JUCE/modules/juce_graphics/geometry/juce_BorderSize.h

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

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

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   licensing.

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

   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
{

//==============================================================================
/**
    Specifies a set of gaps to be left around the sides of a rectangle.

    This is basically the size of the spaces at the top, bottom, left and right of
    a rectangle. It's used by various component classes to specify borders.

    @see Rectangle

    @tags{Graphics}
*/
template <typename ValueType>
class BorderSize
{
    auto tie() const { return std::tie (top, left, bottom, right); }

public:
    //==============================================================================
    /** Creates a null border.
        All sizes are left as 0.
    */
    BorderSize() = default;

    /** Creates a border with the given gaps. */
    BorderSize (ValueType topGap, ValueType leftGap, ValueType bottomGap, ValueType rightGap) noexcept
        : top (topGap), left (leftGap), bottom (bottomGap), right (rightGap)
    {
    }

    /** Creates a border with the given gap on all sides. */
    explicit BorderSize (ValueType allGaps) noexcept
        : top (allGaps), left (allGaps), bottom (allGaps), right (allGaps)
    {
    }

    //==============================================================================
    /** Returns the gap that should be left at the top of the region. */
    ValueType getTop() const noexcept                   { return top; }

    /** Returns the gap that should be left at the left of the region. */
    ValueType getLeft() const noexcept                  { return left; }

    /** Returns the gap that should be left at the bottom of the region. */
    ValueType getBottom() const noexcept                { return bottom; }

    /** Returns the gap that should be left at the right of the region. */
    ValueType getRight() const noexcept                 { return right; }

    /** Returns the sum of the top and bottom gaps. */
    ValueType getTopAndBottom() const noexcept          { return top + bottom; }

    /** Returns the sum of the left and right gaps. */
    ValueType getLeftAndRight() const noexcept          { return left + right; }

    /** Returns true if this border has no thickness along any edge. */
    bool isEmpty() const noexcept                       { return left + right + top + bottom == ValueType(); }

    //==============================================================================
    /** Changes the top gap. */
    void setTop (ValueType newTopGap) noexcept          { top = newTopGap; }

    /** Changes the left gap. */
    void setLeft (ValueType newLeftGap) noexcept        { left = newLeftGap; }

    /** Changes the bottom gap. */
    void setBottom (ValueType newBottomGap) noexcept    { bottom = newBottomGap; }

    /** Changes the right gap. */
    void setRight (ValueType newRightGap) noexcept      { right = newRightGap; }

    //==============================================================================
    /** Returns a rectangle with these borders removed from it. */
    Rectangle<ValueType> subtractedFrom (const Rectangle<ValueType>& original) const noexcept
    {
        return { original.getX() + left,
                 original.getY() + top,
                 original.getWidth() - (left + right),
                 original.getHeight() - (top + bottom) };
    }

    /** Removes this border from a given rectangle. */
    void subtractFrom (Rectangle<ValueType>& rectangle) const noexcept
    {
        rectangle = subtractedFrom (rectangle);
    }

    /** Returns a rectangle with these borders added around it. */
    Rectangle<ValueType> addedTo (const Rectangle<ValueType>& original) const noexcept
    {
        return { original.getX() - left,
                 original.getY() - top,
                 original.getWidth() + (left + right),
                 original.getHeight() + (top + bottom) };
    }

    /** Adds this border around a given rectangle. */
    void addTo (Rectangle<ValueType>& rectangle) const noexcept
    {
        rectangle = addedTo (rectangle);
    }

    /** Removes this border from another border. */
    BorderSize<ValueType> subtractedFrom (const BorderSize<ValueType>& other) const noexcept
    {
        return { other.top    - top,
                 other.left   - left,
                 other.bottom - bottom,
                 other.right  - right };
    }

    /** Adds this border to another border. */
    BorderSize<ValueType> addedTo (const BorderSize<ValueType>& other) const noexcept
    {
        return { other.top    + top,
                 other.left   + left,
                 other.bottom + bottom,
                 other.right  + right };
    }

    /** Multiplies each member of the border by a scalar. */
    template <typename ScalarType>
    BorderSize<ValueType> multipliedBy (ScalarType scalar) const noexcept
    {
        return { static_cast<ValueType> (scalar * top),
                 static_cast<ValueType> (scalar * left),
                 static_cast<ValueType> (scalar * bottom),
                 static_cast<ValueType> (scalar * right) };
    }

    //==============================================================================
    bool operator== (const BorderSize& other) const noexcept { return tie() == other.tie(); }
    bool operator!= (const BorderSize& other) const noexcept { return tie() != other.tie(); }

private:
    //==============================================================================
    ValueType top{}, left{}, bottom{}, right{};
};

} // namespace juce