face-api/src/dom/createCanvas.ts

32 lines
1.1 KiB
TypeScript

import { IDimensions } from '../classes/Dimensions';
import { env } from '../env/index';
import { getContext2dOrThrow } from './getContext2dOrThrow';
import { getMediaDimensions } from './getMediaDimensions';
import { isMediaLoaded } from './isMediaLoaded';
export function createCanvas({ width, height }: IDimensions): HTMLCanvasElement {
const { createCanvasElement } = env.getEnv();
const canvas = createCanvasElement();
canvas.width = width;
canvas.height = height;
return canvas;
}
export function createCanvasFromMedia(media: HTMLImageElement | HTMLVideoElement | ImageData, dims?: IDimensions): HTMLCanvasElement {
const { ImageData } = env.getEnv();
if (!(media instanceof ImageData) && !isMediaLoaded(media)) {
throw new Error('createCanvasFromMedia - media has not finished loading yet');
}
const { width, height } = dims || getMediaDimensions(media);
const canvas = createCanvas({ width, height });
if (media instanceof ImageData) {
getContext2dOrThrow(canvas).putImageData(media, 0, 0);
} else {
getContext2dOrThrow(canvas).drawImage(media, 0, 0, width, height);
}
return canvas;
}