diff --git a/lib/getCanvasObjectLabelAtPoint.ts b/lib/getCanvasObjectLabelAtPoint.ts
index a4f7463..01e0cdd 100644
--- a/lib/getCanvasObjectLabelAtPoint.ts
+++ b/lib/getCanvasObjectLabelAtPoint.ts
@@ -1,5 +1,5 @@
 import { getArrowGeometry } from "./arrowHelpers"
-import { getRectCorners } from "./rectGeometry"
+import { getProjectedRectGeometry } from "./rectGeometry"
 import type {
   Arrow,
   Circle,
@@ -186,9 +186,7 @@ const isRectHit = (
   matrix: Matrix,
   hitSlop: number,
 ) => {
-  const corners = getRectCorners(rect).map((point) =>
-    projectPoint(matrix, point),
-  )
+  const corners = getProjectedRectGeometry(rect, matrix).corners
 
   return (
     isPointInPolygon(screenPoint, corners) ||
diff --git a/lib/rectGeometry.ts b/lib/rectGeometry.ts
index 4a0e668..27308fb 100644
--- a/lib/rectGeometry.ts
+++ b/lib/rectGeometry.ts
@@ -13,6 +13,19 @@ export const getRectRotationRadians = (
   return ((rect.ccwRotationDegrees ?? 0) * Math.PI) / 180
 }
 
+const getScreenRotationMultiplier = (matrix: Matrix) => {
+  // Screen coordinates have +Y downward. Orientation-preserving transforms
+  // therefore need the math angle inverted to look visually CCW.
+  const determinant = matrix.a * matrix.d - matrix.b * matrix.c
+  return determinant < 0 ? 1 : -1
+}
+
+export const getRectRotationRadiansForMatrix = (
+  rect: Pick<Rect, "ccwRotationDegrees">,
+  matrix: Matrix,
+) => {
+  return getRectRotationRadians(rect) * getScreenRotationMultiplier(matrix)
+}
 const rotatePoint = (point: XYPoint, angleRadians: number): XYPoint => {
   const cos = Math.cos(angleRadians)
   const sin = Math.sin(angleRadians)
@@ -25,10 +38,26 @@ const rotatePoint = (point: XYPoint, angleRadians: number): XYPoint => {
 
 export const getRectCorners = (
   rect: Pick<Rect, "center" | "width" | "height" | "ccwRotationDegrees">,
+): Point[] => {
+  return getRectCornersWithAngle(rect, getRectRotationRadians(rect))
+}
+
+export const getRectCornersForMatrix = (
+  rect: Pick<Rect, "center" | "width" | "height" | "ccwRotationDegrees">,
+  matrix: Matrix,
+): Point[] => {
+  return getRectCornersWithAngle(
+    rect,
+    getRectRotationRadiansForMatrix(rect, matrix),
+  )
+}
+
+const getRectCornersWithAngle = (
+  rect: Pick<Rect, "center" | "width" | "height" | "ccwRotationDegrees">,
+  angleRadians: number,
 ): Point[] => {
   const halfWidth = rect.width / 2
   const halfHeight = rect.height / 2
-  const angleRadians = getRectRotationRadians(rect)
 
   return [
     { x: -halfWidth, y: -halfHeight },
@@ -69,7 +98,7 @@ export const getProjectedRectGeometry = (
   rect: Pick<Rect, "center" | "width" | "height" | "ccwRotationDegrees">,
   matrix: Matrix,
 ) => {
-  const corners = getRectCorners(rect).map((point) =>
+  const corners = getRectCornersForMatrix(rect, matrix).map((point) =>
     applyToPoint(matrix, point),
   )
   const center = applyToPoint(matrix, rect.center)
diff --git a/site/components/InteractiveGraphics/InteractiveGraphics.tsx b/site/components/InteractiveGraphics/InteractiveGraphics.tsx
index b4c76cc..3db85b5 100644
--- a/site/components/InteractiveGraphics/InteractiveGraphics.tsx
+++ b/site/components/InteractiveGraphics/InteractiveGraphics.tsx
@@ -387,6 +387,7 @@ export const InteractiveGraphics = ({
   })
 
