Reapply "system/ui: add SCALE env var (#35272)" (#35273)

* Reapply "system/ui: add SCALE env var (#35272)"

This reverts commit e2569a8b32.

* set mouse scale factor

system/ui/README.md

@@ -5,5 +5,6 @@ The user interfaces here are built with [raylib](https://www.raylib.com/).
 Quick start:
 * set `DEBUG_FPS=1` to show the FPS
 * set `STRICT_MODE=1` to kill the app if it drops too much below 60fps
+* set `SCALE=1.5` to scale the entire UI by 1.5x
 * https://www.raylib.com/cheatsheet/cheatsheet.html
 * https://electronstudio.github.io/raylib-python-cffi/README.html#quickstart

system/ui/lib/application.py

@@ -15,6 +15,7 @@ FPS_CRITICAL_THRESHOLD = 0.5  # Critical threshold for triggering strict actions
 ENABLE_VSYNC = os.getenv("ENABLE_VSYNC") == "1"
 DEBUG_FPS = os.getenv("DEBUG_FPS") == '1'
 STRICT_MODE = os.getenv("STRICT_MODE") == '1'
+SCALE = float(os.getenv("SCALE", "1.0"))
 
 DEFAULT_TEXT_SIZE = 60
 DEFAULT_TEXT_COLOR = rl.WHITE
@@ -22,6 +23,7 @@ DEFAULT_TEXT_COLOR = rl.WHITE
 ASSETS_DIR = files("openpilot.selfdrive").joinpath("assets")
 FONT_DIR = ASSETS_DIR.joinpath("fonts")
 
+
 class FontWeight(IntEnum):
   THIN = 0
   EXTRA_LIGHT = 1
@@ -39,6 +41,10 @@ class GuiApplication:
     self._fonts: dict[FontWeight, rl.Font] = {}
     self._width = width
     self._height = height
+    self._scale = SCALE
+    self._scaled_width = int(self._width * self._scale)
+    self._scaled_height = int(self._height * self._scale)
+    self._render_texture: rl.RenderTexture | None = None
     self._textures: dict[str, rl.Texture] = {}
     self._target_fps: int = DEFAULT_FPS
     self._last_fps_log_time: float = time.monotonic()
@@ -62,14 +68,16 @@ class GuiApplication:
       flags |= rl.ConfigFlags.FLAG_VSYNC_HINT
     rl.set_config_flags(flags)
 
-    rl.init_window(self._width, self._height, title)
+    rl.init_window(self._scaled_width, self._scaled_height, title)
+    if self._scale != 1.0:
+      rl.set_mouse_scale(1 / self._scale, 1 / self._scale)
+      self._render_texture = rl.load_render_texture(self._width, self._height)
     rl.set_target_fps(fps)
 
     self._target_fps = fps
     self._set_styles()
     self._load_fonts()
 
-
   def texture(self, asset_path: str, width: int, height: int, alpha_premultiply=False, keep_aspect_ratio=True):
     cache_key = f"{asset_path}_{width}_{height}_{alpha_premultiply}{keep_aspect_ratio}"
     if cache_key in self._textures:
@@ -123,16 +131,32 @@ class GuiApplication:
       rl.unload_font(font)
     self._fonts = {}
 
+    if self._render_texture is not None:
+      rl.unload_render_texture(self._render_texture)
+      self._render_texture = None
+
     rl.close_window()
 
   def render(self):
     try:
       while not (self._window_close_requested or rl.window_should_close()):
+        if self._render_texture:
+          rl.begin_texture_mode(self._render_texture)
+          rl.clear_background(rl.BLACK)
+        else:
           rl.begin_drawing()
           rl.clear_background(rl.BLACK)
 
         yield
 
+        if self._render_texture:
+          rl.end_texture_mode()
+          rl.begin_drawing()
+          rl.clear_background(rl.BLACK)
+          src_rect = rl.Rectangle(0, 0, float(self._width), -float(self._height))
+          dst_rect = rl.Rectangle(0, 0, float(self._scaled_width), float(self._scaled_height))
+          rl.draw_texture_pro(self._render_texture.texture, src_rect, dst_rect, rl.Vector2(0, 0), 0.0, rl.WHITE)
+
         if DEBUG_FPS:
           rl.draw_fps(10, 10)