color-space

问题 Is this (a) an own color space like AdobeRGB and sRGB or is this (b) a name for the RGB color space that the device uses? (in case it is (b) , what color space should be used to render a pdf? is sRGB the default to use? should a pdf viewer application be able to change this 'device' color space?) 回答1: DeviceRGB simply means that its a 3 component space with Red Green and Blue colourants, it is not calibrated. sRGB is a calibrated space (I believe 'standard' RGB, which is where the 's' comes

问题 How do I convert RGB to HSL in C/C++? (Note: This is a (short) self-answer -- I posted it here so people can find it quickly with a search.) 回答1: Translating the code from here, you get: // Assuming sizeof(unsigned int) == 4 * sizeof(unsigned char) unsigned int RgbToHsl(unsigned int rgb) // Alpha value is simply passed through { #ifdef __cplusplus using std::max; using std::min; #endif double r = (rgb >> (0 * CHAR_BIT)) & UCHAR_MAX, g = (rgb >> (1 * CHAR_BIT)) & UCHAR_MAX, b = (rgb >> (2 *

问题 Looking at the docs, I should be able to use BGRA for the internal format of a texture. I am supplying the texture with BGRA data (using GL_RGBA8_OES for glRenderbufferStorage as it seems BGRA there is not allowed). However, the following does not work: glTexImage2D(GL_TEXTURE_2D, 0, **GL_BGRA**, w, h, 0, GL_BGRA, GL_UNSIGNED_BYTE, buffer); ... glReadPixels(0, 0, w,h, GL_BGRA, GL_UNSIGNED_BYTE,buffer, 0); While this gives me a black frame: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL

问题 Looking at the docs, I should be able to use BGRA for the internal format of a texture. I am supplying the texture with BGRA data (using GL_RGBA8_OES for glRenderbufferStorage as it seems BGRA there is not allowed). However, the following does not work: glTexImage2D(GL_TEXTURE_2D, 0, **GL_BGRA**, w, h, 0, GL_BGRA, GL_UNSIGNED_BYTE, buffer); ... glReadPixels(0, 0, w,h, GL_BGRA, GL_UNSIGNED_BYTE,buffer, 0); While this gives me a black frame: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL

问题 This seems like such a simple problem, exactly what colormath was designed for. But calling convert_color appears to return the same object that was passed in. According to the documentation a failed conversion should raise a UndefinedConversionError , not return an object. >>> from colormath.color_objects import sRGBColor, AdobeRGBColor >>> from colormath.color_conversions import convert_color >>> srgb = sRGBColor(0.0, 1.0, 0.0) >>> srgb sRGBColor(rgb_r=0.0,rgb_g=1.0,rgb_b=0.0) >>> argb =

问题 The task I want to achieve is to replicate Photoshop RGB to LAB conversion. For simplicity, I will describe what I did to extract only the L Channel. Extracting Photoshop's L Channel Here is RGB Image which includes all RGB colors (Please click and download): In order to extract Photoshop's LAB what I did is the following: Loaded the image into Photoshop. Set Mode to LAB. Selected the L Channel in the Channel Panel. Set Mode to Grayscale. Set mode to RGB. Saved as PNG. This is the L Channel

问题 Is there a canonical colorspace conversion library? I can't find any pre-existing solutions. Is CIELab conversion is too obscure? 回答1: It is not obscure, I have done it myself recently from RGB to CIELAB. Look at the source of OpenCV there is a lot of color convesrion functions. File is: ../src/cv/cvcolor.cpp Have a look at the function icvBGRx2Lab_32f_CnC3R for example. This is probably what are you looking for. 来源： https://stackoverflow.com/questions/2428304/cielab-colorspace-conversion

问题 I have multiple images with a custom profile embedded in them and want to convert the image to sRGB in order to serve it up to a browser. I have seen code like the following: BufferedImage image = ImageIO.read(fileIn); ColorSpace ics = ColorSpace.getInstance(ColorSpace.CS_sRGB); ColorConvertOp cco = new ColorConvertOp(ics, null); BufferedImage result = cco.filter(image, null); ImageIO.write(result, "PNG", fileOut); where fileIn and fileOut are File objects representing the input file and

问题 I'm trying to automate the enhancement of some images that are to be transfered to a digital frame. I have code in place that resizes, adds a date/time to the least-significant (least details) corner of the image and pastes together pairs of portrait images to avoid displaying a single portrait in the frame's 41:20 low resolution screen. I've implemented a brightness-stretching filter for those pictures where the lighting wasn't so good, using the colorsys.rgb_to_hsv function to calculate H,

问题 For this project I use Python's colorsys to convert RGB to HSV vice versa to be able to manipulate saturation and lightness, but I noticed that some colors yields bogus results. For example, if I take any primary colors there's no problem: However if I chose a random RGB color and convert it to HSV, I sometime gets bogus results. Sometimes these bogus results occurs when I increase or decrease the lightness or the saturation of a color. In this example lightness 10%, 20% and saturation 100%