# [NTG-context] Rendering differences between PDF viewers

Peter Rolf indiego at gmx.net
Tue Apr 24 15:37:51 CEST 2012

Am 24.04.2012 14:42, schrieb Hans Hagen:
> On 20-4-2012 09:50, Peter Rolf wrote:
>> Am 19.04.2012 20:25, schrieb Hans Hagen:
>>> On 18-4-2012 13:12, Peter Rolf wrote:
>>>
>>>> I understand that there is no easy or general solution for this.
>>>> But on the other hand is PNG currently the only way to use transparent
>>>> bitmaps in TeX. The usage of transparent PNG is quite common, so
>>>> this is
>>>> a general problem that should be solved.
>>>>
>>>> I like your idea of automatically adding such groups, if the user
>>>> declares the color space beforehand. Also no answer for the spot color
>>>> problem, but as long as the user does not limit the used color spaces,
>>>> things can stay as they are. Just my 2 cents.
>>>
>>> so first wen need to test with mixed color space documents and such
>>> hacks to see what happens (as we don't want invalid documents)
>>>
>>
>> ok. i don't expect any formal problems, only more or less ugly color
>> shifts. anyhow, we will see.
>>
>> needs some thinking about proper examples (colored text, vector and
>> pixel based graphics in RGB,CMYK,Spot)...
>> i think 'draw ColorCircle(..)' is a perfect candidate for the complete
>> graphic part. one page with transparency and also one page without any
>> transparency (the page group shouldn't kick in). later on we can add
>> some icc profiles to spice things up.
>>
>> i'll start to make a test document on the weekend then. if i have missed
>> something important, let me know. any additional ideas are also
>> welcome :-)
>
> as a prelude, the next beta will have
>
> \setupcolors[pagecolormodel=rgb] % gray rgb cmyk auto none
>
> and issue a warning when no model is set when using transparencies
>

nice. a test document with mixed color spaces is also in work and should
be ready in a few days.

Peter