- y_top = max(win1->_begy, win2->_begy);
- y_bot = min(win1->_maxy, win2->_maxy);
- x_left = max(win1->_begx, win2->_begx);
- x_right = min(win1->_maxx, win2->_maxx);
- starty = y_top - win1->_begy;
- startx = x_left - win1->_begx;
- endy = y_bot - win1->_begy;
- endx = x_right - win1->_begx;
- for (y = starty; y < endy; y++) {
- end = &win1->_y[y][endx];
- x = startx + win1->_begx;
- for (sp = &win1->_y[y][startx]; sp <= end; sp++) {
+ starty = max(win1->_begy, win2->_begy);
+ startx = max(win1->_begx, win2->_begx);
+ endy = min(win1->_maxy + win1->_begy, win2->_maxy + win2->_begx);
+ endx = min(win1->_maxx + win1->_begx, win2->_maxx + win2->_begx);
+# ifdef DEBUG
+ fprintf(outf, "OVERLAY:from (%d,%d) to (%d,%d)\n", starty, startx, endy, endx);
+# endif
+ if (starty >= endy || startx >= endx)
+ return;
+ y1 = starty - win1->_begy;
+ y2 = starty - win2->_begy;
+ for (y = starty; y < endy; y++, y1++, y2++) {
+ end = &win1->_y[y1][endx - win1->_begx];
+ x = startx - win2->_begx;
+ for (sp = &win1->_y[y1][startx - win1->_begx]; sp < end; sp++) {