Data commit

Task/Grayscale-image/11l/grayscale-image.11l

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+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())