currently i'm working on simple image editor can brush alter alpha channel.
my problem is, when uiimageview 0 or near 0 alpha image presented on uiview, has dark color (like brown, black, etc), strange composition appears. image becomes visible alpha has never been changed. when uiview white, normal.
you'll want "keep white" i'm using uiview background canvas , user has ability change color.
the captures took reveal, appearance same on device well. here mean talk:
this image 20% alpha set it's pixels. image looks ok. reveal, can see image has correct alpha channel. everyting should be.
here same image 15% alpha on darker blue background (sorry, while capturing changed alpha). reveal, again looking normal.
but when @ device, see. same uiimage 15% alpha set pixels , presented in uiimageview.
the image appearing on background dark blue uiview, alpha not 15%. changing alpha when working on dark background has not effect. adds blue over, or 100% alpha returns original image. when setting alpha of pixels 0, image visible.
is there i'm missing? why composition (or blending of 2 uiview objects) error/bug/problem appearing? there value forgetting set? or normal , doing wrong?
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