Implemented transparent gradients

src/pdf/SkPDFTypes.h

Index: src/pdf/SkPDFTypes.h
diff --git a/src/pdf/SkPDFTypes.h b/src/pdf/SkPDFTypes.h
index 5ed6386bddc1235d33a9dbcabe65c78a33a8bb6e..7f4d06e8106376a4fd7980c052ef3be2292a94af 100644
--- a/src/pdf/SkPDFTypes.h
+++ b/src/pdf/SkPDFTypes.h
@@ -441,4 +441,85 @@ private:
     typedef SkPDFObject INHERITED;
 };
 
+/** \class SkPDFResourceDict
+
+    A resource dictionary, which also allows generation of a list of referenced
+    SkPDFObjects. These must be added to the dict with insertResource.
+*/
+class SkPDFResourceDict : public SkPDFDict {

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

Not sure I'm happy with how this turned out.  It's very heavy weight compared to
an extra argument to the SkPDFFormXObject constructor.  Would this type be
useful in other parts of the existing code?

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

Looks like it can be used in SkPDFDevice, the only other place where a resource
dict is constructed. It should make the resource list a bit more encapsulated
and the construction slightly prettier and shorter at a slight cost in
efficiency (to do the sub-dict lookup, though that can be heuristically sped-up
by looking through the list in reverse order since similar resources tend to be
added together).

As for possible conflicts with the substitution code, I don't see any. While I
don't fully understand the substitution code, it seems that most substitution
happens in SkPDFCatalog and SkPDFStream. SkPDFDevice itself doesn't know
anything about substitutes, and the code used to construct the resourceDict /
getResources all rely on private variables fFontResources, fShaderResources, ...
. As far as I can tell, code only adds entries, and no code modifies existing
entries. Furthermore, it seems that getResourceDict memoizes the constructed
dict while getResources pulls data from the current resource lists - so if there
was any funny business going on, getResourceDict and getResources (which usually
are called together) would return inconsistent results.
Though, again, since I don't completely understand the substitution code, you
may want to check my logic.

+ public:
+    SK_DECLARE_INST_COUNT(SkPDFResourceDict)
+
+    /** Create a PDF dictionary. Maximum number of entries is 4095.

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

comments are out of date....

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

Done.

+     */
+    SkPDFResourceDict() : SkPDFDict() {};
+
+    /** Create a PDF dictionary with a Type entry.
+     *  @param type   The value of the Type entry.
+     */
+    explicit SkPDFResourceDict(const char type[]) : SkPDFDict(type) {};
+
+
+    /** Add the value to the dictionary with the given key.  Refs value.
+     * The object will NOT be part of the resource list when requested later.
+     *  @param type  The type of resource being entered, like Pattern or ExtGState.
+     *  @param key   The resource key, unique within the type.
+     *  @param value The resource itself.
+     *  @return The value argument is returned.
+     */
+    SkPDFObject* insertResource(SkPDFName* type, SkPDFName* key,
+                                SkPDFObject* value);
+
+    /** Add the value to the dictionary with the given key.  Refs value.
+     * The object will NOT be part of the resource list when requested later.
+     *  This method will create the SkPDFName object.
+     *  @param type  The type of resource being entered, like Pattern or ExtGState.
+     *  @param key   The resource key, unique within the type.
+     *  @param value The resource itself.
+     *  @return The value argument is returned.
+     */
+    SkPDFObject* insertResource(const char type[], const char key[],
+                                SkPDFObject* value);
+
+    /** Add the value SkPDFObject as a reference to the dictionary
+     *  with the given key.  Refs value.
+     *  This object will be part of the resource list when requested later.
+     *  This method will create the SkPDFName object.
+     *  @param type  The type of resource being entered, like Pattern or ExtGState.
+     *  @param key   The resource key, unique within the type.
+     *  @param value The resource itself.
+     *  @return The value argument is returned.
+     */
+    SkPDFObject* insertResourceAsRef(const char type[], const char key[],
+                                     SkPDFObject* value);
+
+    /**
+     * Gets resources inserted into this dictionary.
+     *
+     * @param knownResourceObjects Set containing currently known resources.
+     *     Resources in the dict and in this set will not be added to the output.
+     * @param newResourceObjects   Output set to which non-preexisting resources
+     *     will be added.
+     */
+    void getResources(
+            const SkTSet<SkPDFObject*>& knownResourceObjects,
+            SkTSet<SkPDFObject*>* newResourceObjects);
+
+ private:
+    /**
+     * Returns the sub-dict associated with the resource type type.
+     * If none currently exists, this will create a sub-dict and index it for
+     * future use.
+     */
+    SkPDFDict* getResourceTypeDict(SkPDFName* type);
+
+    SkTSet<SkPDFObject*> fResources;
+
+     struct DictRec {
+       SkPDFName* key;
+       SkPDFDict* value;
+     };
+     SkTDArray<struct DictRec> fTypes;
+};
+
 #endif