Function imageAlpha

quote/generate.js:102–108

(image, alpha)

async function drawPatternBackground(canvas, centerColor, edgeColor, patternImage, patternAlpha) {
  const ctx = canvas.getContext("2d");

  const gradient = ctx.createRadialGradient(
    canvas.width / 2, canvas.height / 2, 0,
    canvas.width / 2, canvas.height / 2, canvas.width / 2
  );
  gradient.addColorStop(0, centerColor);
  gradient.addColorStop(1, edgeColor);

  ctx.fillStyle = gradient;