COLOR

The COLOR statement is used to change the foreground and background colors for printing text.

Syntax

COLOR [foreground&][, background&]

Description

• background& colors are available in all QB64 color SCREEN modes.
• SCREEN mode 10 has only 3 white foreground attributes including flashing.
• To change the background& color only, use a comma and the desired color. Ex: COLOR , background&
• Graphic drawing statements like PSET, PRESET, LINE, etc, also use the colors set by the COLOR statement if no color is passed when they are called.
• The $COLOR metacommand adds named color constants for both text and 32-bit modes.

Screen Mode Attributes

• SCREEN 0 background& colors 0 to 7 can be changed each text character without affecting other text. Use CLS after a background color statement to create a fullscreen background color. 64 DAC hues with 16 high intensity blinking foreground (16 to 31) color attributes. See _BLINK.
  • See example 7 below for more SCREEN 0 background colors.
• SCREEN 1 has 4 background color attributes: 0 = black, 1 = blue, 2 = green, 3 = grey. White foreground color only.
• SCREEN 2 is monochrome with white forecolor and black background.
• SCREEN 7 can use 16 (DAC) colors with background colors. RGB settings can be changed in colors 0 to 7 using _PALETTECOLOR.
• SCREEN 8 has 16 color attributes with 16 background colors.
• SCREEN 9 can use up to 64 DAC color hues in 16 color attributes with background colors assigned to attribute 0 with a _PALETTECOLOR swap. RGB settings can be changed in colors 0 to 5 and 7 using _PALETTECOLOR.
• SCREEN 10 has only 4 color attributes with black background. COLOR 0 = black, 1 = grey, 2 = flash white and 3 = bright white.
• SCREEN 11 is monochrome with white forecolor and a black background.
• SCREEN 12 can use 16 color attributes with a black background. 256K possible RGB color hues. Background colors can be used with QB64.
• SCREEN 13 can use 256 color attributes with a black background. 256K possible RGB hues.
• PALETTE swaps can be made in SCREEN 7 and 9 only. Those screens were DAC screen modes in QBasic.
• _DEST can be used to set the destination page or image to color using QB64.
• _DEFAULTCOLOR returns the current color being used on an image or screen page handle.

24/32-Bit colors using QB64

• Pixel color intensities for red, green, blue and alpha range from 0 to 255 when used with _RGB, _RGBA, _RGB32 and RGBA32.
• Combined RGB function values returned are LONG values. Blue intensity values may be cut off using SINGLE variables.
• _ALPHA transparency values can range from 0 as transparent up to 255 which is fully opaque.
• _CLEARCOLOR can also be used to set a color as transparent.
• Colors can be mixed by using _BLEND (default) in 32-bit screen modes. _DONTBLEND disables blending.
• NOTE: Default 32-bit backgrounds are clear black or _RGBA(0, 0, 0, 0). Use CLS to make the black opaque.

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RGB Palette Intensities

RGB intensity values can be converted to hexadecimal values to create the LONG _PALETTECOLOR value in non-32-bit screens:

SCREEN 12 alpha$ = "FF" 'solid alpha colors only PRINT "Attribute = Hex value Red Green Blue " PRINT COLOR 7 FOR attribute = 1 TO 15 OUT &H3C7, attribute 'set color attribute to read red$ = HEX$(INP(&H3C9) * 255 / 63) 'convert port setting to 32 bit values grn$ = HEX$(INP(&H3C9) * 255 / 63) blu$ = HEX$(INP(&H3C9) * 255 / 63) IF LEN(red$) = 1 THEN red$ = "0" + red$ '2 hex digits required IF LEN(grn$) = 1 THEN grn$ = "0" + grn$ 'for low or zero hex values IF LEN(blu$) = 1 THEN blu$ = "0" + blu$ hex32$ = "&H" + alpha$ + red$ + grn$ + blu$ _PALETTECOLOR attribute, VAL(hex32$) 'VAL converts hex string to a LONG 32 bit value IF attribute THEN COLOR attribute 'exclude black color print PRINT "COLOR" + STR$(attribute) + " = " + hex32$, red$, grn$, blu$ 'returns closest attribute NEXT

