pdf.js/src/core/annotation.js

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/* globals PDFJS, Util, isDict, isName, stringToPDFString, warn, Dict, Stream,
           stringToBytes, assert, Promise, isArray, ObjectLoader, OperatorList,
           isValidUrl, OPS, createPromiseCapability, AnnotationType, 
           stringToUTF8String */

'use strict';

var DEFAULT_ICON_SIZE = 22; // px
var SUPPORTED_TYPES = ['Link', 'Text', 'Widget'];

var Annotation = (function AnnotationClosure() {
  // 12.5.5: Algorithm: Appearance streams
  function getTransformMatrix(rect, bbox, matrix) {
    var bounds = Util.getAxialAlignedBoundingBox(bbox, matrix);
    var minX = bounds[0];
    var minY = bounds[1];
    var maxX = bounds[2];
    var maxY = bounds[3];

    if (minX === maxX || minY === maxY) {
      // From real-life file, bbox was [0, 0, 0, 0]. In this case,
      // just apply the transform for rect
      return [1, 0, 0, 1, rect[0], rect[1]];
    }

    var xRatio = (rect[2] - rect[0]) / (maxX - minX);
    var yRatio = (rect[3] - rect[1]) / (maxY - minY);
    return [
      xRatio,
      0,
      0,
      yRatio,
      rect[0] - minX * xRatio,
      rect[1] - minY * yRatio
    ];
  }

  function getDefaultAppearance(dict) {
    var appearanceState = dict.get('AP');
    if (!isDict(appearanceState)) {
      return;
    }

    var appearance;
    var appearances = appearanceState.get('N');
    if (isDict(appearances)) {
      var as = dict.get('AS');
      if (as && appearances.has(as.name)) {
        appearance = appearances.get(as.name);
      }
    } else {
      appearance = appearances;
    }
    return appearance;
  }

  function Annotation(params) {
    var dict = params.dict;
    var data = this.data = {};

    data.subtype = dict.get('Subtype').name;
    var rect = dict.get('Rect') || [0, 0, 0, 0];
    data.rect = Util.normalizeRect(rect);
    data.annotationFlags = dict.get('F');

    var color = dict.get('C');
    if (!color) {
      // The PDF spec does not mention how a missing color array is interpreted.
      // Adobe Reader seems to default to black in this case.
      data.color = [0, 0, 0];
    } else if (isArray(color)) {
      switch (color.length) {
        case 0:
          // Empty array denotes transparent border.
          data.color = null;
          break;
        case 1:
          // TODO: implement DeviceGray
          break;
        case 3:
          data.color = color;
          break;
        case 4:
          // TODO: implement DeviceCMYK
          break;
      }
    }

    // Some types of annotations have border style dict which has more
    // info than the border array
    if (dict.has('BS')) {
      var borderStyle = dict.get('BS');
      data.borderWidth = borderStyle.has('W') ? borderStyle.get('W') : 1;
    } else {
      var borderArray = dict.get('Border') || [0, 0, 1];
      data.borderWidth = borderArray[2] || 0;

      // TODO: implement proper support for annotations with line dash patterns.
      var dashArray = borderArray[3];
      if (data.borderWidth > 0 && dashArray) {
        if (!isArray(dashArray)) {
          // Ignore the border if dashArray is not actually an array,
          // this is consistent with the behaviour in Adobe Reader.
          data.borderWidth = 0;
        } else {
          var dashArrayLength = dashArray.length;
          if (dashArrayLength > 0) {
            // According to the PDF specification: the elements in a dashArray
            // shall be numbers that are nonnegative and not all equal to zero.
            var isInvalid = false;
            var numPositive = 0;
            for (var i = 0; i < dashArrayLength; i++) {
              var validNumber = (+dashArray[i] >= 0);
              if (!validNumber) {
                isInvalid = true;
                break;
              } else if (dashArray[i] > 0) {
                numPositive++;
              }
            }
            if (isInvalid || numPositive === 0) {
              data.borderWidth = 0;
            }
          }
        }
      }
    }

    this.appearance = getDefaultAppearance(dict);
    data.hasAppearance = !!this.appearance;
    data.id = params.ref.num;
  }

