- left = x - window.screen.width * kSensorSize;
- top = y - window.screen.height * kSensorSize;
- right = x + window.screen.width * kSensorSize;
- bottom = y + window.screen.height * kSensorSize;
+ left = $canvas.x - window.screen.width * kSensorSize;
+ top = $canvas.y - window.screen.height * kSensorSize;
+ right = $canvas.x + window.screen.width * kSensorSize;
+ bottom = $canvas.y + window.screen.height * kSensorSize;