FramebufferDisplay: dirty rows are physical

jepler · jepler · commit b3141933afbd · 2023-09-27T15:15:34.000-05:00
.. so they need a correct row count, which could be the "core.width"
of a 90/180 rotated display.

While I discovered this on the very unusual 320x960 display it could have
affected any framebuffer display that was taller than it was wide,
including sharp memory displays and rgbmatrix displays.
diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
@@ -252,7 +252,9 @@ STATIC void _refresh_display(framebufferio_framebufferdisplay_obj_t *self) {
     displayio_display_core_start_refresh(&self->core);
     const displayio_area_t *current_area = _get_refresh_areas(self);
     if (current_area) {
-        uint8_t dirty_row_bitmask[(self->core.height + 7) / 8];
+        bool transposed = (self->core.rotation == 90 || self->core.rotation == 270);
+        int row_count = transposed ? self->core.width : self->core.height;
+        uint8_t dirty_row_bitmask[(row_count + 7) / 8];
         memset(dirty_row_bitmask, 0, sizeof(dirty_row_bitmask));
         self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
         while (current_area != NULL) {