  Annotation.prototype = {

    getData: function Annotation_getData() {
      return this.data;
    },

    isInvisible: function Annotation_isInvisible() {
      var data = this.data;
      if (data && SUPPORTED_TYPES.indexOf(data.subtype) !== -1) {
        return false;
      } else {
        return !!(data &&
                  data.annotationFlags &&            // Default: not invisible
                  data.annotationFlags & 0x1);       // Invisible
      }
    },

    isViewable: function Annotation_isViewable() {
      var data = this.data;
      return !!(!this.isInvisible() &&
                data &&
                (!data.annotationFlags ||
                 !(data.annotationFlags & 0x22)) &&  // Hidden or NoView
                data.rect);                          // rectangle is necessary
    },

    isPrintable: function Annotation_isPrintable() {
      var data = this.data;
      return !!(!this.isInvisible() &&
                data &&
                data.annotationFlags &&              // Default: not printable
                data.annotationFlags & 0x4 &&        // Print
                !(data.annotationFlags & 0x2) &&     // Hidden
                data.rect);                          // rectangle is necessary
    },

    loadResources: function Annotation_loadResources(keys) {
      return new Promise(function (resolve, reject) {
        this.appearance.dict.getAsync('Resources').then(function (resources) {
          if (!resources) {
            resolve();
            return;
          }
          var objectLoader = new ObjectLoader(resources.map,
                                              keys,
                                              resources.xref);
          objectLoader.load().then(function() {
            resolve(resources);
          }, reject);
        }, reject);
      }.bind(this));
    },

    getOperatorList: function Annotation_getOperatorList(evaluator) {

      if (!this.appearance) {
        return Promise.resolve(new OperatorList());
      }

      var data = this.data;

      var appearanceDict = this.appearance.dict;
      var resourcesPromise = this.loadResources([
        'ExtGState',
        'ColorSpace',
        'Pattern',
        'Shading',
        'XObject',
        'Font'
        // ProcSet
        // Properties
      ]);
      var bbox = appearanceDict.get('BBox') || [0, 0, 1, 1];
      var matrix = appearanceDict.get('Matrix') || [1, 0, 0, 1, 0 ,0];
      var transform = getTransformMatrix(data.rect, bbox, matrix);
      var self = this;

      return resourcesPromise.then(function(resources) {
          var opList = new OperatorList();
          opList.addOp(OPS.beginAnnotation, [data.rect, transform, matrix]);
          return evaluator.getOperatorList(self.appearance, resources, opList).
            then(function () {
              opList.addOp(OPS.endAnnotation, []);
              self.appearance.reset();
              return opList;
            });
        });
    }
  };

  Annotation.getConstructor =
      function Annotation_getConstructor(subtype, fieldType) {

    if (!subtype) {
      return;
    }

    // TODO(mack): Implement FreeText annotations
    if (subtype === 'Link') {
      return LinkAnnotation;
    } else if (subtype === 'Text') {
      return TextAnnotation;
    } else if (subtype === 'Widget') {
      if (!fieldType) {
        return;
      }

      if (fieldType === 'Tx') {
        return TextWidgetAnnotation;
      } else {
        return WidgetAnnotation;
      }
    } else {
      return Annotation;
    }
  };

  Annotation.fromRef = function Annotation_fromRef(xref, ref) {

    var dict = xref.fetchIfRef(ref);
    if (!isDict(dict)) {
      return;
    }

    var subtype = dict.get('Subtype');
    subtype = isName(subtype) ? subtype.name : '';
    if (!subtype) {
      return;
    }

    var fieldType = Util.getInheritableProperty(dict, 'FT');
    fieldType = isName(fieldType) ? fieldType.name : '';

    var Constructor = Annotation.getConstructor(subtype, fieldType);
    if (!Constructor) {
      return;
    }

    var params = {
      dict: dict,
      ref: ref,
    };

    var annotation = new Constructor(params);

    if (annotation.isViewable() || annotation.isPrintable()) {
      return annotation;
    } else {
      if (SUPPORTED_TYPES.indexOf(subtype) === -1) {
        warn('unimplemented annotation type: ' + subtype);
      }
    }
  };

