[poppler] color inversion for a mask image

[Ihar `Philips` Filipau]

Nope. Not it.

I have tested it against the Splash: SplashOutputDev displays the
image as it should be, HtmlOutputDev - not. In both cases, the Decode
array indicates no inversion (and drawImageMask() is called with
invert=false). There is something else in the GfxState which affects
how the mask is painted.

After looking at the Splash code which does it right, and imagining
potential reimplementation say half of it in HtmlOutputDev, honestly,
I'd rather live with the pdftohtml occasionally writing a monochrome
image inverted. (ImageMagick's `convert -negate` does the job.)

If the GfxState/etc had some sort of a way to dump the state - with
some human explanations :) - so that it could be investigated with
naked eyes, I might have tried to find it. But as it is, since I'm
doing it on my spare time, it is pretty much unrealistic for me to
find it. And for just one image - totally pointless, I have to admit.

But thanks for your help anyway!

P.S. Have tried couple of pdf2* alternatives - the same behavior.
poppler's pdfimages likewise doesn't invert the image.

On 3/29/12, Leonard Rosenthol <lrosenth at adobe.com> wrote:
> I can't speak to the Gfxstate, but there are keys in the image dictionary
> (such as Decode) that relate to inversion.
>
> Leonard
>
> On 3/29/12 2:09 AM, "Ihar `Philips` Filipau" <thephilips at gmail.com> wrote:
>
>>Hi All!
>>
>>I have encountered minor yet interesting problem. With the
>>functionality I have recently added to pdftohtml, now also the mask
>>images are extracted (as PNGs).
>>
>>In one document I have, one mask image is extracted with colors
>>inverted: white is black, black is white. Yet, it is displayed by all
>>the PDF viewers correctly.
>>
>>Is there any flag/etc in GfxState/etc which might be responsible for
>>color inversion? the flag pdftohtml doesn't check yet?
>>
>>Thanks.
>>_______________________________________________
>>poppler mailing list
>>poppler at lists.freedesktop.org
>>http://lists.freedesktop.org/mailman/listinfo/poppler
>
>


-- 
Don't walk behind me, I may not lead.
Don't walk in front of me, I may not follow.
Just walk beside me and be my friend.
    -- Albert Camus (attributed to)