xgc
X graphics demo
see also :
X
Synopsis
xgc
[-toolkitoption ...]
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examples
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description
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.
options
Xgc
accepts all of the standard X Toolkit command line
options.
display
to get the default host and display number.
XENVIRONMENT
to get the name of a resource file that overrides the global
resources stored in the RESOURCE_MANAGER property.
environment
x defaults
This program accepts the usual defaults for toolkit applications.
bugs
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.
see also
X
authors
Dan Schmidt,
MIT