CharacterColor.h

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/*
    This file is part of Konsole, KDE's terminal.
    
    Copyright (C) 2007, 2013 by Robert Knight <[email protected]>
    Copyright (C) 1997,1998 by Lars Doelle <[email protected]>

    Rewritten for QT4 by e_k <e_k at users.sourceforge.net>, Copyright (C)2008

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301  USA.
*/

#ifndef CHARACTERCOLOR_H
#define CHARACTERCOLOR_H

// Qt
#include <QColor>

/** 
 * An entry in a terminal display's color palette. 
 *
 * A color palette is an array of 16 ColorEntry instances which map
 * system color indexes (from 0 to 15) into actual colors.
 *
 * Each entry can be set as bold, in which case any text
 * drawn using the color should be drawn in bold.  
 *
 * Each entry can also be transparent, in which case the terminal
 * display should avoid drawing the background for any characters
 * using the entry as a background.
 */
class ColorEntry
{
public:
  /** 
   * Constructs a new color palette entry.
   *
   * @param c The color value for this entry.
   * @param tr Specifies that the color should be transparent when used as a background color.
   * @param b Specifies that text drawn with this color should be bold.
   */
  ColorEntry(QColor c, bool tr, bool b) : color(c), transparent(tr), bold(b) {}

  /**
   * Constructs a new color palette entry with an undefined color, and
   * with the transparent and bold flags set to false.
   */ 
  ColorEntry() : transparent(false), bold(false) {} 
 
  /**
   * Sets the color, transparency and boldness of this color to those of @p rhs.
   */ 
  void operator=(const ColorEntry& rhs) 
  { 
       color = rhs.color; 
       transparent = rhs.transparent; 
       bold = rhs.bold; 
  }

  /** The color value of this entry for display. */
  QColor color;

  /** 
   * If true character backgrounds using this color should be transparent. 
   * This is not applicable when the color is used to render text.
   */
  bool   transparent;
  /**
   * If true characters drawn using this color should be bold.
   * This is not applicable when the color is used to draw a character's background.
   */
  bool   bold;        
};


// Attributed Character Representations ///////////////////////////////

// Colors

#define BASE_COLORS   (2+8)
#define INTENSITIES   2
#define TABLE_COLORS  (INTENSITIES*BASE_COLORS)

#define DEFAULT_FORE_COLOR 0
#define DEFAULT_BACK_COLOR 1

//a standard set of colors using black text on a white background.
//defined in TerminalDisplay.cpp

static const ColorEntry base_color_table[TABLE_COLORS] =
{
    // normal
    ColorEntry(QColor(0x00,0x00,0x00), 1, 0 ), ColorEntry( QColor(0xFF,0xFF,0xFF), 0, 0 ), // Dfore, Dback
    ColorEntry(QColor(0x00,0x00,0x00), 0, 0 ), ColorEntry( QColor(0xB2,0x18,0x18), 0, 0 ), // Black, Red
    ColorEntry(QColor(0x18,0xB2,0x18), 0, 0 ), ColorEntry( QColor(0xB2,0x68,0x18), 0, 0 ), // Green, Yellow
    ColorEntry(QColor(0x18,0x18,0xB2), 0, 0 ), ColorEntry( QColor(0xB2,0x18,0xB2), 0, 0 ), // Blue, Magenta
    ColorEntry(QColor(0x18,0xB2,0xB2), 0, 0 ), ColorEntry( QColor(0xB2,0xB2,0xB2), 0, 0 ), // Cyan, White
    // intensiv
    ColorEntry(QColor(0x00,0x00,0x00), 0, 1 ), ColorEntry( QColor(0xFF,0xFF,0xFF), 1, 0 ),
    ColorEntry(QColor(0x68,0x68,0x68), 0, 0 ), ColorEntry( QColor(0xFF,0x54,0x54), 0, 0 ),
    ColorEntry(QColor(0x54,0xFF,0x54), 0, 0 ), ColorEntry( QColor(0xFF,0xFF,0x54), 0, 0 ),
    ColorEntry(QColor(0x54,0x54,0xFF), 0, 0 ), ColorEntry( QColor(0xFF,0x54,0xFF), 0, 0 ),
    ColorEntry(QColor(0x54,0xFF,0xFF), 0, 0 ), ColorEntry( QColor(0xFF,0xFF,0xFF), 0, 0 )
};

/* CharacterColor is a union of the various color spaces.

