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

include/core/SkDevice.h

@@ -309,10 +309,19 @@ protected:
     virtual void lockPixels();
     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,

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:

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.

src/core/SkCanvas.cpp

@@ -732,6 +732,16 @@ int SkCanvas::saveLayer(const SkRect* bounds, const SkPaint* paint,
         return count;
     }
 
+    // Kill the imagefilter if our device doesn't allow it
+    SkLazyPaint lazyP;
+    if (paint && paint->getImageFilter()) {
+        if (!this->getTopDevice()->allowImageFilter(paint->getImageFilter())) {
+            SkPaint* p = lazyP.set(*paint);
+            p->setImageFilter(NULL);
+            paint = p;
+        }
+    }
+
     bool isOpaque;
     SkBitmap::Config config = resolve_config(this, ir, flags, &isOpaque);
 
@@ -889,7 +899,7 @@ bool DeviceImageFilterProxy::filterImage(SkImageFilter* filter,
     return fDevice->filterImage(filter, src, ctm, result, offset);
 }
 
-void SkCanvas::drawDevice(SkDevice* device, int x, int y,
+void SkCanvas::drawDevice(SkDevice* srcDev, int x, int y,
                           const SkPaint* paint) {
     SkPaint tmp;
     if (NULL == paint) {
@@ -899,20 +909,21 @@ void SkCanvas::drawDevice(SkDevice* device, int x, int y,
 
     LOOPER_BEGIN(*paint, SkDrawFilter::kBitmap_Type)
     while (iter.next()) {
+        SkDevice* dstDev = iter.fDevice;
         paint = &looper.paint();
         SkImageFilter* filter = paint->getImageFilter();
         SkIPoint pos = { x - iter.getX(), y - iter.getY() };
         if (filter) {
-            DeviceImageFilterProxy proxy(device);
+            DeviceImageFilterProxy proxy(dstDev);
             SkBitmap dst;
-            const SkBitmap& src = device->accessBitmap(false);
+            const SkBitmap& src = srcDev->accessBitmap(false);
             if (filter->filterImage(&proxy, src, *iter.fMatrix, &dst, &pos)) {
                 SkPaint tmp(*paint);
                 tmp.setImageFilter(NULL);
-                iter.fDevice->drawSprite(iter, dst, pos.x(), pos.y(), tmp);
+                dstDev->drawSprite(iter, dst, pos.x(), pos.y(), tmp);
             }
         } else {
-            iter.fDevice->drawDevice(iter, device, pos.x(), pos.y(), *paint);
+            dstDev->drawDevice(iter, srcDev, pos.x(), pos.y(), *paint);
         }
     }
     LOOPER_END

src/core/SkDevice.cpp

@@ -107,6 +107,10 @@ bool SkDevice::filterImage(SkImageFilter*, const SkBitmap& src,
     return false;
 }
 
+bool SkDevice::allowImageFilter(SkImageFilter*) {
+    return true;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkDevice::readPixels(SkBitmap* bitmap, int x, int y,

src/device/xps/SkXPSDevice.cpp

@@ -2384,6 +2384,7 @@ SkDevice* SkXPSDevice::onCreateCompatibleDevice(SkBitmap::Config config,
                                                 bool isOpaque,
                                                 Usage usage) {
     if (SkDevice::kGeneral_Usage == usage) {
+        return NULL;
         SK_CRASH();
         //To what stream do we write?
         //SkXPSDevice* dev = new SkXPSDevice(this);
@@ -2409,3 +2410,8 @@ SkXPSDevice::SkXPSDevice(IXpsOMObjectFactory* xpsFactory)
     HRVM(this->fXpsFactory->CreateCanvas(&this->fCurrentXpsCanvas),
          "Could not create canvas for layer.");
 }
+
+bool SkXPSDevice::allowImageFilter(SkImageFilter*) {
+    return false;
+}
+

src/pdf/SkPDFDevice.cpp

@@ -1535,3 +1535,8 @@ bool SkPDFDevice::onReadPixels(const SkBitmap& bitmap, int x, int y,
                                SkCanvas::Config8888) {
     return false;
 }
+
+bool SkPDFDevice::allowImageFilter(SkImageFilter*) {
+    return false;
+}
+