JUCE/modules/juce_gui_basics/layout/juce_ComponentBoundsConstrainer.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
{

ComponentBoundsConstrainer::ComponentBoundsConstrainer() noexcept {}
ComponentBoundsConstrainer::~ComponentBoundsConstrainer() {}

//==============================================================================
void ComponentBoundsConstrainer::setMinimumWidth  (int minimumWidth) noexcept   { minW = minimumWidth; }
void ComponentBoundsConstrainer::setMaximumWidth  (int maximumWidth) noexcept   { maxW = maximumWidth; }
void ComponentBoundsConstrainer::setMinimumHeight (int minimumHeight) noexcept  { minH = minimumHeight; }
void ComponentBoundsConstrainer::setMaximumHeight (int maximumHeight) noexcept  { maxH = maximumHeight; }

void ComponentBoundsConstrainer::setMinimumSize (int minimumWidth, int minimumHeight) noexcept
{
    jassert (maxW >= minimumWidth);
    jassert (maxH >= minimumHeight);
    jassert (minimumWidth > 0 && minimumHeight > 0);

    minW = minimumWidth;
    minH = minimumHeight;

    if (minW > maxW)  maxW = minW;
    if (minH > maxH)  maxH = minH;
}

void ComponentBoundsConstrainer::setMaximumSize (int maximumWidth, int maximumHeight) noexcept
{
    jassert (maximumWidth >= minW);
    jassert (maximumHeight >= minH);
    jassert (maximumWidth > 0 && maximumHeight > 0);

    maxW = jmax (minW, maximumWidth);
    maxH = jmax (minH, maximumHeight);
}

void ComponentBoundsConstrainer::setSizeLimits (int minimumWidth,
                                                int minimumHeight,
                                                int maximumWidth,
                                                int maximumHeight) noexcept
{
    jassert (maximumWidth >= minimumWidth);
    jassert (maximumHeight >= minimumHeight);
    jassert (maximumWidth > 0 && maximumHeight > 0);
    jassert (minimumWidth > 0 && minimumHeight > 0);

    minW = jmax (0, minimumWidth);
    minH = jmax (0, minimumHeight);
    maxW = jmax (minW, maximumWidth);
    maxH = jmax (minH, maximumHeight);
}

void ComponentBoundsConstrainer::setMinimumOnscreenAmounts (int minimumWhenOffTheTop,
                                                            int minimumWhenOffTheLeft,
                                                            int minimumWhenOffTheBottom,
                                                            int minimumWhenOffTheRight) noexcept
{
    minOffTop    = minimumWhenOffTheTop;
    minOffLeft   = minimumWhenOffTheLeft;
    minOffBottom = minimumWhenOffTheBottom;
    minOffRight  = minimumWhenOffTheRight;
}

void ComponentBoundsConstrainer::setFixedAspectRatio (double widthOverHeight) noexcept
{
    aspectRatio = jmax (0.0, widthOverHeight);
}

double ComponentBoundsConstrainer::getFixedAspectRatio() const noexcept
{
    return aspectRatio;
}

void ComponentBoundsConstrainer::setBoundsForComponent (Component* component,
                                                        Rectangle<int> targetBounds,
                                                        bool isStretchingTop,
                                                        bool isStretchingLeft,
                                                        bool isStretchingBottom,
                                                        bool isStretchingRight)
{
    jassert (component != nullptr);

    Rectangle<int> limits, bounds (targetBounds);
    BorderSize<int> border;

    if (auto* parent = component->getParentComponent())
    {
        limits.setSize (parent->getWidth(), parent->getHeight());
    }
    else
    {
        if (auto* peer = component->getPeer())
            border = peer->getFrameSize();

        auto screenBounds = Desktop::getInstance().getDisplays().findDisplayForPoint (targetBounds.getCentre()).userArea;

        limits = component->getLocalArea (nullptr, screenBounds) + component->getPosition();
    }

    border.addTo (bounds);

    checkBounds (bounds,
                 border.addedTo (component->getBounds()), limits,
                 isStretchingTop, isStretchingLeft,
                 isStretchingBottom, isStretchingRight);

    border.subtractFrom (bounds);

    applyBoundsToComponent (*component, bounds);
}

void ComponentBoundsConstrainer::checkComponentBounds (Component* component)
{
    setBoundsForComponent (component, component->getBounds(),
                           false, false, false, false);
}

void ComponentBoundsConstrainer::applyBoundsToComponent (Component& component, Rectangle<int> bounds)
{
    if (auto* positioner = component.getPositioner())
        positioner->applyNewBounds (bounds);
    else
        component.setBounds (bounds);
}

