Commodore Plus 4 - Page 163

a1 ,b1 Corner coordinate (scaled)
a2,b2 Corner coordinate opposite (a1,b1)
(default is the PC)
Because BASIC limits string lengths to 255 characters, the size of the
area you may save is limited. The string size required can be calcu
lated using one of the following (unsealed) formulas:
L(mcm) - INT ((ABS(a1 -a2) + 1) / 4 + .99) * (ABS(b1 - b2) + 1) + 4
L(h-r) = INT((ABS(a1-a2) + 1)/8+ .99) * (ABS(b1 - b2) + 1) + 4
(mem) refers to multi-color mode; (h-r) is high resolution.
The shape is saved row by row. The last four bytes of the string contain
the column and row lengths less one (i.e.: ABS (a1 -a2)) in low/high
byte format (if scaled divide the lengths by 3.2 (X) and 5.12 (Y)).
The command to display a saved shape on any area of the screen:
GSHAPE string t [a,b\ [.mode] J
string Contains shape to be drawn
a,b Top left coordinate telling where
to draw the shape (scaled -
the default is the PC)
mode Replacement mode:
0: place shape as is (default)
1: place field inverted shape
2: OR shape with area
3: AND shape with area
4: XOR shape with area
EXAMPLES:
SSHAPE 1'SHIP1'TO,O Saves shape on screen area from the
upper left corner to the cursor under the
name "SHIP"
GSHAPE "SHIP'1,,,! Displays inverted "SHIP" shape with the
top left corner positioned where the cursor
is located
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