图像缩放和旋转javascript

// 图像缩放
function scaleImage(image, scale) {
  var canvas = document.createElement('canvas');
  var context = canvas.getContext('2d');
  canvas.width = image.width * scale;
  canvas.height = image.height * scale;
  context.drawImage(image, 0, 0, canvas.width, canvas.height);
  return canvas.toDataURL();
}

// 图像旋转
function rotateImage(image, angle) {
  var canvas = document.createElement('canvas');
  var context = canvas.getContext('2d');
  canvas.width = image.width;
  canvas.height = image.height;
  context.translate(canvas.width / 2, canvas.height / 2);
  context.rotate(angle * Math.PI / 180);
  context.drawImage(image, -canvas.width / 2, -canvas.height / 2);
  return canvas.toDataURL();
}

// 使用示例
var img = new Image();
img.src = 'image.jpg';
img.onload = function() {
  var scaledImage = scaleImage(img, 0.5);
  var rotatedImage = rotateImage(img, 90);
  // 处理后的图像可以通过scaledImage和rotatedImage获取到
};