palette.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef GRAPHICS_PALETTE_H
#define GRAPHICS_PALETTE_H

#include "common/hashmap.h"
#include "common/types.h"

#define PALETTE_6BIT_TO_8BIT(x) ((x) * 255 / 63)
#define PALETTE_8BIT_TO_6BIT(x) ((x) * 63 / 255)

namespace Graphics {

enum ColorDistanceMethod {
    kColorDistanceEuclidean, 
    kColorDistanceNaive,     
    kColorDistanceRedmean,   
};

constexpr int PALETTE_COUNT = 256;
constexpr int PALETTE_SIZE = (256 * 3);

extern const byte HGC_A_PALETTE[6];
extern const byte HGC_G_PALETTE[6];


class Palette {
    byte *_data;
    uint16 _size;
    DisposeAfterUse::Flag _disposeAfterUse;

public:
    static const uint16 npos = 0xFFFF;

    Palette(uint size = 0);

    Palette(const byte *data, uint size);

    Palette(byte *data, uint size, DisposeAfterUse::Flag disposeAfterUse);

    Palette(const Palette &p);

    ~Palette();

    static const Palette createEGAPalette();

    Palette &operator=(const Palette &rhs);
    bool operator==(const Palette &rhs) const { return equals(rhs); }
    bool operator!=(const Palette &rhs) const { return !equals(rhs); }

    bool equals(const Palette &p) const;

    bool contains(const Palette &p) const;

    const byte *data() const { return _data; }
    uint size() const { return _size; }
    
    void clear();

    bool empty() const { return _size == 0; }

    void resize(uint newSize, bool preserve);

    void set(uint entry, byte r, byte g, byte b) {
        assert(entry < _size);
        _data[entry * 3 + 0] = r;
        _data[entry * 3 + 1] = g;
        _data[entry * 3 + 2] = b;
    }

    void get(uint entry, byte &r, byte &g, byte &b) const {
        assert(entry < _size);
        r = _data[entry * 3 + 0];
        g = _data[entry * 3 + 1];
        b = _data[entry * 3 + 2];
    }

    uint find(byte r, byte g, byte b) const {
        for (uint i = 0; i < _size; i++) {
            if (_data[i * 3 + 0] == r && _data[i * 3 + 1] == g && _data[i * 3 + 2] == b)
                return i;
        }
        return npos;
    }

    byte findBestColor(byte r, byte g, byte b, ColorDistanceMethod method = kColorDistanceRedmean) const;

    void set(const byte *colors, uint start, uint num);
    void set(const Palette &p, uint start, uint num);

    void grab(byte *colors, uint start, uint num) const;
    void grab(Palette &p, uint start, uint num) const;
};

class PaletteLookup {
public:
    PaletteLookup();
    PaletteLookup(const byte *palette, uint len);

    bool setPalette(const byte *palette, uint len);

    byte findBestColor(byte r, byte g, byte b, ColorDistanceMethod method = kColorDistanceRedmean);

    uint32 *createMap(const byte *srcPalette, uint len, ColorDistanceMethod method = kColorDistanceRedmean);

private:
    Palette _palette;
    uint _paletteSize;
    Common::HashMap<int, byte> _colorHash;
};

} //  // end of namespace Graphics
#endif