- s->set_destination_rectangle(0, 0, c->output_size.w,
- c->output_size.h);
+
+ int x = rect.x;
+ int y = rect.y;
+ int w = rect.w;
+ int h = rect.h;
+
+ // less-than-0 values refer to MAX + 1 - $VALUE
+ // e.g. MAX is either screen width or height
+ if (w < 0) {
+ w = c->output_size.w + 1 + w;
+ }
+ if (h < 0) {
+ h = c->output_size.h + 1 + h;
+ }
+ logdebug("Computed rect={ %d, %d, %d, %d }", x, y, w, h);
+
+ // configure surface to wxh dimensions
+ s->set_configuration(w, h);
+ // set source rect to "entire surface"
+ s->set_source_rectangle(0, 0, w, h);
+ // set destination to the display rectangle
+ s->set_destination_rectangle(x, y, w, h);
+