[cairo] Re: [poppler] Re: poppler profiling on geode with cairo backend

[Carl Worth]

[I'm taking this conversation over to the cairo list---please drop the
poppler list if you reply.]

On Wed, 8 Nov 2006 21:51:36 -0500, Jeff Muizelaar wrote:
> So I had a look at why pixman_compositeGeneral is being hit during text
> rendering. It looks like this gets called for text when the document is
> being rendered at weird scaling factors.

The short answer is that any time compositeGeneral is called there's a
bug somewhere. (That function is so slow, we know we never want to use
it).

> For example with the pdf you provided: calling
>   poppler_page_render_to_pixbuf(..., scale=1.0, ...)
> does not trigger any calls to pixman_compositeGeneral.
...
> However,
>   poppler_page_render_to_pixbuf(..., scale=0.5, ...)
> does.
...
> I will follow up with the cairo people about why this happens and if
> anything can be done to improve the situation. In the mean time it may
> be possible to work around the problem by avoiding bad scaling factors.

That looks really odd to me. In general, text should be rendered
through the same code paths whether or not there is scaling in the CTM
I would think.

If you can construct a pretty small test case demonstrating this
behavior then that would be useful.

Thanks in advance,

-Carl
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