27551 - improve scalable font handling on X

Status: RESOLVED DUPLICATE of bug 74889

(Core :: Layout, defect, P3)

Description

[Erik van der Poel]

The following font properties might tell us whether the user is using a good
scaler that gives beautiful results. In that case, we might want to scale,
rather than using a bitmap font that is too large or too small.

  FONT_TYPE and RASTERIZER_NAME

Comment 1

[Erik van der Poel]

From: Juliusz Chroboczek <[e-mail]>
To: [e-mail]

The TrueType renderer known as ``xfsft'' generates FONT_TYPE
(``TrueType'').  It currently does not generate ``RASTERIZER_NAME'',
but I can add this if you wish.  As far as I know, no other renderer
currently generates these properties.

Comment 2

[Erik van der Poel]

From: Keith Packard <[e-mail]>
To: [e-mail]

XListFontsWithInfo would nominally be cheaper than XLoadQueryFont except
that XListFontsWithInfo returns bounding box information for the glyphs
in the font.  The only way to generate that accurately from scalable
fonts is to rasterize the entire font and see where the pixels fall.

So, if you think you might want to use a particular font, you should
just open it and throw it away if you don't like the rasterizer it used.

Comment 3

[Hixie (not reading bugmail)]

(this bug broke out of bug 13072)

Comment 4

[Erik van der Poel]

Prioritizing my bugs. This one is now M19.

Comment 5

[Frank Tang]

reassign this bug to bstell and mark it as M25. Add helpwanted keyword

Comment 6

[kill this account]

I found this bit:

http://www.xfree86.org/archives/fonts/2000-Feb/0012.shtml
>     There's a trick for this that works well with commonly available X 
>     servers, though it probably has no theoretical justification. 
>     Scaleable fonts returned by XListFonts (0 point and pixel size) that 
>     are just scaled bitmaps have non-0 X and Y resolution fields, while 
>     true scaleable fonts have 0 in those fields. 
> 
>     The GTK+ font selector uses this technique, and I haven't heard 
>     of any complaints about it failing there. 
> 
>     Regards, 
>                                             Owen 

Comment 7

[kill this account]

http://www.XFree86.org/FAQ/#BitmapFontScaling
> Q.E1- How do I get the server to scale vector fonts, but not bitmap fonts?
> 
> In standard X11R6 (and later), in addition to the fonts in "scalable" formats
>  (i.e. Type1, Speedo), bitmap fonts are scaled. This can have the undesirable
> effect of scaling a bitmap font, even though a Type1 font is available (if 
> the bitmap font is listed first in the path). 
> 
> With the 3.2 and later releases of XFree86, you can add the text :unscaled to 
> the end of any directory in the font path to turn off scaling of the bitmap 
> fonts in that directory. This works in both the XF86Config file and the font 
> server's config file. 

Comment 8

[kill this account]

fix for bug 74889 include test for bitmap scaled font

*** This bug has been marked as a duplicate of 74889 ***