Fixes incomplete restore in paintFormXObject

src/canvas.js

@@ -187,6 +187,7 @@ var CanvasExtraState = (function CanvasExtraStateClosure() {
     this.fillAlpha = 1;
     this.strokeAlpha = 1;
     this.lineWidth = 1;
+    this.paintFormXObjectDepth = 0;
 
     this.old = old;
   }
@@ -1102,6 +1103,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
     paintFormXObjectBegin: function CanvasGraphics_paintFormXObjectBegin(matrix,
                                                                         bbox) {
       this.save();
+      this.current.paintFormXObjectDepth++;
 
       if (matrix && isArray(matrix) && 6 == matrix.length)
         this.transform.apply(this, matrix);
@@ -1116,7 +1118,12 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
     },
 
     paintFormXObjectEnd: function CanvasGraphics_paintFormXObjectEnd() {
+      var depth = this.current.paintFormXObjectDepth;
+      do {
         this.restore();
+        // some pdf don't close all restores inside object
+        // closing those for them
+      } while (this.current.paintFormXObjectDepth >= depth);
     },
 
     paintJpegXObject: function CanvasGraphics_paintJpegXObject(objId, w, h) {

test/pdfs/.gitignore

@@ -24,6 +24,7 @@
 !pdfkit_compressed.pdf
 !TAMReview.pdf
 !issue918.pdf
+!issue1905.pdf
 !issue1249.pdf
 !smaskdim.pdf
 !type4psfunc.pdf

test/test_manifest.json

@@ -367,6 +367,12 @@
        "pageLimit": 3,
        "type": "eq"
     },
+    {  "id": "issue1905",
+       "file": "pdfs/issue1905.pdf",
+       "md5": "b1bbd72ca6522ae1502aa26320f81994",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue918",
        "file": "pdfs/issue918.pdf",
        "md5": "d582cc0f2592ae82936589ced2a47e55",