add surface id

include/tgfx/core/Surface.h

@@ -175,6 +175,7 @@ class Surface {
   */
   uint32_t contentVersion() const;
 
+  uint32_t _uniqueID = 0;
   std::shared_ptr<RenderTargetProxy> renderTargetProxy = nullptr;
   uint32_t _renderFlags = 0;
   RenderContext* renderContext = nullptr;

include/tgfx/layers/DisplayList.h

@@ -48,7 +48,9 @@ class DisplayList {
   void render(Surface* surface, bool replaceAll = true);
 
  private:
+  bool needRender(const Surface* surface) const;
   std::shared_ptr<Layer> _root = nullptr;
   uint32_t surfaceContentVersion = 0u;
+  uint32_t surfaceID = 0u;
 };
 }  // namespace tgfx

include/tgfx/layers/LayerProperty.h

@@ -32,11 +32,14 @@ class LayerProperty {
 
  protected:
   /**
-   * Mark the property as dirty and notify the layer that the content needs to be updated.
+   * Invalidate this property and notify the layer that the content needs to be updated.
    */
   void invalidate();
 
-  bool dirty = true;
+  /**
+   * Called when the property is invalidated.
+   */
+  virtual void onInvalidate();
 
  private:
   void attachToLayer(const Layer* layer);

include/tgfx/layers/PathProvider.h

@@ -49,7 +49,11 @@ class PathProvider : public LayerProperty {
 
   virtual Path onGeneratePath();
 
+  void onInvalidate() override;
+
  private:
   Path path = {};
+
+  bool dirty = true;
 };
 }  // namespace tgfx

include/tgfx/layers/filters/LayerFilter.h

@@ -45,7 +45,11 @@ class LayerFilter : public LayerProperty {
    */
   virtual std::shared_ptr<ImageFilter> onCreateImageFilter(float scale) = 0;
 
+  void onInvalidate() override;
+
  private:
+  bool dirty = true;
+
   float lastScale = 1.0f;
 
   std::unique_ptr<Rect> _clipBounds = nullptr;

src/gpu/Surface.cpp

@@ -67,7 +67,7 @@ std::shared_ptr<Surface> Surface::MakeFrom(std::shared_ptr<RenderTargetProxy> re
 }
 
 Surface::Surface(std::shared_ptr<RenderTargetProxy> proxy, uint32_t renderFlags)
-    : renderTargetProxy(std::move(proxy)), _renderFlags(renderFlags) {
+    : _uniqueID(UniqueID::Next()), renderTargetProxy(std::move(proxy)), _renderFlags(renderFlags) {
   DEBUG_ASSERT(this->renderTargetProxy != nullptr);
 }
 

src/layers/DisplayList.cpp

@@ -30,8 +30,7 @@ Layer* DisplayList::root() const {
 }
 
 void DisplayList::render(Surface* surface, bool replaceAll) {
-  if (!surface || (surface->contentVersion() == surfaceContentVersion && !_root->bitFields.dirty &&
-                   replaceAll)) {
+  if (!surface || !needRender(surface)) {
     return;
   }
   auto canvas = surface->getCanvas();
@@ -41,5 +40,12 @@ void DisplayList::render(Surface* surface, bool replaceAll) {
   DrawArgs args(surface->getContext(), surface->renderFlags(), true);
   _root->drawLayer(args, canvas, 1.0f, BlendMode::SrcOver);
   surfaceContentVersion = surface->contentVersion();
+  surfaceID = surface->_uniqueID;
 }
+
+bool DisplayList::needRender(const Surface* surface) const {
+  return surface->_uniqueID != surfaceID || surface->contentVersion() != surfaceContentVersion ||
+         _root->bitFields.dirty;
+}
+
 }  // namespace tgfx

src/layers/LayerProperty.cpp

@@ -22,13 +22,17 @@
 namespace tgfx {
 
 void LayerProperty::invalidate() {
-  dirty = true;
+  onInvalidate();
   for (auto& owner : owners) {
     if (auto layer = owner.lock()) {
       layer->invalidateContent();
     }
   }
 }
+
+void LayerProperty::onInvalidate() {
+}
+
 void LayerProperty::attachToLayer(const Layer* layer) {
   owners.push_back(layer->weakThis);
 }

src/layers/PathProvider.cpp

@@ -41,4 +41,9 @@ Path PathProvider::getPath() {
 Path PathProvider::onGeneratePath() {
   return path;
 }
+
+void PathProvider::onInvalidate() {
+  dirty = true;
+}
+
 }  // namespace tgfx

src/layers/filters/LayerFilter.cpp

@@ -29,4 +29,8 @@ std::shared_ptr<ImageFilter> LayerFilter::getImageFilter(float filterScale) {
   return lastFilter;
 }
 
+void LayerFilter::onInvalidate() {
+  dirty = true;
+}
+
 }  // namespace tgfx