bsb1/arch/textwindow.h

/*! \file
 *  \brief \ref TextWindow provides virtual output windows in text mode
 */

#pragma once
#include "../types.h"
#include "cga.h"

/*! \brief Virtual windows in text mode
 *  \ingroup io
 *
 * Outputs text on a part of the screen in \ref CGA,
 * a window is defined in by position and size (with its own cursor).
 *
 * This allows to separate the output of the application from the debug output
 * on the screen without having to synchronize.
 */
class TextWindow {
  // Prevent copies and assignments
  TextWindow(const TextWindow&) = delete;
  TextWindow& operator=(const TextWindow&) = delete;

  unsigned from_col;
  unsigned to_col;
  unsigned from_row;
  unsigned to_row;
  bool use_cursor;

  unsigned 	pos_x;
  unsigned 	pos_y;

  void scrollUp();

 public:
  /*! \brief Constructor of a text window
   *
   * Creates a virtual, rectangular text window on the screen.
   * The coordinates to construct the window are absolute positions in the
   * \ref CGA screen.
   *
   * \note Overlapping windows are neither supported nor prevented -- better
   *       just try to avoid construction windows with overlapping coordinates!
   *
   * \warning Don't use the hardware cursor in more than one window!
   *
   * \param from_col   Text Window starts in column `from_col`,
   *                   the first (leftmost) possible column is `0`
   * \param to_col     Text Window extends to the right to column `to_col`
   * (exclusive). This column has to be strictly greater than `from_col`, the
   * maximum allowed value is \ref CGA::COLUMNS (rightmost)
   * \param from_row   Text Window starts in row `from_row`,
   *                   the first possible (uppermost) row is `0`
   * \param to_row     Text Window extends down to row `to_row` (exclusive).
   *                   This row has to be strictly greater than `from_row`,
   *                   the maximum allowed value is \ref CGA::ROWS (bottom-most)
   * \param use_cursor Specifies whether the hardware cursor (`true`) or a
   *                   software cursor/variable (`false`) should be used to
   *                   store the current position
   *
   */
  TextWindow(unsigned from_col, unsigned to_col, unsigned from_row,
             unsigned to_row, bool use_cursor = false);

  /*! \brief Set the cursor position in the window
   *
   * Depending on the constructor parameter `use_cursor` either the
   * hardware cursor (and only the hardware cursor!) is used or the position
   * is stored internally in the object.
   *
   * The coordinates are relative to the upper left starting position of
   * the window.
   *
   *  \param rel_x Column in window
   *  \param rel_y Row in window
   */
  void setPos(unsigned rel_x, unsigned rel_y);

  /*! \brief Set the cursor position in the window
   *
   * Depending on the constructor parameter `use_cursor` either the
   * hardware cursor (and only the hardware cursor!) is used or the position
   * is stored internally in the object.
   *
   * The coordinates are relative to the upper left starting position of
   * the window.
   * Negative coordinates are interpreted relative to the right and bottom
   * border of the window.
   *
   */
  void setPos(int rel_x, int rel_y);

  /*! \brief Get the current cursor position in the window
   *
   * Depending on the constructor parameter `use_cursor` either the
   * hardware cursor (and only the hardware cursor!) is used or the position
   * is retrieved from the internally stored object.
   *
   *  \param rel_x Column in window
   *  \param rel_y Row in window
   */
  void getPos(unsigned& rel_x, unsigned& rel_y) const;

  /// \copydoc TextWindow::getPos(unsigned&,unsigned&) const
  void getPos(int& rel_x, int& rel_y) const;

  /*! \brief Display multiple characters in the window
   *
   * Output a character string, starting at the current cursor position.
   * Since the string does not need to contain a `\0` termination (unlike the
   * common C string), a length parameter is required to specify the number
   * of characters in the string.
   * When the output is complete, the cursor is positioned after the last
   * printed character.
   * The same attributes (colors) are used for the entire text.
   *
   * If there is not enough space left at the end of the line,
   * the output continues on the following line.
   * As soon as the last window line is filled, the entire window area is
   * moved up one line: The first line disappears, the bottom line is cleared.
   *
   * A line break also occurs whenever the character `\n` appears in the text.
   *
   *  \param string Text to be printed
   *  \param length Length of text
   *  \param attrib Attribute for text
   */
  void print(const char* string, size_t length,
             CGA::Attribute attrib = CGA::Attribute());  // NOLINT

  /*! \brief Delete all contents in the window and reset the cursor.
   *
   *  \param character Fill character
   *  \param attrib Attribute for fill character
   */
  void reset(char character = ' ', CGA::Attribute attrib = CGA::Attribute());
};