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proc drawcommands


drawcom

proc drawcommands reads and executes sets of commands which specify low-level drawing operations.

The commands may be one of two distinct types:

    ploticus draw commands     - a command language described below for creating lines, polygons, and text, in either absolute space or scaled space. May be useful as a flexible way to add annotation, or to add graphics that the other plotting procedures cannot produce, or to import graphics generated programatically.

If you use the dumpfile attribute, drawdump content is expected. Otherwise, ploticus draw commands are expected.

See also the draw prefab which provides a convenient command line interface for processing drawdump files or drawcommands.






Attributes

dumpfile     filename

    A file containing a drawdump (as generated using pl -drawdump or pl -drawdumpa).
    Security concern: user-supplied values (such as CGI variables) should not be used to build the filename, unless proper measures are taken to detect and remove the ../ construct (used as a hack to see higher levels of the file system).

commands     multiline-text

    A list of one or more ploticus draw commands (see below). One command per line. Ends with a blank line.

file     filename

    A file containing ploticus draw commands (see below). May be stdin to read draw commands from standard input.
    Security concern: user-supplied values (such as CGI variables) should not be used to build the filename, unless proper measures are taken to detect and remove the ../ construct (used as a hack to see higher levels of the file system).




Example of draw commands

For a quick tutorial on draw commands, see below. 
#proc drawcommands
commands:
  color blue
  linetype 0 2 1
  mov 1 1
  lin 1 2
  lin 2 2
  lin 1 1

A Gallery example where proc drawcommands is used is drawcom




The draw command set

Here is a summary of the draw command set. The commands are interpreted, and should be given one per line. Quoting is never used for string literals. Note that proc drawcommands have nothing to do with proc getdata or the "current data set". For an explanation of absolute units and scaled units, see scaleunits.

CommandDescription
mov x y = move to (x,y) in absolute units
lin x y = line to (x,y) in absolute units
path x y = extend current polygon fill path to (x,y) in absolute units (see also fill below).
movs, lins, paths = same as above but for scaled units (assumes proc areadef has already been used to set up a scaled space).
movp, linp, pathp = same as above but operands may be in either absolute space or scaled space. If an operand ends with (s) it is assumed to be in scaled space; otherwise it is assumed to be in absolute space.
text s = display text string s left adjusted at current location. s should not be enclosed in quotes.
centext s = display text string s centered around current location s should not be enclosed in quotes.
rightjust s = display text string s right-aligned to current location s should not be enclosed in quotes.
cblock x1 y1 x2 y2 color outline = display a colored rectangle. The lower left is at (x1,y1) in absolute units; upper right is at (x2,y2) in absolute units; color is the color; outline is 1 to produce an outline, 0 not.
fill = close and fill the polygon path with the current color.
mark x y sym r = produce a symbol at (x,y). sym is a graphcore data point symbol code as described in symboldetails. r is the radius in absolute units.
color c = set the current color to c
    textsize p
= set the current text size to p points
linetype style width dashscale = set the current line details.
clr = clear the display
backcolor c = set the current background color to c





How to use draw commands

Suppose you have an imaginary pen,

color blue sets the pen color to blue
mov x1 y1 would move the "pen" to x1,y1 in inches from lower left corner
lin x2 y2 would lower the "pen" and then draw a line to x2,y2
lin x3 y3 would continue the line to x3,y3

If you don't want to use inches, you can set up a plotting area with whatever xrange and yrange you want. Then..
movs x1 y1 would move the pen to x1,y1 relative to xrange and yrange
lins x2 y2 would lower the pen and then draw a line to x2,y2
lins x3 y3 would continue the line to x3,y3

This is fine for drawing lines, but what about filled shapes? To do shapes, you do the same thing as above, but use path instead of lin, or paths instead of lins. When you have drawn one shape, you fill it in using:
fill red

Then you can begin the next shape.

 


Ploticus 2.42 ... May 2013 Terms of use /