POV-Ray : Newsgroups : povray.binaries.images : Using "transmit all" with an image map : Re: Using "transmit all" with an image map Server Time
4 Feb 2023 00:43:38 EST (-0500)
  Re: Using "transmit all" with an image map  
From: Le Forgeron
Date: 29 Dec 2022 07:22:59
Message: <63ad86a3$1@news.povray.org>
Le 28/12/2022 à 22:42, Dave Blandston a écrit :
> Alain Martel <kua### [at] videotronca> wrote:
>> First, in this case, you don't need to use transmit all.
>> transmit all intent is to give transparency to an image that have NO
>> alpha channel. It makes a picture with NO transparency transparent.
>>
>> Try the same, but without transmit all.
> 
> 
> 
> Unfortunately, that generates an error message "Keyword 'transmit' cannot be
> used with non color-mapped image."
> 
> I'm currently using a workaround, which is to apply the transparency with a
> paint program. Since this is for an animation though, it means preparing many
> images with varying transparency instead of one image that "transmit" can be
> applied to.
> 

color mapped images are image with a palette, not true/direct color.

For example, gif is always palette mapped, whereas jpeg is not.
Png is variable: it could have a palette or not.
("indexed": there is a palette; grayscale & truecolor: no palette)

This has nothing to do with transparency channel;
Gif can have it, png too, but I have never seen jpeg with it.

Alain suggested to not use "transmit all" for that picture, but to have 
the transparency directly from the picture. (without any modifier)

You would edit first the transparency in your favorite editor and voilà.


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