   Assignment is as follows:

   Type  - Space        - Values

   0     - Undefined   - u:  0,      v:0        w:0
   1     - Default     - u:  0..1    v:intense  w:0
   2     - System      - u:  0..7    v:intense  w:0
   3     - Index(256)  - u: 16..255  v:0        w:0
   4     - RGB         - u:  0..255  v:0..256   w:0..256

   Default colour space has two separate colours, namely
   default foreground and default background colour.
*/

#define COLOR_SPACE_UNDEFINED   0
#define COLOR_SPACE_DEFAULT     1
#define COLOR_SPACE_SYSTEM      2
#define COLOR_SPACE_256         3
#define COLOR_SPACE_RGB         4

/**
 * Describes the color of a single character in the terminal.
 */
class CharacterColor
{
    friend class Character;

public:
  /** Constructs a new CharacterColor whoose color and color space are undefined. */
  CharacterColor() 
      : _colorSpace(COLOR_SPACE_UNDEFINED), 
        _u(0), 
        _v(0), 
        _w(0) 
  {}

  /** 
   * Constructs a new CharacterColor using the specified @p colorSpace and with 
   * color value @p co
   *
   * The meaning of @p co depends on the @p colorSpace used.
   *
   * TODO : Document how @p co relates to @p colorSpace
   *
   * TODO : Add documentation about available color spaces.
   */
  CharacterColor(quint8 colorSpace, int co) 
      : _colorSpace(colorSpace), 
        _u(0), 
        _v(0), 
        _w(0)
  {
    switch (colorSpace)
    {
        case COLOR_SPACE_DEFAULT:
            _u = co & 1;
            break;
        case COLOR_SPACE_SYSTEM:
            _u = co & 7;
            _v = (co >> 3) & 1;
            break;
        case COLOR_SPACE_256:  
            _u = co & 255;
            break;
        case COLOR_SPACE_RGB:
            _u = co >> 16;
            _v = co >> 8;
            _w = co;
            break;
        default:
            _colorSpace = COLOR_SPACE_UNDEFINED;
    }
  }

  /** 
   * Returns true if this character color entry is valid.
   */
  bool isValid() 
  {
        return _colorSpace != COLOR_SPACE_UNDEFINED;
  }
    
  /** 
   * Toggles the value of this color between a normal system color and the corresponding intensive
   * system color.
   * 
   * This is only applicable if the color is using the COLOR_SPACE_DEFAULT or COLOR_SPACE_SYSTEM
   * color spaces.
   */
  void toggleIntensive();

  /** 
   * Returns the color within the specified color @palette
   *
   * The @p palette is only used if this color is one of the 16 system colors, otherwise
   * it is ignored.
   */
  QColor color(const ColorEntry* palette) const;
 
  /** 
   * Compares two colors and returns true if they represent the same color value and
   * use the same color space.
   */
  friend bool operator == (const CharacterColor& a, const CharacterColor& b);
  /**
   * Compares two colors and returns true if they represent different color values
   * or use different color spaces.
   */
  friend bool operator != (const CharacterColor& a, const CharacterColor& b);

private:
  quint8 _colorSpace;

  // bytes storing the character color 
  quint8 _u; 
  quint8 _v; 
  quint8 _w; 
};

inline bool operator == (const CharacterColor& a, const CharacterColor& b)
{ 
    return a._colorSpace == b._colorSpace &&
         a._u == b._u &&
         a._v == b._v &&
           a._w == b._w;
}

inline bool operator != (const CharacterColor& a, const CharacterColor& b)
{
    return !operator==(a,b);
}

inline const QColor color256(quint8 u, const ColorEntry* base)
{
  //   0.. 16: system colors
  if (u <   8) return base[u+2            ].color; u -= 8;
  if (u <   8) return base[u+2+BASE_COLORS].color; u -= 8;

  //  16..231: 6x6x6 rgb color cube
  if (u < 216) return QColor(255*((u/36)%6)/5,
                             255*((u/ 6)%6)/5,
                             255*((u/ 1)%6)/5); u -= 216;
  
  // 232..255: gray, leaving out black and white
  int gray = u*10+8; return QColor(gray,gray,gray);
}

inline QColor CharacterColor::color(const ColorEntry* base) const
{
  switch (_colorSpace)
  {
    case COLOR_SPACE_DEFAULT: return base[_u+0+(_v?BASE_COLORS:0)].color;
    case COLOR_SPACE_SYSTEM: return base[_u+2+(_v?BASE_COLORS:0)].color;
    case COLOR_SPACE_256: return color256(_u,base);
    case COLOR_SPACE_RGB: return QColor(_u,_v,_w);
    case COLOR_SPACE_UNDEFINED: return QColor();
  }

  Q_ASSERT(false); // invalid color space

  return QColor();
}

inline void CharacterColor::toggleIntensive()
{
  if (_colorSpace == COLOR_SPACE_SYSTEM || _colorSpace == COLOR_SPACE_DEFAULT)
  {
    _v = !_v;
  }
}

#endif // CHARACTERCOLOR_H