[BUG] GIFReadWriter - degradation on writing

tblanchard at mac.com tblanchard at mac.com
Thu Aug 7 21:31:59 UTC 2003


Is this still likely to be true if the ColorForm reports its depth as 8 
anyhow?
Because that's what happens - the gif imports to an 8 bit ColorForm.

On Thursday, August 7, 2003, at 03:10  PM, Andreas Raab wrote:

> Interesting. That's a bug. GIFReadWriter tries to reduce the color 
> count of
> the image being written (e.g., when you write form > 8bpp) and 
> apparently
> that's broken for ColorForm. It's not quite clear how to fix this 
> though. We
> either need to find out what breaks in colorReduced and/or simply 
> disable
> the call in GIFReadWriter for forms <= 8bpp.
>
> Cheers,
>   - Andreas
>
>> -----Original Message-----
>> From: squeak-dev-bounces at lists.squeakfoundation.org
>> [mailto:squeak-dev-bounces at lists.squeakfoundation.org] On
>> Behalf Of tblanchard at mac.com
>> Sent: Thursday, August 07, 2003 10:19 PM
>> To: The general-purpose Squeak developers list
>> Subject: Re: [BUG] GIFReadWriter - degradation on writing
>>
>>
>>
>> On Thursday, August 7, 2003, at 02:09  PM, Ned Konz wrote:
>>
>>> On Thursday 07 August 2003 12:44 pm, tblanchard at mac.com wrote:
>>>> I don't know a whole lot about image file formats but I've noticed
>>>> that gifs written with GIFReadWriter end up looking worse than when
>>>> they were read.  The (hopefully still) attached image illustrates
>>>> the problem.
>>>
>>> How did the images look in Squeak?
>>
>> Fine.  Only on writing did it get ragged.
>>
>>> You attached a PDF, not a GIF.
>>
>> Yes, that's what OS X uses as its screen capture format.  If you view
>> it full size, you can see from left to right the original image, the
>> written back ragged image, and the view of the image in squeak.  (I
>> overlaid the windows to get that shot) It definitely gets worse on
>> writing.
>>
>>> And I'm not sure what it was, or how you made it, or what you don't
>>> like about it, or what it looked like originally.
>>
>> OK, again - the middle one's characters look much more
>> pixellated than
>> either the original gif (on the left) or the squeak rendering of the
>> gif (on the right).
>>
>>> Can you attach "before" and "after" gifs?
>>
>> Yes - one is clearly (on my screen anyhow) smoother looking than the
>> other.
>>
>>
>
>



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