electron/spec/lib/screen-helpers.ts

93 строки
3.2 KiB
TypeScript

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