Fl_Text_Display.H

//
// Header file for Fl_Text_Display class.
//
// Copyright 2001-2020 by Bill Spitzak and others.
// Original code Copyright Mark Edel.  Permission to distribute under
// the LGPL for the FLTK library granted by Mark Edel.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//

/* \file
 Fl_Text_Display widget . */

#ifndef FL_TEXT_DISPLAY_H
#define FL_TEXT_DISPLAY_H

#include <FL/Fl.H>              // Fl::scrollbar_size()
#include "fl_draw.H"
#include "Fl_Group.H"
#include "Fl_Widget.H"
#include "Fl_Scrollbar.H"
#include "Fl_Text_Buffer.H"

class FL_EXPORT Fl_Text_Display: public Fl_Group {

public:

  enum {
    NORMAL_CURSOR,    
    CARET_CURSOR,     
    DIM_CURSOR,       
    BLOCK_CURSOR,     
    HEAVY_CURSOR,     
    SIMPLE_CURSOR    
  };

  enum {
    CURSOR_POS,
    CHARACTER_POS
  };

  enum {
    DRAG_NONE = -2,
    DRAG_START_DND = -1,
    DRAG_CHAR = 0,
    DRAG_WORD = 1,
    DRAG_LINE = 2
  };

  enum {
    WRAP_NONE,      
    WRAP_AT_COLUMN, 
    WRAP_AT_PIXEL,  
    WRAP_AT_BOUNDS  
  };

  friend void fl_text_drag_me(int pos, Fl_Text_Display* d);

  typedef void (*Unfinished_Style_Cb)(int, void *);

  struct Style_Table_Entry {
    Fl_Color    color;  
    Fl_Font     font;   
    Fl_Fontsize size;   
    unsigned    attr;   
  };

  Fl_Text_Display(int X, int Y, int W, int H, const char *l = 0);
  ~Fl_Text_Display();

  virtual int handle(int e);

  void buffer(Fl_Text_Buffer* buf);

  void buffer(Fl_Text_Buffer& buf) { buffer(&buf); }

  Fl_Text_Buffer* buffer() const { return mBuffer; }

  void redisplay_range(int start, int end);
  void scroll(int topLineNum, int horizOffset);
  void insert(const char* text);
  void overstrike(const char* text);
  void insert_position(int newPos);

  int insert_position() const { return mCursorPos; }
  int position_to_xy(int pos, int* x, int* y) const;

  int in_selection(int x, int y) const;
  void show_insert_position();

  int move_right();
  int move_left();
  int move_up();
  int move_down();
  int count_lines(int start, int end, bool start_pos_is_line_start) const;
  int line_start(int pos) const;
  int line_end(int startPos, bool startPosIsLineStart) const;
  int skip_lines(int startPos, int nLines, bool startPosIsLineStart);
  int rewind_lines(int startPos, int nLines);
  void next_word(void);
  void previous_word(void);

  void show_cursor(int b = 1);

  void hide_cursor() { show_cursor(0); }

  void cursor_style(int style);
  int cursor_style() const { return mCursorStyle; }

  Fl_Color cursor_color() const {return mCursor_color;}

  void cursor_color(Fl_Color n) {mCursor_color = n;}

  int scrollbar_width() const {
      return scrollbar_width_ ? scrollbar_width_ : Fl::scrollbar_size();
  }

  void scrollbar_width(int width) {
      Fl::scrollbar_size(width);
      scrollbar_width_ = 0;
  }

  int scrollbar_size() const {
      return(scrollbar_width_);
  }

  void scrollbar_size(int newSize) {
      scrollbar_width_ = newSize;
  }

  Fl_Align scrollbar_align() const { return scrollbar_align_; }

  void scrollbar_align(Fl_Align a) { scrollbar_align_ = a; }

  int word_start(int pos) const { return buffer()->word_start(pos); }

  int word_end(int pos) const { return buffer()->word_end(pos); }


  void highlight_data(Fl_Text_Buffer *styleBuffer,
                      const Style_Table_Entry *styleTable,
                      int nStyles, char unfinishedStyle,
                      Unfinished_Style_Cb unfinishedHighlightCB,
                      void *cbArg);

  int position_style(int lineStartPos, int lineLen, int lineIndex) const;

