英文:
How to convert color object from parsed PSD into usable RGBA
问题
我正在解析一个PSD,获取正常的RGBA值,最近我遇到了这些奇怪的浮点颜色值:
{
"red": 1.0343483686447144,
"green": 0.9487225413322449,
"blue": -0.12634865939617157,
"alpha": 100,
"rgba": "rgba(1.0343483686447144, 0.9487225413322449, -0.12634865939617157, 1)"
}
这是我的解析函数:
function getRGBColor(color, opacity = 100) {
if ("Clr " in color) {
color = color["Clr "];
}
var type = color.class.id;
var red = color["Rd "];
var green = color["Grn "];
var blue = color["Bl "];
if ("blueFloat" in color) {
red = color.redFloat;
green = color.greenFloat;
blue = color.blueFloat;
}
var rgba = {
red: red,
green: green,
blue: blue,
alpha: opacity,
rgba: `rgba(${red}, ${green}, ${blue}, ${opacity/100})`
}
return rgba;
}
它应该是黄色的。
这个对象来自于strokeColorContent
。
var vectorMask = node.get("vectorMask")?.export();
var vectorStroke = node.get("vectorStroke")?.data;
var vectorStrokeContent = node.get("vectorStrokeContent")?.data;
var fillColor = getRGBColor(vectorStrokeContent);
相关问题:
https://stackoverflow.com/q/75761808/441016
更新:
我已经更新了CSS以使用建议的lab()
颜色空间,似乎有效:
lab(94 -12 103)
我还没有确认alpha值,但这似乎有效:
lab(94 -12 103 / 1)
在大多数浏览器中似乎支持lab()
(目前不支持Firefox,但在Firefox 113中支持)。
要获取rgba()值,需要从lab到rgba的公式。
英文:
I'm parsing a PSD getting normal RGBA values and recently I encountered this strange float color values:
{
"red": 1.0343483686447144,
"green": 0.9487225413322449,
"blue": -0.12634865939617157,
"alpha": 100,
"rgba": "rgba(1.0343483686447144, 0.9487225413322449, -0.12634865939617157, 1)"
}
Here is my parsing function:
function getRGBColor(color, opacity = 100) {
if ("Clr " in color) {
color = color["Clr "];
}
var type = color.class.id;
var red = color["Rd "];
var green = color["Grn "];
var blue = color["Bl "];
if ("blueFloat" in color) {
red = color.redFloat;
green = color.greenFloat;
blue = color.blueFloat;
}
var rgba = {
red: red,
green: green,
blue: blue,
alpha: opacity,
rgba: `rgba(${red}, ${green}, ${blue}, ${opacity/100})`
}
return rgba;
}
It's supposed to be yellow.
The object is coming from strokeColorContent
.
var vectorMask = node.get("vectorMask")?.export();
var vectorStroke = node.get("vectorStroke")?.data;
var vectorStrokeContent = node.get("vectorStrokeContent")?.data;
var fillColor = getRGBColor(vectorStrokeContent);
Related question:
https://stackoverflow.com/q/75761808/441016
Update:
I've updated the CSS to use the lab()
color space as suggested and it seems to work:
lab(94 -12 103)
I haven't confirmed the alpha value yet but this seems to work:
lab(94 -12 103 / 1)
It seems that, in most browsers, lab()
is being supported (not currently in Firefox but in Firefox 113).
To get the rgba() value there needs to be a formula from lab to rgba.
