"song ti" and other bitmap fonts are not available even with `yes-bitmaps' applied

Binary package hint: fontconfig

Having 70-yes-bitmaps.conf replacing 70-no-bitmaps.conf in /etc/fonts/conf.d/ does not make available all bitmap fonts. Reproduce:

1) have 70-yes-bitmaps.conf set;
2) some bitmap fonts in /usr/share/fonts/X11/misc are then available in fc-list. Some others are not.

Example of those are available on both xlsfont and fc-list:
/usr/share/fonts/X11/misc/unifont.pcf.gz in xfonts-unifont package
    xlsfont says

    -gnu-unifont-medium-r-normal--0-0-75-75-c-0-iso10646-1
    -gnu-unifont-medium-r-normal--16-160-75-75-c-80-iso10646-1
    -unifoundry.com-gnu unifont-medium-r-normal--0-0-0-0-p-0-iso10646-1

    fc-list says:

    unifont.pcf:style=Regular
    unifont:style=Medium

Example of those are available on xlsfont but not on fc-list:
/usr/share/fonts/X11/misc/gb16st.pcf.gz in xfonts-base package.
    xlsfont says:

    -isas-song ti-medium-r-normal--0-0-72-72-c-0-gb2312.1980-0
    -isas-song ti-medium-r-normal--16-160-72-72-c-160-gb2312.1980-0
    -isas-song ti-medium-r-normal--24-240-72-72-c-240-gb2312.1980-0

    the font is not in fc-list.

Rationate why we need to make bitmap font available:
+------
| It should not happen that the system asks users to use scalable font instead of bitmap font
| when there is no scalable font replacement available.
+------

In the west there are san-serif, serif as main typefaces, each have an italic typefaces. These can be said of basic typefaces. The four basic typefaces in Chinese typography are:

- Song ti:
    two varients:
    low contrast "book" varient: scalable offered by ttf-arphic-uming package.
    heavy contrast title / strong varient: NO SCALABLE available, xfonts-base offer a bitmap one: "Song Ti"
- Kaiti. scalable offered by ttf-arphic-ukai package.
- Fangsong ti. NO SCALABLE available, xfonts-base offer a bitmap one.
- HeiTi. scalable offered by ttf-droid package.

The four-basics all have scalable versions in MS Windows since 95'.

As you can see some basic things only have bitmap version so far, in Ubuntu packages. It should not be too difficult to make them work.