The PRESET graphic SCREEN statement turns a pixel at a coordinate to the background color or a designated color attribute.
Syntax
PRESET [STEP](column%, row%)[, colorAttribute]
Parameter(s)
- Can use STEP when relative graphics coordinates are required.
- column and row coordinates can be literal ot variable INTEGER values which can be offscreen.
- If the colorAttribute is omitted, PRESET will use the current _DEST page’s _BACKGROUNDCOLOR.
Usage
- Color attributes are limited to those available in the SCREEN mode used. PSET can be used to adopt previously used colors.
- Any color value other than 0 will be white in monochrome SCREEN modes 2 and 11 where the COLOR statement cannot be used.
- PRESET can invisibly locate other graphics objects like CIRCLEs and add color to subsequent graphic objects and DRAW when used.
- The PRESET action can be used in a graphics PUT (graphics statement) to produce a color inverted image on any background. See Example 2.
- The graphic cursor is set to the center of the program window on program start for STEP relative coordinates.
- PRESET can be used in any graphic screen mode, but cannot be used in the default screen mode 0 as it is text only!
Example(s)
Using PRESET to locate a DRAW statement that draws a box that is bright red.
SCREEN 12
PRESET(100, 100)
DRAW "C12 U20 R20 D20 L20"
Explanation: The DRAW string required a color designation as PRESET defaulted to the black background color.
Displays the flags of countries that use simple horizontal or vertical color blocks with a highlighted arrow key menu.
DIM SHARED c$(21), x$(21), gg%(477)
ARRAY
SETUP
SELECTION
TERMINATE
END
SUB ARRAY
c$(1) = "Armenia H040914"
c$(2) = "Austria H041504"
c$(3) = "Belgium V001404"
c$(4) = "Bulgaria H150204"
c$(5) = "Chad V011404"
c$(6) = "C“te D'Ivoire V061502"
c$(7) = "Estonia H090015"
c$(8) = "France V011504"
c$(9) = "Germany H000414"
c$(10) = "Hungary H041502"
c$(11) = "Ireland V021506"
c$(12) = "Italy V021504"
c$(13) = "Lithuania H140204"
c$(14) = "Luxembourg H041509"
c$(15) = "Mali V021404"
c$(16) = "Netherlands H041501"
c$(17) = "Nigeria V021502"
c$(18) = "Romania V091404"
c$(19) = "Russia H150104"
c$(20) = "Sierra Leone H021509"
c$(21) = "Yemen H041500"
END SUB
SUB DISPLAY.FLAG (calc%)
f% = VAL(MID$(x$(calc%), 2, 2))
s% = VAL(MID$(x$(calc%), 4, 2))
t% = VAL(MID$(x$(calc%), 6, 2))
IF LEFT$(x$(calc%), 1) = "V" THEN
LINE (120, 225)-(253, 465), f%, BF
LINE (254, 225)-(385, 465), s%, BF
LINE (386, 225)-(519, 465), t%, BF
END IF
IF LEFT$(x$(calc%), 1) = "H" THEN
LINE (120, 225)-(519, 305), f%, BF
LINE (120, 306)-(519, 386), s%, BF
LINE (120, 387)-(519, 465), t%, BF
END IF
END SUB
SUB SELECTION 'menu selection using arrow keys
x% = 2: y% = 4
DO
WHILE (x% <> prevx% OR y% <> prevy%) AND k$ <> CHR$(27)
k$ = INKEY$
x% = x% + (k$ = (CHR$(0) + "K") AND x% > 1) + ABS(k$ = (CHR$(0) + "M") AND x% < 3)
y% = y% + (k$ = (CHR$(0) + "H") AND y% > 1) + ABS(k$ = (CHR$(0) + "P") AND y% < 7)
calc% = (x% - 1) * 7 + y%: LOCATE 14, 18: PRINT c$(calc%); SPACE$(10)
x1% = 140 + (x% - 1) * 128
x2% = x1% + LEN(c$(calc%)) * 8 + 7
y1% = 48 + y% * 16
IF x1% <> prevx1% OR y1% <> prevy1% THEN
IF g% THEN PUT(prevx1%, prevy1%), gg%(), PSET
GET(x1%, y1%)-(x2%, y1% + 16), gg%(): g% = 1
PUT(x1%, y1%), gg%(), PRESET
prevx1% = x1%: prevx2% = x2%: prevy1% = y1%
DISPLAY.FLAG calc%
END IF
WEND
LOOP UNTIL k$ = CHR$(27)
END SUB
SUB SETUP
SCREEN 12
COLOR 6
c% = 1
FOR x% = 11 TO 50 STEP 16
FOR y% = 1 TO 7
x$(c%) = RIGHT$(c$(c%), 7)
c$(c%) = RTRIM$(LEFT$(c$(c%), LEN(c$(c%)) - 7))
LOCATE y% + 4, x% + 8: PRINT c$(c%)
c% = c% + 1
NEXT y%, x%
COLOR 11: LOCATE 3, 20: PRINT "Use the Cursor Keys to Select a Country:"
LINE (119, 224)-(520, 466), 7, B
END SUB
SUB TERMINATE
FOR c% = 1 TO 219
LINE (116 + c%, 29 + c%)-(523 - c%, 469 - c%), 0, B
NEXT
END SUB
Explanation: Using the PUT (graphics statement) PRESET action highlights the menu selection in graphic screen modes by returning a negative image.