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netsurf/framebuffer/fb_plotters.c
Daniel Silverstone 29d1e44dec Fix line plotting and rectangle clipping segfault 
svn path=/trunk/netsurf/; revision=5430
2008-09-24 11:22:52 +00:00

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/*
* Copyright 2008 Vincent Sanders <vince@simtec.co.uk>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf 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; version 2 of the License.
*
* NetSurf 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, see <http://www.gnu.org/licenses/>.
*/
#include <sys/types.h>
#include <stdint.h>
#include <string.h>
#include <limits.h>
#include "utils/log.h"
#include "utils/utf8.h"
#include "desktop/plotters.h"
#include "framebuffer/fb_gui.h"
#include "framebuffer/fb_plotters.h"
#include "framebuffer/fb_bitmap.h"
#include "framebuffer/fb_font.h"
/* Currently selected ploting routines. */
struct plotter_table plot;
/* Current plotting context */
bbox_t fb_plot_ctx;
enum {
POINT_LEFTOF_REGION = 1,
POINT_RIGHTOF_REGION = 2,
POINT_ABOVE_REGION = 4,
POINT_BELOW_REGION = 8,
};
#define REGION(x,y,cx1,cx2,cy1,cy2) ( ( (y) > (cy2) ? POINT_BELOW_REGION : 0) | \
( (y) < (cy1) ? POINT_ABOVE_REGION : 0) | \
( (x) > (cx2) ? POINT_RIGHTOF_REGION : 0) | \
( (x) < (cx1) ? POINT_LEFTOF_REGION : 0) )
#define SWAP(a, b) do { int t; t=(a); (a)=(b); (b)=t; } while(0)
/* clip a rectangle to another rectangle */
bool fb_plotters_clip_rect(const bbox_t *clip,
int *x0, int *y0, int *x1, int *y1)
{
char region1;
char region2;
if (*x1 < *x0) SWAP(*x0, *x1);
if (*y1 < *y0) SWAP(*y0, *y1);
region1 = REGION(*x0, *y0, clip->x0, clip->x1 - 1, clip->y0, clip->y1 - 1);
region2 = REGION(*x1, *y1, clip->x0, clip->x1 - 1, clip->y0, clip->y1 - 1);
/* area lies entirely outside the clipping rectangle */
if ((region1 | region2) && (region1 & region2))
return false;
if (*x0 < clip->x0)
*x0 = clip->x0;
if (*x0 > clip->x1)
*x0 = clip->x1;
if (*x1 < clip->x0)
*x1 = clip->x0;
if (*x1 > clip->x1)
*x1 = clip->x1;
if (*y0 < clip->y0)
*y0 = clip->y0;
if (*y0 > clip->y1)
*y0 = clip->y1;
if (*y1 < clip->y0)
*y1 = clip->y0;
if (*y1 > clip->y1)
*y1 = clip->y1;
return true;
}
bool fb_plotters_clip_rect_ctx(int *x0, int *y0, int *x1, int *y1)
{
return fb_plotters_clip_rect(&fb_plot_ctx, x0, y0, x1, y1);
}
/** Clip a line to a bounding box.
*/
bool fb_plotters_clip_line(const bbox_t *clip,
int *x0, int *y0, int *x1, int *y1)
{
char region1;
char region2;
region1 = REGION(*x0, *y0, clip->x0, clip->x1 - 1, clip->y0, clip->y1 - 1);
region2 = REGION(*x1, *y1, clip->x0, clip->x1 - 1, clip->y0, clip->y1 - 1);
while (region1 | region2) {
if (region1 & region2) {
/* line lies entirely outside the clipping rectangle */
return false;
}
if (region1) {
/* first point */
if (region1 & POINT_BELOW_REGION) {
/* divide line at bottom */
*x0 = (*x0 + (*x1 - *x0) *
(clip->y1 - 1 - *y0) / (*y1-*y0));
*y0 = clip->y1 - 1;
} else if (region1 & POINT_ABOVE_REGION) {
/* divide line at top */
*x0 = (*x0 + (*x1 - *x0) *
(clip->y0 - *y0) / (*y1-*y0));
*y0 = clip->y0;
} else if (region1 & POINT_RIGHTOF_REGION) {
/* divide line at right */
*y0 = (*y0 + (*y1 - *y0) *
(clip->x1 - 1 - *x0) / (*x1-*x0));
*x0 = clip->x1 - 1;
} else if (region1 & POINT_LEFTOF_REGION) {
/* divide line at right */
*y0 = (*y0 + (*y1 - *y0) *
(clip->x0 - *x0) / (*x1-*x0));
*x0 = clip->x0;
}
region1 = REGION(*x0, *y0,
clip->x0, clip->x1 - 1, clip->y0, clip->y1 - 1);
} else {
/* second point */
if (region2 & POINT_BELOW_REGION) {
/* divide line at bottom*/
*x1 = (*x0 + (*x1 - *x0) *
