec;
        ot->poll= view2d_poll;
}
 
/* ********************************************************* */
/* Registration */

void UI_view2d_operatortypes(void)
{
        WM_operatortype_append(VIEW2D_OT_pan);
        
        WM_operatortype_append(VIEW2D_OT_scroll_left);
        WM_operatortype_append(VIEW2D_OT_scroll_right);
        WM_operatortype_append(VIEW2D_OT_scroll_up);
        WM_operatortype_append(VIEW2D_OT_scroll_down);
        
        WM_operatortype_append(VIEW2D_OT_zoom_in);
        WM_operatortype_append(VIEW2D_OT_zoom_out);
        
        WM_operatortype_append(VIEW2D_OT_zoom);
        WM_operatortype_append(VIEW2D_OT_zoom_border);
        
        WM_operatortype_append(VIEW2D_OT_scroller_activate);

        WM_operatortype_append(VIEW2D_OT_reset);
}

void UI_view2d_keymap(wmKeyConfig *keyconf)
{
        wmKeyMap *keymap= WM_keymap_find(keyconf, "View2D", 0, 0);
        
        /* pan/scroll */
        WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MIDDLEMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MIDDLEMOUSE, KM_PRESS, KM_SHIFT, 0);
        
        WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MOUSEPAN, 0, 0, 0);
        
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", WHEELDOWNMOUSE, KM_PRESS, KM_CTRL, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", WHEELUPMOUSE, KM_PRESS, KM_CTRL, 0);
        
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", WHEELDOWNMOUSE, KM_PRESS, KM_SHIFT, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", WHEELUPMOUSE, KM_PRESS, KM_SHIFT, 0);
        
        /* zoom - single step */
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_out", WHEELOUTMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_in", WHEELINMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_out", PADMINUS, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_in", PADPLUSKEY, KM_PRESS, 0, 0);
        
        /* scroll up/down - no modifiers, only when zoom fails */
                /* these may fail if zoom is disallowed, in which case they should pass on event */
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", WHEELDOWNMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", WHEELUPMOUSE, KM_PRESS, 0, 0);
                /* these may be necessary if vertical scroll is disallowed */
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", WHEELDOWNMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", WHEELUPMOUSE, KM_PRESS, 0, 0);
        
        /* alternatives for page up/down to scroll */
#if 0 // XXX disabled, since this causes conflicts with hotkeys in animation editors
                /* scroll up/down may fall through to left/right */
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", PAGEDOWNKEY, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", PAGEUPKEY, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", PAGEDOWNKEY, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", PAGEUPKEY, KM_PRESS, 0, 0);
                /* shift for moving view left/right with page up/down */
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", PAGEDOWNKEY, KM_PRESS, KM_SHIFT, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", PAGEUPKEY, KM_PRESS, KM_SHIFT, 0);
#endif
        
        /* zoom - drag */
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MIDDLEMOUSE, KM_PRESS, KM_CTRL, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MOUSEZOOM, 0, 0, 0);
        
        /* borderzoom - drag */
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_border", BKEY, KM_PRESS, KM_SHIFT, 0);
        
        /* scrollers */
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroller_activate", LEFTMOUSE, KM_PRESS, 0, 0);

        /* Alternative keymap for buttons listview */
        keymap= WM_keymap_find(keyconf, "View2D Buttons List", 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MIDDLEMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MOUSEPAN, 0, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", WHEELDOWNMOUSE, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", WHEELUPMOUSE, KM_PRESS, 0, 0);
        
        RNA_boolean_set(WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", PAGEDOWNKEY, KM_PRESS, 0, 0)->ptr, "page", 1);
        RNA_boolean_set(WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", PAGEUPKEY, KM_PRESS, 0, 0)->ptr, "page", 1);
        
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MIDDLEMOUSE, KM_PRESS, KM_CTRL, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MOUSEZOOM, 0, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_out", PADMINUS, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_in", PADPLUSKEY, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_reset", HOMEKEY, KM_PRESS, 0, 0);
        WM_keymap_add_item(keymap, "VIEW2D_OT_scroller_activate", LEFTMOUSE, KM_PRESS, 0, 0);
}