Canvas resize

1. Origin coordinate - The coordinate of the top left corner of the new canvas respectively to the current one which has the origin at (0, 0)

2. New size

3. Quick position button - Use these to quickly align the current canvas with the new one

4. Drag nodes - We can also drag these nodes to adjust the size and origin of the new canvas besides entering the numbers at #1 and #2

5. Rescale content - Also resize the canvas content to the new size

6. Lock aspect ratio - Keep the width/height ratio while resizing the canvas

Because canvas resizing is not undoable, we can turn off auto-save before resizing, if the result isn't what we want, we can simply exit the file to revert it back to the original size.