Re: Alpha info from NSBitmapImageRep?
Re: Alpha info from NSBitmapImageRep?
- Subject: Re: Alpha info from NSBitmapImageRep?
- From: j o a r <email@hidden>
- Date: Fri, 28 Sep 2001 03:15:51 +0200
On Friday, September 28, 2001, at 03:04 , Andrew Platzer wrote:
I'm missing a [myBitmap imageAlpha] method in NSBitmapImageRep...
Do you mean [myBitmap hasAlpha]?
- (BOOL)hasAlpha is defined in NSImageRep.h
It's something, but it doesn't help me to decide which of these to use:
kCGImageAlphaNone,
kCGImageAlphaPremultipliedLast, /* For example, premultiplied
RGBA */
kCGImageAlphaPremultipliedFirst, /* For example, premultiplied
ARGB */
kCGImageAlphaLast, /* For example, non-premultiplied
RGBA */
kCGImageAlphaFirst, /* For example, non-premultiplied
ARGB */
kCGImageAlphaNoneSkipLast, /* Equivalent to
kCGImageAlphaNone. */
kCGImageAlphaNoneSkipFirst
A YES from hasAlpha doesn't tell me where that alpha channel is at -
first or last, premultiplied or not. A NO is defenitely useful though,
since then I can use kCGImageAlphaNone.
j o a r