Add support for optional marked content.

Add a new method to the API to get the optional content configuration. Add
a new render task param that accepts the above configuration.
For now, the optional content is not controllable by the user in
the viewer, but renders with the default configuration in the PDF.

All of the test files added exhibit different uses of optional content.

Fixes mozilla#269.

src/core/evaluator.js

@@ -422,8 +422,16 @@ class PartialEvaluator {
         smask,
         isolated: false,
         knockout: false,
+        optionalContent: null,
       };
 
+      if (dict.has("OC")) {
+        groupOptions.optionalContent = this.parseMarkedContentProps(
+          dict.get("OC"),
+          resources
+        );
+      }
+
       var groupSubtype = group.get("S");
       var colorSpace = null;
       if (isName(groupSubtype, "Transparency")) {
@@ -1224,6 +1232,61 @@ class PartialEvaluator {
     throw new FormatError(`Unknown PatternName: ${patternName}`);
   }
 
+  parseMarkedContentProps(contentProperties, resources) {
+    let optionalContent;
+    if (isName(contentProperties)) {
+      const properties = resources.get("Properties");
+      optionalContent = properties.get(contentProperties.name);
+    } else if (isDict(contentProperties)) {
+      optionalContent = contentProperties;
+    } else {
+      throw new Error("Optional content properties malformed.");
+    }
+
+    const optionalContentType = optionalContent.get("Type").name;
+    if (optionalContentType === "OCG") {
+      return {
+        type: optionalContentType,
+        id: optionalContent.objId,
+      };
+    } else if (optionalContentType === "OCMD") {
+      const optionalContentGroups = optionalContent.get("OCGs");
+      if (
+        Array.isArray(optionalContentGroups) ||
+        isDict(optionalContentGroups)
+      ) {
+        const groupIds = [];
+        if (Array.isArray(optionalContentGroups)) {
+          optionalContent.get("OCGs").forEach(ocg => {
+            groupIds.push(ocg.toString());
+          });
+        } else {
+          // Dictionary, just use the obj id.
+          groupIds.push(optionalContentGroups.objId);
+        }
+
+        let expression = null;
+        if (optionalContent.get("VE")) {
+          // TODO support content epxressions.
+          expression = true;
+        }
+
+        return {
+          type: optionalContentType,
+          ids: groupIds,
+          policy: optionalContent.get("P"),
+          expression,
+        };
+      } else if (isRef(optionalContentGroups)) {
+        return {
+          type: optionalContentType,
+          id: optionalContentGroups.toString(),
+        };
+      }
+    }
+    return null;
+  }
+
   getOperatorList({
     stream,
     task,
@@ -1683,9 +1746,6 @@ class PartialEvaluator {
             continue;
           case OPS.markPoint:
           case OPS.markPointProps:
-          case OPS.beginMarkedContent:
-          case OPS.beginMarkedContentProps:
-          case OPS.endMarkedContent:
           case OPS.beginCompat:
           case OPS.endCompat:
             // Ignore operators where the corresponding handlers are known to
@@ -1695,6 +1755,21 @@ class PartialEvaluator {
             // e.g. as done in https://github.com/mozilla/pdf.js/pull/6266,
             // but doing so is meaningless without knowing the semantics.
             continue;
+          case OPS.beginMarkedContentProps:
+            if (!isName(args[0])) {
+              warn(`Expected name for beginMarkedContentProps arg0=${args[0]}`);
+              continue;
+            }
+            fn = OPS.beginMarkedContentProps;
+            if (args[0].name === "OC") {
+              args = ["OC", self.parseMarkedContentProps(args[1], resources)];
+            } else {
+              // Other marked content types aren't supported yet.
+              args = [args[0].name];
+            }
+            break;
+          case OPS.beginMarkedContent:
+          case OPS.endMarkedContent:
           default:
             // Note: Ignore the operator if it has `Dict` arguments, since
             // those are non-serializable, otherwise postMessage will throw

src/core/obj.js

@@ -254,6 +254,62 @@ class Catalog {
     return permissions;
   }
 
+  get optionalContentConfig() {
+    const properties = this.catDict.get("OCProperties");
+    if (!properties) {
+      return null;
+    }
+    const groupsData = properties.get("OCGs");
+    if (!Array.isArray(groupsData)) {
+      return null;
+    }
+    const groups = [];
+    const groupRefs = [];
+    // Ensure all the optional content groups are valid.
+    for (const groupRef of groupsData) {
+      if (!isRef(groupRef)) {
+        continue;
+      }
+      groupRefs.push(groupRef);
+      const group = properties.xref.fetchIfRef(groupRef);
+      groups.push({
+        id: groupRef.toString(),
+        name: group.get("Name"),
+        intent: group.get("Intent"), // TODO validate this.
+      });
+    }
+    const defaultConfig = properties.get("D");
+    if (!defaultConfig) {
+      return null;
+    }
+    const config = this._readOptionalContentConfig(defaultConfig, groupRefs);
+    config.groups = groups;
+    return config;
+  }
+
+  _readOptionalContentConfig(config, contentGroupRefs) {
+    // console.log(contentGroupRefs);
+    function parseOnOff(refs) {
+      const onParsed = [];
+      if (Array.isArray(refs)) {
+        for (const value of refs) {
+          if (contentGroupRefs.includes(value)) {
+            onParsed.push(value.toString());
+          }
+        }
+      }
+      return onParsed;
+    }
+
+    return {
+      name: config.get("Name"),
+      creator: config.get("Creator"),
+      baseState: config.get("BaseState"),
+      on: parseOnOff(config.get("ON")),
+      off: parseOnOff(config.get("OFF")),
+    };
+  }
+
   get numPages() {
     const obj = this.toplevelPagesDict.get("Count");
     if (!Number.isInteger(obj)) {

src/core/worker.js

@@ -485,6 +485,13 @@ class WorkerMessageHandler {
       return pdfManager.ensureCatalog("documentOutline");
     });
 
