Refactor annotation flags code

This patch makes it possible to set and get all possible flags that the PDF specification defines. Even though we do not support all possible annotation types and not all possible annotation flags yet, this general framework makes it easy to access all flags for each annotation such that annotation type implementations can use with this information.

We add constants for all possible annotation flags such that we do not need to hardcode the flags in the code anymore. The `isViewable()` and `isPrintable()` methods are now much easier to read. Additionally, unit tests have been added to ensure correct behavior.

This is another part of #5218.

src/core/annotation.js

@@ -15,7 +15,8 @@
 /* globals PDFJS, Util, isDict, isName, stringToPDFString, warn, Dict, Stream,
            stringToBytes, Promise, isArray, ObjectLoader, OperatorList,
            isValidUrl, OPS, createPromiseCapability, AnnotationType,
-           stringToUTF8String, AnnotationBorderStyleType, ColorSpace */
+           stringToUTF8String, AnnotationBorderStyleType, ColorSpace,
+           AnnotationFlag */
 
 'use strict';
 
@@ -121,7 +122,8 @@ var Annotation = (function AnnotationClosure() {
     var data = this.data = {};
 
     data.subtype = dict.get('Subtype').name;
-    data.annotationFlags = dict.get('F');
+
+    this.setFlags(dict.get('F'));
 
     this.setRectangle(dict.get('Rect'));
     data.rect = this.rectangle;
@@ -138,6 +140,70 @@ var Annotation = (function AnnotationClosure() {
   }
 
   Annotation.prototype = {
+    /**
+     * Set the flags.
+     *
+     * @public
+     * @memberof Annotation
+     * @param {number} flags - Unsigned 32-bit integer specifying annotation
+     *                         characteristics
+     * @see {@link shared/util.js}
+     */
+    setFlags: function Annotation_setFlags(flags) {
+      if (flags === (flags | 0)) {
+        this.flags = flags;
+      } else {
+        this.flags = 0;
+      }
+    },
+
+    /**
+     * Check if a provided flag is set.
+     *
+     * @public
+     * @memberof Annotation
+     * @param {number} flag - Hexadecimal representation for an annotation
+     *                        characteristic
+     * @return {boolean}
+     * @see {@link shared/util.js}
+     */
+    hasFlag: function Annotation_hasFlag(flag) {
+      if (this.flags) {
+        return (this.flags & flag) > 0;
+      }
+      return false;
+    },
+
+    /**
+     * Check if the annotation is viewable.
+     *
+     * @public
+     * @memberof Annotation
+     * @return {boolean}
+     */
+    isViewable: function Annotation_isViewable() {
+      if (this.flags) {
+        return !this.hasFlag(AnnotationFlag.INVISIBLE) &&
+               !this.hasFlag(AnnotationFlag.HIDDEN) &&
+               !this.hasFlag(AnnotationFlag.NOVIEW);
+      }
+      return true;
+    },
+
+    /**
+     * Check if the annotation is printable.
+     *
+     * @public
+     * @memberof Annotation
+     * @return {boolean}
+     */
+    isPrintable: function Annotation_isPrintable() {
+      if (this.flags) {
+        return this.hasFlag(AnnotationFlag.PRINT);
+      }
+      return false;
+    },
+
     /**
      * Set the rectangle.
      *
@@ -237,32 +303,6 @@ var Annotation = (function AnnotationClosure() {
       }
     },
 
-    isInvisible: function Annotation_isInvisible() {
-      var data = this.data;
-      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) {

src/shared/util.js

@@ -48,6 +48,19 @@ var AnnotationType = {
   LINK: 3
 };
 
+var AnnotationFlag = {
+  INVISIBLE: 0x01,
+  HIDDEN: 0x02,
+  PRINT: 0x04,
+  NOZOOM: 0x08,
+  NOROTATE: 0x10,
+  NOVIEW: 0x20,
+  READONLY: 0x40,
+  LOCKED: 0x80,
+  TOGGLENOVIEW: 0x100,
+  LOCKEDCONTENTS: 0x200
+};
+
 var AnnotationBorderStyleType = {
   SOLID: 1,
   DASHED: 2,

test/unit/annotation_layer_spec.js

@@ -1,10 +1,31 @@
 /* globals expect, it, describe, Dict, Name, Annotation, AnnotationBorderStyle,
-           AnnotationBorderStyleType */
+           AnnotationBorderStyleType, AnnotationFlag */
 
 'use strict';
 
 describe('Annotation layer', function() {
   describe('Annotation', function() {
+    it('should set and get flags', function() {
+      var dict = new Dict();
+      dict.set('Subtype', '');
+      var annotation = new Annotation({ dict: dict, ref: 0 });
+      annotation.setFlags(13);
+
+      expect(annotation.hasFlag(AnnotationFlag.INVISIBLE)).toEqual(true);
+      expect(annotation.hasFlag(AnnotationFlag.NOZOOM)).toEqual(true);
+      expect(annotation.hasFlag(AnnotationFlag.PRINT)).toEqual(true);
+      expect(annotation.hasFlag(AnnotationFlag.READONLY)).toEqual(false);
+    });
+
+    it('should be viewable and not printable by default', function() {
+      var dict = new Dict();
+      dict.set('Subtype', '');
+      var annotation = new Annotation({ dict: dict, ref: 0 });
+
+      expect(annotation.isViewable()).toEqual(true);
+      expect(annotation.isPrintable()).toEqual(false);
+    });
+
     it('should set and get a valid rectangle', function() {
       var dict = new Dict();
       dict.set('Subtype', '');