Welcome to MGRX 1.3.1!

MGRX is a 2D graphics C library derived from the GRX library. GRX was
originaly written by Csaba Biegl for DJ Delorie's DOS port of the GCC
compiler.

From version 1.3.0 MGRX comes with GrGUI, a mini Graphics User Interface
specifically designed for MGRX.

Supported platforms
===================

MGRX supports the following four platforms:

  DOS using DJGPP v2.05; with EGA, VGA, VESA and memory drivers
  Linux fb using gcc; with framebuffer and memory drivers
  Linux X11 using gcc; x11(windowed) and memory drivers
  Win32 using TDM-GCC (a Mingw32 distribution); w32(windowed) and
  memory drivers

  For the Linux framebuffer and the Linux X11 versions three
  architectures are supported: i386 (32bit), x86_64 (64bit)
  and ARM (32bit, tested in a Raspberry Pi 4 using Raspbian).

Why MGRX
========

MGRX (mgrx.fgrim.com) is a fork of GRX (grx.gnu.de). Because I liked the
GRX C API interface, I began to maintain GRX when it was orphaned at the
end of 2000. But GRX has not only the C API, it has a Pascal API, a BGI
compatibility API, support for Turbo C, Wattcom, MSC and some obscure X11
implementations over mainframes. At the end it was not funny, it was easy
to break things I didn't know . So I stopped maintaining GRX at the end
of 2003.

After that I developed a fork for my own use, only the C API, no Pascal,
no BGI, no Turbo C support, only the 4 platforms I can test. It comes
with a new (and better I think) input API and some (limited) Intl support.
I have released it for fun, maybe it can be useful for someone.

MGRX installation instructions
==============================

Requirements:
-------------

  The source files and fonts:  mgrx131.tar.gz or mgrx131s.zip
  This document:               readme
  
Dependencies:
-------------

The only dependencies are libjpeg (for reading and writing JPEG files)
and libpng and zlib (for reading and writing PNG files). But you can
disable those capabilities to have no dependencies at all (see belloow).

Anyway it's easy to install the binary libraries in Linux and DJGPP. And
for the TDM-GCC (Win32) compiler you can download a precompiled package
from the MGRX site.

A. Unpacking the MGRX archive
-----------------------------

  1) 'cd' to a directory where you want the MGRX file tree to be created
     as a subdirectory. Examples are:

       DJGPP : C:\DJGPP
       Mingw : C:\MINGW or C:\TDM-GCC-32
       Linux : /usr/local/src or ~ (your home dir)

  2) Choose and download the .tar.gz or .zip archive. You can use either.
     The .zip is intended for dos and win32 users, specialy for DJGPP users,
     because it expand to the contrib subdir and has manifest files.

  3) Unpack the MGRX archive:

         tar xzvf mgrx131.tar.gz   (1)
     or
         unzip mgrx131s.zip        (2)

     (1) This will create the subdirectory 'mgrx131'.
     (2) This will create the subdirectory 'contrib/mgrx131'.

B. Edit "makedefs.grx"
----------------------

  1) Go to MGRX base dir and edit "makedefs.grx" to customize it for
     your system. The file is well comented.

  Some things you can change:
  
  - not to include GrGUI, set INCLUDE_GRGUI=n
  
  - remove support for reading/writing JPEG files, set HAVE_LIBJPEG=n
  
  - remove support for reading/writing PNG files, set HAVE_LIBPNG=n
  and NEED_ZLIB=n
  
  - For linux framebuffer and X11 select i386, x86_64 or ARM architecture.
  By default the makefiles build the library for the x86_64 architecture. To
  build the i386 library you must set BUILD_I386=y, BUILD_X86_64=n and
  BUILD_ARM=n. To build for ARM set BUILD_ARM=y, BUILD_I386=n and
  BUILD_X86_64=n.
  
  - For linux framebuffer and X11 select shared or static libraries. By
  default only the static libraries are build (and it is the recomended
  option). To build the shared libraries set INCLUDE_SHARED_SUPPORT=y

  - For linux framebuffer and X11 if your glibc version is < 2.17 you
  need to set NEED_LIBRT=y

C. Compiling MGRX
-----------------

  1) Switch to the "src" sub dir

  2) run 'make -f <your makefile>':

     makefile.dj2 for DOS/DJGPPv2
     makefile.w32 for Win32/Mingw
     makefile.lnx for Linux/framebuffer
     makefile.x11 for Linux/X11

     This process generates the MGRX lib in the "lib/---" (where ---
     is dj2, win32 or linux) subdir and some utility programs in the
     "bin" subdir.

     Note for DJGPP/Mingw users: Do _not_ use an environment variable
     `SHELL' leading to `bash', e.g. `SHELL=/djgpp/bin/bash.exe'.
     Do not use MSYS either. The DJGPP/Mingw Makefiles must be run with
     the normal 'command.com'.
     
     Note for Mingw users: use "mingw32-make" instead "make". The 
     compilation was tested with the 32 bit version of "TDM-GCC"
     mingw32 distribution.

