Adds support for the new mozPrintCallback api.

web/viewer.js

@@ -379,6 +379,11 @@ var PDFView = {
     return currentPageNumber;
   },
 
+  get supportsPrinting() {
+    var canvas = document.createElement('canvas');
+    return 'mozPrintCallback' in canvas;
+  },
+
   open: function pdfViewOpen(url, scale, password) {
     var parameters = {password: password};
     if (typeof url === 'string') { // URL
@@ -1041,6 +1046,22 @@ var PDFView = {
       params[unescape(key)] = unescape(value);
     }
     return params;
+  },
+
+  beforePrint: function pdfViewSetupBeforePrint() {
+    if (!this.supportsPrinting) {
+      alert('Printing is not supported by this browser.');
+      return;
+    }
+    for (var i = 0, ii = this.pages.length; i < ii; ++i) {
+      this.pages[i].beforePrint();
+    }
+  },
+
+  afterPrint: function pdfViewSetupAfterPrint() {
+    var div = document.getElementById('printContainer');
+    while (div.hasChildNodes())
+      div.removeChild(div.lastChild);
   }
 };
 
@@ -1360,6 +1381,40 @@ var PageView = function pageView(container, pdfPage, id, scale,
     div.setAttribute('data-loaded', true);
   };
 
+  this.beforePrint = function pageViewBeforePrint() {
+    var pdfPage = this.pdfPage;
+    var viewport = pdfPage.getViewport(1);
+
+    var canvas = this.canvas = document.createElement('canvas');
+    canvas.width = viewport.width;
+    canvas.height = viewport.height;
+    canvas.style.width = viewport.width + 'pt';
+    canvas.style.height = viewport.height + 'pt';
+
+    var printContainer = document.getElementById('printContainer');
+    printContainer.appendChild(canvas);
+
+    var self = this;
+    canvas.mozPrintCallback = function(obj) {
+      var ctx = obj.context;
+      var renderContext = {
+        canvasContext: ctx,
+        viewport: viewport
+      };
+
+      pdfPage.render(renderContext).then(function() {
+        // Tell the printEngine that rendering this canvas/page has finished.
+        obj.done();
+        self.pdfPage.destroy();
+      }, function(error) {
+        console.error(error);
+        // Tell the printEngine that rendering this canvas/page has failed.
+        // This will make the print proces stop.
+        obj.abort();
+      });
+    };
+  };
+
   this.updateStats = function pageViewUpdateStats() {
     if (PDFJS.pdfBug && Stats.enabled) {
       var stats = this.stats;
@@ -1960,3 +2015,11 @@ window.addEventListener('keydown', function keydown(evt) {
     evt.preventDefault();
   }
 });
+
+window.addEventListener('beforeprint', function beforePrint(evt) {
+  PDFView.beforePrint();
+});
+
+window.addEventListener('afterprint', function afterPrint(evt) {
+  PDFView.afterPrint();
+});