  Annotation.appendToOperatorList = function Annotation_appendToOperatorList(
      annotations, opList, pdfManager, partialEvaluator, intent) {

    function reject(e) {
      annotationsReadyCapability.reject(e);
    }

    var annotationsReadyCapability = createPromiseCapability();

    var annotationPromises = [];
    for (var i = 0, n = annotations.length; i < n; ++i) {
      if (intent === 'display' && annotations[i].isViewable() ||
          intent === 'print' && annotations[i].isPrintable()) {
        annotationPromises.push(
          annotations[i].getOperatorList(partialEvaluator));
      }
    }
    Promise.all(annotationPromises).then(function(datas) {
      opList.addOp(OPS.beginAnnotations, []);
      for (var i = 0, n = datas.length; i < n; ++i) {
        var annotOpList = datas[i];
        opList.addOpList(annotOpList);
      }
      opList.addOp(OPS.endAnnotations, []);
      annotationsReadyCapability.resolve();
    }, reject);

    return annotationsReadyCapability.promise;
  };

  return Annotation;
})();

var WidgetAnnotation = (function WidgetAnnotationClosure() {

  function WidgetAnnotation(params) {
    Annotation.call(this, params);

    var dict = params.dict;
    var data = this.data;

    data.fieldValue = stringToPDFString(
      Util.getInheritableProperty(dict, 'V') || '');
    data.alternativeText = stringToPDFString(dict.get('TU') || '');
    data.defaultAppearance = Util.getInheritableProperty(dict, 'DA') || '';
    var fieldType = Util.getInheritableProperty(dict, 'FT');
    data.fieldType = isName(fieldType) ? fieldType.name : '';
    data.fieldFlags = Util.getInheritableProperty(dict, 'Ff') || 0;
    this.fieldResources = Util.getInheritableProperty(dict, 'DR') || Dict.empty;

    // Building the full field name by collecting the field and
    // its ancestors 'T' data and joining them using '.'.
    var fieldName = [];
    var namedItem = dict;
    var ref = params.ref;
    while (namedItem) {
      var parent = namedItem.get('Parent');
      var parentRef = namedItem.getRaw('Parent');
      var name = namedItem.get('T');
      if (name) {
        fieldName.unshift(stringToPDFString(name));
      } else if (parent && ref) {
        // The field name is absent, that means more than one field
        // with the same name may exist. Replacing the empty name
        // with the '`' plus index in the parent's 'Kids' array.
        // This is not in the PDF spec but necessary to id the
        // the input controls.
        var kids = parent.get('Kids');
        var j, jj;
        for (j = 0, jj = kids.length; j < jj; j++) {
          var kidRef = kids[j];
          if (kidRef.num === ref.num && kidRef.gen === ref.gen) {
            break;
          }
        }
        fieldName.unshift('`' + j);
      }
      namedItem = parent;
      ref = parentRef;
    }
    data.fullName = fieldName.join('.');
  }

  var parent = Annotation.prototype;
  Util.inherit(WidgetAnnotation, Annotation, {
    isViewable: function WidgetAnnotation_isViewable() {
      if (this.data.fieldType === 'Sig') {
        warn('unimplemented annotation type: Widget signature');
        return false;
      }

      return parent.isViewable.call(this);
    }
  });

  return WidgetAnnotation;
})();

var TextWidgetAnnotation = (function TextWidgetAnnotationClosure() {
  function TextWidgetAnnotation(params) {
    WidgetAnnotation.call(this, params);

    this.data.textAlignment = Util.getInheritableProperty(params.dict, 'Q');
    this.data.annotationType = AnnotationType.WIDGET;
    this.data.hasHtml = !this.data.hasAppearance && !!this.data.fieldValue;
  }

  Util.inherit(TextWidgetAnnotation, WidgetAnnotation, {
    getOperatorList: function TextWidgetAnnotation_getOperatorList(evaluator) {
      if (this.appearance) {
        return Annotation.prototype.getOperatorList.call(this, evaluator);
      }

      var opList = new OperatorList();
      var data = this.data;

