threeLearn/index.html at master · lzw10168/threeLearn · GitHub

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<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8" />
  <title>图像处理示例</title>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/camanjs/4.0.0/caman.full.min.js"></script>
  <script src="https://unpkg.com/draggabilly@3/dist/draggabilly.pkgd.min.js"></script>

</head>
<style>
  img {
    width: 500px;
  }

  .container {
    position: relative;
    width: 100%;
    height: 500px;
    transform-origin: 0 0;
  }

  canvas {
    transform-origin: 0 0;
    position: absolute;
    /* center */
    top: 0;
    left: 0;
    transform: scale(0.3);
  }

</style>

<body>
  <h1>图像处理示例</h1>
  <img src="./public/1.png" id="imageA" onload="transformBlue()" />
  <img src="./public/2.png" id="imageB" onload="transformRed()" />
  <div class="container">
    <canvas id="canvas1"></canvas>
    <div class="c2w">
      <canvas id="canvas2"></canvas>
    </div>
  </div>
  <script>
    // container监听鼠标滚轮事件放大缩小
    container = document.querySelector('.container')
    container.addEventListener('wheel', function (e) {
      e.preventDefault();
      // 拿到当前的scale
      let scale = container.style.transform.match(/scale\((\d+\.?\d*)\)/)
      console.log('scale: ', scale);
      if (scale) {
        scale = +scale[1]
      } else {
        scale = 1
      }
      console.log('e.deltaY: ', e.deltaY);
      // 放大缩小
      if (e.deltaY < 0) {
        scale += 0.1
      } else {
        scale -= 0.1
      }
      container.style.transform = `scale(${scale})`
    })

    var draggie = new Draggabilly('.c2w', {
      // options...
    });
  </script>
  <script>
    function transformBlue() {
      let canvas = document.getElementById("canvas1");
      let ctx = canvas.getContext("2d");
      let img = document.getElementById("imageA");
      canvas.width = img.naturalWidth
      canvas.height = img.naturalHeight
      // ctx.save();
      // ctx.scale(0.5, 0.5);
      ctx.drawImage(img, 0, 0);
      // ctx.restore();

      // ctx.globalAlpha = 0;
      let imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      let pixels = imageData.data;

      for (let i = 0; i < pixels.length; i += 4) {
        //
        let r = pixels[i];
        let g = pixels[i + 1];
        let b = pixels[i + 2];
        // todo: 透明度处理
        if ([r, g, b].every(v => v < 256 && v > 245)) pixels[i + 3] = 0
        let brightness = (r + g + b) / 3;
        if (brightness < 250) {
          // 把颜色在原来基础上,变蓝, 保留原来的透明度
          pixels[i] = r;
          pixels[i + 1] = g;
          pixels[i + 2] = 255;

        }
      }
      ctx.putImageData(imageData, 0, 0);
    }
    function transformRed() {
      let canvas = document.getElementById("canvas2");
      let ctx = canvas.getContext("2d");
      let img = document.getElementById("imageB");
      canvas.width = img.naturalWidth;
      canvas.height = img.naturalHeight;

      // ctx.save();
      // ctx.scale(0.5, 0.5);
      ctx.drawImage(img, 0, 0);
      // ctx.restore();
      let imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
      let pixels = imageData.data;
      for (let i = 0; i < pixels.length; i += 4) {
        //
        let r = pixels[i];
        let g = pixels[i + 1];
        let b = pixels[i + 2];
        // todo: 透明度处理
        if ([r, g, b].every(v => v < 256 && v > 245)) pixels[i + 3] = 0
        let brightness = (r + g + b) / 3;
        if (brightness < 250) {
          // 把颜色在原来基础上,变红, 保留原来的透明度
          pixels[i] = 255;
          pixels[i + 1] = g;
          pixels[i + 2] = b;

        }
      }
      ctx.putImageData(imageData, 0, 0);
    }
  </script>
</body>

</html>