Commodore Plus 4 - High resolution graphics

HIGH
RESOLUTION
GRAPHICS
Your Plus/4 screen contains 25 rows of 40 characters each, or 1000
total character positions on the screen. Each character is formed out of
single dots, with 8 rows of 8 dots each making an entire character. Your
screen has a total of 320 dots on each row, and 200 rows of dots, or
64.000 dots all together. Your Plus/4 has control over every single dot.
Using normal graphics, you have limited control over the individual
dots. You must use the 256 characters in each character set built into
the Plus/4, which lets you create many pictures. But think of how many
you could create if you could control each dot by itself!
The high resolution graphics ability of the Plus/4 lets you do just that.
You can use commands that let you draw and erase dots, lines, circles,
and other shapes.
There is one limit to high-res graphics The Plus/4 can only use two
colors in each 8x8 character position. That is, each 8x8 space on
the screen where characters usually go is limited to two colors (fore
ground and background color for that square). You can use different
colors for each different character position, but only two colors within
that position Another graphic mode that will be covered later in this
section, multi-color mode, allows up to four different colors per
character position at the cost of the resolution available in the high-
resolution mode
This program utilizes some of the high resolution graphics capability of
the Plus/4, in particular the GRAPHIC command. Start by typing NEW
and hitting return Hit the RETURN key after typing each
line. After typing in the entire program, type RUN and hit RETURN
as usual.
10 COLOR 0,1
20 GRAPHIC 1,1
30 FOR L = 2 TO 16
40 COLOR 1.L.2
50 DRAW l,0.L"12 TO 319.1/12
60 DRAW 1,1/18,0 TO 1/18.199
70 NEXTL
80FORL-lTO5u00:NEXT
90 COLOR 1,2,3
100 GRAPHIC 0
Notice that the colors change near the intersections.
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