JUCE/modules/juce_graphics/colour/juce_PixelFormats.h

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
#if JUCE_MSVC
 #pragma pack (push, 1)
#endif

class PixelRGB;
class PixelAlpha;

inline uint32 maskPixelComponents (uint32 x) noexcept
{
    return (x >> 8) & 0x00ff00ff;
}

inline uint32 clampPixelComponents (uint32 x) noexcept
{
    return (x | (0x01000100 - maskPixelComponents (x))) & 0x00ff00ff;
}

//==============================================================================
/**
    Represents a 32-bit INTERNAL pixel with premultiplied alpha, and can perform compositing
    operations with it.

    This is used internally by the imaging classes.

    @see PixelRGB

    @tags{Graphics}
*/
class JUCE_API  PixelARGB
{
public:
    /** Creates a pixel without defining its colour. */
    PixelARGB() = default;
    ~PixelARGB() = default;

    PixelARGB (const uint8 a, const uint8 r, const uint8 g, const uint8 b) noexcept
    {
        components.b = b;
        components.g = g;
        components.r = r;
        components.a = a;
    }

    //==============================================================================
    /** Returns a uint32 which represents the pixel in a platform dependent format. */
    forcedinline uint32 getNativeARGB() const noexcept { return internal; }

    /** Returns a uint32 which will be in argb order as if constructed with the following mask operation
        ((alpha << 24) | (red << 16) | (green << 8) | blue). */
    forcedinline uint32 getInARGBMaskOrder() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) ((components.a << 24) | (components.r << 16) | (components.g << 8) | (components.b << 0));
       #else
        return getNativeARGB();
       #endif
    }

    /** Returns a uint32 which when written to memory, will be in the order a, r, g, b. In other words,
        if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b*/
    inline uint32 getInARGBMemoryOrder() const noexcept
    {
       #if JUCE_BIG_ENDIAN
        return getInARGBMaskOrder();
       #else
        return (uint32) ((components.b << 24) | (components.g << 16) | (components.r << 8) | components.a);
       #endif
    }

    /** Return channels with an even index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent. */
    forcedinline uint32 getEvenBytes() const noexcept { return 0x00ff00ff & internal; }

    /** Return channels with an odd index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent. */
    forcedinline uint32 getOddBytes() const noexcept  { return 0x00ff00ff & (internal >> 8); }

    //==============================================================================
    forcedinline uint8 getAlpha() const noexcept      { return components.a; }
    forcedinline uint8 getRed() const noexcept        { return components.r; }
    forcedinline uint8 getGreen() const noexcept      { return components.g; }
    forcedinline uint8 getBlue() const noexcept       { return components.b; }

   #if JUCE_GCC
    // NB these are here as a workaround because GCC refuses to bind to packed values.
    forcedinline uint8& getAlpha() noexcept           { return comps [indexA]; }
    forcedinline uint8& getRed() noexcept             { return comps [indexR]; }
    forcedinline uint8& getGreen() noexcept           { return comps [indexG]; }
    forcedinline uint8& getBlue() noexcept            { return comps [indexB]; }
   #else
    forcedinline uint8& getAlpha() noexcept           { return components.a; }
    forcedinline uint8& getRed() noexcept             { return components.r; }
    forcedinline uint8& getGreen() noexcept           { return components.g; }
    forcedinline uint8& getBlue() noexcept            { return components.b; }
   #endif

    //==============================================================================
    /** Copies another pixel colour over this one.

        This doesn't blend it - this colour is simply replaced by the other one.
    */
    template <class Pixel>
    forcedinline void set (const Pixel& src) noexcept
    {
        internal = src.getNativeARGB();
    }

    //==============================================================================
    /** Sets the pixel's colour from individual components. */
    void setARGB (const uint8 a, const uint8 r, const uint8 g, const uint8 b) noexcept
    {
        components.b = b;
        components.g = g;
        components.r = r;
        components.a = a;
    }

    //==============================================================================
    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src) noexcept
    {
        uint32 rb = src.getEvenBytes();
        uint32 ag = src.getOddBytes();

        const uint32 alpha = 0x100 - (ag >> 16);

        rb += maskPixelComponents (getEvenBytes() * alpha);
        ag += maskPixelComponents (getOddBytes() * alpha);

        internal = clampPixelComponents (rb) | (clampPixelComponents (ag) << 8);
    }

    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    forcedinline void blend (const PixelRGB src) noexcept;


    /** Blends another pixel onto this one, applying an extra multiplier to its opacity.

