From 3f41d2b9d7fb9b11d2b496d0f35f0dc8984a3887 Mon Sep 17 00:00:00 2001
From: Sassan Haradji <me@sassanh.com>
Date: Tue, 29 Oct 2024 16:01:27 +0400
Subject: [PATCH] feat: add `show_update_regions` property to `HeadlessWidget`
 to show the regions that are updated in each frame as a debug feature

---
 CHANGELOG.md            |  1 +
 headless_kivy/_debug.py | 26 ++++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d05e95e..8650182 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 - feat: divide each frame into multiple rectangles, compare rectangle with the same rectangle in the previous frame and update only the changed ones
 - feat: add two throttling mechanisms to avoid sending too many frames to the display, one based on total bandwidth of all draw commands of all `HeadlessWidget`s and the other based on set fps of a particular `HeadlessWidget`
+- feat: add `show_update_regions` property to `HeadlessWidget` to show the regions that are updated in each frame as a debug feature
 
 ## Version 0.11.1
 
diff --git a/headless_kivy/_debug.py b/headless_kivy/_debug.py
index 9dda04a..3736e23 100644
--- a/headless_kivy/_debug.py
+++ b/headless_kivy/_debug.py
@@ -6,13 +6,14 @@
 from pathlib import Path
 from typing import TYPE_CHECKING, ClassVar, Self
 
+import numpy as np
 from kivy.metrics import dp
+from kivy.properties import BooleanProperty
 
 from headless_kivy import config
 from headless_kivy.logger import logger
 
 if TYPE_CHECKING:
-    import numpy as np
     from kivy.graphics.context_instructions import Color
     from kivy.graphics.fbo import Fbo
     from kivy.graphics.vertex_instructions import Rectangle
@@ -23,6 +24,7 @@ class DebugMixin:
     fbo: Fbo
     fbo_render_color: Color
     fbo_render_rectangle: Rectangle
+    show_update_regions = BooleanProperty(0)
 
     x: int
     y: int
@@ -56,9 +58,29 @@ def set_debug_info(self: Self) -> None:
     def render_debug_info(
         self: Self,
         rect_: tuple[int, int, int, int],
-        _: list[tuple[int, int, int, int]],
+        regions: list[tuple[int, int, int, int]],
         data: NDArray[np.uint8],
     ) -> None:
+        if self.show_update_regions:
+            for rect in regions:
+                self.update_region_seed = (self.update_region_seed + 1) % 3
+                data[
+                    rect[1] : rect[3],
+                    rect[0] : rect[2],
+                    :,
+                ] = (
+                    data[
+                        rect[1] : rect[3],
+                        rect[0] : rect[2],
+                        :,
+                    ]
+                    * 0.5
+                ).astype(np.uint8)
+                data[
+                    rect[1] : rect[3],
+                    rect[0] : rect[2],
+                    [(rect[0] + rect[1] + self.update_region_seed) % 7 % 3, 3],
+                ] += 127
         if config.is_debug_mode():
             x1, y1, x2, y2 = rect_
             self.rendered_frames += 1