ScrollBar.c

Go to the documentation of this file.

#include <stdlib.h>

#include <math.h>

#include "MEM_guardedalloc.h"

#include "Basic.h"
#include "ScrollBar.h"

struct _ScrollBar {
        int             rect[2][2];
        float   thumbpos, thumbpct;
        
        int             inset;
        int             minthumb;

        int             scrolling;
        float   scrolloffs;
};

static int scrollbar_get_thumbH(ScrollBar *sb) {
        int scrollable_h= rect_height(sb->rect) - 2*sb->inset;
        
        return clamp_i(sb->thumbpct*scrollable_h, sb->minthumb, scrollable_h);
}
static int scrollbar_get_thumbableH(ScrollBar *sb) {
        int scrollable_h= rect_height(sb->rect) - 2*sb->inset;
        int thumb_h= scrollbar_get_thumbH(sb);
        
        return scrollable_h - thumb_h;
}

static float scrollbar_co_to_pos(ScrollBar *sb, int yco) {
        int thumb_h= scrollbar_get_thumbH(sb);
        int thumbable_h= scrollbar_get_thumbableH(sb);
        int thumbable_y= (sb->rect[0][1]+sb->inset) + thumb_h/2;

        return (float) (yco-thumbable_y)/thumbable_h;
}



ScrollBar *scrollbar_new(int inset, int minthumb) {
        ScrollBar *sb= MEM_callocN(sizeof(*sb), "scrollbar_new");
        sb->inset= inset;
        sb->minthumb= minthumb;
        
        return sb;
}

void scrollbar_get_thumb(ScrollBar *sb, int thumb_r[2][2]) {
        int thumb_h= scrollbar_get_thumbH(sb);
        int thumbable_h= scrollbar_get_thumbableH(sb);

        thumb_r[0][0]= sb->rect[0][0]+sb->inset;
        thumb_r[1][0]= sb->rect[1][0]-sb->inset;

        thumb_r[0][1]= sb->rect[0][1]+sb->inset + sb->thumbpos*thumbable_h;
        thumb_r[1][1]= thumb_r[0][1] + thumb_h;
}

int scrollbar_is_scrolling(ScrollBar *sb) {
        return sb->scrolling;
}
int scrollbar_contains_pt(ScrollBar *sb, int pt[2]) {
        return rect_contains_pt(sb->rect, pt);
}

void scrollbar_start_scrolling(ScrollBar *sb, int yco) {
        int thumb_h_2= scrollbar_get_thumbH(sb)/2;
        int thumbable_h= scrollbar_get_thumbableH(sb);
        float npos= scrollbar_co_to_pos(sb, yco);

        sb->scrolloffs= sb->thumbpos - npos;
        if (fabs(sb->scrolloffs) >= (float) thumb_h_2/thumbable_h) {
                sb->scrolloffs= 0.0;
        }

        sb->scrolling= 1;
        sb->thumbpos= clamp_f(npos + sb->scrolloffs, 0.0, 1.0);
}
void scrollbar_keep_scrolling(ScrollBar *sb, int yco) {
        float npos= scrollbar_co_to_pos(sb, yco);

        sb->thumbpos= clamp_f(npos + sb->scrolloffs, 0.0, 1.0);
}
void scrollbar_stop_scrolling(ScrollBar *sb) {
        sb->scrolling= 0;
        sb->scrolloffs= 0.0;
}

void scrollbar_set_thumbpct(ScrollBar *sb, float pct) {
        sb->thumbpct= pct;
}
void scrollbar_set_thumbpos(ScrollBar *sb, float pos) {
        sb->thumbpos= clamp_f(pos, 0.0, 1.0);
}
void scrollbar_set_rect(ScrollBar *sb, int rect[2][2]) {
        rect_copy(sb->rect, rect);
}

float scrollbar_get_thumbpct(ScrollBar *sb) {
        return sb->thumbpct;
}
float scrollbar_get_thumbpos(ScrollBar *sb) {
        return sb->thumbpos;
}
void scrollbar_get_rect(ScrollBar *sb, int rect_r[2][2]) {
        rect_copy(rect_r, sb->rect);
}

void scrollbar_free(ScrollBar *sb) {
        MEM_freeN(sb);
}