[poppler] [PATCH] initial clean poppler-qt implementation
krh at bitplanet.net
Fri Apr 1 14:09:34 PST 2005
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
> 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...
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