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Linus Rath
f7a7828bfa
The host reads the size a PNG, GIF, JPEG, WebP or BMP declares in its header first: over 50 megapixels it answers too_big, trackers and tiny images are never decoded, a format whose header it can't read is unsupported, and large images are decoded at the target width. A browser that throws a TypeError on createImageBitmap's options decodes without them. The tests' stand-in pictures are now PNG headers instead of JSON (the code reads the header), so image-shrink.test.ts and plugin-host-attachment-image.test.ts build them that way, and the first shrink test expects the resize options on createImageBitmap.
43 lines
2.5 KiB
TypeScript
43 lines
2.5 KiB
TypeScript
import { describe, expect, it } from 'vitest';
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import { imageDimensions } from '../image-size';
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// The size an image declares, read from the header of each format.
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const bytes = (...parts: (number[] | string)[]) => new Uint8Array(parts.flatMap((p) => (typeof p === 'string' ? [...p].map((c) => c.charCodeAt(0)) : p)));
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const be32 = (n: number) => [(n >>> 24) & 255, (n >>> 16) & 255, (n >>> 8) & 255, n & 255];
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const le16 = (n: number) => [n & 255, (n >>> 8) & 255];
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const le24 = (n: number) => [n & 255, (n >>> 8) & 255, (n >>> 16) & 255];
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const le32 = (n: number) => [...le16(n & 0xffff), ...le16(n >>> 16)];
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describe('imageDimensions', () => {
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it('reads PNG and GIF', () => {
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expect(imageDimensions(bytes([0x89], 'PNG', [13, 10, 26, 10, 0, 0, 0, 13], 'IHDR', be32(40_000), be32(30_000), [8, 2, 0, 0, 0]))).toEqual({ width: 40_000, height: 30_000 });
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expect(imageDimensions(bytes('GIF89a', le16(320), le16(200), [0, 0, 0]))).toEqual({ width: 320, height: 200 });
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});
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it('reads a JPEG frame header after an EXIF block', () => {
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const app1 = [0xff, 0xe1, 0x00, 0x10, ...new Array(14).fill(0)];
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const sof = [0xff, 0xc2, 0x00, 0x11, 8, 0x0b, 0xb8, 0x0f, 0xa0, 3, ...new Array(9).fill(0)];
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expect(imageDimensions(bytes([0xff, 0xd8], app1, sof))).toEqual({ width: 4000, height: 3000 });
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// No frame header before the image data: unknown.
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expect(imageDimensions(bytes([0xff, 0xd8], app1, [0xff, 0xda, 0, 2, 0, 0, 0, 0, 0, 0]))).toBeNull();
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});
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it('reads the three kinds of WebP', () => {
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const riff = (chunk: string, body: number[]) => bytes('RIFF', [0, 0, 0, 0], 'WEBP', chunk, [0, 0, 0, 0], body);
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expect(imageDimensions(riff('VP8 ', [0, 0, 0, 0x9d, 0x01, 0x2a, ...le16(640), ...le16(480)]))).toEqual({ width: 640, height: 480 });
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// VP8L: 14 bits each of width - 1 and height - 1 after the 0x2f signature.
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const w = 1023;
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const h = 767;
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const packed = (w - 1) | ((h - 1) << 14);
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expect(imageDimensions(riff('VP8L', [0x2f, ...le32(packed), 0]))).toEqual({ width: w, height: h });
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expect(imageDimensions(riff('VP8X', [0, 0, 0, 0, ...le24(16_383), ...le24(9_999)]))).toEqual({ width: 16_384, height: 10_000 });
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});
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it('reads BMP, and nothing from what it does not know', () => {
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expect(imageDimensions(bytes('BM', new Array(16).fill(0), le32(800), le32(-600 >>> 0)))).toEqual({ width: 800, height: 600 });
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expect(imageDimensions(bytes('<svg width="100000" height="100000">'))).toBeNull();
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expect(imageDimensions(new Uint8Array(0))).toBeNull();
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});
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});
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