simple2k13/dist/image/canvasDrawImage/index.js

some simple functions

import { dataType } from '../..';
const canvasDrawImage = (canvas, url, options = {}) => {
    const { interceptors, crossOrigin = 'Anonymous', zoom = 1, debug = false } = options;
    return new Promise((resolve, reject) => {
        try {
            const ctx = canvas?.getContext('2d');
            const cW = canvas.width;
            const cH = canvas.height;
            let scale = 1;
            const img = new Image();
            img.crossOrigin = crossOrigin;
            img.src = url;
            img.onload = () => {
                let iW = img.width;
                let iH = img.height;
                if ((cW / cH) > (iW / iH)) {
                    scale = cH / iH;
                }
                else {
                    scale = cW / iW;
                }
                iW = iW * scale * zoom;
                iH = iH * scale * zoom;
                debug && console.log({
                    cW,
                    cH,
                    scale,
                    zoom,
                    originIW: img.width,
                    originIH: img.height,
                    iW,
                    iH
                });
                const [dx, dy, dw, dh] = [(cW - iW) / 2, (cH - iH) / 2, iW, iH];
                if (typeof interceptors === 'function') {
                    const result = interceptors();
                    if (dataType(result) !== 'Promise')
                        throw reject(new Error('interceptors must be Promise'));
                    result.then((pass) => {
                        if (pass) {
                            ctx?.drawImage(img, dx, dy, dw, dh);
                            resolve('success');
                        }
                        else {
                            reject('cancel');
                        }
                    }, () => {
                        reject('cancel');
                    });
                    return;
                }
                ctx?.drawImage(img, dx, dy, dw, dh);
                resolve('success');
            };
            img.onerror = (error) => {
                reject(error);
            };
        }
        catch (error) {
            reject(error);
        }
    });
};
export default canvasDrawImage;
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