        The opacity of the pixel being overlaid is scaled by the extraAlpha factor before
        being used, so this can blend semi-transparently from a PixelRGB argument.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src, uint32 extraAlpha) noexcept
    {
        uint32 rb = maskPixelComponents (extraAlpha * src.getEvenBytes());
        uint32 ag = maskPixelComponents (extraAlpha * src.getOddBytes());

        const uint32 alpha = 0x100 - (ag >> 16);

        rb += maskPixelComponents (getEvenBytes() * alpha);
        ag += maskPixelComponents (getOddBytes() * alpha);

        internal = clampPixelComponents (rb) | (clampPixelComponents (ag) << 8);
    }

    /** Blends another pixel with this one, creating a colour that is somewhere
        between the two, as specified by the amount.
    */
    template <class Pixel>
    forcedinline void tween (const Pixel& src, const uint32 amount) noexcept
    {
        uint32 dEvenBytes = getEvenBytes();
        dEvenBytes += (((src.getEvenBytes() - dEvenBytes) * amount) >> 8);
        dEvenBytes &= 0x00ff00ff;

        uint32 dOddBytes = getOddBytes();
        dOddBytes += (((src.getOddBytes() - dOddBytes) * amount) >> 8);
        dOddBytes &= 0x00ff00ff;
        dOddBytes <<= 8;

        dOddBytes |= dEvenBytes;
        internal = dOddBytes;
    }

    //==============================================================================
    /** Replaces the colour's alpha value with another one. */
    forcedinline void setAlpha (const uint8 newAlpha) noexcept
    {
        components.a = newAlpha;
    }

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (int multiplier) noexcept
    {
        // increment alpha by 1, so that if multiplier == 255 (full alpha),
        // this function will not change the values.
        ++multiplier;

        internal = ((((uint32) multiplier) * getOddBytes()) & 0xff00ff00)
                | (((((uint32) multiplier) * getEvenBytes()) >> 8) & 0x00ff00ff);
    }

    forcedinline void multiplyAlpha (const float multiplier) noexcept
    {
        multiplyAlpha ((int) (multiplier * 255.0f));
    }


    inline PixelARGB getUnpremultiplied() const noexcept { PixelARGB p (internal); p.unpremultiply(); return p; }

    /** Premultiplies the pixel's RGB values by its alpha. */
    forcedinline void premultiply() noexcept
    {
        const uint32 alpha = components.a;

        if (alpha < 0xff)
        {
            if (alpha == 0)
            {
                components.b = 0;
                components.g = 0;
                components.r = 0;
            }
            else
            {
                components.b = (uint8) ((components.b * alpha + 0x7f) >> 8);
                components.g = (uint8) ((components.g * alpha + 0x7f) >> 8);
                components.r = (uint8) ((components.r * alpha + 0x7f) >> 8);
            }
        }
    }

    /** Unpremultiplies the pixel's RGB values. */
    forcedinline void unpremultiply() noexcept
    {
        const uint32 alpha = components.a;

        if (alpha < 0xff)
        {
            if (alpha == 0)
            {
                components.b = 0;
                components.g = 0;
                components.r = 0;
            }
            else
            {
                components.b = (uint8) jmin ((uint32) 0xffu, (components.b * 0xffu) / alpha);
                components.g = (uint8) jmin ((uint32) 0xffu, (components.g * 0xffu) / alpha);
                components.r = (uint8) jmin ((uint32) 0xffu, (components.r * 0xffu) / alpha);
            }
        }
    }

    forcedinline void desaturate() noexcept
    {
        if (components.a < 0xff && components.a > 0)
        {
            const int newUnpremultipliedLevel = (0xff * ((int) components.r + (int) components.g + (int) components.b) / (3 * components.a));

            components.r = components.g = components.b
                = (uint8) ((newUnpremultipliedLevel * components.a + 0x7f) >> 8);
        }
        else
        {
            components.r = components.g = components.b
                = (uint8) (((int) components.r + (int) components.g + (int) components.b) / 3);
        }
    }

    //==============================================================================
    /** The indexes of the different components in the byte layout of this type of colour. */
  #if JUCE_ANDROID
   #if JUCE_BIG_ENDIAN
    enum { indexA = 0, indexR = 3, indexG = 2, indexB = 1 };
   #else
    enum { indexA = 3, indexR = 0, indexG = 1, indexB = 2 };
   #endif
  #else
   #if JUCE_BIG_ENDIAN
    enum { indexA = 0, indexR = 1, indexG = 2, indexB = 3 };
   #else
    enum { indexA = 3, indexR = 2, indexG = 1, indexB = 0 };
   #endif
  #endif

private:
    //==============================================================================
    PixelARGB (const uint32 internalValue) noexcept
        : internal (internalValue)
    {
    }