答案1
得分: 1
显然,psd.js 的颜色输出对象将LAB值与RGB值混淆。
不幸的是,你只能将LAB转换为更通用的RGB近似值。
你不能精确地将LAB转换为RGB(没有目标颜色空间的定义)
LAB颜色系统的整个理念是提供一种表示人眼可辨别的所有颜色的系统,作为所有种类颜色转换的参考颜色空间。
解决方法:通用RGB近似:
假设你的psd使用了更通用的RGB颜色配置文件,例如类似于sRGB,你可以使用antimatter15的rgb-lab库。
let psdCols = {
"red": 1.0343483686447144,
"green": 0.9487225413322449,
"blue": -0.12634865939617157,
"alpha": 100,
}
let labRGBAVals = [[psdCols.green, psdCols.blue, psdCols.red].map(val => +(val * 100).toFixed(0)), psdCols.alpha / 100].flat();
console.log('LAB values: ', labRGBAVals.join(' '));
let rgba = lab2rgb(labRGBAVals).map(val => +(val).toFixed(0));
labToRgb.style.backgroundColor = `rgba( ${rgba.join(', ')} )`
console.log('RGB values: ', rgba)
/**
* 基于
* https://github.com/antimatter15/rgb-lab/blob/master/color.js
*/
function lab2rgb(lab) {
let y = (lab[0] + 16) / 116,
x = lab[1] / 500 + y,
z = y - lab[2] / 200,
r, g, b;
x = 0.95047 * ((x * x * x > 0.008856) ? x * x * x : (x - 16 / 116) / 7.787);
y = 1.00000 * ((y * y * y > 0.008856) ? y * y * y : (y - 16 / 116) / 7.787);
z = 1.08883 * ((z * z * z > 0.008856) ? z * z * z : (z - 16 / 116) / 7.787);
r = x * 3.2406 + y * -1.5372 + z * -0.4986;
g = x * -0.9689 + y * 1.8758 + z * 0.0415;
b = x * 0.0557 + y * -0.2040 + z * 1.0570;
r = (r > 0.0031308) ? (1.055 * Math.pow(r, 1 / 2.4) - 0.055) : 12.92 * r;
g = (g > 0.0031308) ? (1.055 * Math.pow(g, 1 / 2.4) - 0.055) : 12.92 * g;
b = (b > 0.0031308) ? (1.055 * Math.pow(b, 1 / 2.4) - 0.055) : 12.92 * b;
return [Math.max(0, Math.min(1, r)) * 255,
Math.max(0, Math.min(1, g)) * 255,
Math.max(0, Math.min(1, b)) * 255]
}
.color {
width: 200px;
height: 200px;
border: 1px solid #ccc;
}
#rgb {
background: rgb(255, 242, 0)
}
<h3>rgba(255, 242, 0, 1)</h3>
<div class="color" id="rgb"></div>
<h3>LAB*a (95, -13, 103, 1) to RGB</h3>
<div class="color" id="labToRgb"></div>
理想情况下,你可以解析“输出意图”(目标)颜色配置文件
例如,一个 .icc 文件,然后将LAB颜色转换为满足所需目标颜色空间的颜色。
英文:
So apparently, the psd.js color output object confuses RGB with LAB values.
Unfortunately, you can only convert LAB to to a more generic RGB approximation.
You can't precisely convert LAB to RGB (without a target color space definition)
The whole idea behind the LAB color system is to provide a system that represents all colors distinguishable by the human eye as a reference color space for all kind of color conversions.
Workaround: generic RGB approximation:
Provided, your psd used a more generic RGB color profile e.g similar to sRGB, you can use antimatter15's rgb-lab library
<!-- begin snippet: js hide: false console: false babel: false -->
<!-- language: lang-js -->
let psdCols = {
"red": 1.0343483686447144,
"green": 0.9487225413322449,
"blue": -0.12634865939617157,
"alpha": 100,
}
let labRGBAVals = [[psdCols.green, psdCols.blue, psdCols.red].map(val=>+(val*100).toFixed(0)) ,psdCols.alpha / 100].flat();
console.log('LAB values: ', labRGBAVals.join(' '));
let rgba = lab2rgb(labRGBAVals).map(val=>+(val).toFixed(0) );
labToRgb.style.backgroundColor = `rgba( ${rgba.join(', ')} )`
console.log('RGB values: ', rgba)
/**
* based on
* https://github.com/antimatter15/rgb-lab/blob/master/color.js
*/
function lab2rgb(lab){
let y = (lab[0] + 16) / 116,
x = lab[1] / 500 + y,
z = y - lab[2] / 200,
r, g, b;
x = 0.95047 * ((x * x * x > 0.008856) ? x * x * x : (x - 16/116) / 7.787);
y = 1.00000 * ((y * y * y > 0.008856) ? y * y * y : (y - 16/116) / 7.787);
z = 1.08883 * ((z * z * z > 0.008856) ? z * z * z : (z - 16/116) / 7.787);
r = x * 3.2406 + y * -1.5372 + z * -0.4986;
g = x * -0.9689 + y * 1.8758 + z * 0.0415;
b = x * 0.0557 + y * -0.2040 + z * 1.0570;
r = (r > 0.0031308) ? (1.055 * Math.pow(r, 1/2.4) - 0.055) : 12.92 * r;
g = (g > 0.0031308) ? (1.055 * Math.pow(g, 1/2.4) - 0.055) : 12.92 * g;
b = (b > 0.0031308) ? (1.055 * Math.pow(b, 1/2.4) - 0.055) : 12.92 * b;
return [Math.max(0, Math.min(1, r)) * 255,
Math.max(0, Math.min(1, g)) * 255,
Math.max(0, Math.min(1, b)) * 255]
}
<!-- language: lang-css -->
.color {
width: 200px;
height: 200px;
border: 1px solid #ccc;
}
#rgb {
background: rgb(255, 242, 0)
}
<!-- language: lang-html -->
<h3>rgba(255, 242, 0, 1)</h3>
<div class="color" id="rgb"></div>
<h3>LAB*a (95, -13, 103, 1) to RGB</h3>
<div class="color" id="labToRgb"></div>
<!-- end snippet -->
Ideally, you could parse a "output-intent" (target) color profile
E.g an .icc file and then convert LAB colors to meet the desired target color space.
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