Re: [PATCH 1/2] font: Add font scaling feature to grub_font_draw_glyph()

[Zhang Boyang]

Hi,

In fact it is pretty "fast" because only the displayed glyphs are 
scaled. That's a very small subset of the whole font. It will be slower 
if we scale every glyph when loading the font. Also, the scale factor 
are hard to determine at font loading time, because the video driver may 
haven't been loaded at that time.

It is possible to cache the scaled glyphs, so only one scaling pass is 
needed for one glyph. But this will not change the computational 
complexity because the drawing algorithm itself is O(n) and scaling is 
also O(n). So I think we can optimize later if this simple-but-slow 
scaling code become performance bottleneck.


Best Regards,
Zhang Boyang


On 2022/5/31 19:36, Gerd Hoffmann wrote:
>    Hi,
>
> > +      /* FIXME: Scale bitmap pixel by pixel is slow */
>
> So how about doing the scaling when loading the font,
> so you have to do it only once?
>
> take care,
>    Gerd