JUCE/src/gui/graphics/colour/juce_ColourGradient.cpp

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

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-9 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE 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.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

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

#include "../../../core/juce_StandardHeader.h"

BEGIN_JUCE_NAMESPACE

#include "juce_ColourGradient.h"


//==============================================================================
ColourGradient::ColourGradient() throw()
{
#ifdef JUCE_DEBUG
    x1 = 987654.0f;
#endif
}

ColourGradient::ColourGradient (const Colour& colour1,
                                const float x1_,
                                const float y1_,
                                const Colour& colour2,
                                const float x2_,
                                const float y2_,
                                const bool isRadial_) throw()
    : x1 (x1_),
      y1 (y1_),
      x2 (x2_),
      y2 (y2_),
      isRadial (isRadial_)
{
    colours.add (0);
    colours.add (colour1.getARGB());

    colours.add (1 << 16);
    colours.add (colour2.getARGB());
}

ColourGradient::~ColourGradient() throw()
{
}

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

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

    const uint32 pos = jlimit (0, 65535, roundToInt (proportionAlongGradient * 65536.0));

    int i;
    for (i = 0; i < colours.size(); i += 2)
        if (colours.getUnchecked(i) > pos)
            break;

    colours.insert (i, pos);
    colours.insert (i + 1, colour.getARGB());
}

void ColourGradient::multiplyOpacity (const float multiplier) throw()
{
    for (int i = 1; i < colours.size(); i += 2)
    {
        const Colour c (colours.getUnchecked(i));
        colours.set (i, c.withMultipliedAlpha (multiplier).getARGB());
    }
}

//==============================================================================
int ColourGradient::getNumColours() const throw()
{
    return colours.size() >> 1;
}

double ColourGradient::getColourPosition (const int index) const throw()
{
    return jlimit (0.0, 1.0, colours [index << 1] / 65535.0);
 }

const Colour ColourGradient::getColour (const int index) const throw()
{
    return Colour (colours [(index << 1) + 1]);
}

const Colour ColourGradient::getColourAtPosition (const float position) const throw()
{
    jassert (colours.getUnchecked (0) == 0); // the first colour specified has to go at position 0

    const int integerPos = jlimit (0, 65535, roundToInt (position * 65536.0f));

    if (integerPos <= 0 || colours.size() <= 2)
        return getColour (0);

    int i = colours.size() - 2;
    while (integerPos < (int) colours.getUnchecked(i))
        i -= 2;

    if (i >= colours.size() - 2)
        return Colour (colours.getUnchecked(i));

    const int pos1 = colours.getUnchecked (i);
    const Colour col1 (colours.getUnchecked (i + 1));

    const int pos2 = colours.getUnchecked (i + 2);
    const Colour col2 (colours.getUnchecked (i + 3));

    return col1.interpolatedWith (col2, (integerPos - pos1) / (float) (pos2 - pos1));
}

//==============================================================================
int ColourGradient::createLookupTable (const AffineTransform& transform, HeapBlock <PixelARGB>& lookupTable) const throw()
{
#ifdef JUCE_DEBUG
    // trying to use the object without setting its co-ordinates? Have a careful read of
    // the comments for the constructors.
    jassert (x1 != 987654.0f);
#endif

    const int numColours = colours.size() >> 1;

    float tx1 = x1, ty1 = y1, tx2 = x2, ty2 = y2;
    transform.transformPoint (tx1, ty1);
    transform.transformPoint (tx2, ty2);
    const double distance = juce_hypot (tx1 - tx2, ty1 - ty2);

    const int numEntries = jlimit (1, (numColours - 1) << 8, 3 * (int) distance);
    lookupTable.malloc (numEntries);

    if (numColours >= 2)
    {
        jassert (colours.getUnchecked (0) == 0); // the first colour specified has to go at position 0

        PixelARGB pix1 (colours.getUnchecked (1));
        pix1.premultiply();
        int index = 0;

        for (int j = 2; j < colours.size(); j += 2)
        {
            const int numToDo = ((colours.getUnchecked (j) * (numEntries - 1)) >> 16) - index;
            PixelARGB pix2 (colours.getUnchecked (j + 1));
            pix2.premultiply();

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

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

            pix1 = pix2;
        }

        while (index < numEntries)
            lookupTable [index++] = pix1;
    }
    else
    {
        jassertfalse // no colours specified!
    }

    return numEntries;
}

bool ColourGradient::isOpaque() const throw()
{
    for (int i = 1; i < colours.size(); i += 2)
        if (PixelARGB (colours.getUnchecked(i)).getAlpha() < 0xff)
            return false;

    return true;
}

bool ColourGradient::isInvisible() const throw()
{
    for (int i = 1; i < colours.size(); i += 2)
        if (PixelARGB (colours.getUnchecked(i)).getAlpha() > 0)
            return false;

    return true;
}


END_JUCE_NAMESPACE