Carla/source/modules/juce_graphics/geometry/juce_PathIterator.cpp

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

   This file is part of the JUCE 7 technical preview.
   Copyright (c) 2022 - Raw Material Software Limited

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

   For the technical preview this file cannot be licensed commercially.

   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 && JUCE_DEBUG
 #pragma optimize ("t", on)
#endif

//==============================================================================
PathFlatteningIterator::PathFlatteningIterator (const Path& pathToUse,
                                                const AffineTransform& t,
                                                float tolerance)
    : x2 (0),
      y2 (0),
      closesSubPath (false),
      subPathIndex (-1),
      path (pathToUse),
      transform (t),
      source (path.data.begin()),
      toleranceSquared (tolerance * tolerance),
      isIdentityTransform (t.isIdentity())
{
    stackPos = stackBase;
}

PathFlatteningIterator::~PathFlatteningIterator()
{
}

bool PathFlatteningIterator::isLastInSubpath() const noexcept
{
    return stackPos == stackBase.get()
             && (source == path.data.end() || isMarker (*source, Path::moveMarker));
}

bool PathFlatteningIterator::next()
{
    x1 = x2;
    y1 = y2;

    float x3 = 0;
    float y3 = 0;
    float x4 = 0;
    float y4 = 0;

    for (;;)
    {
        float type;

        if (stackPos == stackBase.get())
        {
            if (source == path.data.end())
                return false;

            type = *source++;

            if (! isMarker (type, Path::closeSubPathMarker))
            {
                x2 = *source++;
                y2 = *source++;

                if (isMarker (type, Path::quadMarker))
                {
                    x3 = *source++;
                    y3 = *source++;

                    if (! isIdentityTransform)
                        transform.transformPoints (x2, y2, x3, y3);
                }
                else if (isMarker (type, Path::cubicMarker))
                {
                    x3 = *source++;
                    y3 = *source++;
                    x4 = *source++;
                    y4 = *source++;

                    if (! isIdentityTransform)
                        transform.transformPoints (x2, y2, x3, y3, x4, y4);
                }
                else
                {
                    if (! isIdentityTransform)
                        transform.transformPoint (x2, y2);
                }
            }
        }
        else
        {
            type = *--stackPos;

            if (! isMarker (type, Path::closeSubPathMarker))
            {
                x2 = *--stackPos;
                y2 = *--stackPos;

                if (isMarker (type, Path::quadMarker))
                {
                    x3 = *--stackPos;
                    y3 = *--stackPos;
                }
                else if (isMarker (type, Path::cubicMarker))
                {
                    x3 = *--stackPos;
                    y3 = *--stackPos;
                    x4 = *--stackPos;
                    y4 = *--stackPos;
                }
            }
        }

        if (isMarker (type, Path::lineMarker))
        {
            ++subPathIndex;

            closesSubPath = stackPos == stackBase.get()
                             && source != path.data.end()
                             && *source == Path::closeSubPathMarker
                             && x2 == subPathCloseX
                             && y2 == subPathCloseY;

            return true;
        }

        if (isMarker (type, Path::quadMarker))
        {
            const size_t offset = (size_t) (stackPos - stackBase);

            if (offset >= stackSize - 10)
            {
                stackSize <<= 1;
                stackBase.realloc (stackSize);
                stackPos = stackBase + offset;
            }

            auto m1x = (x1 + x2) * 0.5f;
            auto m1y = (y1 + y2) * 0.5f;
            auto m2x = (x2 + x3) * 0.5f;
            auto m2y = (y2 + y3) * 0.5f;
            auto m3x = (m1x + m2x) * 0.5f;
            auto m3y = (m1y + m2y) * 0.5f;

            auto errorX = m3x - x2;
            auto errorY = m3y - y2;

            auto outsideTolerance = errorX * errorX + errorY * errorY > toleranceSquared;
            auto canBeSubdivided = (m3x != m1x && m3x != m2x)
                                || (m3y != m1y && m3y != m2y);

            if (outsideTolerance && canBeSubdivided)
            {
                *stackPos++ = y3;
                *stackPos++ = x3;
                *stackPos++ = m2y;
                *stackPos++ = m2x;
                *stackPos++ = Path::quadMarker;

                *stackPos++ = m3y;
                *stackPos++ = m3x;
                *stackPos++ = m1y;
                *stackPos++ = m1x;
                *stackPos++ = Path::quadMarker;
            }
            else
            {
                *stackPos++ = y3;
                *stackPos++ = x3;
                *stackPos++ = Path::lineMarker;

                *stackPos++ = m3y;
                *stackPos++ = m3x;
                *stackPos++ = Path::lineMarker;
            }

            jassert (stackPos < stackBase + stackSize);
        }
        else if (isMarker (type, Path::cubicMarker))
        {
            const size_t offset = (size_t) (stackPos - stackBase);

            if (offset >= stackSize - 16)
            {
                stackSize <<= 1;
                stackBase.realloc (stackSize);
                stackPos = stackBase + offset;
            }

            auto m1x = (x1 + x2) * 0.5f;
            auto m1y = (y1 + y2) * 0.5f;
            auto m2x = (x3 + x2) * 0.5f;
            auto m2y = (y3 + y2) * 0.5f;
            auto m3x = (x3 + x4) * 0.5f;
            auto m3y = (y3 + y4) * 0.5f;
            auto m4x = (m1x + m2x) * 0.5f;
            auto m4y = (m1y + m2y) * 0.5f;
            auto m5x = (m3x + m2x) * 0.5f;
            auto m5y = (m3y + m2y) * 0.5f;

            auto error1X = m4x - x2;
            auto error1Y = m4y - y2;
            auto error2X = m5x - x3;
            auto error2Y = m5y - y3;

            auto outsideTolerance = error1X * error1X + error1Y * error1Y > toleranceSquared
                                 || error2X * error2X + error2Y * error2Y > toleranceSquared;
            auto canBeSubdivided = (m4x != m1x && m4x != m2x)
                                || (m4y != m1y && m4y != m2y)
                                || (m5x != m3x && m5x != m2x)
                                || (m5y != m3y && m5y != m2y);

            if (outsideTolerance && canBeSubdivided)
            {
                *stackPos++ = y4;
                *stackPos++ = x4;
                *stackPos++ = m3y;
                *stackPos++ = m3x;
                *stackPos++ = m5y;
                *stackPos++ = m5x;
                *stackPos++ = Path::cubicMarker;

                *stackPos++ = (m4y + m5y) * 0.5f;
                *stackPos++ = (m4x + m5x) * 0.5f;
                *stackPos++ = m4y;
                *stackPos++ = m4x;
                *stackPos++ = m1y;
                *stackPos++ = m1x;
                *stackPos++ = Path::cubicMarker;
            }
            else
            {
                *stackPos++ = y4;
                *stackPos++ = x4;
                *stackPos++ = Path::lineMarker;

                *stackPos++ = m5y;
                *stackPos++ = m5x;
                *stackPos++ = Path::lineMarker;

                *stackPos++ = m4y;
                *stackPos++ = m4x;
                *stackPos++ = Path::lineMarker;
            }
        }
        else if (isMarker (type, Path::closeSubPathMarker))
        {
            if (x2 != subPathCloseX || y2 != subPathCloseY)
            {
                x1 = x2;
                y1 = y2;
                x2 = subPathCloseX;
                y2 = subPathCloseY;
                closesSubPath = true;

                return true;
            }
        }
        else
        {
            jassert (isMarker (type, Path::moveMarker));

            subPathIndex = -1;
            subPathCloseX = x1 = x2;
            subPathCloseY = y1 = y2;
        }
    }
}

#if JUCE_MSVC && JUCE_DEBUG
  #pragma optimize ("", on)  // resets optimisations to the project defaults
#endif

} // namespace juce