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Copy pathimage.ts
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165 lines (146 loc) · 5.3 KB
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import {getSVGFilterMatrixValue} from '../../generators/svg-filter';
import {bgFetch} from './network';
import {getURLHost} from '../../utils/url';
import {loadAsDataURL} from '../../utils/network';
import {FilterConfig} from '../../definitions';
export interface ImageDetails {
src: string;
dataURL: string;
width: number;
height: number;
isDark: boolean;
isLight: boolean;
isTransparent: boolean;
isLarge: boolean;
}
export async function getImageDetails(url: string) {
let dataURL: string;
if (url.startsWith('data:')) {
dataURL = url;
} else {
dataURL = await getImageDataURL(url);
}
const image = await urlToImage(dataURL);
const info = analyzeImage(image);
return {
src: url,
dataURL,
width: image.naturalWidth,
height: image.naturalHeight,
...info,
};
}
async function getImageDataURL(url: string) {
if (getURLHost(url) === location.host) {
return await loadAsDataURL(url);
}
return await bgFetch({url, responseType: 'data-url'});
}
async function urlToImage(url: string) {
return new Promise<HTMLImageElement>((resolve, reject) => {
const image = new Image();
image.onload = () => resolve(image);
image.onerror = () => reject(`Unable to load image ${url}`);
image.src = url;
});
}
const MAX_ANALIZE_PIXELS_COUNT = 32 * 32;
let canvas: HTMLCanvasElement | OffscreenCanvas;
let context: CanvasRenderingContext2D | OffscreenCanvasRenderingContext2D;
function createCanvas() {
const maxWidth = MAX_ANALIZE_PIXELS_COUNT;
const maxHeight = MAX_ANALIZE_PIXELS_COUNT;
canvas = document.createElement('canvas');
canvas.width = maxWidth;
canvas.height = maxHeight;
context = canvas.getContext('2d');
context.imageSmoothingEnabled = false;
}
function removeCanvas() {
canvas = null;
context = null;
}
function analyzeImage(image: HTMLImageElement) {
if (!canvas) {
createCanvas();
}
const {naturalWidth, naturalHeight} = image;
const naturalPixelsCount = naturalWidth * naturalHeight;
const k = Math.min(1, Math.sqrt(MAX_ANALIZE_PIXELS_COUNT / naturalPixelsCount));
const width = Math.ceil(naturalWidth * k);
const height = Math.ceil(naturalHeight * k);
context.clearRect(0, 0, width, height);
context.drawImage(image, 0, 0, naturalWidth, naturalHeight, 0, 0, width, height);
const imageData = context.getImageData(0, 0, width, height);
const d = imageData.data;
const TRANSPARENT_ALPHA_THRESHOLD = 0.05;
const DARK_LIGHTNESS_THRESHOLD = 0.4;
const LIGHT_LIGHTNESS_THRESHOLD = 0.7;
let transparentPixelsCount = 0;
let darkPixelsCount = 0;
let lightPixelsCount = 0;
let i: number, x: number, y: number;
let r: number, g: number, b: number, a: number;
let l: number;
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
i = 4 * (y * width + x);
r = d[i + 0] / 255;
g = d[i + 1] / 255;
b = d[i + 2] / 255;
a = d[i + 3] / 255;
if (a < TRANSPARENT_ALPHA_THRESHOLD) {
transparentPixelsCount++;
} else {
// Use sRGB to determine the `pixel Lightness`
// https://en.wikipedia.org/wiki/Relative_luminance
l = 0.2126 * r + 0.7152 * g + 0.0722 * b;
if (l < DARK_LIGHTNESS_THRESHOLD) {
darkPixelsCount++;
}
if (l > LIGHT_LIGHTNESS_THRESHOLD) {
lightPixelsCount++;
}
}
}
}
const totalPixelsCount = width * height;
const opaquePixelsCount = totalPixelsCount - transparentPixelsCount;
const DARK_IMAGE_THRESHOLD = 0.7;
const LIGHT_IMAGE_THRESHOLD = 0.7;
const TRANSPARENT_IMAGE_THRESHOLD = 0.1;
const LARGE_IMAGE_PIXELS_COUNT = 800 * 600;
return {
isDark: ((darkPixelsCount / opaquePixelsCount) >= DARK_IMAGE_THRESHOLD),
isLight: ((lightPixelsCount / opaquePixelsCount) >= LIGHT_IMAGE_THRESHOLD),
isTransparent: ((transparentPixelsCount / totalPixelsCount) >= TRANSPARENT_IMAGE_THRESHOLD),
isLarge: (naturalPixelsCount >= LARGE_IMAGE_PIXELS_COUNT),
};
}
const objectURLs = new Set<string>();
export function getFilteredImageDataURL({dataURL, width, height}: ImageDetails, filter: FilterConfig) {
const matrix = getSVGFilterMatrixValue(filter);
const svg = [
`<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="${width}" height="${height}">`,
'<defs>',
'<filter id="darkreader-image-filter">',
`<feColorMatrix type="matrix" values="${matrix}" />`,
'</filter>',
'</defs>',
`<image width="${width}" height="${height}" filter="url(#darkreader-image-filter)" xlink:href="${dataURL}" />`,
'</svg>',
].join('');
const bytes = new Uint8Array(svg.length);
for (let i = 0; i < svg.length; i++) {
bytes[i] = svg.charCodeAt(i);
}
const blob = new Blob([bytes], {type: 'image/svg+xml'});
const objectURL = URL.createObjectURL(blob);
objectURLs.add(objectURL);
return objectURL;
}
export function cleanImageProcessingCache() {
removeCanvas();
objectURLs.forEach((u) => URL.revokeObjectURL(u));
objectURLs.clear();
}