+ if ((gx2_out - gx1_out) != (gx2 - gx1) ||
+ (gy2_out - gy1_out) != (gy2 - gy1))
+ have_zoom_for_this_update = 1;
+
+ /* 'background' type of screen update (as opposed to 'destructive')
+ can be used to disable scaling if scaling is active */
+ zoom_off = blizzard.zoom_on && !have_zoom_for_this_update &&
+ (gx1_out == 0) && (gx2_out == blizzard.screen_width) &&
+ (gy1_out == 0) && (gy2_out == blizzard.screen_height) &&
+ (gx1 == 0) && (gy1 == 0);
+
+ if (blizzard.zoom_on && !have_zoom_for_this_update && !zoom_off &&
+ check_1d_intersect(blizzard.zoom_area_gx1, blizzard.zoom_area_gx2,
+ gx1_out, gx2_out) &&
+ check_1d_intersect(blizzard.zoom_area_gy1, blizzard.zoom_area_gy2,
+ gy1_out, gy2_out)) {
+ /* Previous screen update was using scaling, current update
+ * is not using it. Additionally, current screen update is
+ * going to overlap with the scaled area. Scaling needs to be
+ * disabled in order to avoid 'magnifying glass' effect.
+ * Dummy setup of background window can be used for this.
+ */
+ set_window_regs(0, 0, blizzard.screen_width,
+ blizzard.screen_height,
+ 0, 0, blizzard.screen_width,
+ blizzard.screen_height,
+ BLIZZARD_COLOR_RGB565, 1, flags);
+ blizzard.zoom_on = 0;
+ }
+
+ /* remember scaling settings if we have scaled update */
+ if (have_zoom_for_this_update) {
+ blizzard.zoom_on = 1;
+ blizzard.zoom_area_gx1 = gx1_out;
+ blizzard.zoom_area_gx2 = gx2_out;
+ blizzard.zoom_area_gy1 = gy1_out;
+ blizzard.zoom_area_gy2 = gy2_out;
+ }
+