22.3 Graphics

The following program illustrates how to use the various graphics functions.

MODULE 'intuition/intuition'

PROC main()
  DEF wptr, i
  wptr:=OpenW(20,50,200,100,IDCMP_CLOSEWINDOW,
              WFLG_CLOSEGADGET OR WFLG_ACTIVATE,
              'Graphics demo window',NIL,1,NIL)
  IF wptr  /* Check to see we opened a window */
    Colour(1,3)
    TextF(20,30,'Hello World')
    SetTopaz(11)
    TextF(20,60,'Hello World')
    FOR i:=10 TO 150 STEP 8  /* Plot a few points */
      Plot(i,40,2)
    ENDFOR
    Line(160,40,160,70,3)
    Line(160,70,170,40,2)
    Box(10,75,160,85,1)
    WHILE WaitIMessage(wptr)<>IDCMP_CLOSEWINDOW
    ENDWHILE
    CloseW(wptr)
  ELSE
    WriteF('Error -- could not open window!\n')
  ENDIF
ENDPROC

First of all a small window is opened with a close gadget and activated (so it is the selected window). Clicks on the close gadget will be reported via IDCMP, and this is the only way to quit the program. The graphics functions are used as follows:

• Colour is used to set the foreground colour to pen one and the background colour to pen three. This will make the text nicely highlighted.
• Text is output in the standard font.
• The font is set to Topaz 11.
• More text is output (probably now in a different font).
• The FOR loop plots a dotted line in pen two.
• A vertical line in pen three is drawn.
• A diagonal line in pen two is drawn. This and the previous line together produce a vee shape.
• A filled box is drawn in pen one.

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