Attribute Hex value Red Green Blue COLOR 1 = &HFF0000AA 00 00 AA COLOR 2 = &HFF00AA00 00 AA 00 COLOR 3 = &HFF00AAAA 00 AA AA COLOR 4 = &HFFAA0000 AA 00 00 COLOR 5 = &HFFAA00AA AA 00 AA COLOR 6 = &HFFAA5500 AA 55 00 COLOR 7 = &HFFAAAAAA AA AA AA COLOR 8 = &HFF555555 55 55 55 COLOR 9 = &HFF5555FF 55 55 FF COLOR 10 = &HFF55FF55 55 FF 55 COLOR 11 = &HFF55FFFF 55 FF FF COLOR 12 = &HFFFF5555 FF 55 55 COLOR 13 = &HFFFF55FF FF 55 FF COLOR 14 = &HFFFFFF55 FF FF 55 COLOR 15 = &HFFFFFFFF FF FF FF

Explanation: The DAC intensity values are multiplied by (255 / 63) to get the _RGB intensity values as hexadecimal values. The individual 2 digit HEX$ intensity values can be added to "&HFF" to make up the 32-bit hexadecimal string value necessary for VAL to return to _PALETTECOLOR. The statement is only included in the example to show how that can be done with any 32-bit color value.

Read & write color port intensities with INP & OUT

• Legacy code may use INP and OUT to read or set color port intensities. QB64 emulates VGA memory to maintain compatibility.
• The same can be achieved using _PALETTECOLOR (recommended practice).

OUT &H3C7, attribute 'Set port to read RGB settings with:

color_intensity = INP(&H3C9) 'reads present intensity setting

OUT &H3C8, attribute 'Set port to write RGB settings with:

OUT &H3C9, color_intensity 'writes new intensity setting

• After every 3 reads or writes, changes to next higher color attribute. Loops can be used to set more than one attribute's intensities.
• Color port setting of red, green and blue intensities can be done in ascending order.
• Color port attribute intensity values range from 0 to 63 (1/4 of the 32-bit values) in QBasic's legacy 4 and 8 bit screen modes.

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Examples

Example 1: Reading the default RGB color settings of color attribute 15.

OUT &H3C7, 15 red% = INP(&H3C9) green% = INP(&H3C9) blue% = INP(&H3C9) PRINT red%, green%, blue%

63 63 63

Example 2: Changing the color settings of attribute 0 (the background) to blue in SCREENs 12 or 13.

SCREEN 12 OUT &H3C8, 0 'set color port attribute to write OUT &H3C9, 0 'red intensity OUT &H3C9, 0 'green intensity OUT &H3C9, 42 'blue intensity OUT &H3C7, 0 PRINT INP(&H3C9); INP(&H3C9); INP(&H3C9) END

0 0 42

Example 3: Printing in fullscreen SCREEN 0 mode with a color background under the text only.

SCREEN 0: _FULLSCREEN ' used for fullscreen instead of window COLOR 14, 6: LOCATE 4, 4: PRINT "Hello!"

Hello!

Example 4: Using CLS after setting the background color in SCREEN 0 to make the color cover the entire screen.

SCREEN 0: _FULLSCREEN COLOR , 7: CLS COLOR 9: PRINT "Hello"

Hello

Example 5: Using a different foreground color for each letter:

SCREEN 0 COLOR 1: PRINT "H"; COLOR 3: PRINT "E"; COLOR 4: PRINT "L"; COLOR 5: PRINT "L"; COLOR 6: PRINT "O" COLOR 9: PRINT "W"; COLOR 11: PRINT "O"; COLOR 12: PRINT "R"; COLOR 13: PRINT "L"; COLOR 14: PRINT "D"

HELLO WORLD

See also

• $COLOR (metacommand)
• _RGB, _RGBA, _RGB32, RGBA32.
• _RED, _GREEN, _BLUE
• _RED32, _GREEN32, _BLUE32
• _ALPHA, _ALPHA32, _CLEARCOLOR
• PRINT, LOCATE, SCREEN
• POINT, SCREEN (function)
• OUT, INP, PALETTE
• _BLINK
• _DEFAULTCOLOR
• _BACKGROUNDCOLOR
• _PALETTECOLOR
• Color Dialog Box
• $COLOR:0 Name Table
• $COLOR:32 Name Table

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