school/qiniu-js/lib/compress.js

"use strict";

var _interopRequireDefault = require("@babel/runtime-corejs2/helpers/interopRequireDefault");

var _Object$defineProperty = require("@babel/runtime-corejs2/core-js/object/define-property");

_Object$defineProperty(exports, "__esModule", {
  value: true
});

exports["default"] = void 0;

var _keys = _interopRequireDefault(require("@babel/runtime-corejs2/core-js/object/keys"));

var _iterator = _interopRequireDefault(require("@babel/runtime-corejs2/core-js/symbol/iterator"));

var _symbol = _interopRequireDefault(require("@babel/runtime-corejs2/core-js/symbol"));

var _promise = _interopRequireDefault(require("@babel/runtime-corejs2/core-js/promise"));

var _assign = _interopRequireDefault(require("@babel/runtime-corejs2/core-js/object/assign"));

var _exifJs = require("exif-js");

var _utils = require("./utils");

var __assign = void 0 && (void 0).__assign || function () {
  __assign = _assign["default"] || function (t) {
    for (var s, i = 1, n = arguments.length; i < n; i++) {
      s = arguments[i];

      for (var p in s) {
        if (Object.prototype.hasOwnProperty.call(s, p)) t[p] = s[p];
      }
    }

    return t;
  };

  return __assign.apply(this, arguments);
};

var __awaiter = void 0 && (void 0).__awaiter || function (thisArg, _arguments, P, generator) {
  function adopt(value) {
    return value instanceof P ? value : new P(function (resolve) {
      resolve(value);
    });
  }

  return new (P || (P = _promise["default"]))(function (resolve, reject) {
    function fulfilled(value) {
      try {
        step(generator.next(value));
      } catch (e) {
        reject(e);
      }
    }

    function rejected(value) {
      try {
        step(generator["throw"](value));
      } catch (e) {
        reject(e);
      }
    }

    function step(result) {
      result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected);
    }

    step((generator = generator.apply(thisArg, _arguments || [])).next());
  });
};

var __generator = void 0 && (void 0).__generator || function (thisArg, body) {
  var _ = {
    label: 0,
    sent: function sent() {
      if (t[0] & 1) throw t[1];
      return t[1];
    },
    trys: [],
    ops: []
  },
      f,
      y,
      t,
      g;
  return g = {
    next: verb(0),
    "throw": verb(1),
    "return": verb(2)
  }, typeof _symbol["default"] === "function" && (g[_iterator["default"]] = function () {
    return this;
  }), g;

  function verb(n) {
    return function (v) {
      return step([n, v]);
    };
  }

  function step(op) {
    if (f) throw new TypeError("Generator is already executing.");

    while (_) {
      try {
        if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
        if (y = 0, t) op = [op[0] & 2, t.value];

        switch (op[0]) {
          case 0:
          case 1:
            t = op;
            break;

          case 4:
            _.label++;
            return {
              value: op[1],
              done: false
            };

          case 5:
            _.label++;
            y = op[1];
            op = [0];
            continue;

          case 7:
            op = _.ops.pop();

            _.trys.pop();

            continue;

          default:
            if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) {
              _ = 0;
              continue;
            }

            if (op[0] === 3 && (!t || op[1] > t[0] && op[1] < t[3])) {
              _.label = op[1];
              break;
            }

            if (op[0] === 6 && _.label < t[1]) {
              _.label = t[1];
              t = op;
              break;
            }

            if (t && _.label < t[2]) {
              _.label = t[2];

              _.ops.push(op);

              break;
            }

            if (t[2]) _.ops.pop();

            _.trys.pop();

            continue;
        }

        op = body.call(thisArg, _);
      } catch (e) {
        op = [6, e];
        y = 0;
      } finally {
        f = t = 0;
      }
    }

    if (op[0] & 5) throw op[1];
    return {
      value: op[0] ? op[1] : void 0,
      done: true
    };
  }
};

var __read = void 0 && (void 0).__read || function (o, n) {
  var m = typeof _symbol["default"] === "function" && o[_iterator["default"]];
  if (!m) return o;
  var i = m.call(o),
      r,
      ar = [],
      e;

  try {
    while ((n === void 0 || n-- > 0) && !(r = i.next()).done) {
      ar.push(r.value);
    }
  } catch (error) {
    e = {
      error: error
    };
  } finally {
    try {
      if (r && !r.done && (m = i["return"])) m.call(i);
    } finally {
      if (e) throw e.error;
    }
  }

  return ar;
};

var __spread = void 0 && (void 0).__spread || function () {
  for (var ar = [], i = 0; i < arguments.length; i++) {
    ar = ar.concat(__read(arguments[i]));
  }

  return ar;
};

var mimeTypes = {
  PNG: 'image/png',
  JPEG: 'image/jpeg',
  WEBP: 'image/webp',
  BMP: 'image/bmp'
};
var maxSteps = 4;
var scaleFactor = Math.log(2);
var supportMimeTypes = (0, _keys["default"])(mimeTypes).map(function (type) {
  return mimeTypes[type];
});
var defaultType = mimeTypes.JPEG;

function isSupportedType(type) {
  return supportMimeTypes.includes(type);
}

var Compress =
/** @class */
function () {
  function Compress(file, config) {
    this.file = file;
    this.config = config;
    this.config = __assign({
      quality: 0.92,
      noCompressIfLarger: false
    }, this.config);
  }

