JUCE/modules/juce_graphics/colour/juce_ColourGradient.cpp

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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

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

   For this technical preview, this file is not subject to commercial licensing.

   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
{

ColourGradient::ColourGradient() noexcept  : isRadial (false)
{
   #if JUCE_DEBUG
    point1.setX (987654.0f);
    #define JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED   jassert (point1.x != 987654.0f);
   #else
    #define JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED
   #endif
}

ColourGradient::ColourGradient (const ColourGradient& other)
    : point1 (other.point1), point2 (other.point2), isRadial (other.isRadial), colours (other.colours)
{}

ColourGradient::ColourGradient (ColourGradient&& other) noexcept
    : point1 (other.point1), point2 (other.point2), isRadial (other.isRadial),
      colours (std::move (other.colours))
{}

ColourGradient& ColourGradient::operator= (const ColourGradient& other)
{
    point1 = other.point1;
    point2 = other.point2;
    isRadial = other.isRadial;
    colours = other.colours;
    return *this;
}

ColourGradient& ColourGradient::operator= (ColourGradient&& other) noexcept
{
    point1 = other.point1;
    point2 = other.point2;
    isRadial = other.isRadial;
    colours = std::move (other.colours);
    return *this;
}

ColourGradient::ColourGradient (Colour colour1, float x1, float y1,
                                Colour colour2, float x2, float y2, bool radial)
    : ColourGradient (colour1, Point<float> (x1, y1),
                      colour2, Point<float> (x2, y2), radial)
{
}

ColourGradient::ColourGradient (Colour colour1, Point<float> p1,
                                Colour colour2, Point<float> p2, bool radial)
    : point1 (p1),
      point2 (p2),
      isRadial (radial)
{
    colours.add (ColourPoint { 0.0, colour1 },
                 ColourPoint { 1.0, colour2 });
}

ColourGradient::~ColourGradient() {}

ColourGradient ColourGradient::vertical (Colour c1, float y1, Colour c2, float y2)
{
    return { c1, 0, y1, c2, 0, y2, false };
}

ColourGradient ColourGradient::horizontal (Colour c1, float x1, Colour c2, float x2)
{
    return { c1, x1, 0, c2, x2, 0, false };
}

bool ColourGradient::operator== (const ColourGradient& other) const noexcept
{
    return point1 == other.point1 && point2 == other.point2
            && isRadial == other.isRadial
            && colours == other.colours;
}

bool ColourGradient::operator!= (const ColourGradient& other) const noexcept
{
    return ! operator== (other);
}

//==============================================================================
void ColourGradient::clearColours()
{
    colours.clear();
}

int ColourGradient::addColour (const double proportionAlongGradient, Colour colour)
{
    // must be within the two end-points
    jassert (proportionAlongGradient >= 0 && proportionAlongGradient <= 1.0);

    if (proportionAlongGradient <= 0)
    {
        colours.set (0, { 0.0, colour });
        return 0;
    }

    auto pos = jmin (1.0, proportionAlongGradient);

    int i;
    for (i = 0; i < colours.size(); ++i)
        if (colours.getReference(i).position > pos)
            break;

    colours.insert (i, { pos, colour });
    return i;
}

void ColourGradient::removeColour (int index)
{
    jassert (index > 0 && index < colours.size() - 1);
    colours.remove (index);
}

void ColourGradient::multiplyOpacity (const float multiplier) noexcept
{
    for (auto& c : colours)
        c.colour = c.colour.withMultipliedAlpha (multiplier);
}

//==============================================================================
int ColourGradient::getNumColours() const noexcept
{
    return colours.size();
}

double ColourGradient::getColourPosition (int index) const noexcept
{
    if (isPositiveAndBelow (index, colours.size()))
        return colours.getReference (index).position;

    return 0;
 }

Colour ColourGradient::getColour (int index) const noexcept
{
    if (isPositiveAndBelow (index, colours.size()))
        return colours.getReference (index).colour;

    return {};
}

void ColourGradient::setColour (int index, Colour newColour) noexcept
{
    if (isPositiveAndBelow (index, colours.size()))
        colours.getReference (index).colour = newColour;
}

Colour ColourGradient::getColourAtPosition (double position) const noexcept
{
    jassert (colours.getReference(0).position == 0.0); // the first colour specified has to go at position 0

    if (position <= 0 || colours.size() <= 1)
        return colours.getReference(0).colour;

    int i = colours.size() - 1;
    while (position < colours.getReference(i).position)
        --i;

    auto& p1 = colours.getReference (i);

    if (i >= colours.size() - 1)
        return p1.colour;

    auto& p2 = colours.getReference (i + 1);

    return p1.colour.interpolatedWith (p2.colour, (float) ((position - p1.position) / (p2.position - p1.position)));
}

//==============================================================================
void ColourGradient::createLookupTable (PixelARGB* const lookupTable, const int numEntries) const noexcept
{
    JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED // Trying to use this object without setting its coordinates?
    jassert (colours.size() >= 2);
    jassert (numEntries > 0);
    jassert (colours.getReference(0).position == 0.0); // The first colour specified has to go at position 0

    auto pix1 = colours.getReference (0).colour.getPixelARGB();
    int index = 0;

    for (int j = 1; j < colours.size(); ++j)
    {
        auto& p = colours.getReference (j);
        auto numToDo = roundToInt (p.position * (numEntries - 1)) - index;
        auto pix2 = p.colour.getPixelARGB();

        for (int i = 0; i < numToDo; ++i)
        {
            jassert (index >= 0 && index < numEntries);

            lookupTable[index] = pix1;
            lookupTable[index].tween (pix2, (uint32) ((i << 8) / numToDo));
            ++index;
        }

        pix1 = pix2;
    }

    while (index < numEntries)
        lookupTable [index++] = pix1;
}

int ColourGradient::createLookupTable (const AffineTransform& transform, HeapBlock<PixelARGB>& lookupTable) const
{
    JUCE_COLOURGRADIENT_CHECK_COORDS_INITIALISED // Trying to use this object without setting its coordinates?
    jassert (colours.size() >= 2);

    auto numEntries = jlimit (1, jmax (1, (colours.size() - 1) << 8),
                              3 * (int) point1.transformedBy (transform)
                                              .getDistanceFrom (point2.transformedBy (transform)));
    lookupTable.malloc (numEntries);
    createLookupTable (lookupTable, numEntries);
    return numEntries;
}

bool ColourGradient::isOpaque() const noexcept
{
    for (auto& c : colours)
        if (! c.colour.isOpaque())
            return false;

    return true;
}

bool ColourGradient::isInvisible() const noexcept
{
    for (auto& c : colours)
        if (! c.colour.isTransparent())
            return false;

    return true;
}

bool ColourGradient::ColourPoint::operator== (ColourPoint other) const noexcept
{
    return position == other.position && colour == other.colour;
}

bool ColourGradient::ColourPoint::operator!= (ColourPoint other) const noexcept
{
    return position != other.position || colour != other.colour;
}

} // namespace juce