92 lines
3.2 KiB
TypeScript
92 lines
3.2 KiB
TypeScript
import * as path from 'path';
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import * as fs from 'fs';
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import { screen, desktopCapturer, NativeImage } from 'electron';
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const fixtures = path.resolve(__dirname, 'fixtures');
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export enum HexColors {
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GREEN = '#00b140',
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PURPLE = '#6a0dad',
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RED = '#ff0000',
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BLUE = '#0000ff'
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};
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/**
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* Capture the screen at the given point.
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*
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* NOTE: Not yet supported on Linux in CI due to empty sources list.
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*/
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export const captureScreen = async (point: Electron.Point = { x: 0, y: 0 }): Promise<NativeImage> => {
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const display = screen.getDisplayNearestPoint(point);
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const sources = await desktopCapturer.getSources({ types: ['screen'], thumbnailSize: display.size });
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// Toggle to save screen captures for debugging.
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const DEBUG_CAPTURE = process.env.DEBUG_CAPTURE || false;
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if (DEBUG_CAPTURE) {
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for (const source of sources) {
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await fs.promises.writeFile(path.join(fixtures, `screenshot_${source.display_id}_${Date.now()}.png`), source.thumbnail.toPNG());
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}
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}
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const screenCapture = sources.find(source => source.display_id === `${display.id}`);
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// Fails when HDR is enabled on Windows.
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// https://bugs.chromium.org/p/chromium/issues/detail?id=1247730
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if (!screenCapture) {
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const displayIds = sources.map(source => source.display_id);
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throw new Error(`Unable to find screen capture for display '${display.id}'\n\tAvailable displays: ${displayIds.join(', ')}`);
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}
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return screenCapture.thumbnail;
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};
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const formatHexByte = (val: number): string => {
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const str = val.toString(16);
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return str.length === 2 ? str : `0${str}`;
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};
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/**
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* Get the hex color at the given pixel coordinate in an image.
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*/
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export const getPixelColor = (image: Electron.NativeImage, point: Electron.Point): string => {
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// image.crop crashes if point is fractional, so round to prevent that crash
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const pixel = image.crop({ x: Math.round(point.x), y: Math.round(point.y), width: 1, height: 1 });
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// TODO(samuelmaddock): NativeImage.toBitmap() should return the raw pixel
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// color, but it sometimes differs. Why is that?
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const [b, g, r] = pixel.toBitmap();
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return `#${formatHexByte(r)}${formatHexByte(g)}${formatHexByte(b)}`;
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};
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const hexToRgba = (hexColor: string) => {
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const match = hexColor.match(/^#([0-9a-fA-F]{6,8})$/);
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if (!match) return;
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const colorStr = match[1];
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return [
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parseInt(colorStr.substring(0, 2), 16),
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parseInt(colorStr.substring(2, 4), 16),
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parseInt(colorStr.substring(4, 6), 16),
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parseInt(colorStr.substring(6, 8), 16) || 0xFF
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];
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};
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/** Calculate euclidian distance between colors. */
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const colorDistance = (hexColorA: string, hexColorB: string) => {
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const colorA = hexToRgba(hexColorA);
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const colorB = hexToRgba(hexColorB);
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if (!colorA || !colorB) return -1;
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return Math.sqrt(
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Math.pow(colorB[0] - colorA[0], 2) +
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Math.pow(colorB[1] - colorA[1], 2) +
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Math.pow(colorB[2] - colorA[2], 2)
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);
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};
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/**
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* Determine if colors are similar based on distance. This can be useful when
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* comparing colors which may differ based on lossy compression.
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*/
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export const areColorsSimilar = (
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hexColorA: string,
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hexColorB: string,
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distanceThreshold = 90
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): boolean => {
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const distance = colorDistance(hexColorA, hexColorB);
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return distance <= distanceThreshold;
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};
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