Add partial display update support.

Different operations to the display tree have different costs. Be
aware of these costs when optimizing your code.
* Changing tiles indices in a TileGrid will update an area
covering them all.
* Changing a palette will refresh every object that references it.
* Moving a TileGrid will update both where it was and where it moved to.
* Adding something to a Group will refresh each individual area it
covers.
* Removing things from a Group will refresh one area that covers all
previous locations. (Not separate areas like add.)
* Setting a new top level Group will refresh the entire display.

Only TileGrid moves are optimized for overlap. All other overlaps
cause sending of duplicate pixels.

This also adds flip_x, flip_y and transpose_xy to TileGrid. They
change the direction of the pixels but not the location.

Fixes #1169. Fixes #1705. Fixes #1923.

1 files changed, 20 insertions, 12 deletions

diff --git a/supervisor/shared/display.c b/supervisor/shared/display.c
index 5eab74e16..c3afb3e00 100644
--- a/supervisor/shared/display.c
+++ b/supervisor/shared/display.c
@@ -50,6 +50,10 @@ void supervisor_start_terminal(uint16_t width_px, uint16_t height_px) {
     }
     width_in_tiles = (width_px - blinka_bitmap.width * scale) / (grid->tile_width * scale);
     uint16_t height_in_tiles = height_px / (grid->tile_height * scale);
+    uint16_t remaining_pixels = height_px % (grid->tile_height * scale);
+    if (remaining_pixels > 0) {
+        height_in_tiles += 1;
+    }
     circuitpython_splash.scale = scale;
 
     uint16_t total_tiles = width_in_tiles * height_in_tiles;
@@ -67,11 +71,13 @@ void supervisor_start_terminal(uint16_t width_px, uint16_t height_px) {
     if (tiles == NULL) {
         return;
     }
-
+    if (remaining_pixels > 0) {
+        grid->y -= (grid->tile_height - remaining_pixels);
+    }
     grid->width_in_tiles = width_in_tiles;
     grid->height_in_tiles = height_in_tiles;
-    grid->area.x2 = grid->area.x1 + width_in_tiles * grid->tile_width;
-    grid->area.y2 = grid->area.y1 + height_in_tiles * grid->tile_height;
+    grid->pixel_width = width_in_tiles * grid->tile_width;
+    grid->pixel_height = height_in_tiles * grid->tile_height;
     grid->tiles = tiles;
 
     supervisor_terminal.cursor_x = 0;
@@ -157,12 +163,10 @@ displayio_tilegrid_t blinka_sprite = {
     .base = {.type = &displayio_tilegrid_type },
     .bitmap = &blinka_bitmap,
     .pixel_shader = &blinka_palette,
-    .area = {
-        .x1 = 0,
-        .y1 = 0,
-        .x2 = 16,
-        .y2 = 16
-    },
+    .x = 0,
+    .y = 0,
+    .pixel_width = 16,
+    .pixel_height = 16,
     .bitmap_width_in_tiles = 1,
     .width_in_tiles = 1,
     .height_in_tiles = 1,
@@ -171,8 +175,12 @@ displayio_tilegrid_t blinka_sprite = {
     .top_left_x = 16,
     .top_left_y = 16,
     .tiles = 0,
-    .needs_refresh = false,
-    .inline_tiles = true
+    .partial_change = false,
+    .full_change = false,
+    .first_draw = true,
+    .moved = false,
+    .inline_tiles = true,
+    .in_group = true
 };
 
 displayio_group_child_t splash_children[2] = {
@@ -188,5 +196,5 @@ displayio_group_t circuitpython_splash = {
     .size = 2,
     .max_size = 2,
     .children = splash_children,
-    .needs_refresh = true
+    .item_removed = false
 };