I have to create a very simple GUI for an iPad application.
I have a 1024x768 png and I want to use this file for the GUI. I have to make an area of this png tappable and able to run some action. This area is not a rectangle (it's a trapezoid) so I can't create a button. Is it possible somehow?
you can do it in code by overriding - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
and - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
in the view that's displaying the image. that'll mean you have to decide whether a point is within the touch area of the image.
Make a UIImageView that displays an image which shows the trapezoid and is otherwise transparent.
Turn on the UIImageView's userInteractionEnabled
to make it tappable.
Put a UITapGestureRecognizer on the UIImageView to respond to the tap.
In the tap gesture recognizer's action handler, respond only if the point where the user tapped is non-transparent. To learn whether the point the user touched is transparent, see Retrieving a pixel alpha value for a UIImage .
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