@Asperamanca No, I didn't set these two flags ItemClipsToShape, ItemClipsChildrenToShape. Then I tried setting only one flag ItemClipsToShape, and both of ItemClipsToShape, ItemClipsChildrenToShape. For each, it still check if the point is in the boundingrect() firstly, and then check the shape() which means if point is not in boundingrect(), it wouldn't bother to check shape(). So now my solution is still enlarging the boundingrect() area.

Check the "Canvas element" in the Qt5_cadaques book: http://qmlbook.github.io/en/ch07/index.html

Hii.. Sorry to disturb you but if you are free then please give me answer of below question https://forum.qt.io/topic/60399/adobe-photoshop-cc-2015-plugin I am newbie to this Qt framework.