Taken from the same Wikipedia article where you got the image: Translating to values which range from 0 to 255: rOut = (rA * aA / 255) + (rB * aB * (255 – aA) / (255*255)) gOut = (gA * aA / 255) + (gB * aB * (255 – aA) / (255*255)) bOut … Read more
Since alpha value both attenuates the background color and the color value, something like this could do the trick: function rgba2rgb(RGB_background, RGBA_color) { var alpha = RGBA_color.a; return new Color( (1 – alpha) * RGB_background.r + alpha * RGBA_color.r, (1 – alpha) * RGB_background.g + alpha * RGBA_color.g, (1 – alpha) * RGB_background.b + alpha … Read more
Green color is HSV space has H = 120 and it’s in range [0, 360]. OpenCV halves the H values to fit the range [0,255], so H value instead of being in range [0, 360], is in range [0, 180]. S and V are still in range [0, 255]. As a consequence, the value of … Read more
The solution by PeterVR has the disadvantage that the additional color displays on top of the entire HTML block – meaning that it also shows up on top of div content, not just on top of the background image. This is fine if your div is empty, but if it is not using a linear … Read more
This is now possible with custom properties: .brown { –rgb: 118, 76, 41; } .green { –rgb: 51, 91, 11; } a { display: block; position: relative; } div { position: absolute; bottom: 0; background-color: rgba(var(–rgb), 0.8); } a:hover div { background-color: rgba(var(–rgb), 1); } To understand how this works, see How do I apply … Read more
Will this do? var rgbRegex = /^rgba?\((\d+),\s*(\d+),\s*(\d+)(?:,\s*(\d+(?:\.\d+)?))?\)$/
I have made a quick JSfiddle form that allows you to convert from 8-digit hex code into CSS rgba values 😉 https://jsfiddle.net/teddyrised/g02s07n4/embedded/result/ The basis is rather simple — to split the string you have provided into parts of 2-digits, and perform conversion into percentage ratios for the alpha channel, and to decimals for the RGB … Read more
Bleh, this is an acknowledged issue as far as the canvas spec is concerned. It notes: Due to the lossy nature of converting to and from premultiplied alpha color values, pixels that have just been set using putImageData() might be returned to an equivalent getImageData() as different values. So this: var can = document.createElement(‘canvas’); var … Read more
Take the lowest color component, and convert that to an alpha value. Then scale the color components by subtracting the lowest, and dividing by the alpha value. Example: 152 converts to an alpha value of (255 – 152) / 255 ~ 0.404 152 scales using (152 – 152) / 0.404 = 0 177 scales using … Read more
To simulate RGBA and HSLA background in IE, you can use a gradient filter, with the same start and end color (alpha channel is the first pair in the value of HEX) background: rgba(255, 255, 255, 0.3); /* browsers */ filter: progid:DXImageTransform.Microsoft.gradient(GradientType=0,startColorstr=”#4cffffff”, endColorstr=”#4cffffff”); /* IE */