Documentation for the layer composite

diff --git a/synfig-core/src/synfig/layer_composite.cpp b/synfig-core/src/synfig/layer_composite.cpp
index 6a25efc..5d03787 100644 (file)
--- a/synfig-core/src/synfig/layer_composite.cpp
+++ b/synfig-core/src/synfig/layer_composite.cpp
@@ -92,18 +92,22 @@ Layer_Composite::accelerated_render(Context context,Surface *surface,int quality
 
        image.push_back(0);     // Alpha black
 
-       // Render the backdrop
+       // Render the backdrop on the surface layer's surface.
        if(!context.accelerated_render(&surfacelayer->surface,quality,renddesc,&stageone))
                return false;
-
+       // Sets up the interpolation of the context (now the surface layer is the first one)
+       // depending on the quality
        if(quality<=4)surfacelayer->c=3;else
        if(quality<=5)surfacelayer->c=2;
        else if(quality<=6)surfacelayer->c=1;
        else surfacelayer->c=0;
        surfacelayer->tl=renddesc.get_tl();
        surfacelayer->br=renddesc.get_br();
+       // Sets the blend method to straight. See below
        surfacelayer->set_blend_method(Color::BLEND_STRAIGHT);
-
+       // Push this layer on the image. The blending result is only this layer
+       // adn the surface layer. The rest of the context is ignored by the straight
+       // blend method of surface layer
        image.push_front(const_cast<synfig::Layer_Composite*>(this));
 
        // Set up a surface target
@@ -136,8 +140,9 @@ Layer_Composite::get_full_bounding_rect(Context context)const
 Layer::Vocab
 Layer_Composite::get_param_vocab()const
 {
+       //! First fills the returning vocabulary with the ancestor class
        Layer::Vocab ret(Layer::get_param_vocab());
-
+       //! Now inserts the two parameters that this layer knows.
        ret.push_back(ParamDesc(amount_,"amount")
                .set_local_name(_("Amount"))
        );
@@ -200,9 +205,12 @@ Layer_Composite::set_param(const String & param, const ValueBase &value)
 ValueBase
 Layer_Composite::get_param(const String & param)const
 {
+       //! First check if the parameter's string is known.
        if(param=="amount")
                return get_amount();
        if(param=="blend_method")
                return static_cast<int>(get_blend_method());
+       //! If it is unknown then call the ancestor's get param member
+       //! to see if it can handle that parameter's string.
        return Layer::get_param(param);
 }

diff --git a/synfig-core/src/synfig/layer_composite.h b/synfig-core/src/synfig/layer_composite.h
index cb9497d..458bae7 100644 (file)
--- a/synfig-core/src/synfig/layer_composite.h
+++ b/synfig-core/src/synfig/layer_composite.h
@@ -48,13 +48,13 @@ class Layer_NoDeform {};
 class Layer_Composite : public Layer
 {
 private:
-
+       //! The amount of composite
        float amount_;
-
+       //! The blend method for the composition
        Color::BlendMethod blend_method_;
 
 protected:
-
+       //! Default constructor. Not used directly.
        Layer_Composite(
                float   amount=1.0,
                Color::BlendMethod      blend_method=Color::BLEND_COMPOSITE
@@ -64,32 +64,37 @@ protected:
                converted_blend_        (false),
                transparent_color_      (false)
        { }
-
+       //! Converted blend is used to check if an old version of canvas
+       //! is used in the composition. Old Straight was used as new Composite
+       //! \todo verify this
        bool converted_blend_;
+       //! Transparent color is used for old canvas versions.
+       //!Old Straight plus transparent color seems to be the same new than alpha over.
        bool transparent_color_;
 
 public:
-
+       //! Gets the amount of the layer
        float get_amount()const { return amount_; }
-
+       //! Sets the amount of the layer and returns this layer
        Layer_Composite& set_amount(float x) { amount_=x; return *this; }
-
+       //! Gets the blend method of the layer
        Color::BlendMethod get_blend_method()const { return blend_method_; }
-
+       //! Sets the blend method of the layer and returns this layer
        Layer_Composite& set_blend_method(Color::BlendMethod x) { blend_method_=x; return *this; }
-
+       //! Returns true is amount is 1 and blend method is straight
        virtual bool is_solid_color()const { return amount_==1.0f && blend_method_==Color::BLEND_STRAIGHT; }
-
+       //! Returns true if the amount is zero.
        bool is_disabled()const { return amount_==0.0f; }
-
+       //! Gets the parameter vocabulary. To be overrided by the derived.
        virtual Vocab get_param_vocab()const;
-
+       //! Sets the value for the given parameter.
        virtual bool set_param(const String &param, const ValueBase &value);
-
+       //! Gets the value of the given parameter
        virtual ValueBase get_param(const String &param)const;
-
+       //!Returns the rectangle that includes the context of the layer and
+       //! the intersection of the layer in case it is active and not onto
        virtual Rect get_full_bounding_rect(Context context)const;
-
+       //! Renders the layer composited on the context and puts it on the target surface.
        virtual bool accelerated_render(Context context,Surface *surface,int quality, const RendDesc &renddesc, ProgressCallback *cb)const;
 }; // END of class Layer_Composite