JUCE/modules/juce_graphics/fonts/juce_AttributedString.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
{

namespace
{
    int getLength (const Array<AttributedString::Attribute>& atts) noexcept
    {
        return atts.size() != 0 ? atts.getReference (atts.size() - 1).range.getEnd() : 0;
    }

    void splitAttributeRanges (Array<AttributedString::Attribute>& atts, int position)
    {
        for (int i = atts.size(); --i >= 0;)
        {
            const auto& att = atts.getUnchecked (i);
            auto offset = position - att.range.getStart();

            if (offset >= 0)
            {
                if (offset > 0 && position < att.range.getEnd())
                {
                    atts.insert (i + 1, AttributedString::Attribute (att));
                    atts.getReference (i).range.setEnd (position);
                    atts.getReference (i + 1).range.setStart (position);
                }

                break;
            }
        }
    }

    inline bool areInvariantsMaintained (const String& text, const Array<AttributedString::Attribute>& atts)
    {
        if (atts.isEmpty())
            return true;

        if (atts.getFirst().range.getStart() != 0)
            return false;

        if (atts.getLast().range.getEnd() != text.length())
            return false;

        for (auto it = std::next (atts.begin()); it != atts.end(); ++it)
            if (it->range.getStart() != std::prev (it)->range.getEnd())
                return false;

        return true;
    }

    Range<int> splitAttributeRanges (Array<AttributedString::Attribute>& atts, Range<int> newRange)
    {
        newRange = newRange.getIntersectionWith ({ 0, getLength (atts) });

        if (! newRange.isEmpty())
        {
            splitAttributeRanges (atts, newRange.getStart());
            splitAttributeRanges (atts, newRange.getEnd());
        }

        return newRange;
    }

    void mergeAdjacentRanges (Array<AttributedString::Attribute>& atts)
    {
        for (int i = atts.size() - 1; --i >= 0;)
        {
            auto& a1 = atts.getReference (i);
            auto& a2 = atts.getReference (i + 1);

            if (a1.colour == a2.colour && a1.font == a2.font)
            {
                a1.range.setEnd (a2.range.getEnd());
                atts.remove (i + 1);

                if (i < atts.size() - 1)
                    ++i;
            }
        }
    }

    void appendRange (Array<AttributedString::Attribute>& atts,
                      int length, const Font* f, const Colour* c)
    {
        if (atts.size() == 0)
        {
            atts.add ({ Range<int> (0, length), f != nullptr ? *f : Font(), c != nullptr ? *c : Colour (0xff000000) });
        }
        else
        {
            auto start = getLength (atts);
            atts.add ({ Range<int> (start, start + length),
                        f != nullptr ? *f : atts.getReference (atts.size() - 1).font,
                        c != nullptr ? *c : atts.getReference (atts.size() - 1).colour });

            mergeAdjacentRanges (atts);
        }
    }

    void applyFontAndColour (Array<AttributedString::Attribute>& atts,
                             Range<int> range, const Font* f, const Colour* c)
    {
        range = splitAttributeRanges (atts, range);

        for (auto& att : atts)
        {
            if (range.getStart() < att.range.getEnd())
            {
                if (range.getEnd() <= att.range.getStart())
                    break;

                if (c != nullptr) att.colour = *c;
                if (f != nullptr) att.font = *f;
            }
        }

        mergeAdjacentRanges (atts);
    }

    void truncate (Array<AttributedString::Attribute>& atts, int newLength)
    {
        splitAttributeRanges (atts, newLength);

        for (int i = atts.size(); --i >= 0;)
            if (atts.getReference (i).range.getStart() >= newLength)
                atts.remove (i);
    }
}

//==============================================================================
AttributedString::Attribute::Attribute (Range<int> r, const Font& f, Colour c) noexcept
    : range (r), font (f), colour (c)
{
}

//==============================================================================
void AttributedString::setText (const String& newText)
{
    auto newLength = newText.length();
    auto oldLength = getLength (attributes);

    if (newLength > oldLength)
        appendRange (attributes, newLength - oldLength, nullptr, nullptr);
    else if (newLength < oldLength)
        truncate (attributes, newLength);

    text = newText;
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::append (const String& textToAppend)
{
    text += textToAppend;
    appendRange (attributes, textToAppend.length(), nullptr, nullptr);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::append (const String& textToAppend, const Font& font)
{
    text += textToAppend;
    appendRange (attributes, textToAppend.length(), &font, nullptr);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::append (const String& textToAppend, Colour colour)
{
    text += textToAppend;
    appendRange (attributes, textToAppend.length(), nullptr, &colour);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::append (const String& textToAppend, const Font& font, Colour colour)
{
    text += textToAppend;
    appendRange (attributes, textToAppend.length(), &font, &colour);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::append (const AttributedString& other)
{
    auto originalLength = getLength (attributes);
    auto originalNumAtts = attributes.size();
    text += other.text;
    attributes.addArray (other.attributes);

    for (auto i = originalNumAtts; i < attributes.size(); ++i)
        attributes.getReference (i).range += originalLength;

    mergeAdjacentRanges (attributes);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::clear()
{
    text.clear();
    attributes.clear();
}

void AttributedString::setJustification (Justification newJustification) noexcept
{
    justification = newJustification;
}

void AttributedString::setWordWrap (WordWrap newWordWrap) noexcept
{
    wordWrap = newWordWrap;
}

void AttributedString::setReadingDirection (ReadingDirection newReadingDirection) noexcept
{
    readingDirection = newReadingDirection;
}

void AttributedString::setLineSpacing (const float newLineSpacing) noexcept
{
    lineSpacing = newLineSpacing;
}

void AttributedString::setColour (Range<int> range, Colour colour)
{
    applyFontAndColour (attributes, range, nullptr, &colour);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::setFont (Range<int> range, const Font& font)
{
    applyFontAndColour (attributes, range, &font, nullptr);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::setColour (Colour colour)
{
    setColour ({ 0, getLength (attributes) }, colour);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::setFont (const Font& font)
{
    setFont ({ 0, getLength (attributes) }, font);
    jassert (areInvariantsMaintained (text, attributes));
}

void AttributedString::draw (Graphics& g, const Rectangle<float>& area) const
{
    if (text.isNotEmpty() && g.clipRegionIntersects (area.getSmallestIntegerContainer()))
    {
        jassert (text.length() == getLength (attributes));

        if (! g.getInternalContext().drawTextLayout (*this, area))
        {
            TextLayout layout;
            layout.createLayout (*this, area.getWidth());
            layout.draw (g, area);
        }
    }
}

} // namespace juce