add allowImageFilter() so a device can allow/disallow filters

(esp. for printing)



git-svn-id: http://skia.googlecode.com/svn/trunk@2981 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 14 insertions, 1 deletions

diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 8c351f9e51..c026a4b493 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -310,9 +310,18 @@ protected:
     virtual void unlockPixels();
 
     /**
+     *  Returns true if the device allows processing of this imagefilter. If
+     *  false is returned, then the filter is ignored. This may happen for
+     *  some subclasses that do not support pixel manipulations after drawing
+     *  has occurred (e.g. printing). The default implementation returns true.
+     */
+    virtual bool allowImageFilter(SkImageFilter*);
+
+    /**
      *  Override and return true for filters that the device handles
      *  intrinsically. Returning false means call the filter.
-     *  Default impl returns false.
+     *  Default impl returns false. This will only be called if allowImageFilter()
+     *  returned true.
      */
     virtual bool filterImage(SkImageFilter*, const SkBitmap& src,
                              const SkMatrix& ctm,
diff --git a/include/device/xps/SkXPSDevice.h b/include/device/xps/SkXPSDevice.h
index c948a902fb..686e1687ec 100644
--- a/include/device/xps/SkXPSDevice.h
+++ b/include/device/xps/SkXPSDevice.h
@@ -144,6 +144,8 @@ protected:
                               int y,
                               SkCanvas::Config8888) SK_OVERRIDE;
 
+    virtual bool allowImageFilter(SkImageFilter*) SK_OVERRIDE;
+
 private:
     class TypefaceUse : ::SkNoncopyable {
     public:
diff --git a/include/pdf/SkPDFDevice.h b/include/pdf/SkPDFDevice.h
index 006994e304..45511495c4 100644
--- a/include/pdf/SkPDFDevice.h
+++ b/include/pdf/SkPDFDevice.h
@@ -161,6 +161,8 @@ protected:
     virtual bool onReadPixels(const SkBitmap& bitmap, int x, int y,
                               SkCanvas::Config8888) SK_OVERRIDE;
 
+    virtual bool allowImageFilter(SkImageFilter*) SK_OVERRIDE;
+
 private:
     // TODO(vandebo): push most of SkPDFDevice's state into a core object in
     // order to get the right access levels without using friend.