The checker bg should not be part of an image. this can be seen if you choose Rotate - All Layers and the checker background rotates too. When you click ok the bg is drawn properly again. This also happens with scale - All Layers.
In the code it is because the 'rendered image' has the bg drawn as the bottom layer. it would make the tool nicer both for users and for codeing features if the bg was not drawn in the image.
for example when saving ArtPaint has to draw the image without the bg, save the image, and re-draw it with the checker bg again.
The checker bg should not be part of an image. this can be seen if you choose Rotate - All Layers and the checker background rotates too. When you click ok the bg is drawn properly again. This also happens with scale - All Layers.
In the code it is because the 'rendered image' has the bg drawn as the bottom layer. it would make the tool nicer both for users and for codeing features if the bg was not drawn in the image.
for example when saving ArtPaint has to draw the image without the bg, save the image, and re-draw it with the checker bg again.