BASIC Palette Statements and Functions - fvdhoef/aquarius-plus GitHub Wiki

DEF RGBLIST

TYPE: plusBASIC graphics statement

FORMAT: DEF RGBLIST var$ = rgb_values

Action: Creates an RGB color list.

  • var$ is a simple string variable.
  • rgb_values is a series of semi-colon separated RGB triplets.
    • Each RGB triplet is a red, green, and blue value separated with commas.
Example:

DEF RGBLIST R$ = 15,0,0; 0,15,0; 0,0,15

Creates an RGB color list consisting of the colors red, green, and blue.

LOAD PALETTE

TYPE: plusBASIC disk statement

FORMAT: LOAD PALETTE palette , filespec

Action: Loads palette definition from SD card and writes it to palette.

  • palette is the palette number to be loaded (see SET PALETTE).
  • filespec is a string expression containing an optional path and the full file name.
  • File not found error results if the specified file does not exist.
  • Overflow error results if the file length is not exactly 32 or 64 bytes.
Example: 
LOAD PALETTE 0,"grayscale.pal"

Reads file grayscale.pal and writes contents to palette 0.

FORMAT: LOAD PALETTE palette , filespec , ASC

Action: As above, but reads an ASCII text files containing six-digit RGB hex values.

File format:
  • The file must contain multiple lines of ASCII text.
  • Any lines matching one of the following formats is parsed as an RGB value:
    • Lines starting with # (as of v0.23c) or $ (as of v0.27b).
      • Bad file error occurs if such line is less than 7 characters long or characters 2 through 7 are not hexadecimal digits.
      • Any characters after the six-digit hexadecimal value are ignored.
    • Lines exactly 6 characters long (as of v0.27b).
      • Bad file error occurs if the line contains any characters that are not hexadecimal digits.
    • Lines exactly 8 characters long beginning with hex digits FF (as of v0.27b).
      • Bad file error occurs if the rest of characters that are not hexadecimal digits.
  • All other lines are ignored.
  • Bad file error occurs if the number of RGB values parsed is not exactly 32.

FORMAT: LOAD PALETTE palette , filespec , HEX

Action: As above, but reads a file containing a 64 character hex string.

  • Bad file error occurs if the file is not exactly 64 bytes long or contains any non hex-digit characters.

SET PALETTE

TYPE: plusBASIC graphics statement

FORMAT: SET PALETTE palette TO rgb_list

Action: Sets one or more palette entries to the specified colors.

  • palette is the palette to modify (0 through 3).
    • Screen 0 (text) always uses palette 0.
    • Screen 1 (bitmap) always uses palette 1.
    • Illegal quantity results if palette is not between 0 and 3.
  • rgb_list is a string of RGB values created with the DEF RGBLIST statement.
Example: 
DEF RGBLIST W$ = 15,15,15
SET PALETTE 0 TO W$

Sets the first index of palette 0 to white, changing text screen color 0 from black to white.

DEF RGBLIST B$ = 0,0,0
SET PALETTE 0 TO B$

Sets the first index of palette 0 to black, changing text screen color 0 back to black.

DEF RGBLIST P$ = 0,0,0; 0,0,$F; 0,$F,0; 0,$F,$F; $F,0,0; $F,0,$F; $F,$F,0; $F,$F,$F
SET PALETTE 1 TO P$

Sets the first eight bitmap colors to black, blue, green, cyan, red, magenta, yellow, and white.

DEF RGBLIST G$ = 0,0,0; 1,1,1; 2,2,2; 3,3,3; 4,4,4; 5,5,5; 6,6,6; 7,7,7; 8,8,8; 9,9,9; 10,10,10; 11,11,11; 12,12,12; 13,13,13; 14,14,14; 15,15,15
SET PALETTE 0 TO G$

Sets the text screen colors to shades of gray.

FORMAT: SET PALETTE palette INDEX index TO rgb_values

Action: As above, but entries are set starting at the specified index.

Example: 
SET PALETTE 0 INDEX 6 TO RGB$(15,15,15)

Sets color entry 6 of palette 0 to white, changing text color 6 from cyan to white.

DEF RGBLIST P$ = 0,0,0; 0,0,$F; 0,$F,0; 0,$F,$F; $F,0,0; $F,0,$F; $F,$F,0; $F,$F,$F
SET PALETTE 1 INDEX 8 TO P$

Sets the last eight bitmap colors to black, blue, green, cyan, red, magenta, yellow, and white.

RESET PALETTE

TYPE: plusBASIC graphics statement

FORMAT: RESET PALETTE palette

Action: Sets the specified palette to the default palette

  • palette is the palette to modify (0 through 3).
    • Illegal quantity results if palette is not between 0 and 3.

RGB

TYPE: plusBASIC graphics function

FORMAT: RGB( red , green , blue )

Action: Returns an integer representing a single RGB palette entry.

  • red, green, and blue are integer expressions specifying the intensity of each primary color.
  • Illegal quantity results if any argument is not in the range 0 through 15.
Example:

RGB(0,0,0)

Returns 0 (black)

RGB$(15,15,15)

Returns 4095 (white)

RGB$

TYPE: plusBASIC graphics function

FORMAT: RGB$( red , green , blue )

Action: Returns a two-byte binary string containing a single RGB palette entry.

  • red, green, and blue are integer expressions specifying the intensity of each primary color.
  • Illegal quantity results if any argument is not in the range 0 through 15.
Example:

RGB$(0,0,0)

Returns an RGB$ string representing the color black.

RGB$(15,15,15)

Returns an RGB$ string representing the color white.

The Default Palette

Index RGB Color Index RGB Color
0 111 Black 8 CCC Grey
1 F11 Red 9 3BB Dark Cyan
2 1F1 Green 10 C2C Dark Magenta
3 FF1 Yellow 11 419 Dark Blue
4 22E Blue 12 FF7 Light Yellow
5 F1F Magenta 13 2D4 Dark green
6 3CC Cyan 14 B22 Dark red
7 FFF White 15 333 Dark grey
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