(clip->y1 - 1 - *y0) / (*y1-*y0));
*y1 = clip->y1 - 1;
} else if (region2 & POINT_ABOVE_REGION) {
/* divide line at top*/
*x1 = (*x0 + (*x1 - *x0) *
(clip->y0 - *y0) / (*y1-*y0));
*y1 = clip->y0;
} else if (region2 & POINT_RIGHTOF_REGION) {
/* divide line at right*/
*y1 = (*y0 + (*y1 - *y0) *
(clip->x1 - 1 - *x0) / (*x1 - *x0));
*x1 = clip->x1 - 1;
} else if (region2 & POINT_LEFTOF_REGION) {
/* divide line at right*/
*y1 = (*y0 + (*y1 - *y0) *
(clip->x0 - *x0) / (*x1 - *x0));
*x1 = clip->x0;
}
region2 = REGION(*x1, *y1,
clip->x0, clip->x1 - 1, clip->y0, clip->y1 - 1);
}
}
return true;
}
bool fb_plotters_clip_line_ctx(int *x0, int *y0, int *x1, int *y1)
{
return fb_plotters_clip_line(&fb_plot_ctx, x0, y0, x1, y1);
}
/* generic setting of clipping rectangle */
bool fb_clip(int x0, int y0, int x1, int y1)
{
bbox_t clip;
struct gui_window *g;
g = window_list;
/* LOG(("x0 %d, y0 %d, x1 %d, y1 %d", x0, y0, x1, y1)); */
if (x1 < x0) SWAP(x0, x1);
if (y1 < y0) SWAP(y0, y1);
clip.x0 = g->x;
clip.y0 = g->y;
clip.x1 = g->x + g->width;
clip.y1 = g->x + g->height;
if (fb_plotters_clip_rect(&clip, &x0, &y0, &x1, &y1)) {
/* new clipping region is inside the root window */
fb_plot_ctx.x0 = x0;
fb_plot_ctx.y0 = y0;
fb_plot_ctx.x1 = x1;
fb_plot_ctx.y1 = y1;
}
return true;
}
colour fb_plotters_ablend(colour pixel, colour scrpixel)
{
int opacity = (pixel >> 24) & 0xFF;
int r,g,b;
r = (((pixel & 0xFF) * opacity) >> 8) +
(((scrpixel & 0xFF) * (0xFF - opacity)) >> 8);
g = ((((pixel & 0xFF00) >> 8) * opacity) >> 8) +
((((scrpixel & 0xFF00) >> 8) * (0xFF - opacity)) >> 8);
b = ((((pixel & 0xFF0000) >> 16) * opacity) >> 8) +
((((scrpixel & 0xFF0000) >> 16) * (0xFF - opacity)) >> 8);
return r | (g << 8) | (b << 16);
}
bool
fb_plotters_polygon(int *p, unsigned int n, colour fill,bool (linefn)(int x0, int y0, int x1, int y1, int width, colour c, bool dotted, bool dashed))
{
unsigned int pnt;
int *cur = p;
for (pnt = 1; pnt < n; pnt++) {
cur = p + (pnt << 1);
linefn(cur[-2], cur[-1], cur[0], cur[1], 1, fill, false, false);
}
linefn(cur[0], cur[1], p[0], p[1], 1, fill, false, false);
return true;
}
bool fb_plotters_bitmap_tile(int x, int y,
int width, int height,
struct bitmap *bitmap, colour bg,
bool repeat_x, bool repeat_y,
struct content *content,
bool (bitmapfn)(int x, int y,
int width, int height,
struct bitmap *bitmap,
colour bg,
struct content *content))
{
int xf,yf;
/* x and y define top left hand corner of tile start, the width height
* are the mage scaling and the bounding box defines teh extent of the
* repeat
*/
LOG(("x %d, y %d, width %d, height %d, bitmap %p, repx %d repy %d content %p", x,y,width,height,bitmap,repeat_x, repeat_y, content));
if (!(repeat_x || repeat_y)) {
/* Not repeating at all, so just pass it on */
LOG(("Not repeating"));
return bitmapfn(x, y, width, height, bitmap, bg,content);
}
for (xf = x; xf < fb_plot_ctx.x1; xf += width) {
for (yf = y; yf < fb_plot_ctx.y1; yf += height) {
bitmapfn(xf, yf, width, height, bitmap, bg, content);
if (!repeat_y)
break;
}
if (!repeat_x)
break;
}
return true;
}
bool fb_plotters_move_block(int srcx, int srcy, int width, int height, int dstx, int dsty)
{
LOG(("from (%d,%d) w %d h %d to (%d,%d)",srcx,srcy,width,height,dstx,dsty));
uint8_t *srcptr = (framebuffer->ptr +
(srcy * framebuffer->linelen) +
(srcx));
uint8_t *dstptr = (framebuffer->ptr +
(dsty * framebuffer->linelen) +
(dstx));
memmove(dstptr, srcptr, (width * height * framebuffer->bpp) / 8);
return true;
}
/*
* Local Variables:
* c-basic-offset:8
* End:
*/
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