  Compress.prototype.process = function () {
    return __awaiter(this, void 0, void 0, function () {
      var srcDimension, originImage, canvas, scale, scaleCanvas, distBlob;
      return __generator(this, function (_a) {
        switch (_a.label) {
          case 0:
            this.outputType = this.file.type;
            srcDimension = {};

            if (!isSupportedType(this.file.type)) {
              throw new Error("unsupported file type: " + this.file.type);
            }

            return [4
            /*yield*/
            , this.getOriginImage()];

          case 1:
            originImage = _a.sent();
            return [4
            /*yield*/
            , this.getCanvas(originImage)];

          case 2:
            canvas = _a.sent();
            scale = 1;

            if (this.config.maxWidth) {
              scale = Math.min(1, this.config.maxWidth / canvas.width);
            }

            if (this.config.maxHeight) {
              scale = Math.min(1, scale, this.config.maxHeight / canvas.height);
            }

            srcDimension.width = canvas.width;
            srcDimension.height = canvas.height;
            return [4
            /*yield*/
            , this.doScale(canvas, scale)];

          case 3:
            scaleCanvas = _a.sent();
            distBlob = this.toBlob(scaleCanvas);

            if (distBlob.size > this.file.size && this.config.noCompressIfLarger) {
              return [2
              /*return*/
              , {
                dist: this.file,
                width: srcDimension.width,
                height: srcDimension.height
              }];
            }

            return [2
            /*return*/
            , {
              dist: distBlob,
              width: scaleCanvas.width,
              height: scaleCanvas.height
            }];
        }
      });
    });
  };

  Compress.prototype.clear = function (ctx, width, height) {
    // jpeg 没有 alpha 通道，透明区间会被填充成黑色，这里把透明区间填充为白色
    if (this.outputType === defaultType) {
      ctx.fillStyle = '#fff';
      ctx.fillRect(0, 0, width, height);
    } else {
      ctx.clearRect(0, 0, width, height);
    }
  };
  /** 通过 file 初始化 image 对象 */


  Compress.prototype.getOriginImage = function () {
    var _this = this;

    return new _promise["default"](function (resolve, reject) {
      var url = (0, _utils.createObjectURL)(_this.file);
      var img = new Image();

      img.onload = function () {
        resolve(img);
      };

      img.onerror = function () {
        reject('image load error');
      };

      img.src = url;
    });
  };

  Compress.prototype.getCanvas = function (img) {
    var _this = this;

    return new _promise["default"](function (resolve, reject) {
      // 通过得到图片的信息来调整显示方向以正确显示图片，主要解决 ios 系统上的图片会有旋转的问题
      _exifJs.EXIF.getData(img, function () {
        var orientation = _exifJs.EXIF.getTag(img, 'Orientation') || 1;

        var _a = (0, _utils.getTransform)(img, orientation),
            width = _a.width,
            height = _a.height,
            matrix = _a.matrix;

        var canvas = document.createElement('canvas');
        var context = canvas.getContext('2d');
        canvas.width = width;
        canvas.height = height;

        if (!context) {
          reject(new Error('context is null'));
          return;
        }

        _this.clear(context, width, height);

        context.transform.apply(context, __spread(matrix));
        context.drawImage(img, 0, 0);
        resolve(canvas);
      });
    });
  };

  Compress.prototype.doScale = function (source, scale) {
    return __awaiter(this, void 0, void 0, function () {
      var sctx, steps, factor, mirror, mctx, width, height, originWidth, originHeight, src, context, i, dw, dh, canvas, data;
      return __generator(this, function (_a) {
        if (scale === 1) {
          return [2
          /*return*/
          , source];
        }

        sctx = source.getContext('2d');
        steps = Math.min(maxSteps, Math.ceil(1 / scale / scaleFactor));
        factor = Math.pow(scale, 1 / steps);
        mirror = document.createElement('canvas');
        mctx = mirror.getContext('2d');
        width = source.width, height = source.height;
        originWidth = width;
        originHeight = height;
        mirror.width = width;
        mirror.height = height;

        if (!mctx || !sctx) {
          throw new Error("mctx or sctx can't be null");
        }

        for (i = 0; i < steps; i++) {
          dw = width * factor | 0 // eslint-disable-line no-bitwise
          ;
          dh = height * factor | 0 // eslint-disable-line no-bitwise
          ; // 到最后一步的时候 dw, dh 用目标缩放尺寸，否则会出现最后尺寸偏小的情况

          if (i === steps - 1) {
            dw = originWidth * scale;
            dh = originHeight * scale;
          }

          if (i % 2 === 0) {
            src = source;
            context = mctx;
          } else {
            src = mirror;
            context = sctx;
          } // 每次画前都清空，避免图像重叠


          this.clear(context, width, height);
          context.drawImage(src, 0, 0, width, height, 0, 0, dw, dh);
          width = dw;
          height = dh;
        }

        canvas = src === source ? mirror : source;
        data = context.getImageData(0, 0, width, height); // resize

        canvas.width = width;
        canvas.height = height; // store image data

        context.putImageData(data, 0, 0);
        return [2
        /*return*/
        , canvas];
      });
    });
  };
  /** 这里把 base64 字符串转为 blob 对象 */


  Compress.prototype.toBlob = function (result) {
    var dataURL = result.toDataURL(this.outputType, this.config.quality);
    var buffer = atob(dataURL.split(',')[1]).split('').map(function (_char) {
      return _char.charCodeAt(0);
    });
    var blob = new Blob([new Uint8Array(buffer)], {
      type: this.outputType
    });
    return blob;
  };

  return Compress;
}();

var compressImage = function compressImage(file, options) {
  return new Compress(file, options).process();
};

var _default = compressImage;
exports["default"] = _default;