JUCE/modules/juce_gui_basics/positioning/juce_RelativeRectangle.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
{

namespace RelativeRectangleHelpers
{
    inline void skipComma (String::CharPointerType& s)
    {
        s = s.findEndOfWhitespace();

        if (*s == ',')
            ++s;
    }

    static bool dependsOnSymbolsOtherThanThis (const Expression& e)
    {
        if (e.getType() == Expression::operatorType && e.getSymbolOrFunction() == ".")
            return true;

        if (e.getType() == Expression::symbolType)
        {
            switch (RelativeCoordinate::StandardStrings::getTypeOf (e.getSymbolOrFunction()))
            {
                case RelativeCoordinate::StandardStrings::x:
                case RelativeCoordinate::StandardStrings::y:
                case RelativeCoordinate::StandardStrings::left:
                case RelativeCoordinate::StandardStrings::right:
                case RelativeCoordinate::StandardStrings::top:
                case RelativeCoordinate::StandardStrings::bottom:   return false;
                case RelativeCoordinate::StandardStrings::width:
                case RelativeCoordinate::StandardStrings::height:
                case RelativeCoordinate::StandardStrings::parent:
                case RelativeCoordinate::StandardStrings::unknown:

                default: break;
            }

            return true;
        }
        else
        {
            for (int i = e.getNumInputs(); --i >= 0;)
                if (dependsOnSymbolsOtherThanThis (e.getInput(i)))
                    return true;
        }

        return false;
    }
}

//==============================================================================
RelativeRectangle::RelativeRectangle()
{
}

RelativeRectangle::RelativeRectangle (const RelativeCoordinate& left_, const RelativeCoordinate& right_,
                                      const RelativeCoordinate& top_, const RelativeCoordinate& bottom_)
    : left (left_), right (right_), top (top_), bottom (bottom_)
{
}

RelativeRectangle::RelativeRectangle (const Rectangle<float>& rect)
    : left (rect.getX()),
      right (Expression::symbol (RelativeCoordinate::Strings::left) + Expression ((double) rect.getWidth())),
      top (rect.getY()),
      bottom (Expression::symbol (RelativeCoordinate::Strings::top) + Expression ((double) rect.getHeight()))
{
}

RelativeRectangle::RelativeRectangle (const String& s)
{
    String error;
    String::CharPointerType text (s.getCharPointer());
    left = RelativeCoordinate (Expression::parse (text, error));
    RelativeRectangleHelpers::skipComma (text);
    top = RelativeCoordinate (Expression::parse (text, error));
    RelativeRectangleHelpers::skipComma (text);
    right = RelativeCoordinate (Expression::parse (text, error));
    RelativeRectangleHelpers::skipComma (text);
    bottom = RelativeCoordinate (Expression::parse (text, error));
}

bool RelativeRectangle::operator== (const RelativeRectangle& other) const noexcept
{
    return left == other.left && top == other.top && right == other.right && bottom == other.bottom;
}

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

//==============================================================================
// An expression context that can evaluate expressions using "this"
class RelativeRectangleLocalScope  : public Expression::Scope
{
public:
    RelativeRectangleLocalScope (const RelativeRectangle& rect_)  : rect (rect_) {}

    Expression getSymbolValue (const String& symbol) const
    {
        switch (RelativeCoordinate::StandardStrings::getTypeOf (symbol))
        {
            case RelativeCoordinate::StandardStrings::x:
            case RelativeCoordinate::StandardStrings::left:     return rect.left.getExpression();
            case RelativeCoordinate::StandardStrings::y:
            case RelativeCoordinate::StandardStrings::top:      return rect.top.getExpression();
            case RelativeCoordinate::StandardStrings::right:    return rect.right.getExpression();
            case RelativeCoordinate::StandardStrings::bottom:   return rect.bottom.getExpression();
            case RelativeCoordinate::StandardStrings::width:
            case RelativeCoordinate::StandardStrings::height:
            case RelativeCoordinate::StandardStrings::parent:
            case RelativeCoordinate::StandardStrings::unknown:
            default: break;
        }

        return Expression::Scope::getSymbolValue (symbol);
    }

private:
    const RelativeRectangle& rect;