      // Even if there is an appearance stream, ignore it. This is the
      // behaviour used by Adobe Reader.
      if (!data.defaultAppearance) {
        return Promise.resolve(opList);
      }

      var stream = new Stream(stringToBytes(data.defaultAppearance));
      return evaluator.getOperatorList(stream, this.fieldResources, opList).
        then(function () {
          return opList;
        });
    }
  });

  return TextWidgetAnnotation;
})();

var InteractiveAnnotation = (function InteractiveAnnotationClosure() {
  function InteractiveAnnotation(params) {
    Annotation.call(this, params);

    this.data.hasHtml = true;
  }

  Util.inherit(InteractiveAnnotation, Annotation, { });

  return InteractiveAnnotation;
})();

var TextAnnotation = (function TextAnnotationClosure() {
  function TextAnnotation(params) {
    InteractiveAnnotation.call(this, params);

    var dict = params.dict;
    var data = this.data;

    var content = dict.get('Contents');
    var title = dict.get('T');
    data.annotationType = AnnotationType.TEXT;
    data.content = stringToPDFString(content || '');
    data.title = stringToPDFString(title || '');

    if (data.hasAppearance) {
      data.name = 'NoIcon';
    } else {
      data.rect[1] = data.rect[3] - DEFAULT_ICON_SIZE;
      data.rect[2] = data.rect[0] + DEFAULT_ICON_SIZE;
      data.name = dict.has('Name') ? dict.get('Name').name : 'Note';
    }

    if (dict.has('C')) {
      data.hasBgColor = true;
    }
  }

  Util.inherit(TextAnnotation, InteractiveAnnotation, { });

  return TextAnnotation;
})();

var LinkAnnotation = (function LinkAnnotationClosure() {
  function LinkAnnotation(params) {
    InteractiveAnnotation.call(this, params);

    var dict = params.dict;
    var data = this.data;
    data.annotationType = AnnotationType.LINK;

    var action = dict.get('A');
    if (action && isDict(action)) {
      var linkType = action.get('S').name;
      if (linkType === 'URI') {
        var url = action.get('URI');
        if (isName(url)) {
          // Some bad PDFs do not put parentheses around relative URLs.
          url = '/' + url.name;
        } else if (url) {
          url = addDefaultProtocolToUrl(url);
        }
        // TODO: pdf spec mentions urls can be relative to a Base
        // entry in the dictionary.
        if (!isValidUrl(url, false)) {
          url = '';
        }
        // According to ISO 32000-1:2008, section 12.6.4.7, 
        // URI should to be encoded in 7-bit ASCII.
        // Some bad PDFs may have URIs in UTF-8 encoding, see Bugzilla 1122280.
        try {
          data.url = stringToUTF8String(url);
        } catch (e) {
          // Fall back to a simple copy.
          data.url = url;
        }
      } else if (linkType === 'GoTo') {
        data.dest = action.get('D');
      } else if (linkType === 'GoToR') {
        var urlDict = action.get('F');
        if (isDict(urlDict)) {
          // We assume that the 'url' is a Filspec dictionary
          // and fetch the url without checking any further
          url = urlDict.get('F') || '';
        }

        // TODO: pdf reference says that GoToR
        // can also have 'NewWindow' attribute
        if (!isValidUrl(url, false)) {
          url = '';
        }
        data.url = url;
        data.dest = action.get('D');
      } else if (linkType === 'Named') {
        data.action = action.get('N').name;
      } else {
        warn('unrecognized link type: ' + linkType);
      }
    } else if (dict.has('Dest')) {
      // simple destination link
      var dest = dict.get('Dest');
      data.dest = isName(dest) ? dest.name : dest;
    }
  }

  // Lets URLs beginning with 'www.' default to using the 'http://' protocol.
  function addDefaultProtocolToUrl(url) {
    if (url && url.indexOf('www.') === 0) {
      return ('http://' + url);
    }
    return url;
  }

  Util.inherit(LinkAnnotation, InteractiveAnnotation, { });

  return LinkAnnotation;
})();