Documentation for the layer composite

[synfig.git] / synfig-core / src / synfig / layer_composite.cpp

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);
 }