shithub: puzzles

Info  •  Files  •  Log  •  Branches

GNUstep compatibility: avoid attempting blitter_save with a partially
out-of-bounds rectangle. Instead, take the intersection of the
rectangle with the window boundary and do a smaller operation on
what's left.

[originally from svn r9503]

--- a/osx.m

+++ b/osx.m

@@ -1421,11 +1421,42 @@

 static void osx_blitter_save(void *handle, blitter *bl, int x, int y)

 {

     frontend *fe = (frontend *)handle;

+    int sx, sy, sX, sY, dx, dy, dX, dY;

     [fe->image unlockFocus];

     [bl->img lockFocus];

-    [fe->image drawInRect:NSMakeRect(0, 0, bl->w, bl->h)

-	fromRect:NSMakeRect(x, fe->h - y - bl->h, bl->w, bl->h)

-	operation:NSCompositeCopy fraction:1.0];

+

+    /*

+     * Find the intersection of the source and destination rectangles,

+     * so as to avoid trying to copy from outside the source image,

+     * which GNUstep dislikes.

+     *

+     * Lower-case x,y coordinates are bottom left box corners;

+     * upper-case X,Y are the top right.

+     */

+    sx = x; sy = fe->h - y - bl->h;

+    sX = sx + bl->w; sY = sy + bl->h;

+    dx = dy = 0;

+    dX = bl->w; dY = bl->h;

+    if (sx < 0) {

+        dx += -sx;

+        sx = 0;

+    }

+    if (sy < 0) {

+        dy += -sy;

+        sy = 0;

+    }

+    if (sX > fe->w) {

+        dX -= (sX - fe->w);

+        sX = fe->w;

+    }

+    if (sY > fe->h) {

+        dY -= (sY - fe->h);

+        sY = fe->h;

+    }

+

+    [fe->image drawInRect:NSMakeRect(dx, dy, dX-dx, dY-dy)

+                 fromRect:NSMakeRect(sx, sy, sX-sx, sY-sy)

+                operation:NSCompositeCopy fraction:1.0];

     [bl->img unlockFocus];

     [fe->image lockFocus];

     bl->x = x;