Re: Optimized pixel manipulation
Re: Optimized pixel manipulation
- Subject: Re: Optimized pixel manipulation
- From: Jean-Daniel Dupas <email@hidden>
- Date: Wed, 8 Oct 2008 19:00:25 +0200
How do you create your bitmap context ?
AFAK, to create a bitmap context, you should use
CGBitmapContextCreate() that take as first argument the image backing
store.
So you already have it.
The other way I know, is the create an NSBitmapImageRep, and then
using it to create an NSGraphicsContext. NSBitmapImageRep as a
bitmapData method that returns it's buffer.
Le 8 oct. 08 à 18:26, Christian Giordano a écrit :
If you've created a bitmap context, then you should already own the
backing
bitmap data buffer. You can just manipulate it directly without
making a
copy (via a CGImage).
How could I access its buffer?
Cheers, chr
On Wed, Oct 8, 2008 at 5:21 PM, Ken Thomases <email@hidden>
wrote:
On Oct 8, 2008, at 11:02 AM, Christian Giordano wrote:
After drawing the shapes, I do pixel operations, of course.
Are these pixel operations not something which can be accomplished by
changing the way you draw, for example using compositing modes?
Alternatively, do you have access to Core Image and does it do what
you
need? Another thing to look at might be vImage.
For this
reason I create a bitmap context and after the drawing I get the
CGImageRef generated, I copy the pixels, I modify the pixels and
then
I create a new image
Cheers,
Ken
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