@thi.ng/pixel/internal/codegen.js

Typedarray integer & float pixel buffers w/ customizable formats, blitting, drawing, convolution

import { __luminanceABGR } from "./utils.js";
const __compileLShift = (x, shift) => shift > 0 ? `(${x} << ${shift})` : shift < 0 ? `(${x} >>> ${-shift})` : `${x}`;
const __compileRShift = (x, shift) => __compileLShift(x, -shift);
const __hex = (x) => `0x${x.toString(16)}`;
const __compileGrayFromABGR = (size) => {
  const shift = 8 - size;
  const mask = (1 << size) - 1;
  return new Function(
    "luma",
    `return (x) => ${__compileRShift("luma(x)", shift)} & ${mask};`
  )(__luminanceABGR);
};
const __compileGrayToABGR = (size) => {
  let body;
  if (size !== 8) {
    const mask = (1 << size) - 1;
    const scale = 255 / mask;
    body = `(((x & ${mask}) * ${scale}) | 0)`;
  } else {
    body = "x";
  }
  return new Function("x", `return 0xff000000 | (${body} * 0x010101);`);
};
const __compileFromABGR = (chans) => new Function(
  "x",
  "return (" + chans.map((ch) => {
    const shift = ch.abgrShift + (8 - ch.size);
    return `(${__compileRShift("x", shift)} & ${__hex(
      ch.maskA
    )})`;
  }).join(" | ") + ") >>> 0;"
);
const __compileToABGR = (chans, hasAlpha) => {
  const body = chans.map((ch) => {
    if (ch.size !== 8) {
      const mask = ch.mask0;
      const scale = 255 / mask;
      const inner = __compileRShift("x", ch.shift);
      return __compileLShift(
        `((${inner} & ${mask}) * ${scale})`,
        24 - ch.lane * 8
      );
    } else {
      return __compileLShift(
        `(x & ${__hex(ch.maskA)})`,
        ch.abgrShift
      );
    }
  }).join(" | ");
  const alpha = !hasAlpha ? `0xff000000 | ` : "";
  return new Function("x", `return (${alpha}${body}) >>> 0;`);
};
export {
  __compileFromABGR,
  __compileGrayFromABGR,
  __compileGrayToABGR,
  __compileToABGR
};