colors.spin2

CON
  ' BGR 5+6+5 16bits/pixel (RGB reversed)
  black                 = $0000
  white                 = $FFFF
  blue                  = $F800
  green                 = $07E0
  red                   = $001F
  yellow                = red+green
  orange                = %00000_100000_11111
  purple                = red+blue
  cyan                  = green+blue
  dark_turquoise        = $A421
  grey                  = $7BEF
  lightgrey              = %10000_100000_10000
  darkgrey              = %01000_010000_01000

PUB null()

PUB color_to_rgb(c):r,g,b
'Returns the red, green and blue
'components of a BGR 565 16bit color
  r := (%11111) & c
  g := ((%111111 << 5) & c) >> 5
  b := ((%11111  << 11) & c) >> 11

PUB set_color(r,g,b):c
'Returns a BGR 565 16 bit color
'from 0-255 color components
  b := 0 #> b/8 <# $1F
  g := 0 #> g/4 <# $3F
  r := 0 #> r/8 <# $1F
  c := b<<11|g<<5|r

PUB lighten(c,f):light|r,g,b
'Lightens the color c by a factor f
  f := f <# 31
  r,g,b := color_to_rgb(c)
  r := 0 #> (r+f) <# $1F
  g := 0 #> (g+ (2*f)) <# $3F
  b := 0 #> (b+f) <# $1F
  light := (b<<11) | (g<<5) | r

PUB darken(c,f):dark_color|r,g,b
'Darkens the color c by a factor f
  f := f <# 31
  r,g,b := color_to_rgb(c)
  r := 0 #> (r - f) <# $1F
  g := 0 #> (g - (2*f)) <# $3F '$3F
  b := 0 #> (b - f) <# $1F
  dark_color := (b<<11) | (g<<5) | r

PUB transition(c, r, g, b):result | bc, gc, rc
  bc := (0 #> (($1F<<11&c)>>11+b) <# $1F)
  gc := (0 #> (($3F<<5&c)>>5+g) <# $3F)
  rc := (0 #> (($1F&c)+r) <# $1F)
  result := bc<<11 | gc<<5 | rc

PUB mix_color(c,r,g,b):result
'Mixes color c with rgb components
  b := 0 #> b <# $1F
  g := 0 #> g <# $3F
  r := 0 #> r <# $1F
  result := (c & $1F<<11)+(b<<11)| (c & $3F<<5)+(g<<5)| (c & $1F) + r

PUB invert_color(c):i|r,g,b
'Returns the inverted color of c
  r,g,b := color_to_rgb(c)
  i := ($1F - b)<<11 | ($3F - g)<<5 | ($1F - r)