    //==============================================================================
    struct Components
    {
      #if JUCE_ANDROID
       #if JUCE_BIG_ENDIAN
        uint8 a, b, g, r;
       #else
        uint8 r, g, b, a;
       #endif
      #else
       #if JUCE_BIG_ENDIAN
        uint8 a, r, g, b;
       #else
        uint8 b, g, r, a;
       #endif
      #endif
    } JUCE_PACKED;

    union
    {
        uint32 internal;
        Components components;
       #if JUCE_GCC
        uint8 comps[4];  // helper struct needed because gcc does not allow references to packed union members
       #endif
    };
}
#ifndef DOXYGEN
 JUCE_PACKED
#endif
;


//==============================================================================
/**
    Represents a 24-bit RGB pixel, and can perform compositing operations on it.

    This is used internally by the imaging classes.

    @see PixelARGB

    @tags{Graphics}
*/
class JUCE_API  PixelRGB
{
public:
    /** Creates a pixel without defining its colour. */
    PixelRGB() = default;
    ~PixelRGB() = default;

    //==============================================================================
    /** Returns a uint32 which represents the pixel in a platform dependent format which is compatible
        with the native format of a PixelARGB.

        @see PixelARGB::getNativeARGB */
    forcedinline uint32 getNativeARGB() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) ((0xff << 24) | r | (g << 8) | (b << 16));
       #else
        return (uint32) ((0xff << 24) | b | (g << 8) | (r << 16));
       #endif
    }

    /** Returns a uint32 which will be in argb order as if constructed with the following mask operation
        ((alpha << 24) | (red << 16) | (green << 8) | blue). */
    forcedinline uint32 getInARGBMaskOrder() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) ((0xff << 24) | (r << 16) | (g << 8) | (b << 0));
       #else
        return getNativeARGB();
       #endif
    }

    /** Returns a uint32 which when written to memory, will be in the order a, r, g, b. In other words,
        if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b*/
    inline uint32 getInARGBMemoryOrder() const noexcept
    {
       #if JUCE_BIG_ENDIAN
        return getInARGBMaskOrder();
       #else
        return (uint32) ((b << 24) | (g << 16) | (r << 8) | 0xff);
       #endif
    }

    /** Return channels with an even index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getEvenBytes of the PixelARGB class.

        @see PixelARGB::getEvenBytes */
    forcedinline uint32 getEvenBytes() const noexcept
    {
       #if JUCE_ANDROID
        return (uint32) (r | (b << 16));
       #else
        return (uint32) (b | (r << 16));
       #endif
    }

    /** Return channels with an odd index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getOddBytes of the PixelARGB class.

        @see PixelARGB::getOddBytes */
    forcedinline uint32 getOddBytes() const noexcept       { return (uint32)0xff0000 | g; }

    //==============================================================================
    forcedinline uint8 getAlpha() const noexcept    { return 0xff; }
    forcedinline uint8 getRed() const noexcept      { return r; }
    forcedinline uint8 getGreen() const noexcept    { return g; }
    forcedinline uint8 getBlue() const noexcept     { return b; }

    forcedinline uint8& getRed() noexcept           { return r; }
    forcedinline uint8& getGreen() noexcept         { return g; }
    forcedinline uint8& getBlue() noexcept          { return b; }

    //==============================================================================
    /** Copies another pixel colour over this one.

        This doesn't blend it - this colour is simply replaced by the other one.
        Because PixelRGB has no alpha channel, any alpha value in the source pixel
        is thrown away.
    */
    template <class Pixel>
    forcedinline void set (const Pixel& src) noexcept
    {
        b = src.getBlue();
        g = src.getGreen();
        r = src.getRed();
    }

    /** Sets the pixel's colour from individual components. */
    void setARGB (const uint8, const uint8 red, const uint8 green, const uint8 blue) noexcept
    {
        r = red;
        g = green;
        b = blue;
    }

    //==============================================================================
    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src) noexcept
    {
        const uint32 alpha = (uint32) (0x100 - src.getAlpha());

        // getEvenBytes returns 0x00rr00bb on non-android
        uint32 rb = clampPixelComponents (src.getEvenBytes() + maskPixelComponents (getEvenBytes() * alpha));
        // getOddBytes returns 0x00aa00gg on non-android
        uint32 ag = clampPixelComponents (src.getOddBytes() + ((g * alpha) >> 8));

        g = (uint8) (ag & 0xff);

       #if JUCE_ANDROID
        b = (uint8) (rb >> 16);
        r = (uint8) (rb & 0xff);
       #else
        r = (uint8) (rb >> 16);
        b = (uint8) (rb & 0xff);
       #endif
    }

    forcedinline void blend (const PixelRGB src) noexcept
    {
        set (src);
    }

    /** Blends another pixel onto this one, applying an extra multiplier to its opacity.

