From: Kai Ma <justksqsf@gmail.com>
To: Po Lu <luangruo@yahoo.com>
Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
Subject: Re: Text shadows
Date: Sun, 12 Mar 2023 17:23:40 +0800 [thread overview]
Message-ID: <795E6DF6-EC17-4E68-B8A7-A99E81B072C7@gmail.com> (raw)
In-Reply-To: <87356acq6a.fsf@yahoo.com>
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> On Mar 12, 2023, at 16:46, Po Lu <luangruo@yahoo.com> wrote:
>> Theoretically, nothing. I targeted Cairo because (I think) it is the most popular option on GNU/Linux.
>>
>> Speaking of this specific implementation, gaussian_blur() relies on a specific Cairo image format ARGB32, (this assumption could be easily removed), and then it is used by ftcrfont_draw() to generate shadows.
>>
>> I don’t know whether non-Cairo builds (non-cairo X, win32) can/should use gaussian_blur() though, since I’m not familiar with them.
>
> Non-Cairo builds and Cairo builds alike should use the X Rendering
> Extension, where an arbitrary blur kernel is a standard picture filter.
> Cairo builds on X should as well.
I agree XRender should be used for non-Cairo X builds (when XRender is available).
But it’s probably not a good idea to use XRender on X+Cairo. In this setting, cairo_show_glyphs is used to draw glyphs, but Cairo does not expose any interface to the underlying Picture object. So it would require additional memory copies between X and Cairo just for blurring. I guess it would be slower as the image to blur is usually small. I will do the benchmarks once I get XRender blurring working.
> P.S: the GNU project rejects the Unix convention that `foo()' refers to
> the function `foo': `foo()' is a function declarator that returns int
> and takes any number of arguments, or alternatively a function call to
> `foo' with no arguments.
Point taken.
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next prev parent reply other threads:[~2023-03-12 9:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-12 4:06 Text shadows Kai Ma
2023-03-12 4:18 ` Kai Ma
2023-03-12 7:12 ` Eli Zaretskii
2023-03-12 8:24 ` Kai Ma
2023-03-12 8:46 ` Po Lu
2023-03-12 9:23 ` Kai Ma [this message]
2023-03-12 10:33 ` Po Lu
2023-03-12 9:14 ` Eli Zaretskii
2023-03-12 9:55 ` Kai Ma
2023-03-12 11:33 ` Eli Zaretskii
2023-03-12 11:49 ` Kai Ma
2023-03-12 12:36 ` Eli Zaretskii
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