old-www/HOWTO/text/X-Big-Cursor

272 lines
9.3 KiB
Plaintext

X11-big-cursor MINIHOWTO
How to use enlarged mouse cursors with the X window system
Jörg Schneider <mailto:joerg.schneider@ira.uka.de>
v2, 11 August 1997
This document describes how to use enlarged mouse cursors with the X
window system.
______________________________________________________________________
Table of Contents
1. Introduction
2. About this document
3. How to do it
4. Notes and limitations
5. Technical discussion
6. Other ideas how to make the mouse cursor more visible
7. Related info
7.1 How to use a font server
7.1.1 Setting up a font server
7.2 How to get the bdf source for some font
______________________________________________________________________
1. Introduction
There are several reasons why the standard X mouse cursors are hard to
track for some people:
· when running X on a notebook with low contrast LCD
· on normal screens when using high resolution, 1600x1280 e. g.
· for visually impaired persons even on normal hardware
In all cases it might help to use enlarged mouse cursors. Ideally this
job should be done by a single X program that automatically enlarges
every mouse cursor.
To my knowledge there is no simple way to write a utility like this,
because the X protocol has no provision to query mouse cursors. For
more details see section ``Technical discussion'' below.
If we aim for a less general goal, though, something can be done:
There is a set of standard mouse cursors that can be found in the
cursor font (try xfd -fn cursor to look at it). Most programs use
these mouse cursors and the key idea is to replace the standard cursor
font with an enlarged version.
2. About this document
The motivation for this MINIHOWTO was a visually impaired co-student
who asked me how to enlarge the mouse cursor under X. After I found
out how this can be done, I wrote an initial version of this document.
The knowledge about the method described here does not seem to be
common, so I decided to share it and submitted this document as a
Linux MINIHOWTO, despite the fact that it is not specific to Linux at
all. As all other MINIHOWTOs it can be found in the home of of the
Linux Documentation Project (LDP) <http://sunsite.unc.edu/LDP/HOWTO/>.
The master <http://i11www.ira.uka.de/~schneid/X11-big-cursor/master/>
of this document is maintained in the SGML/linuxdoc format. This makes
it possible to automatically provide versions in the following formats
(which can be found in the same place as the master): html, text,
LaTeX, DVI, PostScript, GNU info.
Shinobu Miyata <mailto:shinobu@emichan.rim.or.jp> has done a Japanese
translation of this MINIHOWTO. It can be found in
<http://i11www.ira.uka.de/~schneid/jp/X11-big-cursor/>.
3. How to do it
Follow the steps detailed below. If you don't want to get and compile
the bdfresize package yourself, you can skip to step 3 and download a
magnified font instead of creating it.
1. get cursor.bdf, the source of the cursor font, from some X
distribution, e. g. from
<ftp://ftp.x.org/pub/R6.3/xc/fonts/bdf/misc/cursor.bdf> (if you
don't find it there try an archie search or get it from my copy
<http://i11www.ira.uka.de/~schneid/X11-big-cursor/cursor.bdf>).
2. get, compile and install the bdfresize package from
<ftp://ftp.cs.titech.ac.jp/X11/contrib/Local/bdfresize-1.4.tar.Z>
(or from my copy <http://i11www.ira.uka.de/~schneid/X11-big-
cursor/bdfresize-1.4.tar.gz>):
zcat bdfresize-1.4.tar.Z | tar xf -
cd bdfresize-1.4
xmkmf
make
On Linux you probably have to use:
make CCOPTIONS='-include /usr/include/bsd/bsd.h' clean all
3. create a directory and install a magnified cursor font in it
(magnification factor 2 in this example):
mkdir $HOME/fonts
bdfresize -f 2 cursor.bdf | bdftopcf >$HOME/fonts/cursor2.pcf
mkfontdir $HOME/fonts
I have prepared some cursor fonts
<http://i11www.ira.uka.de/~schneid/X11-big-cursor/fonts/> with the
following magnification factors: 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8 and 16.
You can download one of them an copy it to $HOME/fonts if you don't
want to use bdfresize.