//==============================================================================
void ComponentBoundsConstrainer::resizeStart()
{
}

void ComponentBoundsConstrainer::resizeEnd()
{
}

//==============================================================================
void ComponentBoundsConstrainer::checkBounds (Rectangle<int>& bounds,
                                              const Rectangle<int>& old,
                                              const Rectangle<int>& limits,
                                              bool isStretchingTop,
                                              bool isStretchingLeft,
                                              bool isStretchingBottom,
                                              bool isStretchingRight)
{
    if (isStretchingLeft)
        bounds.setLeft (jlimit (old.getRight() - maxW, old.getRight() - minW, bounds.getX()));
    else
        bounds.setWidth (jlimit (minW, maxW, bounds.getWidth()));

    if (isStretchingTop)
        bounds.setTop (jlimit (old.getBottom() - maxH, old.getBottom() - minH, bounds.getY()));
    else
        bounds.setHeight (jlimit (minH, maxH, bounds.getHeight()));

    if (bounds.isEmpty())
        return;

    if (minOffTop > 0)
    {
        const int limit = limits.getY() + jmin (minOffTop - bounds.getHeight(), 0);

        if (bounds.getY() < limit)
        {
            if (isStretchingTop)
                bounds.setTop (limits.getY());
            else
                bounds.setY (limit);
        }
    }

    if (minOffLeft > 0)
    {
        const int limit = limits.getX() + jmin (minOffLeft - bounds.getWidth(), 0);

        if (bounds.getX() < limit)
        {
            if (isStretchingLeft)
                bounds.setLeft (limits.getX());
            else
                bounds.setX (limit);
        }
    }

    if (minOffBottom > 0)
    {
        const int limit = limits.getBottom() - jmin (minOffBottom, bounds.getHeight());

        if (bounds.getY() > limit)
        {
            if (isStretchingBottom)
                bounds.setBottom (limits.getBottom());
            else
                bounds.setY (limit);
        }
    }

    if (minOffRight > 0)
    {
        const int limit = limits.getRight() - jmin (minOffRight, bounds.getWidth());

        if (bounds.getX() > limit)
        {
            if (isStretchingRight)
                bounds.setRight (limits.getRight());
            else
                bounds.setX (limit);
        }
    }

    // constrain the aspect ratio if one has been specified..
    if (aspectRatio > 0.0)
    {
        bool adjustWidth;

        if ((isStretchingTop || isStretchingBottom) && ! (isStretchingLeft || isStretchingRight))
        {
            adjustWidth = true;
        }
        else if ((isStretchingLeft || isStretchingRight) && ! (isStretchingTop || isStretchingBottom))
        {
            adjustWidth = false;
        }
        else
        {
            const double oldRatio = (old.getHeight() > 0) ? std::abs (old.getWidth() / (double) old.getHeight()) : 0.0;
            const double newRatio = std::abs (bounds.getWidth() / (double) bounds.getHeight());

            adjustWidth = (oldRatio > newRatio);
        }

        if (adjustWidth)
        {
            bounds.setWidth (roundToInt (bounds.getHeight() * aspectRatio));

            if (bounds.getWidth() > maxW || bounds.getWidth() < minW)
            {
                bounds.setWidth (jlimit (minW, maxW, bounds.getWidth()));
                bounds.setHeight (roundToInt (bounds.getWidth() / aspectRatio));
            }
        }
        else
        {
            bounds.setHeight (roundToInt (bounds.getWidth() / aspectRatio));

            if (bounds.getHeight() > maxH || bounds.getHeight() < minH)
            {
                bounds.setHeight (jlimit (minH, maxH, bounds.getHeight()));
                bounds.setWidth (roundToInt (bounds.getHeight() * aspectRatio));
            }
        }

        if ((isStretchingTop || isStretchingBottom) && ! (isStretchingLeft || isStretchingRight))
        {
            bounds.setX (old.getX() + (old.getWidth() - bounds.getWidth()) / 2);
        }
        else if ((isStretchingLeft || isStretchingRight) && ! (isStretchingTop || isStretchingBottom))
        {
            bounds.setY (old.getY() + (old.getHeight() - bounds.getHeight()) / 2);
        }
        else
        {
            if (isStretchingLeft)
                bounds.setX (old.getRight() - bounds.getWidth());

            if (isStretchingTop)
                bounds.setY (old.getBottom() - bounds.getHeight());
        }
    }

    jassert (! bounds.isEmpty());
}

} // namespace juce