feat(renderer): draw selection overlay

renderer/screen-rect.ts

@@ -0,0 +1,12 @@
+import type { Rect } from "@core/geometry";
+import type { ViewportState } from "@editor/state";
+import type { ScreenRect } from "./types";
+
+export function documentRectToScreenRect(canvas: HTMLCanvasElement, rect: Rect, viewport: ViewportState): ScreenRect {
+  return {
+    x: Math.round(canvas.width / 2 + (rect.x - viewport.center.x) * viewport.zoom),
+    y: Math.round(canvas.height / 2 + (rect.y - viewport.center.y) * viewport.zoom),
+    w: Math.max(0, Math.round(rect.w * viewport.zoom)),
+    h: Math.max(0, Math.round(rect.h * viewport.zoom)),
+  };
+}