Can't show the tabbar icon, even with size 30*30

I prepared some PNG icons, size 30*30, but with colors, not only black/white. The icons are OK when 开发者_StackOverflowI want to display them on buttons.

It can't be shown in the tabbar. I am wondering if the iphone only supports some simple icons (the black/white icons with lines).

Do you have any ideas?

Thanks in advance. Michael

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TabBar icons displayed in gray scale even if they are color, and iPhone uses the alpha channel for masking.

I recommend checking this site, most iPhone developers like it :

http://www.glyphish.com/

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The alpha component of the image is all that is used to draw the icon on the tab bar. So you need to make sure your image has a alpha channel or it will either not show up or show up as a blank square in the tab bar.

This does mean that effectively only monochrome images can be used in the tab bar.

I'm not at my mac right now and I can't remember if it is 1.0 alpha or 0.0 alpha that shows up as white in the tab bar, or if you need to have a black or white background, but if you create an image with varying transparency it should be easy enough to work out.