+    handler.on(
+      "GetOptionalContentConfig",
+      function wphSetupGetOptionalContentConfig(data) {
+        return pdfManager.ensureCatalog("optionalContentConfig");
+      }
+    );
+
     handler.on("GetPermissions", function (data) {
       return pdfManager.ensureCatalog("permissions");
     });

src/display/api.js

@@ -54,6 +54,7 @@ import { GlobalWorkerOptions } from "./worker_options.js";
 import { isNodeJS } from "../shared/is_node.js";
 import { MessageHandler } from "../shared/message_handler.js";
 import { Metadata } from "./metadata.js";
+import { OptionalContentConfig } from "./optional_content_config.js";
 import { PDFDataTransportStream } from "./transport_stream.js";
 import { WebGLContext } from "./webgl.js";
 
@@ -709,6 +710,15 @@ class PDFDocumentProxy {
     return this._transport.getOutline();
   }
 
+  /**
+   * @returns {Promise} A promise that is resolved with an
+   * {OptionalContentConfig} that will have all the optional content groups (if
+   * the document has any). @see {OptionalContentConfig}
+   */
+  getOptionalContentConfig() {
+    return this._transport.getOptionalContentConfig();
+  }
+
   /**
    * @returns {Promise} A promise that is resolved with an {Array} that contains
    *   the permission flags for the PDF document, or `null` when
@@ -882,6 +892,11 @@ class PDFDocumentProxy {
  *                    CSS <color> value, a CanvasGradient object (a linear or
  *                    radial gradient) or a CanvasPattern object (a repetitive
  *                    image). The default value is 'rgb(255,255,255)'.
+ * @property {Promise} [optionalContentConfigPromise] - A promise that should
+ *                     resolve with an {OptionalContentConfig} created from
+ *                     PDFDocumentProxy.getOptionalContentConfig. If null, the
+ *                     config will automatically fetched with the default
+ *                     visibility states set.
  */
 
 /**
@@ -1004,6 +1019,7 @@ class PDFPageProxy {
     imageLayer = null,
     canvasFactory = null,
     background = null,
+    optionalContentConfigPromise = null,
   }) {
     if (this._stats) {
       this._stats.time("Overall");
@@ -1014,6 +1030,10 @@ class PDFPageProxy {
     // this call to render.
     this.pendingCleanup = false;
 
+    if (!optionalContentConfigPromise) {
+      optionalContentConfigPromise = this._transport.getOptionalContentConfig();
+    }
+
     let intentState = this._intentStates.get(renderingIntent);
     if (!intentState) {
       intentState = Object.create(null);
@@ -1106,16 +1126,22 @@ class PDFPageProxy {
     intentState.renderTasks.push(internalRenderTask);
     const renderTask = internalRenderTask.task;
 
-    intentState.displayReadyCapability.promise
-      .then(transparency => {
+    Promise.all([
+      intentState.displayReadyCapability.promise,
+      optionalContentConfigPromise,
+    ])
+      .then(([transparency, optionalContentConfig]) => {
         if (this.pendingCleanup) {
           complete();
           return;
         }
         if (this._stats) {
           this._stats.time("Rendering");
         }
-        internalRenderTask.initializeGraphics(transparency);
+        internalRenderTask.initializeGraphics({
+          transparency,
+          optionalContentConfig,
+        });
         internalRenderTask.operatorListChanged();
       })
       .catch(complete);
@@ -2447,6 +2473,16 @@ class WorkerTransport {
     return this.messageHandler.sendWithPromise("GetOutline", null);
   }
 
+  getOptionalContentConfig() {
+    return this.messageHandler
+      .sendWithPromise("GetOptionalContentConfig", null)
+      .then(results => {
+        const config = new OptionalContentConfig();
+        config.initialize(results);
+        return config;
+      });
+  }
+
   getPermissions() {
     return this.messageHandler.sendWithPromise("GetPermissions", null);
   }
@@ -2659,7 +2695,7 @@ const InternalRenderTask = (function InternalRenderTaskClosure() {
       });
     }
 
-    initializeGraphics(transparency = false) {
+    initializeGraphics({ transparency = false, optionalContentConfig }) {
       if (this.cancelled) {
         return;
       }
@@ -2697,7 +2733,8 @@ const InternalRenderTask = (function InternalRenderTaskClosure() {
         this.objs,
         this.canvasFactory,
         this.webGLContext,
-        imageLayer
+        imageLayer,
+        optionalContentConfig
       );
       this.gfx.beginDrawing({
         transform,