Advanced Programming Tips; Filling And Hatching; Filling A Bar - HP 7470A Interfacing And Programming Manual

320 PRINT "LT"
330 F0R x=1 T0 12
340 REHD Y
350 PRINT "PH";X;Y;"PU"
350 NEXT x
3?0 PRINT "PU5,1S5PD?.1,1ESPU"
380 PRINT "SP1;LT4,B"
390 @0503 1000 _
IIJH'||Fl|'||M||,l|H||',l|r.1|l-!|l_JlI'!||J||'|lF1||'llS||,I|Ul|'||t\lI|JHDII
410 DRTH 55,s0,s3,s2,5s,54.50,45,4?,49,53,se
420 STOP
1000 1 PLUTTING SUBRUUTIHE
1010 REHD X,Y,P
1020 IF P=1 THEN PRINT "PU";H;Y
1030 IF P=0 THEN PRINT "Pu";H;Y
1040 IF P=3 THEN 1090
1050 DRTH 1,as,0,2,100,1,3,102,1,4,105,1,s,10?,1,e,110,1
1060 DHTH ?,125,1,e,112,1,9,115,1,10,125,1,11,130,1
1070 DHTH 12,122,1,0,0,3
1080 GDTU 1010
1080 PRINT "LT4,B PU3.2,1Ei5 PB-4.?,'1Ei5EiF'0;"
1100 RETURN
1110 END
Advanced Programming Tips
Filling and Hatching
Two kinds of area fill are commonly used in bar graphs and pie charts;
solid fill and hatching. Solid fill totally covers the area with color,
whereas hatching fills the area with evenly spaced parallel lines. If
there are lines in two directions at 90 degree angles, we call the
hatching crosshatching. Sometimes a graph will have both narrow
and wide hatching or crosshatching, the wide hatching having more
space between the lines than the narrow.
Filling a Bar
The following two program segments, together with lines 10 to 100 and
400 of this chapter's program, will each fill a bar which represents the
March data for line 1, i.e., 3, 18 (see line 260, in the program). To create
an aesthetically pleasing and easily comprehendible bar graph, the bar
is centered over the X data point and is slightly wider than one-half the
distance between data points on the X—axis. The increment variable P
depends on pen width. A Value of P = 20 plotter units is suitable for a
wide pen and 10 for a narrow pen.
The first program segment should be used when plotting on paper.
Notice the pen does not lift; the routine is faster and prolongs pen—tip
life by limiting up/down moves. The second segment should be used
when plotting on transparency film to achieve uniform ink distribution.
8-10 PUTTING THE COMMANDS TO WORK