image-tools/tests/fixtures/images.ts

export const VALID_PNG_BASE64 =
  "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=";

export function pngFixture(
  width: number,
  height: number,
  options: {
    readonly animated?: boolean;
    readonly exif?: boolean;
    readonly text?: boolean;
    readonly paddingBytes?: number;
  } = {},
): Uint8Array {
  const chunks: number[][] = [
    chunk("IHDR", [...u32be(width), ...u32be(height), 8, 6, 0, 0, 0]),
  ];
  if (options.paddingBytes) {
    chunks.push(chunk("ruSt", new Array<number>(options.paddingBytes).fill(0)));
  }
  if (options.animated) chunks.push(chunk("acTL", [...u32be(2), ...u32be(0)]));
  if (options.exif) chunks.push(chunk("eXIf", tiffOrientation(6)));
  if (options.text) chunks.push(chunk("tEXt", asciiBytes("Comment\0fixture")));
  chunks.push(chunk("IDAT", []));
  return Uint8Array.from([
    0x89,
    0x50,
    0x4e,
    0x47,
    0x0d,
    0x0a,
    0x1a,
    0x0a,
    ...chunks.flat(),
  ]);
}

export function jpegFixture(
  width: number,
  height: number,
  options: {
    readonly orientation?: number;
    readonly multiPicture?: boolean;
  } = {},
): Uint8Array {
  const segments: number[][] = [];
  if (options.orientation) {
    segments.push(
      jpegSegment(0xe1, [
        ...asciiBytes("Exif\0\0"),
        ...tiffOrientation(options.orientation),
      ]),
    );
  }
  if (options.multiPicture)
    segments.push(jpegSegment(0xe2, asciiBytes("MPF\0fixture")));
  segments.push(
    jpegSegment(0xc0, [
      8,
      ...u16be(height),
      ...u16be(width),
      3,
      1,
      0x11,
      0,
      2,
      0x11,
      0,
      3,
      0x11,
      0,
    ]),
  );
  return Uint8Array.from([0xff, 0xd8, ...segments.flat(), 0xff, 0xd9]);
}

export function webpFixture(
  width: number,
  height: number,
  options: {
    readonly animated?: boolean;
    readonly alpha?: boolean;
    readonly metadata?: boolean;
    readonly animationChunk?: boolean;
    readonly paddingBytes?: number;
  } = {},
): Uint8Array {
  const flags =
    (options.animated ? 0x02 : 0) |
    (options.alpha ? 0x10 : 0) |
    (options.metadata ? 0x2c : 0);
  const payload = [flags, 0, 0, 0, ...u24le(width - 1), ...u24le(height - 1)];
  const vp8x = riffChunk("VP8X", payload);
  const padding = options.paddingBytes
    ? riffChunk("JUNK", new Array<number>(options.paddingBytes).fill(0))
    : [];
  const animation = options.animationChunk
    ? riffChunk("ANIM", new Array<number>(6).fill(0))
    : [];
  const chunks = [...vp8x, ...padding, ...animation];
  const size = 4 + chunks.length;
  return Uint8Array.from([
    ...asciiBytes("RIFF"),
    ...u32le(size),
    ...asciiBytes("WEBP"),
    ...chunks,
  ]);
}

function jpegSegment(marker: number, data: readonly number[]): number[] {
  return [0xff, marker, ...u16be(data.length + 2), ...data];
}

function chunk(type: string, data: readonly number[]): number[] {
  return [...u32be(data.length), ...asciiBytes(type), ...data, 0, 0, 0, 0];
}

function riffChunk(type: string, data: readonly number[]): number[] {
  return [
    ...asciiBytes(type),
    ...u32le(data.length),
    ...data,
    ...(data.length % 2 ? [0] : []),
  ];
}

function tiffOrientation(orientation: number): number[] {
  return [
    0x49,
    0x49,
    0x2a,
    0x00,
    0x08,
    0x00,
    0x00,
    0x00,
    0x01,
    0x00,
    0x12,
    0x01,
    0x03,
    0x00,
    0x01,
    0x00,
    0x00,
    0x00,
    orientation,
    0x00,
    0x00,
    0x00,
    0x00,
    0x00,
    0x00,
    0x00,
  ];
}

function asciiBytes(value: string): number[] {
  return Array.from(value, (character) => character.charCodeAt(0));
}

function u16be(value: number): number[] {
  return [(value >>> 8) & 0xff, value & 0xff];
}

function u32be(value: number): number[] {
  return [
    (value >>> 24) & 0xff,
    (value >>> 16) & 0xff,
    (value >>> 8) & 0xff,
    value & 0xff,
  ];
}

function u32le(value: number): number[] {
  return [
    value & 0xff,
    (value >>> 8) & 0xff,
    (value >>> 16) & 0xff,
    (value >>> 24) & 0xff,
  ];
}

function u24le(value: number): number[] {
  return [value & 0xff, (value >>> 8) & 0xff, (value >>> 16) & 0xff];
}