Recognizing text

I'm using VNImageRequestHandler to recognize text using the camera. In my handler I'm using the topLeft, topRight, bottomLeft, bottomRight properties, which I'm scaling to the size of the canvas, to draw an outline around each text object. When I do this the Y position and Height are correct, but the Width is slightly smaller, and the X position centers the outline around the text. Any idea why this would be a different size?