        The opacity of the pixel being overlaid is scaled by the extraAlpha factor before
        being used, so this can blend semi-transparently from a PixelRGB argument.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src, uint32 extraAlpha) noexcept
    {
        uint32 ag = maskPixelComponents (extraAlpha * src.getOddBytes());
        uint32 rb = maskPixelComponents (extraAlpha * src.getEvenBytes());

        const uint32 alpha = 0x100 - (ag >> 16);

        ag = clampPixelComponents (ag + (g * alpha >> 8));
        rb = clampPixelComponents (rb + maskPixelComponents (getEvenBytes() * alpha));

        g = (uint8) (ag & 0xff);

       #if JUCE_ANDROID
        b = (uint8) (rb >> 16);
        r = (uint8) (rb & 0xff);
       #else
        r = (uint8) (rb >> 16);
        b = (uint8) (rb & 0xff);
       #endif
    }

    /** Blends another pixel with this one, creating a colour that is somewhere
        between the two, as specified by the amount.
    */
    template <class Pixel>
    forcedinline void tween (const Pixel& src, const uint32 amount) noexcept
    {
        uint32 dEvenBytes = getEvenBytes();
        dEvenBytes += (((src.getEvenBytes() - dEvenBytes) * amount) >> 8);

        uint32 dOddBytes = getOddBytes();
        dOddBytes += (((src.getOddBytes() - dOddBytes) * amount) >> 8);

        g = (uint8) (dOddBytes & 0xff);  // dOddBytes =  0x00aa00gg

       #if JUCE_ANDROID
        r = (uint8) (dEvenBytes & 0xff); // dEvenBytes = 0x00bb00rr
        b = (uint8) (dEvenBytes >> 16);
       #else
        b = (uint8) (dEvenBytes & 0xff); // dEvenBytes = 0x00rr00bb
        r = (uint8) (dEvenBytes >> 16);
       #endif
    }

    //==============================================================================
    /** This method is included for compatibility with the PixelARGB class. */
    forcedinline void setAlpha (const uint8) noexcept {}

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (int) noexcept {}

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (float) noexcept {}

    /** Premultiplies the pixel's RGB values by its alpha. */
    forcedinline void premultiply() noexcept {}

    /** Unpremultiplies the pixel's RGB values. */
    forcedinline void unpremultiply() noexcept {}

    forcedinline void desaturate() noexcept
    {
        r = g = b = (uint8) (((int) r + (int) g + (int) b) / 3);
    }

    //==============================================================================
    /** The indexes of the different components in the byte layout of this type of colour. */
   #if JUCE_MAC
    enum { indexR = 0, indexG = 1, indexB = 2 };
   #else
    enum { indexR = 2, indexG = 1, indexB = 0 };
   #endif

private:
    //==============================================================================
    PixelRGB (const uint32 internal) noexcept
    {
      #if JUCE_ANDROID
        b = (uint8) (internal >> 16);
        g = (uint8) (internal >> 8);
        r = (uint8) (internal);
      #else
        r = (uint8) (internal >> 16);
        g = (uint8) (internal >> 8);
        b = (uint8) (internal);
      #endif
    }

    //==============================================================================
   #if JUCE_MAC
    uint8 r, g, b;
   #else
    uint8 b, g, r;
   #endif

}
#ifndef DOXYGEN
 JUCE_PACKED
#endif
;

forcedinline void PixelARGB::blend (const PixelRGB src) noexcept
{
    set (src);
}

//==============================================================================
/**
    Represents an 8-bit single-channel pixel, and can perform compositing operations on it.

    This is used internally by the imaging classes.

    @see PixelARGB, PixelRGB

    @tags{Graphics}
*/
class JUCE_API  PixelAlpha
{
public:
    /** Creates a pixel without defining its colour. */
    PixelAlpha() = default;
    ~PixelAlpha() = default;

    //==============================================================================
    /** Returns a uint32 which represents the pixel in a platform dependent format which is compatible
        with the native format of a PixelARGB.

