Re: Rendering grayscale on opengl using nsbitmaprep

[Fred Kiefer]

Thank you very much for the example. As this reproduces the issue on
your machine without any GL code, I was off with my comments. Sorry for
that. Saturday I was ill, so I stopped coding for GNUstep but thought
that my code review skills would still work. I was wrong.

Now, as for the test, it works perfectly on my machine. See attached
screen shot. This means we must have some differences between our
computers. Could you please provide some details of your setup?
Processor, Operation System and the used GNUstep backend (xlib, art or
cairo)? Perhaps also the version of your tiff library.

There haven't been a lot of changes in the tiff handling of GNUstep gui.
Wolfgang Lux fixed a bug about two months ago, but this only affected
cases where the bits per sample != 8. This isn't the case here after the
conversion.

Fred


Am 27.02.2011 17:28, schrieb AN Indie:
>  I accept their is mismatch between parameter/arguments. But this code
> just works!
> [
>  But good news is, I was able to reproduce the bug in package
> gnustep-examples-1.2.0
> 
> I modified NSImage test case a little and  reproduced this bug!!
> 
> 
> I changed
> 
> 
> image = [[NSImage alloc] initWithContentsOfFile: file ];
> [mview setImage: image];
> 
> with
> 
> 
> image = [[NSImage alloc] initWithContentsOfFile: file ];
> NSImage  * aximage =  [[NSImage alloc] initWithData:[image
> TIFFRepresentationUsingCompression:NSTIFFCompressionNone factor:0]];
> [mview setImage: aximage];
> 
> An now  the gray scale image is not renders properly.
> 
> 
> I attached test case along with this mail. Please confirm with latest
> GNUstep as I am using the older version.
> 
> -Thanks
> AN Indie
> 
> On Sat, 26 Feb 2011 01:21:36 +0530, Fred Kiefer <fredkiefer@gmx.de> wrote:
>> Now having had a short look at your code I am almost sure that my
>> initial suspicion is correct. You first convert a grey scale image into
>> an RGB one, that step should work. Next you copy the data of this
>> converted bitmap into a large data structure where you extended width
>> and height to the next power of two. Here you have to copy over each row
>> separately. (You could save that step by supplying a corresponding
>> bytesPerRow value into the conversion.) Then you call your
>> initWithData:... method and hand over an unpackRowLength you computed
>> from the original data. But you don't use that value instead you use the
>> rounded up width (Line 524).
>>
>> Not that I understand any of the stuff that goes on in this method, but
>> I am very sure that this is the cause of your trouble.
>>
>> Cheers
>> Fred
>>
>>
>> Am 25.02.2011 19:15, schrieb AN Indie:
>>> On Wed, 23 Feb 2011 15:22:09 +0530, Fred Kiefer <fredkiefer@gmx.de>
>>> wrote:
>>>
>>> Sure. I always worried that, it may off the topic here.
>>> Code is already hosted on internet. It is hosted in a public git
>>> repository at github(https://github.com/ANindie/cocos2d-GNUstep).
>>>
>>> You can take a quick look on problematic code at
>>> https://github.com/ANindie/cocos2d-GNUstep/blob/85c5097047126107ef225b9025e972b97e60335d/src/cocostep/CCTexture2D.m.
>>>
>>>
>>>
>>> I included th code you pointed here. Also added test case at
>>> https://github.com/ANindie/cocos2d-GNUstep/blob/85c5097047126107ef225b9025e972b97e60335d/src/tests/BasicSpriteTest/BasicSprite.m
>>>
>>>
>>>
>>> -Thanks
>>> Indie AN
>>>
>>>
>>>
>>>
>>>> Thank you, with that explanation I finally understand where you trying
>>>> to get to. And the code that I pointed you to should work quite well
>>>> for
>>>> that purpose. My feeling is still that your code that is calling this
>>>> has a problem. If you want you can send me the code off line and I have
>>>> a quick look at what may go wrong here.
>>>>
>>>> Fred
>>>>
>>>> Am 23.02.2011 05:21, schrieb Indie AN:
>>>>> Ok. Let me clear it for once. I am trying to render image using
>>>>> opengl, that we normally do for games. Opengl do not speak nsimage.
>>>>> They speak textures . All i needed is magic piece of code that
>>>>> converts every image to raw rbga or rbg data. In mac they do using
>>>>> coreimage framework.         But its ok. I can live happily without
>>>>> gray scale images. White image is sufficient.  Thanks to everybodies
>>>>> time.
>>>>>
>>>>> On 2/16/11, Fred Kiefer <fredkiefer@gmx.de> wrote:
>>>>>> Sorry, I still don't understand your problem. Why are you converting
>>>>>> the
>>>>>> image? The standard code should work fine in displaying it. Actually
>>>>>> the
>>>>>> code I pointed you to is used for that.
>>>>>> From your screen shot I would expect that your drawing code uses the
>>>>>> wrong sizes. To verify this it would help if you sent a bit more of
>>>>>> your
>>>>>> code.
>>>>>>
>>>>>> Fred
>>>>>>
>>>>>> PS: For drawing pre-multiplied images get used. Better convert in to
>>>>>> that format. But this is completely unrelated to your problem.

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