Hi,
trying to debug certain stuff in PRICE, I found out that a certain
assumption I made is perhaps not true or only conditionally true. I'm
investigating on Mac 10.4, not yet on GNUstep, so this is not a bug, I
ask what to do best.
In PRICE all filters need to access the "raw data", that is, they
manipulates pixesl directly or even their components. To do that, I need
to access the data in the NSBitmapImageRep.
NSImages are allocated in the standard way, by opening TIFFS or jpegs.
What I always did is get the first representation of the representation.
It has always been an NSBitmaImageRep and it is very fast, it is already
there.
I had the suspect that this assumption was fragile and only found in
quick examples, although it always worked for TIFF or JPEGS or PNGs.
However I have a consistent way of proving it wrong: Open a 16bit depth
image on Mac. Be it grayscale or RGB. What happens is:
- after loading I have an NSimage, with a single 16-bit depth bitmap rep
with either 1 or 3 samples (that is, 16bit or 48bit)
- as soon as i want tor un the filter, the only representation present
is a CachedImageRep, which is unsuitable for my purpose, it is the image
used for rendering to the screen. Pixel size changed and most notably,
it is an 8bit image, it can even be a color image instead of a grayscale
image
I understand I can have more representations, I expected to find BOTH
the cached representation but also he original image. How can I get the
original image data, as I had after opening the file? Instead I end
having only the screen representation, this confuses me.
Perhaps by playing with the cache use options?
Riccardo
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