Grayscale image: Difference between revisions
Added 11l
m (Updated description and link for Fōrmulæ solution) |
Alextretyak (talk | contribs) (Added 11l) |
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When using floating-point arithmetic make sure that rounding errors would not cause run-time problems or else distorted results when calculated luminance is stored as an unsigned integer.
<br><br>
=={{header|11l}}==
{{trans|Python}}
<lang 11l>T Colour
Byte r, g, b
F (r, g, b)
.r = r
.g = g
.b = b
F ==(other)
R .r == other.r & .g == other.g & .b == other.b
V black = Colour(0, 0, 0)
V white = Colour(255, 255, 255)
T Bitmap
Int width, height
Colour background
[[Colour]] map
F (width = 40, height = 40, background = white)
assert(width > 0 & height > 0)
.width = width
.height = height
.background = background
.map = (0 .< height).map(h -> (0 .< @width).map(w -> @@background))
F fillrect(x, y, width, height, colour = black)
assert(x >= 0 & y >= 0 & width > 0 & height > 0)
L(h) 0 .< height
L(w) 0 .< width
.map[y + h][x + w] = colour
F set(x, y, colour = black)
.map[y][x] = colour
F get(x, y)
R .map[y][x]
F togreyscale()
L(h) 0 .< .height
L(w) 0 .< .width
V (r, g, b) = .get(w, h)
V l = Int(0.2126 * r + 0.7152 * g + 0.0722 * b)
.set(w, h, Colour(l, l, l))
F writeppmp3()
V magic = "P3\n"
V comment = "# generated from Bitmap.writeppmp3\n"
V s = magic‘’comment‘’("#. #.\n#.\n".format(.width, .height, 255))
L(h) (.height - 1 .< -1).step(-1)
L(w) 0 .< .width
V (r, g, b) = .get(w, h)
s ‘’= ‘ #3 #3 #3’.format(r, g, b)
s ‘’= "\n"
R s
V bitmap = Bitmap(4, 4, white)
bitmap.fillrect(1, 0, 1, 2, Colour(127, 0, 63))
bitmap.set(3, 3, Colour(0, 127, 31))
print(‘Colour:’)
print(bitmap.writeppmp3())
print(‘Grey:’)
bitmap.togreyscale()
print(bitmap.writeppmp3())</lang>
{{out}}
<pre>
Colour:
P3
# generated from Bitmap.writeppmp3
4 4
255
255 255 255 255 255 255 255 255 255 0 127 31
255 255 255 255 255 255 255 255 255 255 255 255
255 255 255 127 0 63 255 255 255 255 255 255
255 255 255 127 0 63 255 255 255 255 255 255
Grey:
P3
# generated from Bitmap.writeppmp3
4 4
255
254 254 254 254 254 254 254 254 254 93 93 93
254 254 254 254 254 254 254 254 254 254 254 254
254 254 254 31 31 31 254 254 254 254 254 254
254 254 254 31 31 31 254 254 254 254 254 254
</pre>
=={{header|Ada}}==
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