  int shortcut() const {return shortcut_;}

  void shortcut(int s) {shortcut_ = s;}

  Fl_Font textfont() const {return textfont_;}

  void textfont(Fl_Font s) {textfont_ = s; mColumnScale = 0; }

  Fl_Fontsize textsize() const {return textsize_;}

  void textsize(Fl_Fontsize s) {textsize_ = s; mColumnScale = 0; }

  Fl_Color textcolor() const {return textcolor_;}

  void textcolor(Fl_Color n) {textcolor_ = n;}

  int wrapped_column(int row, int column) const;
  int wrapped_row(int row) const;
  void wrap_mode(int wrap, int wrap_margin);

  virtual void recalc_display();
  virtual void resize(int X, int Y, int W, int H);

  double x_to_col(double x) const;

  double col_to_x(double col) const;

  void linenumber_width(int width);
  int linenumber_width() const;
  void linenumber_font(Fl_Font val);
  Fl_Font linenumber_font() const;
  void linenumber_size(Fl_Fontsize val);
  Fl_Fontsize linenumber_size() const;
  void linenumber_fgcolor(Fl_Color val);
  Fl_Color linenumber_fgcolor() const;
  void linenumber_bgcolor(Fl_Color val);
  Fl_Color linenumber_bgcolor() const;
  void linenumber_align(Fl_Align val);
  Fl_Align linenumber_align() const;
  void linenumber_format(const char* val);
  const char* linenumber_format() const;

protected:
  // Most (all?) of this stuff should only be called from resize() or
  // draw().
  // Anything with "vline" indicates thats it deals with currently
  // visible lines.

  virtual void draw();
  void draw_text(int X, int Y, int W, int H);
  void draw_range(int start, int end);
  void draw_cursor(int, int);

  void draw_string(int style, int x, int y, int toX, const char *string,
                   int nChars) const;

  void draw_vline(int visLineNum, int leftClip, int rightClip,
                  int leftCharIndex, int rightCharIndex);

  int find_x(const char *s, int len, int style, int x) const;

  enum {
    DRAW_LINE,
    FIND_INDEX,
    FIND_INDEX_FROM_ZERO,
    GET_WIDTH,
    FIND_CURSOR_INDEX   // STR #2788
  };

  int handle_vline(int mode,
                   int lineStart, int lineLen, int leftChar, int rightChar,
                   int topClip, int bottomClip,
                   int leftClip, int rightClip) const;

  void draw_line_numbers(bool clearAll);

  void clear_rect(int style, int x, int y, int width, int height) const;
  void display_insert();

  void offset_line_starts(int newTopLineNum);

  void calc_line_starts(int startLine, int endLine);

  void update_line_starts(int pos, int charsInserted, int charsDeleted,
                          int linesInserted, int linesDeleted, int *scrolled);

  void calc_last_char();

  int position_to_line( int pos, int* lineNum ) const;
  double string_width(const char* string, int length, int style) const;

  static void scroll_timer_cb(void*);

  static void buffer_predelete_cb(int pos, int nDeleted, void* cbArg);
  static void buffer_modified_cb(int pos, int nInserted, int nDeleted,
                                 int nRestyled, const char* deletedText,
                                 void* cbArg);

  static void h_scrollbar_cb(Fl_Scrollbar* w, Fl_Text_Display* d);
  static void v_scrollbar_cb( Fl_Scrollbar* w, Fl_Text_Display* d);
  void update_v_scrollbar();
  void update_h_scrollbar();
  int measure_vline(int visLineNum) const;
  int longest_vline() const;
  int empty_vlines() const;
  int vline_length(int visLineNum) const;
  int xy_to_position(int x, int y, int PosType = CHARACTER_POS) const;

  void xy_to_rowcol(int x, int y, int* row, int* column,
                    int PosType = CHARACTER_POS) const;
  void maintain_absolute_top_line_number(int state);
  int get_absolute_top_line_number() const;
  void absolute_top_line_number(int oldFirstChar);
  int maintaining_absolute_top_line_number() const;
  void reset_absolute_top_line_number();
  int position_to_linecol(int pos, int* lineNum, int* column) const;
  int scroll_(int topLineNum, int horizOffset);

  void extend_range_for_styles(int* start, int* end);

  void find_wrap_range(const char *deletedText, int pos, int nInserted,
                       int nDeleted, int *modRangeStart, int *modRangeEnd,
                       int *linesInserted, int *linesDeleted);
  void measure_deleted_lines(int pos, int nDeleted);
  void wrapped_line_counter(Fl_Text_Buffer *buf, int startPos, int maxPos,
                            int maxLines, bool startPosIsLineStart,
                            int styleBufOffset, int *retPos, int *retLines,
                            int *retLineStart, int *retLineEnd,
                            bool countLastLineMissingNewLine = true) const;
  void find_line_end(int pos, bool start_pos_is_line_start, int *lineEnd,
                     int *nextLineStart) const;
  double measure_proportional_character(const char *s, int colNum, int pos) const;
  int wrap_uses_character(int lineEndPos) const;

