Fix drawing semi-transparent windows in double buffering mode

JetBrains · Mar 22, 2022 · bce0735 · bce0735
1 parent 250177d
commit bce0735
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/.../org/jetbrains/projector/client/common/canvas/buffering/DoubleBufferedRenderingSurface.kt b/.../org/jetbrains/projector/client/common/canvas/buffering/DoubleBufferedRenderingSurface.kt
@@ -49,7 +49,11 @@ class DoubleBufferedRenderingSurface(bufferCanvasFactory: CanvasFactory, private
     // optimization: flush only if the buffer is changed
     if (buffer.changed) {
       buffer.resetChanged()
-      target.context2d.drawImage(buffer.imageSource, 0.0, 0.0)
+      target.context2d.apply {
+        // clear canvas so that semi-transparent parts won't stack on top of each other
+        clearRect(0.0, 0.0, buffer.width.toDouble(), buffer.height.toDouble())
+        drawImage(buffer.imageSource, 0.0, 0.0)
+      }
     }
   }