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COLOR

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

Contents

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.


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 OUT &H3C8, 0: OUT &H3C9, 0: OUT &H3C9, 0: OUT &H3C9, 20 'set black background to dark blue PRINT "Attribute = Hex value Red Green Blue " PRINT COLOR 7 FOR attribute = 0 TO 15 OUT &H3C7, attribute 'set color attribute to read red$ = HEX$(INP(&H3C9) * 4) 'convert port setting to 32 bit values grn$ = HEX$(INP(&H3C9) * 4) blu$ = HEX$(INP(&H3C9) * 4) IF LEN(red$) = 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 0 = &HFF000050 00 00 50 COLOR 1 = &HFF0000A8 00 00 A8 COLOR 2 = &HFF00A800 00 A8 00 COLOR 3 = &HFF00A8A8 00 A8 A8 COLOR 4 = &HFFA80000 A8 00 00 COLOR 5 = &HFFA800A8 A8 00 A8 COLOR 6 = &HFFA85400 A8 54 00 COLOR 7 = &HFFA8A8A8 A8 A8 A8 COLOR 8 = &HFF545454 54 54 54 COLOR 9 = &HFF5454FC 54 54 FC COLOR 10 = &HFF54FC54 54 FC 54 COLOR 11 = &HFF5454FC 54 FC FC COLOR 12 = &HFFFC5454 FC 54 54 COLOR 13 = &HFFFC54FC FC 54 FC COLOR 14 = &HFFFCFC54 FC FC 54 COLOR 15 = &HFFFCFCFC FC FC FC

Explanation: The RGB intensity values are multiplied by 4 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.
Note: Black has a blue hex value of 50 due to the OUT background color setting which makes it dark blue.


Reading and setting color port intensities using INP and 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 dark 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, 30 'blue intensity OUT &H3C7, 0 PRINT INP(&H3C9); INP(&H3C9); INP(&H3C9) END

0 0 30


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 30, 6: LOCATE 12, 4: PRINT "Hello!"

Result: Hello! is printed in flashing high intensity yellow with brown background behind text only when in Qbasic fullscreen.


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

Result: The blue word Hello is printed to a totally grey background in fullscreen.


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


Example 6: Doing the same as Example 5 but in only a few lines:

SCREEN 0 text$ = "HelloWorld" FOR textpos = 1 TO LEN(text$) COLOR textpos IF textpos <> 5 THEN PRINT MID$(text$, textpos, 1); IF textpos = 5 THEN PRINT MID$(text$, textpos, 1) 'start print on next row NEXT

Hello World

Explanation:Semicolon(;) means that the next PRINT happens on the same line, we don't want that when it comes to position 5 so when it is at position 5 the next PRINT will move to the next line (when it isn't at position 5 we want it to continue printing the letter side-by-side on the same line though).


Example 7: Since SCREEN 0 only uses background colors 0 to 7 by default, use _PALETTECOLOR to change color intensities of color 0.

_PALETTECOLOR 0, _RGB32(255, 255, 255) 'change color 0 intensity _PALETTECOLOR 8, _RGB32(0, 0, 0) 'change color 8 intensity COLOR 8: PRINT "Black on bright white!"

Black on bright white!


Explanation: Since QB64 does not have DAC SCREEN 0 limitations, changing color intensities for custom background colors is possible.


Example 8: Changing light gray text in SCREEN 0 to a 32 bit custom color using a LONG HTML hexadecimal value:

COLOR 7 PRINT "Color 7 is gray" K$ = INPUT$(1) _PALETTECOLOR 7, &HFFDAA520 ' FF alpha makes the color translucent PRINT "Color 7 is now Goldenrod in SCREEN 0!

Color 7 is gray Color 7 is now Goldenrod in SCREEN 0!

Explanation: _RGB32 could be used to make custom 32 bit colors or HTML values could be used after &HFF for solid colors.

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See also



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