Layer.hh

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#ifndef LAYER_HH
#define LAYER_HH
 
#include "stl.hh"
 
namespace openmsx {
 
class Display;
class OutputSurface;
 
class Layer
{
public:
        enum class ZIndex {
                BACKGROUND,
                MSX_PASSIVE,
                MSX_ACTIVE,
                OSDGUI,
                IMGUI,
        };
        [[nodiscard]] friend auto operator<=>(ZIndex x, ZIndex y) { return to_underlying(x) <=> to_underlying(y); }
 
        enum class Coverage {
                FULL,
                PARTIAL,
                NONE
        };
 
        virtual ~Layer() = default;
 
        virtual void paint(OutputSurface& output) = 0;
 
        [[nodiscard]] ZIndex getZ() const { return z; }
        [[nodiscard]] bool isActive() const { return getZ() == ZIndex::MSX_ACTIVE; }
 
        [[nodiscard]] Coverage getCoverage() const { return coverage; }
 
        void setDisplay(Display& display_) { display = &display_; }
 
protected:
        explicit Layer(Coverage coverage_, ZIndex z_)
                : coverage(coverage_), z(z_)
        {
        }
 
        void setCoverage(Coverage coverage_) { coverage = coverage_; }
 
        void setZ(ZIndex z);
 
private:
        Display* display = nullptr;
 
        Coverage coverage;
 
        ZIndex z;
 
        friend class ScopedLayerHider; // for setCoverage()
};
 
 
class ScopedLayerHider
{
public:
        explicit ScopedLayerHider(Layer& layer);
        ScopedLayerHider(const ScopedLayerHider&) = delete;
        ScopedLayerHider(ScopedLayerHider&&) = delete;
        ScopedLayerHider& operator=(const ScopedLayerHider&) = delete;
        ScopedLayerHider& operator=(ScopedLayerHider&&) = delete;
        ~ScopedLayerHider();
private:
        Layer& layer;
        Layer::Coverage originalCoverage;
};
 
} // namespace openmsx
 
#endif