Implemented transparent gradients

src/pdf/SkPDFFormXObject.cpp

Index: src/pdf/SkPDFFormXObject.cpp
diff --git a/src/pdf/SkPDFFormXObject.cpp b/src/pdf/SkPDFFormXObject.cpp
index 884e6db2e4a1535c20d6f1dd62e87e637eceb2c1..a5ac6a4d1a36e8286b60bb0c687bccedc8364eaa 100644
--- a/src/pdf/SkPDFFormXObject.cpp
+++ b/src/pdf/SkPDFFormXObject.cpp
@@ -26,8 +26,6 @@ SkPDFFormXObject::SkPDFFormXObject(SkPDFDevice* device) {
     SkAutoTUnref<SkStream> content(device->content());
     setData(content.get());
 
-    insertName("Type", "XObject");
-    insertName("Subtype", "Form");
     SkSafeUnref(this->insert("BBox", device->copyMediaBox()));
     insert("Resources", device->getResourceDict());
 
@@ -44,10 +42,37 @@ SkPDFFormXObject::SkPDFFormXObject(SkPDFDevice* device) {
         insert("Matrix", SkPDFUtils::MatrixToArray(inverse))->unref();
     }
 
+    commonInit(NULL);

[vandebo (ex-Chrome), 2013/07/08 19:02:25]

nit: move to line 28

[ducky, 2013/07/09 02:56:23]

Done.

+}
+
+/**
+ * Creates a FormXObject from a content stream and associated resources.
+ */
+SkPDFFormXObject::SkPDFFormXObject(SkData* content, SkRect bbox,
+                                   SkPDFResourceDict* resourceDict) {
+    SkTSet<SkPDFObject*> emptySet;
+    SkSafeUnref(this->insert("BBox", SkPDFUtils::RectToArray(bbox)));
+    insert("Resources", resourceDict);
+    resourceDict->ref();
+    resourceDict->getResources(emptySet, &fResources);
+
+    setData(content);
+
+    commonInit("DeviceRGB");
+}
+
+void SkPDFFormXObject::commonInit(const char colorSpace[]) {

[vandebo (ex-Chrome), 2013/07/08 19:02:25]

pass as much as possible into init. i.e. bbox and resourceDict

[ducky, 2013/07/09 02:56:23]

Done. Though, it's still not a completely clean solution, as bbox is now unref'd
inside init (while being created outside init) and the different resourceDict
styles mean different code exists to handle resources. Should the new
resourceDict style work, this may become much cleaner.

[vandebo (ex-Chrome), 2013/07/09 17:47:44]

As you pointed out at a different point, you probably want to own the object on
the calling side.

At the least, the ownership semantics should be documented and preferably be the
same for all the arguments.

[ducky, 2013/07/10 21:42:26]

Fixed. Ownership is no longer transferred, and the caller is responsible for
cleaning up. Two more lines of boilerplate, but should be more intuitive.

+    insertName("Type", "XObject");
+    insertName("Subtype", "Form");
+
     // Right now SkPDFFormXObject is only used for saveLayer, which implies
     // isolated blending.  Do this conditionally if that changes.
     SkAutoTUnref<SkPDFDict> group(new SkPDFDict("Group"));
     group->insertName("S", "Transparency");
+
+    if (colorSpace != NULL) {
+        group->insertName("CS", colorSpace);
+    }
     group->insert("I", new SkPDFBool(true))->unref();  // Isolated.
     insert("Group", group.get());
 }