        @see PixelARGB::getNativeARGB */
    forcedinline uint32 getNativeARGB() const noexcept      { return (uint32) ((a << 24) | (a << 16) | (a << 8) | a); }

    /** Returns a uint32 which will be in argb order as if constructed with the following mask operation
        ((alpha << 24) | (red << 16) | (green << 8) | blue). */
    forcedinline uint32 getInARGBMaskOrder() const noexcept { return getNativeARGB(); }

    /** Returns a uint32 which when written to memory, will be in the order a, r, g, b. In other words,
        if the return-value is read as a uint8 array then the elements will be in the order of a, r, g, b*/
    inline uint32 getInARGBMemoryOrder() const noexcept     { return getNativeARGB(); }

    /** Return channels with an even index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getEvenBytes of the PixelARGB class.

        @see PixelARGB::getEvenBytes */
    forcedinline uint32 getEvenBytes() const noexcept      { return (uint32) ((a << 16) | a); }

    /** Return channels with an odd index and insert zero bytes between them. This is useful for blending
        operations. The exact channels which are returned is platform dependent but compatible with the
        return value of getOddBytes of the PixelARGB class.

        @see PixelARGB::getOddBytes */
    forcedinline uint32 getOddBytes() const noexcept       { return (uint32) ((a << 16) | a); }

    //==============================================================================
    forcedinline uint8 getAlpha() const noexcept    { return a; }
    forcedinline uint8& getAlpha() noexcept         { return a; }

    forcedinline uint8 getRed() const noexcept      { return 0; }
    forcedinline uint8 getGreen() const noexcept    { return 0; }
    forcedinline uint8 getBlue() const noexcept     { return 0; }

    //==============================================================================
    /** Copies another pixel colour over this one.

        This doesn't blend it - this colour is simply replaced by the other one.
    */
    template <class Pixel>
    forcedinline void set (const Pixel& src) noexcept
    {
        a = src.getAlpha();
    }

    /** Sets the pixel's colour from individual components. */
    forcedinline void setARGB (const uint8 a_, const uint8 /*r*/, const uint8 /*g*/, const uint8 /*b*/) noexcept
    {
        a = a_;
    }

    //==============================================================================
    /** Blends another pixel onto this one.

        This takes into account the opacity of the pixel being overlaid, and blends
        it accordingly.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src) noexcept
    {
        const int srcA = src.getAlpha();
        a = (uint8) ((a * (0x100 - srcA) >> 8) + srcA);
    }

    /** Blends another pixel onto this one, applying an extra multiplier to its opacity.

        The opacity of the pixel being overlaid is scaled by the extraAlpha factor before
        being used, so this can blend semi-transparently from a PixelRGB argument.
    */
    template <class Pixel>
    forcedinline void blend (const Pixel& src, uint32 extraAlpha) noexcept
    {
        ++extraAlpha;
        const int srcAlpha = (int) ((extraAlpha * src.getAlpha()) >> 8);
        a = (uint8) ((a * (0x100 - srcAlpha) >> 8) + srcAlpha);
    }

    /** Blends another pixel with this one, creating a colour that is somewhere
        between the two, as specified by the amount.
    */
    template <class Pixel>
    forcedinline void tween (const Pixel& src, const uint32 amount) noexcept
    {
        a += ((src.getAlpha() - a) * amount) >> 8;
    }

    //==============================================================================
    /** Replaces the colour's alpha value with another one. */
    forcedinline void setAlpha (const uint8 newAlpha) noexcept
    {
        a = newAlpha;
    }

    /** Multiplies the colour's alpha value with another one. */
    forcedinline void multiplyAlpha (int multiplier) noexcept
    {
        ++multiplier;
        a = (uint8) ((a * multiplier) >> 8);
    }

    forcedinline void multiplyAlpha (const float multiplier) noexcept
    {
        a = (uint8) (a * multiplier);
    }

    /** Premultiplies the pixel's RGB values by its alpha. */
    forcedinline void premultiply() noexcept {}

    /** Unpremultiplies the pixel's RGB values. */
    forcedinline void unpremultiply() noexcept {}

    forcedinline void desaturate() noexcept {}

    //==============================================================================
    /** The indexes of the different components in the byte layout of this type of colour. */
    enum { indexA = 0 };

private:
    //==============================================================================
    PixelAlpha (const uint32 internal) noexcept
    {
        a = (uint8) (internal >> 24);
    }

    //==============================================================================
    uint8 a;
}
#ifndef DOXYGEN
 JUCE_PACKED
#endif
;

#if JUCE_MSVC
 #pragma pack (pop)
#endif

} // namespace juce