[poppler] [PATCH] initial clean poppler-qt implementation

[Kristian Høgsberg]

Leonard Rosenthol wrote:
> At 04:08 PM 4/1/2005, Kristian Høgsberg wrote:
> 
>>>  - We have an option to draw with paperColor different than wait so 
>>> either we need a QColor parameter to renderToPixmap or a 
>>> setPaperColor(QColor c) operation
>>
>>
>> Oh... hmm... is this really useful?  Do you have that option in kpdf? 
>> The PDF spec says that the drawing is expected to be composited 
>> against a white background.
> 
> 
>         I don't believe that to be the case (that the spec says anything 
> about background).   Can you site the reference?

PDF 1.6 second to last paragraph in section 7.1:

"The notion of current page is generalized to refer to a transparency 
group consisting of the entire stack of objects placed on the page, 
composited with a backdrop that is pure white and fully opaque. 
Logically, this entire stack is then rasterized to determine the actual 
pixel values to be transmitted to the output device."

But I didn't mention it as a definitive argument that we don't want to 
provide this option.  Other requirements in the PDF spec may be worth 
sidestepping, for example, anti aliased rendering seems to be against 
the spec.

>         And yes, it is useful - because when doing compositing to a 
> SlashBitmap with alpha, you may want to have the default alpha be 1 
> (transparent) if you are planning to composite the PDF on top of 
> somethign else.

Maybe what we should do then is just to default to transparent background...

cheers,
Kristian