I’ve upvoted Johannes’ answer because he’s right about that. * A few comments have been raised that my original answer was not correct. It worked if alpha values were inverted from the normal. By definition, however, this won’t work in most cases. I’ve therefore updated the formula below to be correct for the normal case. … Read more
RGB distance in the euclidean space is not very similar to “average human perception”. You can use YUV color space, it takes into account this factor : | Y’ | | 0.299 0.587 0.114 | | R | | U | = | -0.14713 -0.28886 0.436 | | G | | V | | 0.615 … Read more
In iOS 5 you could use: CGFloat red = 0.0, green = 0.0, blue = 0.0, alpha =0.0; [multipliedColor getRed:&red green:&green blue:&blue alpha:&alpha];
If you want to convert hex to rgb you can use sscanf: <?php $hex = “#ff9900”; list($r, $g, $b) = sscanf($hex, “#%02x%02x%02x”); echo “$hex -> $r $g $b”; ?> Output: #ff9900 -> 255 153 0
Yes, this way: im = Image.open(‘image.gif’) rgb_im = im.convert(‘RGB’) r, g, b = rgb_im.getpixel((1, 1)) print(r, g, b) (65, 100, 137) The reason you were getting a single value before with pix[1, 1] is because GIF pixels refer to one of the 256 values in the GIF color palette. See also this SO post: Python … Read more
OpenCV uses BGR as its default colour order for images, matplotlib uses RGB. When you display an image loaded with OpenCv in matplotlib the channels will be back to front. The easiest way of fixing this is to use OpenCV to explicitly convert it back to RGB, much like you do when creating the greyscale … Read more
Let’s say you’re working with RGB colors: each color is represented with three intensities or brightnesses. You’ve got to choose between “linear RGB” and “sRGB”. For now, we’ll simplify things by ignoring the three different intensities, and assume you just have one intensity: that is, you’re only dealing with shades of gray. In a linear … Read more
There’s a difference between additive colors (http://en.wikipedia.org/wiki/Additive_color) and subtractive colors (http://en.wikipedia.org/wiki/Subtractive_color). With additive colors, the more you add, the brighter the colors become. This is because they are emitting light. This is why the day light is (more or less) white, since the Sun is emitting in almost all the visible wavelength spectrum. On the … Read more
I believe that this does what you are looking for: h = input(‘Enter hex: ‘).lstrip(‘#’) print(‘RGB =’, tuple(int(h[i:i+2], 16) for i in (0, 2, 4))) (The above was written for Python 3) Sample run: Enter hex: #B4FBB8 RGB = (180, 251, 184) Writing to a file To write to a file with handle fhandle while … Read more
Here’s a detailed explanation of the entire conversion process: http://www.fourmilab.ch/documents/specrend/. Source code included!