   const filterRects = useFilterRects({
+    realToScreen,
     isPointOnScreen,
     doesLineIntersectViewport,
     filterLayerAndStep,
diff --git a/site/components/InteractiveGraphics/hooks/useFilterRects.ts b/site/components/InteractiveGraphics/hooks/useFilterRects.ts
index 457cd9c..d1de3a3 100644
--- a/site/components/InteractiveGraphics/hooks/useFilterRects.ts
+++ b/site/components/InteractiveGraphics/hooks/useFilterRects.ts
@@ -1,5 +1,6 @@
+import { getRectCornersForMatrix } from "lib/rectGeometry"
 import { useMemo } from "react"
-import { getRectCorners } from "lib/rectGeometry"
+import type { Matrix } from "transformation-matrix"
 
 type Rect = {
   center: { x: number; y: number }
@@ -11,6 +12,7 @@ type Rect = {
 }
 
 type UseFilterRectsParams = {
+  realToScreen: Matrix
   isPointOnScreen: (point: { x: number; y: number }) => boolean
   doesLineIntersectViewport: (
     p1: { x: number; y: number },
@@ -20,6 +22,7 @@ type UseFilterRectsParams = {
 }
 
 export const useFilterRects = ({
+  realToScreen,
   isPointOnScreen,
   doesLineIntersectViewport,
   filterLayerAndStep,
@@ -31,7 +34,8 @@ export const useFilterRects = ({
 
       // For rectangles, check if any corner or the center is visible
       const { center } = rect
-      const [topLeft, topRight, bottomRight, bottomLeft] = getRectCorners(rect)
+      const [topLeft, topRight, bottomRight, bottomLeft] =
+        getRectCornersForMatrix(rect, realToScreen)
 
       // Check if any corner or center is visible
       if (
@@ -52,5 +56,10 @@ export const useFilterRects = ({
         doesLineIntersectViewport(bottomLeft, topLeft)
       )
     }
-  }, [isPointOnScreen, doesLineIntersectViewport, filterLayerAndStep])
+  }, [
+    realToScreen,
+    isPointOnScreen,
+    doesLineIntersectViewport,
+    filterLayerAndStep,
+  ])
 }
diff --git a/tests/SVGRenderer.test.tsx b/tests/SVGRenderer.test.tsx
index 5216b15..2e7d39e 100644
--- a/tests/SVGRenderer.test.tsx
+++ b/tests/SVGRenderer.test.tsx
@@ -1,10 +1,15 @@
 import { describe, expect, test, beforeAll } from "bun:test"
+import { act } from "react"
 import { createRoot } from "react-dom/client"
 import SVGRenderer from "../site/components/SVGRenderer"
 import "bun-match-svg"
 import * as jsdom from "jsdom"
 import { getSvgsFromLogString } from "../lib"
 
+declare global {
+  var IS_REACT_ACT_ENVIRONMENT: boolean
+}
+
 // Setup global DOM environment
 beforeAll(() => {
   const { JSDOM } = jsdom
@@ -13,10 +18,11 @@ beforeAll(() => {
   global.document = dom.window.document
   global.window = dom.window as unknown as Window & typeof globalThis
   global.navigator = dom.window.navigator
+  globalThis.IS_REACT_ACT_ENVIRONMENT = true
 })
 
 describe("SVGRenderer", () => {
-  test("snapshot matches expected SVG output", () => {
+  test("snapshot matches expected SVG output", async () => {
     const container = document.createElement("div")
     document.body.appendChild(container)
 
@@ -25,38 +31,33 @@ describe("SVGRenderer", () => {
 
     const root = createRoot(container)
 
-    return new Promise<void>((resolve) => {
-      // Render the SVGs
-      root.render(
-        graphics.length > 0 ? (
-          <div className="space-y-8">
-            {graphics.map(({ title, svg }, index) => (
-              <SVGRenderer key={index} title={title} svg={svg} />
-            ))}
-          </div>
-        ) : null,
-      )
+    try {
+      await act(async () => {
+        // Render the SVGs
+        root.render(
+          graphics.length > 0 ? (
+            <div className="space-y-8">
+              {graphics.map(({ title, svg }, index) => (
+                <SVGRenderer key={index} title={title} svg={svg} />
+              ))}
+            </div>
+          ) : null,
+        )
+      })
 
