Re: TIFFRepresentation, different TIFF format under Snow Leopard
Re: TIFFRepresentation, different TIFF format under Snow Leopard
- Subject: Re: TIFFRepresentation, different TIFF format under Snow Leopard
- From: Ken Ferry <email@hidden>
- Date: Mon, 12 Oct 2009 08:07:31 -0700
On Mon, Oct 12, 2009 at 4:36 AM, Peter C <email@hidden> wrote:
> I just stumble into a feature (or a bug ?), NSImage TIFFRepresentation
> produce RGB TIFF with a layer (when open under Photoshop). Previously it
> produce plain RGB TIFF under OS 10.5 and below. This cause some part of my
> programs interpret wrong RGB data, expecting 3 bytes instead of 4 bytes for
> a RGB pixel. There is no mention in the documents about this "feature".
>
> Is there a way to restore the previous behavior of TIFFRepresentation ?
You can look at CGImageDestination to get more options, but I don't think
there's anything that provides control at that level.
In many cases there _must_ be data munging between the in memory pixel
format and the on-disk file format. The precise munging is not defined on
either input or output.
That is, don't make pixel format assumptions. The AppKit release
notes<http://developer.apple.com/mac/library/releasenotes/Cocoa/AppKit.html>discuss
how to avoid making pixel format assumptions in the section
"NSBitmapImageRep: CoreGraphics impedence matching and performance notes".
-Ken
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden