Grayscale image: Difference between revisions
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m (→{{header|Sidef}}: minor code simplifications) |
(Lingo added) |
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The task description is silent on the issue of companded sRGB versus linear RGB. Most images are actually sRGB, and strictly speaking, the transformation to get Y from RGB is applicable to linear RGB. I imagine that, unlike the ''rc'' version, the ''julia'' version reverses compansion prior to applying the CIE transformation to extract luminance from RGB. |
The task description is silent on the issue of companded sRGB versus linear RGB. Most images are actually sRGB, and strictly speaking, the transformation to get Y from RGB is applicable to linear RGB. I imagine that, unlike the ''rc'' version, the ''julia'' version reverses compansion prior to applying the CIE transformation to extract luminance from RGB. |
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=={{header|Lingo}}== |
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<lang lingo>on rgbToGrayscaleImageFast (img) |
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res = image(img.width, img.height, 8) |
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res.paletteRef = #grayScale |
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res.copyPixels(img, img.rect, img.rect) |
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return res |
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end |
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on rgbToGrayscaleImageCustom (img) |
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res = image(img.width, img.height, 8) |
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res.paletteRef = #grayScale |
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repeat with x = 0 to img.width-1 |
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repeat with y = 0 to img.height-1 |
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c = img.getPixel(x,y) |
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n = c.red*0.2126 + c.green*0.7152 + c.blue*0.0722 |
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res.setPixel(x,y, color(256-n)) |
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end repeat |
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end repeat |
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return res |
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end</lang> |
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=={{header|Lua}}== |
=={{header|Lua}}== |
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