-      // Use setTimeout to allow rendering to complete
-      setTimeout(() => {
-        try {
-          const renderedSvgs = container.querySelectorAll("svg")
-          expect(renderedSvgs.length).toBeGreaterThan(0)
-          const firstRenderedSvg = renderedSvgs[0]?.outerHTML
-          // Perform snapshot test
-          expect(firstRenderedSvg).toMatchSvgSnapshot(
-            import.meta.path,
-            "renderer-graphics",
-          )
-          root.unmount()
-          document.body.removeChild(container)
-          resolve()
-        } catch (error) {
-          root.unmount()
-          document.body.removeChild(container)
-          throw error
-        }
-      }, 50)
-    })
+      const renderedSvgs = container.querySelectorAll("svg")
+      expect(renderedSvgs.length).toBeGreaterThan(0)
+      const firstRenderedSvg = renderedSvgs[0]?.outerHTML
+      // Perform snapshot test
+      expect(firstRenderedSvg).toMatchSvgSnapshot(
+        import.meta.path,
+        "renderer-graphics",
+      )
+    } finally {
+      await act(async () => {
+        root.unmount()
+      })
+      document.body.removeChild(container)
+    }
   })
 })
diff --git a/tests/__snapshots__/getPngBufferFromGraphicsObject-rotated-rects.snap.png b/tests/__snapshots__/getPngBufferFromGraphicsObject-rotated-rects.snap.png
index 649912d..af8ca56 100644
Binary files a/tests/__snapshots__/getPngBufferFromGraphicsObject-rotated-rects.snap.png and b/tests/__snapshots__/getPngBufferFromGraphicsObject-rotated-rects.snap.png differ
diff --git a/tests/getCanvasObjectLabelAtPoint.test.ts b/tests/getCanvasObjectLabelAtPoint.test.ts
index 3d76894..92fb30b 100644
--- a/tests/getCanvasObjectLabelAtPoint.test.ts
+++ b/tests/getCanvasObjectLabelAtPoint.test.ts
@@ -109,7 +109,7 @@ describe("getCanvasObjectLabelAtPoint", () => {
       getCanvasObjectLabelAtPoint(graphics, identityMatrix, { x: 5, y: 5 }),
     ).toBe("Rotated rect")
     expect(
-      getCanvasObjectLabelAtPoint(graphics, identityMatrix, { x: 8, y: -8 }),
+      getCanvasObjectLabelAtPoint(graphics, identityMatrix, { x: 8, y: 8 }),
     ).toBeNull()
   })
 
diff --git a/tests/rectGeometry.test.ts b/tests/rectGeometry.test.ts
new file mode 100644
index 0000000..f34540c
--- /dev/null
+++ b/tests/rectGeometry.test.ts
@@ -0,0 +1,50 @@
+import { describe, expect, test } from "bun:test"
+import type { Matrix } from "transformation-matrix"
+import { getProjectedRectGeometry } from "../lib/rectGeometry"
+import type { Rect } from "../lib/types"
+
+const screenMatrix = {
+  a: 1,
+  b: 0,
+  c: 0,
+  d: 1,
+  e: 0,
+  f: 0,
+} as Matrix
+
+const cartesianMatrix = {
+  a: 1,
+  b: 0,
+  c: 0,
+  d: -1,
+  e: 0,
+  f: 0,
+} as Matrix
+
+describe("rectGeometry", () => {
+  test("renders positive ccwRotationDegrees as visually counterclockwise on screen transforms", () => {
+    const rect: Rect = {
+      center: { x: 0, y: 0 },
+      width: 10,
+      height: 4,
+      ccwRotationDegrees: 30,
+    }
+
+    const projected = getProjectedRectGeometry(rect, screenMatrix)
+    expect(projected.angleDegrees).toBeCloseTo(-30)
+    expect(projected.corners[1]!.y).toBeLessThan(projected.corners[0]!.y)
+  })
+
+  test("keeps positive ccwRotationDegrees visually counterclockwise with cartesian y-flip transforms", () => {
+    const rect: Rect = {
+      center: { x: 0, y: 0 },
+      width: 10,
+      height: 4,
+      ccwRotationDegrees: 30,
+    }
+
+    const projected = getProjectedRectGeometry(rect, cartesianMatrix)
+    expect(projected.angleDegrees).toBeCloseTo(-30)
+    expect(projected.corners[1]!.y).toBeLessThan(projected.corners[0]!.y)
+  })
+})