Re: Drawing an image as hilighted?
Re: Drawing an image as hilighted?
- Subject: Re: Drawing an image as hilighted?
- From: Ricky Sharp <email@hidden>
- Date: Sun, 4 Sep 2005 19:08:35 -0500
On Sep 4, 2005, at 3:57 PM, Stéphane Sudre wrote:
Colin Cornaby wrote:
Is there any Apple supplied code to draw an image as hilighted?
For example, the way an image hilights when it's clicked in
iPhoto's bottom toolbar (I know they're buttons which have that
functionality built in, but I'm not using buttons).
If by highlighting, you mean darkened, it's quite easy to achieve
IIRC.
- create a new NSImage the size of your image
- lock the new image
- draw your image
- draw a black rectangle with a specific alpha alpha value (0.33f
maybe but YMMV)
- unlock the new image
And then you have your highlighted image.
Or, if you don't want to make the alternate image, render the image
followed by something like this:
[[[NSColor blackColor] colorWithAlphaComponent:0.33] set];
NSRectFillUsingOperation (theRect, NSCompositeSourceOver);
As Stéphane mentioned, try different alpha values. You may also want
to try different colors and composite modes. I think the above two
approaches may apply shading in any areas of your image that are
completely transparent.
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Ricky A. Sharp mailto:email@hidden
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