include/rive/text/cursor.hpp

#ifndef _RIVE_CURSOR_HPP_
#define _RIVE_CURSOR_HPP_

#ifdef WITH_RIVE_TEXT
#include <cstdint>
#include "rive/text_engine.hpp"
#include "rive/text/glyph_lookup.hpp"
#include "rive/text/fully_shaped_text.hpp"

#include <vector>

namespace rive
{
class ShapePaintPath;

class CursorVisualPosition
{
public:
  static CursorVisualPosition missing() { return CursorVisualPosition(); }

  CursorVisualPosition(float x, float top, float bottom)
      : m_found(true)
      , m_x(x)
      , m_top(top)
      , m_bottom(bottom)
  {}

  bool found() const { return m_found; }
  float x() const { return m_x; }
  float top() const { return m_top; }
  float bottom() const { return m_bottom; }

private:
  CursorVisualPosition()
      : m_found(false)
      , m_x(0.0f)
      , m_top(0.0f)
      , m_bottom(0.0f)
  {}

  bool m_found;
  float m_x;
  float m_top;
  float m_bottom;
};

class CursorPosition
{
public:
  CursorPosition(uint32_t lineIndex, uint32_t codePointIndex)
      : m_lineIndex(lineIndex)
      , m_codePointIndex(codePointIndex)
  {}

  CursorPosition(uint32_t codePointIndex)
      : m_lineIndex(-1)
      , m_codePointIndex(codePointIndex)
  {}

  uint32_t lineIndex() const { return m_lineIndex; }
  uint32_t lineIndex(int32_t inc) const;
  uint32_t codePointIndex() const { return m_codePointIndex; }
  uint32_t codePointIndex(int32_t inc) const;

  static CursorPosition zero() { return CursorPosition(0, 0); }

  CursorPosition& operator+=(uint32_t v)
  {
    m_codePointIndex += v;
    return *this;
  }

  CursorPosition& operator-=(uint32_t v)
  {
    if (m_codePointIndex >= v)
    {
      m_codePointIndex -= v;
    }
    else
    {
      m_codePointIndex = 0;
    }
    return *this;
  }

  bool hasLineIndex() const { return m_lineIndex != -1; }

  // Find the closest lineIndex() for the codePointIndex().
  void resolveLine(const TextLayoutView& shape);

  CursorVisualPosition visualPosition(const TextLayoutView& shape) const;

  // Move this cursor to the given translation and return the visual position.
  static CursorPosition fromTranslation(
      const Vec2D translation,
      const TextLayoutView& shape);

  static CursorPosition fromLineX(
      uint32_t lineIndex,
      float x,
      const TextLayoutView& shape);

  static CursorPosition atIndex(
      uint32_t codePointIndex,
      const TextLayoutView& shape);

  CursorPosition clamped(const TextLayoutView& shape) const;

private:
  static CursorPosition fromOrderedLine(
      const OrderedLine& orderedLine,
      uint32_t lineIndex,
      float translationX,
      const TextLayoutView& shape);
  uint32_t m_lineIndex;
  uint32_t m_codePointIndex;
};

// Add an offset to the code point index of the cursor and return a cursor with
// undetermined line.
inline CursorPosition operator+(
    const CursorPosition& cursor,
    const int32_t offset)
{
  return CursorPosition(cursor.codePointIndex(offset));
}

inline CursorPosition operator-(
    const CursorPosition& cursor,
    const int32_t offset)
{
  return CursorPosition(cursor.codePointIndex(-offset));
}

inline bool operator==(const CursorPosition& a, const CursorPosition& b)
{
  return a.lineIndex() == b.lineIndex() &&
         a.codePointIndex() == b.codePointIndex();
}

inline bool operator!=(const CursorPosition& a, const CursorPosition& b)
{
  return a.lineIndex() != b.lineIndex() ||
         a.codePointIndex() != b.codePointIndex();
}

inline bool operator<(const CursorPosition& a, const CursorPosition& b)
{
  return a.codePointIndex() < b.codePointIndex();
}

inline bool operator>(const CursorPosition& a, const CursorPosition& b)
{
  return a.codePointIndex() > b.codePointIndex();
}

inline bool operator<=(const CursorPosition& a, const CursorPosition& b)
{
  return a.codePointIndex() <= b.codePointIndex();
}

inline bool operator>=(const CursorPosition& a, const CursorPosition& b)
{
  return a.codePointIndex() >= b.codePointIndex();
}

class Cursor
{
public:
  Cursor(CursorPosition start, CursorPosition end) : m_start(start), m_end(end)
  {}

  static Cursor collapsed(CursorPosition position)
  {
    return Cursor(position, position);
  }

  static Cursor zero() { return Cursor::collapsed(CursorPosition::zero()); }

  static Cursor atStart()
  {
    return Cursor(CursorPosition::zero(), CursorPosition::zero());
  }

  CursorPosition start() const { return m_start; }
  CursorPosition end() const { return m_end; }

  CursorPosition first() const { return m_start < m_end ? m_start : m_end; }
  CursorPosition last() const { return m_start < m_end ? m_end : m_start; }

  bool isCollapsed() const { return m_start == m_end; }
  bool hasSelection() const { return m_start != m_end; }

  void selectionRects(std::vector<AABB>& rects, const TextLayoutView& shape)
      const;

  void updateSelectionPath(
      ShapePaintPath& path,
      const std::vector<AABB>& rects,
      const TextLayoutView& shape) const;

  bool resolveLinePositions(const TextLayoutView& shape);

  bool contains(uint32_t codePointIndex) const;

private:
  CursorPosition m_start;
  CursorPosition m_end;
};

inline bool operator==(const Cursor& a, const Cursor& b)
{
  return a.start() == b.start() && a.end() == b.end();
}

inline bool operator!=(const Cursor& a, const Cursor& b)
{
  return a.start() != b.start() || a.end() != b.end();
}
} // namespace rive

#endif
#endif