xgc - X graphics demo


   xgc [-toolkitoption ...]


   The  xgc  program  demonstrates  various  features  of  the  X graphics
   primitives.  In X, most  of  the  details  about  the  graphics  to  be
   generated are stored in a resource called a graphics context (GC).  The
   xgc  program  provides  a  user  interface  for  setting   various   GC
   components.   Pressing  the  "Run"  button  causes  these results to be
   displayed in the large drawing window on the right.  Timing information
   is displayed in the window immediately below.

   The items in the upper left hand window work as follows:

   Function  -  specify  the  logical  function with which primitives will
   drawn.  The most usual setting is "set", i.e. simply to  render  pixels
   without regard to what has been drawn before.

   LineStyle  - specify whether lines should be drawn solid in foreground,
   dashed in foreground or alternating foreground and background.

   CapStyle - specify the appearance of the ends of a line.

   JoinStyle - specify the appearance of joints between consecutive  lines
   drawn within a single graphics primitive.

   FillStyle  -  specify  whether lines, text and fill requests are solid,
   tiled with a pixmap or stippled.

   FillRule - specifies the rule used to fill polygons.  The EvenOdd  rule
   means that if areas overlap an odd number of times, they are not drawn.
   Winding rule means that overlapping areas are always filled, regardless
   of how many times they overlap.

   ArcMode  - specifies the rule for filling of arcs.  The boundary of the
   arc is either a Chord or two radii.

   planemask - specifies which planes of the drawing window are  modified.
   By default, all planes are modified.

   dashlist - specifies a pattern to be used when drawing dashed lines.

   Line  Width - specifies the width in pixels of lines to be drawn.  Zero
   means to draw using the server's fastest algorithm with a line width of
   one pixel.

   Font - specifies the font to be used for text primitives.

   Foreground and Background - specify the pixel values to be applied when
   drawing primitives.  The Foreground value is used as  the  pixel  value
   for  set bits in the source in all primitives.  The Background value is
   used as the pixel value for unset bits in the source  when  using  Copy
   Plane,  drawing  lines  with  LineStyle  of DoubleDash and filling with
   FillStyle of OpaqueStippled.

   Percentage of Test - scrollbar permits specifying only a percentage  of
   the  test  to  be  run.   The  number at the left indicates the current
   setting, which defaults to 100%.

   The window labeled "Test" permits choice of one a  number  of  graphics
   primitive  tests,  including  Points,  Segments, Lines, Arcs and Filled
   Arcs, 8-bit Text and Image  Text,  Rectangles  and  Filled  Rectangles,
   Image draws, as well as Copy Plane and Copy Area.

   The   window   to   the   right   of  this  has  buttons  which  permit
   record/playback of the primitives rendered.


   Xgc accepts all of the standard X Toolkit command line options.


   This program accepts the usual defaults for toolkit applications.


   DISPLAY to get the default host and display number.

           to get the name of a resource file that  overrides  the  global
           resources stored in the RESOURCE_MANAGER property.




   This  program isn't really finished yet, but it probably never will be,
   since it only demonstrates the original  X11  core  protocol  rendering
   operations, which few modern programs use anymore.


   Dan Schmidt, MIT


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