D. Testing MGRX
---------------

  1) Switch to the "test" sub dir

  2) run 'make -f <your makefile>'

  3) run the 'demomgrx' program ('xdemomgrx' for the X11 version)
  (see bellow on running mgrx programs in Linux framebuffer)

E. Testing GrGUI (if compiled in)
---------------------------------

  1) Switch to the "testgui" sub dir

  2) run 'make -f <your makefile>'

  3) run the 'demmgrx2' program ('xdemmgrx2' for the X11 version)
  (see bellow on running mgrx programs in Linux framebuffer)

F. Installing MGRX lib for your compiler (optional)
---------------------------------------------------

  Copy the library from <MGRX base>/lib/<your system> to the compiler
  library directory.
  Copy the header files mgrx.h, mgrxkeys.h and mgrxcolr.h from
  <MGRX base>/include to your compiler include directory.

  Or you can let makefiles do it for you, switch to the "src" sub dir and
  run 'make -f <your makefile> install'. You can uninstall the library
  running 'make -f <your makefile> uninstall'.

  Note for Linux users: probably you must be root to do that.
  
  Note 2 for Linux users: if you have build the sahred libraries don't
  forget to run 'ldconfig' to register them.

G. Installing MGRX utility programs (optional)
----------------------------------------------

  MGRX come with some utility programs like modetest. They are compiled
  with the library and stored in the "bin" sub dir. To install them in
  your system run 'make -f <your makefile> install-bin'

  You can uninstall them running 'make -f <your makefile> uninstall-bin'

  Note for Linux users: probably you must be root to do that.

H. Installing MGRX fonts (optional)
-----------------------------------

  Only if you have defined a default font directory in "makedefs.grx"
  you can install them running 'make -f <your makefile> install-fonts'

  You can uninstall them running 'make -f <your makefile> uninstall-fonts'

  Note for Linux users: probably you must be root to do that.

Environment variables for using MGRX programs
=============================================

  1) You can set set the default driver and graphics mode (but it
     is not required).
     
     DOS or Windows:

       SET MGRXDRV=<driver> gw <width> gh <height> nc <colors>

     Linux:

       export MGRXDRV="<driver> gw <width> gh <height> nc <colors>"

     Available drivers are for:

       DOS      : stdega, stdvga, VESA, memory
       Linux fb : linuxfb, memory
       Linux X11: xwin, memory
       Win32    : win32, memory

     Values for gw and gh can be by example 640,480 or 800,600
     Values for nc can be 2, 16, 256, 64K or 16M.
     
  2) Set the keyboard system encoding. MGRX try to guess it, but if
     unsure it will use this variable.
     
     DOS or Windows:
     
       SET MGRXKBSYSENCODING=<kbsysencoding>
       
     Linux:
     
       export MGRXKBSYSENCODING="<kbsysencoding>"
       
     Posible values are: "CP437", "CP850", "CP1252", "ISO_8859_1", "UTF_8"
     or "UCS_2".

  3) Set the GRX font dir (not required if you have set the default font
     path in 'makedefs.grx' or if your program know where it is).
     
     in DOS or Windows:

       SET MGRXFONT=<directory for the MGRX fonts>

     in linux:

       export MGRXFONT=<directory for the MGRX fonts>

  4) the linux framebuffer driver opens the "/dev/fb0" device file by
     default, if you want to open an alternate device file, set the
     $FRAMEBUFFER environment variable:

       export FRAMEBUFFER=<device file>

Running mgrx programs for Linux framebuffer
===========================================

On most Linux distributios the device framebuffer "/dev/fb0" and the
mouse device "/dev/input/mice" are not accesible to normal users by
default. So to run mgrx programs for Linux framebuffer you have to
choose one of these solutions (beware that you are changing the security
policy of your distribution, but as the programmer you know better :)

- run the program with root supersuser, either changing user or using
the sudo command.

- set the root suid for your mgrx programs (read the "chmod" man page
to know how to do it).

- change the "/dev/fb0" and "/dev/input/mice" permissions (with root).

- add your user to the "video" and "input" groups, editing (with root)
the "/etc/group" file. I think this is the best solultion (it seems
to be the default in Raspbian, so nothing to do in that case).

Help
====

  Read the MGRX programmer's manual in the "doc/mgrxpm.htm" file.
  
  Read the GrGUI programmer's guide in the "doc/grguipm.htm" file.

  See the MGRX site (mgrx.fgrim.com) for updates, tips, ... 

  Send me a mail (malfer at telefonica.net)

License
=======

  MGRX is a derived work of GRX, so MGRX uses the same license as
  GRX. The MGRX graphics library is free software; you can redistribute
  it and/or modify it under some conditions; see the "copying.grx" file
  for details.

Credits
=======

  If you think MGRX is a good library, it is thanks to the people who
  wrote and maintained GRX:

  Csaba Biegl <csaba at vuse.vanderbilt.edu> who wrote it.
  Michael Goffioul <goffioul at emic.ucl.ac.be> who released 2.1
  Hartmut Schirmer <hsc at techfak.uni-kiel.de> who released 2.2 and 2.3
  and other people, see the "doc/credits.doc" for details.


Enjoy, M.Alvarez <malfer at telefonica.net>

