On Apr 25, 2008, at 12:12 PM, David Duncan wrote:
On Apr 25, 2008, at 7:51 AM, Carter R. Harrison wrote:
This bug in my code has been driving me nuts for days, but I have
finally isolated the issue - only problem now is I don't understand
what I'm doing wrong.
I have a CGImage that I want to get the raw data bytes for. My
code is below:
CGImageRef sectionToCache =
CGImageCreateWithImageInRect(backingStore, CGRectMake(x, y, cx, cy));
NSLog(@"CGImage to cache has dimensions %d x %d and %d bytes per
row", CGImageGetWidth(sectionToCache),
CGImageGetHeight(sectionToCache),
CGImageGetBytesPerRow(sectionToCache));
CFDataRef dataRef =
CGDataProviderCopyData(CGImageGetDataProvider(sectionToCache));
NSLog(@"Length of cachedImage data: %d", CFDataGetLength(dataRef));
When the code runs, the log spits out the following:
CGImage to cache has dimensions 417 x 234 and 1668 bytes per row
Length of cachedImage data: 6672
What is killing me here is that the CGImage has dimensions 417x234
and 1668 bytes per row. That to me means that the CFDataRef that I
am obtaining should be 390,312 bytes (234 x 1668). But the
CFDataRef is only 6,672 bytes which is nowhere close to what I
think I should be getting. So I must be doing something wrong in
trying to get the bitmap data, but I'm not sure what else to do and
I even found some Apple docs with an example doing the exact same
thing that I am doing. Can anybody provide some insight on this?
Thanks everybody.
This seems to be related to the CGImageCreateWithImageInRect() call,
but I can't imagine why. CGDataProviderCopyData() seems to work
perfectly with an original image in my limited testing, so please
file a bug (and let me know what the bug number is).
Thanks David. The bug number is 5889934. For the time being I will
use the workaround provided by an earlier poster.
--
David Duncan
Apple DTS Animation and Printing
[EMAIL PROTECTED]
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