/*
 * Copyright 2011, Haiku, Inc.
 * All rights reserved. Distributed under the terms of the MIT License.
 */
#ifndef COLLAPSING_LAYOUTER_H   
#define COLLAPSING_LAYOUTER_H

#include "Layouter.h"


namespace BPrivate {
namespace Layout {


/* This layouter wraps either a Compound, Simple or OneElement layouter, and
 * removes elements which have no constraints, or min/max constraints of
 * B_SIZE_UNSET. The child layouter is given only the constraints for the
 * remaining elements. When using the LayoutInfo of this layouter,
 * collapsed (removed) elements are given no space on screen.
 */
class CollapsingLayouter : public Layouter {
public:
                                                                CollapsingLayouter(int32 elementCount,
                                                                        float spacing);
        virtual                                         ~CollapsingLayouter();

        virtual void                            AddConstraints(int32 element, int32 length,
                                                                        float min, float max, float preferred);
        virtual void                            SetWeight(int32 element, float weight);

        virtual float                           MinSize();
        virtual float                           MaxSize();
        virtual float                           PreferredSize();

        virtual LayoutInfo*                     CreateLayoutInfo();
        
        virtual void                            Layout(LayoutInfo* layoutInfo, float size);

        virtual Layouter*                       CloneLayouter();


private:
        class   ProxyLayoutInfo;
        struct  Constraint;
        struct  ElementInfo;

                        void                            _ValidateLayouter();
                        Layouter*                       _CreateLayouter();
                        void                            _DoCollapse();
                        void                            _AddConstraints();
                        void                            _AddConstraints(int32 position,
                                                                        const Constraint* c);
                        void                            _SetWeights();

                        int32                           fElementCount;
                        ElementInfo*            fElements;
                        int32                           fValidElementCount;
                        bool                            fHaveMultiElementConstraints;
                        float                           fSpacing;
                        Layouter*                       fLayouter;
};

} // namespace Layout
} // namespace BPrivate

using BPrivate::Layout::CollapsingLayouter;

#endif // COLLAPSING_LAYOUTER_H