  int damage_range1_start, damage_range1_end;
  int damage_range2_start, damage_range2_end;
  int mCursorPos;
  int mCursorOn;
  int mCursorOldY;              /* Y pos. of cursor for blanking */
  int mCursorToHint;            /* Tells the buffer modified callback
                                 where to move the cursor, to reduce
                                 the number of redraw calls */
  int mCursorStyle;             /* One of enum cursorStyles above */
  int mCursorPreferredXPos;     /* Pixel position for vert. cursor movement */
  int mNVisibleLines;           /* # of visible (displayed) lines. This is
                                   also the size of the mLineStarts[] array. */
  int mNBufferLines;            /* # of newlines in the buffer */
  Fl_Text_Buffer* mBuffer;      /* Contains text to be displayed */
  Fl_Text_Buffer* mStyleBuffer; /* Optional parallel buffer containing
                                 color and font information */
  int mFirstChar, mLastChar;    /* Buffer positions of first and last
                                 displayed character (lastChar points
                                 either to a newline or one character
                                 beyond the end of the buffer) */
  int mContinuousWrap;          /* Wrap long lines when displaying */
  int mWrapMarginPix;           /* Margin in # of pixels for
                                 wrapping in continuousWrap mode */
  int* mLineStarts;             /* Array of the size mNVisibleLines.
                                   This array only keeps track of lines
                                   within the display area. Each entry
                                   contains the starting character offset
                                   (from the beginning of the text buffer)
                                   for each /visible/ line.
                                   If wrap enabled, points to the beginning
                                   of each wrap. So a long line wrapping
                                   into 3 separate lines in the display
                                   will take up 3 separate array entries. */
  int mTopLineNum;              /* Line number of top displayed line
                                 of file (first line of file is 1) */
  int mAbsTopLineNum;           /* In continuous wrap mode, the line
                                  number of the top line if the text
                                  were not wrapped (note that this is
                                  only maintained as needed). */
  int mNeedAbsTopLineNum;       /* Externally settable flag to continue
                                 maintaining absTopLineNum even if
                                 it isn't needed for line # display */
  int mHorizOffset;             /* Horizontal scroll pos. in pixels */
  int mTopLineNumHint;          /* Line number of top displayed line
                                 of file (first line of file is 1) */
  int mHorizOffsetHint;         /* Horizontal scroll pos. in pixels */
  int mNStyles;                 /* Number of entries in styleTable */
  const Style_Table_Entry *mStyleTable; /* Table of fonts and colors for
                                         coloring/syntax-highlighting */
  char mUnfinishedStyle;        /* Style buffer entry which triggers
                                 on-the-fly reparsing of region */
  Unfinished_Style_Cb mUnfinishedHighlightCB; /* Callback to parse "unfinished" */
  /* regions */
  void* mHighlightCBArg;        /* Arg to unfinishedHighlightCB */

  int mMaxsize;

  int mSuppressResync;          /* Suppress resynchronization of line
                                 starts during buffer updates */
  int mNLinesDeleted;           /* Number of lines deleted during
                                 buffer modification (only used
                                 when resynchronization is suppressed) */
  int mModifyingTabDistance;    /* Whether tab distance is being modified XXX: UNUSED */

  mutable double mColumnScale; /* Width in pixels of an average character. This
                                 value is calculated as needed (lazy eval); it
                                 needs to be mutable so that it can be calculated
                                 within a method marked as "const" */

  Fl_Color mCursor_color;

  Fl_Scrollbar* mHScrollBar;
  Fl_Scrollbar* mVScrollBar;
  int scrollbar_width_;         // size of scrollbar trough (behavior changed in 1.4)
  Fl_Align scrollbar_align_;
  int dragPos, dragType, dragging;
  int display_insert_position_hint;
  struct { int x, y, w, h; } text_area;

  int shortcut_;

  Fl_Font textfont_;
  Fl_Fontsize textsize_;
  Fl_Color textcolor_;

  // Line number margin and width
  int mLineNumLeft, mLineNumWidth;

  // Line number font/colors
  Fl_Font     linenumber_font_;
  Fl_Fontsize linenumber_size_;
  Fl_Color    linenumber_fgcolor_;
  Fl_Color    linenumber_bgcolor_;
  Fl_Align    linenumber_align_;
  const char* linenumber_format_;
};

#endif