![]() Int defaultTextViewColor = textView.getTextColors(). int rgba_color = Color.parseColor("#8a000000") //textViewColor Here is some java code (works on Android API 24): //int rgb_background = Color.parseColor("#ffffff") //white background If the color is in non pre-multiplied color-space, then you can just discard the alpha channel. If the RGBA is in pre-multiplied color-space and is semi-transparent, you need to divide out alpha to get the correct RGB color. In my case, I wanted to convert an RGBA image to RGB and the following worked just as expected: rgbImage = cv2.cvtColor(npimage, cv2.COLOR_RGBA2RGB) version rgba(0,0,0,0) with matte rgb(ff,ff,ff) will be changed to rgb(0,0,0). This changed version works fine for me, because in prev. Solution provided by Andras Zoltan should be slightly changed to: Source => Target = (BGColor + Source) = To get the final 0-255 values for Target you simply multiply all the normalised values back up by 255, making sure you cap at 255 if any of the combined values exceed 1.0 (this is over-exposure and there are more complex algorithms dealing with this that involve whole-image processing etc.).ĮDIT: In your question you said you want a white background - in that case just fix BGColor to 255,255,255. Target.B = ((1 - Source.A) * BGColor.B) + (Source.A * Source.B) Target.G = ((1 - Source.A) * BGColor.G) + (Source.A * Source.G) Target.R = ((1 - Source.A) * BGColor.R) + (Source.A * Source.R) Now, the conversion is defined as (in complete psuedo code here!): Source => Target = (BGColor + Source) = We'll call the result BGColor Note - if the background colour is also transparent, then you'll have to recurse the process for that first (again, choosing a matte) to get the source RGB for this operation. Normalise also the matte colour (black, white whatever).Normalise the RGBA values so that they're all between 0 and 1 - just divide each value by 255 to do this.There is an algorithm for this (from this wikipedia link): This ends up being equal to answer below *Ī more specific answer, however, incorporates the alpha value into the actual colour result based on an opaque background colour (or 'matte' as it's referred to). I've therefore updated the formula below to be correct for the normal case. By definition, however, this won't work in most cases. It worked if alpha values were inverted from the normal. * A few comments have been raised that my original answer was not correct. Hope this shit helps you out and feel free to tweak it further.I've upvoted Johannes' answer because he's right about that. The solution I submitted in my PR for work actually wasn't as thorough as the solution I've provided here, so I guess I had some fun optimizing it just for this blog post. Return the resulting RGB colour (Line 35). Get the target RGB values based on the algorithm for alpha compositing or alpha blending (Lines 31-33). Test case of rgb(255,), the RGB values are 255, NaN, undefined.Test case of rgba(36), the RGBA values are 36, undefined, undefined, undefined.CodeīgRgb ? : string } ) => to check this repeating pattern for the RGB values with an optional comma separating them, so the input may not have all values or be in a poor format, therefore not caught by the Regex pattern. Test cases are included below, along with a walkthrough of the code. Here's the solution that I came up with: a helper function to get from a source RGBA colour based on a background color (defaults to white) to the resulting RGB colour. Instead of doing this manually, there has to be a way via code to convert a colour with opacity to the equivalent "solid" colour without opacity, so from a RGBA colour to a RGB colour. ![]() Using the colour picker, I can get the equivalent colour: rgba(246,252,250,1) or rgb(246,252,250) without the alpha (opacity). I have a div element with a background colour of teal green at an opacity of 5%: rgba(36,193,144,0.05) ![]() There has got to be a function to do that, and there is! Problem Ok, this worked, but what if I didn't want to hard code this result? We had our colour palette as constants in the theme config, so I wanted to be able to pass that colour constant and get the equivalent RGB colour. Frustrated as fuck□, I consulted B, who told me that I could just get the equivalent RGB or hex colour without any opacity by using the colour picker in dev tools. Everything was working smoothly, until I noticed my columns kept overlapping the text when scrolling to the left.Ĭhecking the styles, the column had a background colour with opacity. If you want to have cool fonts, please also try our font keyboard to help easily get fonts at Font Keyboard iOS app and Font Keyboard Android app. It comes with many options and it demonstrates instantly. Recently for work, I was working on a ticket to implement sticky columns for an existing table component. A RGBA and Hex Color CSS generator that helps you quickly convert and generate RGBA and Hex Color CSS declarations for your website.
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