4. modify your .xinitrc or .xsession file: before any X client (that
uses cursors) is started the following commands must be executed:
xset +fp $HOME/fonts
xsetroot -cursor_name X_cursor
5. leave your X session and restart.
That's it--now all mouse cursors should have doubled in size.
4. Notes and limitations
· X servers may have a limit for the maximum cursor size, especially
if they use a hardware implementation for the mouse cursor. Others
do not have such a limit. E. g. XF86_S3 3.3 works even with a
512x512 mouse cursor (rather slowly).
· The magnified cursor font must have the same name as the original
font (the font name must be cursor, file name does not
matter)--that is no problem as bdfresize does not change the font
name.
· The directory with the new cursor font must be placed before the
directory with the standard cursor font in the the font path--this
is accomplished with xset +fp (as opposed to xset fp+).
· Changes in $HOME/fonts/ will be visible only after the command
mkfontdir $HOME/fonts; xset fp rehash and only in newly started X
clients (more exactly: for newly created cursors).
· xset +fp path may not work on a X-Terminal. In this case a font
server (see the section ``How to use a fontserver'') can be used if
supported by the X-Terminal or some other method to install the
font on the X-Terminal (this can generally only be done by your
system administrator).
· The same approach can be used for olcursor and decw$cursor fonts
and any other cursor font you may encounter.
· Cursor fonts produced by bdfresize don't look smooth, especially at
larger magnification factors. It would be nice if someone could
create better looking handcrafted version at some common sizes.
5. Technical discussion
Is it possible to write a X program that enlarges cursors
automatically?
(Partial) solution 1
Use the XTestCompareCursor from the XTEST extension. For all
windows that the mouse pointer enters compare the cursor of this
window with a set of `known' cursors (e. g. from the cursor
font). If the cursor is found, replace it with an enlarged
version, otherwise either leave it alone or substitute a
standard cursor. This will only work where the XTest extension
is available.
Solution 2
Write a proxy X server that relays all client requests unchanged
to the real X server, except that it intercepts all requests
corresponing to the XCreate*Cursor Xlib functions.
XCreate*Cursor requests should be modified to use an enlarged
cursor.
This proxy server simulates a new display, e. g. :1. All clients
that connect to this display (e. g. xterm -display :1) are
displayed on the real server (normally :0) and their mouse
cursors are enlarged automatically. The mouse cursors of clients
that connect to :0 will remain unchanged.
6. Other ideas how to make the mouse cursor more visible
Here are some ideas for rather simple X programs that might make mouse
cursors easier to track.
· When a hot key is pressed display something (big cursor, small
window, shaped window) at pointer position for 0.5s.
· use XRecolorCursor to change the mouse cursor color every 0.1s
A more demanding project would be mouse trails à la windoze, i. e.
when the mouse is moved and the mouse cursor needs to be drawn in a
different position, then the old mouse cursor does not disappear at
once, but after a short delay. Mouse trails would be probably best
implemented in a X server, but it might be feasible to do it as a X
client, or better as a proxy server (see section ``Technical
discussion'' for details).
7. Related info
7.1. How to use a font server
A font server is a net service that provides a set of X11 fonts with a
simple protocol. It can be queried which fonts it provides and will
supply the font bitmap data on request.
You might want to use a font server to provide the X server with a
modified cursor font, instead of telling it where to find the font on
the file system.
This method is especially handy if you use several machines that don't
share a common file system or if you use X terminals that support the
font server protocol.
A font server program and associated tools comes with the X11R5+
distribution (AFAIK).
7.1.1. Setting up a font server
Read the manual pages fs(1), fslsfonts(1) (or xfs(1), xfslsfonts(1)
under X11R6) and try it--it isn't hard. Say, you are running the
server on host some.host.edu on port 7100. You can test the setup with
the command
fslsfonts -server some.host.edu:7100
To actually use the server issue the command
xset +fp tcp/some.host.edu:7100
which should return without an error message.
7.2. How to get the bdf source for some font
If you have set up a font server simply use fstobdf which comes with
the font server.
Alternatively you may try getbdf which can dump any installed X11 font
to a bdf file.