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Fixed X11 line implementation - clip lines that are going to go outside the window.

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This commit is contained in:
Sam Lantinga
2009-12-11 09:59:36 +00:00
parent c0e3ce55fd
commit 54af8f9682
2 changed files with 123 additions and 12 deletions
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134
src/video/x11/SDL_x11render.c
View File

@@ -23,6 +23,8 @@
#if SDL_VIDEO_RENDER_X11
#include <limits.h> /* For INT_MIN and INT_MAX */
#include "SDL_x11video.h"
#include "../SDL_rect_c.h"
#include "../SDL_pixels_c.h"
@@ -647,26 +649,134 @@ X11_RenderLines(SDL_Renderer * renderer, const SDL_Point * points, int count)
SDL_Window *window = SDL_GetWindowFromID(renderer->window);
SDL_Rect clip, rect;
unsigned long foreground;
XPoint *xpoints, *xpoint;
int i, xcount;
int minx, miny;
int maxx, maxy;
clip.x = 0;
clip.y = 0;
clip.w = window->w;
clip.h = window->h;
if (data->makedirty) {
/* Get the smallest rectangle that contains everything */
SDL_EnclosePoints(points, count, NULL, &rect);
if (!SDL_IntersectRect(&rect, &clip, &rect)) {
/* Nothing to draw */
return 0;
}
SDL_AddDirtyRect(&data->dirty, &rect);
}
foreground = renderdrawcolor(renderer, 1);
XSetForeground(data->display, data->gc, foreground);
/* FIXME: Can we properly handle lines that extend beyond visible space? */
//XDrawLine(data->display, data->drawable, data->gc, x1, y1, x2, y2);
xpoint = xpoints = SDL_stack_alloc(XPoint, count);
xcount = 0;
minx = INT_MAX;
miny = INT_MAX;
maxx = INT_MIN;
maxy = INT_MIN;
for (i = 0; i < count; ++i) {
int x = points[i].x;
int y = points[i].y;
/* If the point is inside the window, add it to the list */
if (x >= 0 && x < window->w && y >= 0 && y < window->h) {
if (x < minx) {
minx = x;
} else if (x > maxx) {
maxx = x;
}
if (y < miny) {
miny = y;
} else if (y > maxy) {
maxy = y;
}
xpoint->x = (short)x;
xpoint->y = (short)y;
++xpoint;
++xcount;
continue;
}
/* We need to clip the line segments joined by this point */
if (xcount > 0) {
int x1 = xpoint[-1].x;
int y1 = xpoint[-1].y;
int x2 = x;
int y2 = y;
if (SDL_IntersectRectAndLine(&clip, &x1, &y1, &x2, &y2)) {
if (x2 < minx) {
minx = x2;
} else if (x2 > maxx) {
maxx = x2;
}
if (y2 < miny) {
miny = y2;
} else if (y2 > maxy) {
maxy = y2;
}
xpoint->x = (short)x2;
xpoint->y = (short)y2;
++xpoint;
++xcount;
}
XDrawLines(data->display, data->drawable, data->gc,
xpoints, xcount, CoordModeOrigin);
if (xpoints[0].x != x2 || xpoints[0].y != y2) {
XDrawPoint(data->display, data->drawable, data->gc, x2, y2);
}
if (data->makedirty) {
SDL_Rect rect;
rect.x = minx;
rect.y = miny;
rect.w = (maxx - minx) + 1;
rect.h = (maxy - miny) + 1;
SDL_AddDirtyRect(&data->dirty, &rect);
}
xpoint = xpoints;
xcount = 0;
minx = INT_MAX;
miny = INT_MAX;
maxx = INT_MIN;
maxy = INT_MIN;
}
if (i < (count-1)) {
int x1 = x;
int y1 = y;
int x2 = points[i+1].x;
int y2 = points[i+1].y;
if (SDL_IntersectRectAndLine(&clip, &x1, &y1, &x2, &y2)) {
if (x1 < minx) {
minx = x1;
} else if (x1 > maxx) {
maxx = x1;
}
if (y1 < miny) {
miny = y1;
} else if (y1 > maxy) {
maxy = y1;
}
xpoint->x = (short)x1;
xpoint->y = (short)y1;
++xpoint;
++xcount;
}
}
}
if (xcount > 1) {
int x2 = xpoint[-1].x;
int y2 = xpoint[-1].y;
XDrawLines(data->display, data->drawable, data->gc, xpoints, xcount,
CoordModeOrigin);
if (xpoints[0].x != x2 || xpoints[0].y != y2) {
XDrawPoint(data->display, data->drawable, data->gc, x2, y2);
}
if (data->makedirty) {
SDL_Rect rect;
rect.x = minx;
rect.y = miny;
rect.w = (maxx - minx) + 1;
rect.h = (maxy - miny) + 1;
SDL_AddDirtyRect(&data->dirty, &rect);
}
}
SDL_stack_free(xpoints);
return 0;
}

1
src/video/x11/SDL_x11sym.h
View File

@@ -95,6 +95,7 @@ SDL_X11_SYM(int,XPeekEvent,(Display* a,XEvent* b),(a,b),return)
SDL_X11_SYM(int,XPending,(Display* a),(a),return)
SDL_X11_SYM(int,XPutImage,(Display* a,Drawable b,GC c,XImage* d,int e,int f,int g,int h,unsigned int i,unsigned int j),(a,b,c,d,e,f,g,h,i,j),return)
SDL_X11_SYM(int,XDrawLines,(Display* a, Drawable b, GC c, XPoint* d, int e, int f),(a,b,c,d,e,f),return)
SDL_X11_SYM(int,XDrawPoint,(Display* a, Drawable b, GC c, int d, int e),(a,b,c,d,e),return)
SDL_X11_SYM(int,XDrawPoints,(Display* a, Drawable b, GC c, XPoint* d, int e, int f),(a,b,c,d,e,f),return)
SDL_X11_SYM(int,XQueryColors,(Display* a,Colormap b,XColor* c,int d),(a,b,c,d),return)
SDL_X11_SYM(int,XQueryKeymap,(Display* a,char *b),(a,b),return)