Ygl Version 2.8 Description

Copyright (C) 1993/94 by Fred Hucht (fred@hal6000.Uni-Duisburg.DE)

Please see the LICENSE file for further details. You may not distribute this project without this file (ReadMe.html) and the LICENSE file included. Here you can read the CHANGES history.

Description:

• On our RS/6000 GT4 hardware, Ygl is up to twenty times faster than GL (strange, isn't it?...)
• 2D graphics runs on non GL hardware and even on remote X-Servers.

Since Version 2.8, all Ygl functions do have a FORTRAN interface. The FORTRAN versions of all functions have an underscore appended, so the FORTRAN compiler must append a '_' to all function names. f2c does this, xlf (under AIX 3.2) requires the option -qextname. See smile_f77.f for an example program. Set FortranBindings to 0 in Imakefile or change Makefile.std if you don't want these bindings. FORTRAN bindings are not tested because I have no programs.f to test. If you find bugs, feel free to report them to me.

You can always download the latest version of Ygl from ftp.thp.Uni-Duisburg.DE (134.91.141.1), as pub/source/X11/Ygl.tar.gz

Details:

Environment variables:

1. The environment variable YGL_PRIVATECOLORMAP or YGL_PCM can be set to 1 to force Ygl to use a private colormap. While GL always uses a private colormap, Ygl uses the global map by default to avoid technicolor effects on X-Servers not capable of more than one colormap at a time. Note that you can only redefine the color of already drawn objects when you use a private colormap.
2. The environment variable YGL_FLUSHTIME or YGL_FT (default value: 0.1) can be used to adjust the time in seconds between flushes of the graphics pipeline. It can be set to 0 to disable the automatic update via interval timer. Setting YGL_FLUSHTIME to -1 will put the X-Server into synchronous mode (see XSynchronize). This mode seems to be veeeryyy slooow, but is good for debugging...
3. The environment variable YGL_BACKINGSTORE or YGL_BS can be set to 1 to enables BackingStore support for all Ygl windows. With BackingStore, the X-Server remembers the contents of a window when it gets obscured or iconified. You must start your X-Server with the option "-bs" ("+bs" on some systems) to use this feature.
4. The environment variable YGL_SINGLEGC or YGL_GC can be set to 1 to force Ygl to use a single graphics context for colormap windows. Per default Ygl uses one GC for each color, i.e. 256 GCs for a 8 bit colormap window, because this speeds up drawing with many color changes by a factor of 2 or so on many systems. Using a single GC may be faster if you use many mapcolor calls as in colormap animation.
5. The environment variables YGL_CMAPVISUAL or YGL_CV and YGL_RGBVISUAL or YGL_RV control the selection of visuals for cmapmode and RGBmode. Set these variables to the visual id of the desired visual as returned by xdpyinfo, (both hex and decimal is ok).

Double buffering:

Note for AIX < 3.2.5:
This extension is new in X11R5 and is included in the lpp X11dev.src under AIX. To use doublebuffering you have to link the "Multi-Buffering" extension into your X-Server (under AIX, see /usr/lpp/X11/Xamples/README, "Linking the Sample Extensions into the Server").

Note for AIX >= 3.2.5:
You don't need to recompile the X-Server anymore to use doublebuffering under AIX 3.2.5 (AIXWindows 1.2.3). You simply have to add the option "-x mbx" to the X-Servers command line on startup.

RGB mode:

 Colormap mode <-> PseudoColor, StaticColor,
                   GrayScale ,StaticGray,
                   TrueColor or DirectColor visual

 RGB mode      <-> TrueColor or DirectColor visual

Multiple Expose events (REDRAW) in qread:

Automatic flushing of the graphics pipeline:

Note that sleep() and usleep() always return 0.

You can use "sleep(0)" to flush the graphics pipeline explicitly. If you have problems with sleep() and usleep(), undefine COVERSLEEP in header.h.

Supported routines:

Window related routines:

Color related routines:

Device related routines:

• Currently supported devices are: REDRAW, KEYBD, INPUTCHANGE, LEFTMOUSE, MIDDLEMOUSE, RIGHTMOUSE, MOUSEX, MOUSEY, WINQUIT, and all individual keys as F1KEY, ESCKEY, UPARROWKEY, and so on.
• qenter does only support the REDRAW device.

Misc routines:

Drawing routines:

Routines not in SGI's GL:

• (GC*) getXgc()
  return pointer to current graphics context

• Int32 crectread(Screencoord x1, Screencoord y1, Screencoord x2, Screencoord y2, Uint8 *data)
  read screen data to unsigned char array 'data'

• void crectwrite(Screencoord x1, Screencoord y1, Screencoord x2, Screencoord y2, Uint8 *data)
  write unsigned char array 'data' to screen

• void arcxs(Scoord x,Scoord y,Scoord rx,Scoord ry,Angle s,Angle e)
  void arcxi(Icoord x,Icoord y,Icoord rx,Icoord ry,Angle s,Angle e)
  void arcx(Coord x,Coord y,Coord rx,Coord ry,Angle s,Angle e)
  draw ellipses

• void arcxfs(Scoord x,Scoord y,Scoord rx,Scoord ry,Angle s,Angle e)
  void arcxfi(Icoord x,Icoord y,Icoord rx,Icoord ry,Angle s,Angle e)
  void arcxf(Coord x,Coord y,Coord rx,Coord ry,Angle s,Angle e)
  draw filled ellipses

• int gl2ppm(char *filename)
  write out active Ygl window to portable pixmap file 'filename'. When filename[0] == '|', use popen instead of fopen.

Acknowledgements: