Tandy 1000 Basic Reference Manual page 253

Chapter 10
I
BASIC Keywords
This means that instead of stopping when
1
line of points has
been painted without changing the color, PAINT can continue, if
you specify background. For example, normally you cannot draw
alternating blue and red lines on a red background because
PAINT stops after painting the first red line. However, by speci-
fying red as the background color (&HAA), you can draw the red
line over the red background.
PAINT must start on a nonborder point. If the point is already
border or color color, BASIC does not execute t h e PAINT
statement.
PAINT can fill any figure, but painting jagged edges or very
complex figures may result in a n "Out of memory" error. If this
happens, you must use the CLEAR statement to increase the
amount of stack space available.
Tiling
Tiling lets you select a pattern to be used when painting an area
on the screen. The tile mask is 8-bits wide and may be a maxi-
mum of 64 bytes long:
X,Y
8 7 6
5 4 3 2 1 tile byte
0,0
0,1
012
0 7 3
. . . . . . . .
1
. . . . . . . .
2
. . . . . . . .
3
. . . . . . . .
4
0,63
. . . . . . . .
64
Each byte in the mask represents 8 points along the horizontal
row and 1 point along the vertical row. PAINT repeats the tile
mask pattern (horizontally and vertically)
to
create a uniform
pattern over the entire area being painted.
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