    JUCE_DECLARE_NON_COPYABLE (RelativeRectangleLocalScope)
};

const Rectangle<float> RelativeRectangle::resolve (const Expression::Scope* scope) const
{
    if (scope == nullptr)
    {
        RelativeRectangleLocalScope defaultScope (*this);
        return resolve (&defaultScope);
    }
    else
    {
        const double l = left.resolve (scope);
        const double r = right.resolve (scope);
        const double t = top.resolve (scope);
        const double b = bottom.resolve (scope);

        return Rectangle<float> ((float) l, (float) t, (float) jmax (0.0, r - l), (float) jmax (0.0, b - t));
    }
}

void RelativeRectangle::moveToAbsolute (const Rectangle<float>& newPos, const Expression::Scope* scope)
{
    left.moveToAbsolute (newPos.getX(), scope);
    right.moveToAbsolute (newPos.getRight(), scope);
    top.moveToAbsolute (newPos.getY(), scope);
    bottom.moveToAbsolute (newPos.getBottom(), scope);
}

bool RelativeRectangle::isDynamic() const
{
    using namespace RelativeRectangleHelpers;

    return dependsOnSymbolsOtherThanThis (left.getExpression())
            || dependsOnSymbolsOtherThanThis (right.getExpression())
            || dependsOnSymbolsOtherThanThis (top.getExpression())
            || dependsOnSymbolsOtherThanThis (bottom.getExpression());
}

String RelativeRectangle::toString() const
{
    return left.toString() + ", " + top.toString() + ", " + right.toString() + ", " + bottom.toString();
}

void RelativeRectangle::renameSymbol (const Expression::Symbol& oldSymbol, const String& newName, const Expression::Scope& scope)
{
    left = left.getExpression().withRenamedSymbol (oldSymbol, newName, scope);
    right = right.getExpression().withRenamedSymbol (oldSymbol, newName, scope);
    top = top.getExpression().withRenamedSymbol (oldSymbol, newName, scope);
    bottom = bottom.getExpression().withRenamedSymbol (oldSymbol, newName, scope);
}

//==============================================================================
class RelativeRectangleComponentPositioner  : public RelativeCoordinatePositionerBase
{
public:
    RelativeRectangleComponentPositioner (Component& comp, const RelativeRectangle& r)
        : RelativeCoordinatePositionerBase (comp),
          rectangle (r)
    {
    }

    bool registerCoordinates() override
    {
        bool ok = addCoordinate (rectangle.left);
        ok = addCoordinate (rectangle.right) && ok;
        ok = addCoordinate (rectangle.top) && ok;
        ok = addCoordinate (rectangle.bottom) && ok;
        return ok;
    }

    bool isUsingRectangle (const RelativeRectangle& other) const noexcept
    {
        return rectangle == other;
    }

    void applyToComponentBounds() override
    {
        for (int i = 32; --i >= 0;)
        {
            ComponentScope scope (getComponent());
            const Rectangle<int> newBounds (rectangle.resolve (&scope).getSmallestIntegerContainer());

            if (newBounds == getComponent().getBounds())
                return;

            getComponent().setBounds (newBounds);
        }

        jassertfalse; // Seems to be a recursive reference!
    }

    void applyNewBounds (const Rectangle<int>& newBounds) override
    {
        if (newBounds != getComponent().getBounds())
        {
            ComponentScope scope (getComponent());
            rectangle.moveToAbsolute (newBounds.toFloat(), &scope);

            applyToComponentBounds();
        }
    }

private:
    RelativeRectangle rectangle;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (RelativeRectangleComponentPositioner)
};

void RelativeRectangle::applyToComponent (Component& component) const
{
    if (isDynamic())
    {
        RelativeRectangleComponentPositioner* current = dynamic_cast<RelativeRectangleComponentPositioner*> (component.getPositioner());

        if (current == nullptr || ! current->isUsingRectangle (*this))
        {
            RelativeRectangleComponentPositioner* p = new RelativeRectangleComponentPositioner (component, *this);

            component.setPositioner (p);
            p->apply();
        }
    }
    else
    {
        component.setPositioner (nullptr);
        component.setBounds (resolve (nullptr).getSmallestIntegerContainer());
    }
}

} // namespace juce