Function getBgImageInfo

tests/inject/dynamic/image-analysis.tests.ts:85–123

(bgImageValue: string)

}

async function getBgImageInfo(bgImageValue: string) {
    const bgImageURL = bgImageValue.match(/^url\("(.*)"\)$/)![1];
    const image = await urlToImage(bgImageURL);

    const width = 8;
    const height = 8;
    const canvas = document.createElement('canvas');
    canvas.width = width;
    canvas.height = height;
    const context = canvas.getContext('2d')!;
    context.drawImage(image, 0, 0, width, height);

    const d = context.getImageData(0, 0, width, height).data;
    let lightPixels = 0;
    let darkPixels = 0;
    let opaquePixels = 0;
    for (let y = 0; y < height; y++) {
        for (let x = 0; x < width; x++) {
            const i = 4 * (x + width * y);
            const r = d[i + 0];
            const g = d[i + 1];
            const b = d[i + 2];
            const a = d[i + 3];
            if (a > 127) {
                opaquePixels++;
                const lightness = (r + g + b) / 3 / 255;
                if (lightness > 0.7) {
                    lightPixels++;
                } else if (lightness < 0.3) {
                    darkPixels++;
                }
            }
        }
    }
    return {
        lightness: lightPixels / opaquePixels,
        darkness: darkPixels / opaquePixels,
    };
}

describe('IMAGE ANALYSIS', () => {
    it('should analyze dark icon', async () => {