Apple

On Nov 18, 2008, at 12:19 PM, Darrin Cardani wrote:

On Nov 18, 2008, at 8:22 AM, Stonewall Ballard wrote:

How did it happen that Motion's ARGB 32-bit float pixels are a format that Quartz won't process? I'm more surprised that Quartz requires 32-bit float pixels to be in RGBA format, but this precludes using Quartz to process and draw on Motion's float FxBitmaps.

Or am I missing something?

It happened because a) Motion doesn't make any direct use of Quartz (at least that I know of), and b) we wanted developers to be able to reuse their After Effects plugin code in their FxPlugs. (I know it's not always possible, but it's at least sometimes possible.)

Can't you tell Quartz what order your pixel values are in? For example, if you call CGBitmapContextCreate (), you could pass any of these constants as the CGBitmapInfo parameter:

enum CGImageAlphaInfo {
kCGImageAlphaNone, /* For example, RGB. */
kCGImageAlphaPremultipliedLast, /* For example, premultiplied RGBA */
kCGImageAlphaPremultipliedFirst, /* For example, premultiplied ARGB */
kCGImageAlphaLast, /* For example, non-premultiplied RGBA */
kCGImageAlphaFirst, /* For example, non-premultiplied ARGB */
kCGImageAlphaNoneSkipLast, /* For example, RBGX. */
kCGImageAlphaNoneSkipFirst, /* For example, XRGB. */
kCGImageAlphaOnly /* No color data, alpha data only */
};
typedef enum CGImageAlphaInfo CGImageAlphaInfo;

So you'd probably want kCGImageAlphaPremultipliedFirst, I believe. Or did you try that and it didn't work?

Darrin

References:
	>Quartz vs Motion float pixels (From: Stonewall Ballard <email@hidden>)
	>Re: Quartz vs Motion float pixels (From: Darrin Cardani <email@hidden>)