Apple IIe - Page 152

152 Apple lie Users Handbook
Example
10 REM SET UP SCREEN
20 TEXT:HGR
30 FOR X = 7936 TO 7946
40 READ V:REM READ IN SHAPE
50 POKE X,V:REM POKE SHAPE INTO MEMORY
60 NEXT X
70 REM TELL WHERE SHAPE IS AT
80 POKE 232,0: POKE 233,31
90 HCOLOR = 3
100 ROT= 0
110 FOR X = 10 TO 273 STEP 24
120 INPUT "ENTER SCALE ";S
130 IFS < 1THENX=273: GOTO 160
140 IFS > 50 THEN X = 273: GOTO 160
150 SCALE= S: DRAW 1 AT X,100
160 NEXT X
170 DAT A 1,0,4,0,39,36,45,53,54,63,0
180 END
In
the preceding example, line 20 initialized the screen so that
graphics could be drawn. The shape table was then read using
the FOR NEXT loop in lines 30 to 60. Line 80 POKE'd the starting
address
of the shape. Lines 90 and 100 defined a color and
rotation for the shape. Lines 110to160 then prompted the user to
enter a scale size. The number entered will be the size of the next
shape drawn on the screen. The program will then exit after the
entry of eleven sizes or when the value entered is less than one
or greater than fifty.
•
Applesoft
SCRN
• Integer
SCRN is used in the low resolution graphics mode to return the
color code of the point specified as its argument.