TextDisplay.h

00001 /* mbed TextDisplay Library Base Class
00002  * Copyright (c) 2007-2009 sford
00003  * Released under the MIT License: http://mbed.org/license/mit
00004  *
00005  * A common base class for Text displays
00006  * To port a new display, derive from this class and implement
00007  * the constructor (setup the display), character (put a character
00008  * at a location), rows and columns (number of rows/cols) functions.
00009  * Everything else (locate, printf, putc, cls) will come for free
00010  *
00011  * The model is the display will wrap at the right and bottom, so you can
00012  * keep writing and will always get valid characters. The location is 
00013  * maintained internally to the class to make this easy
00014  */
00015 
00016 #ifndef MBED_TEXTDISPLAY_H
00017 #define MBED_TEXTDISPLAY_H
00018 
00019 #include "mbed.h"
00020 
00021 /** A common base class for Text displays
00022 */
00023 class TextDisplay : public Stream {
00024 public:
00025 
00026     // functions needing implementation in derived implementation class
00027     // ----------------------------------------------------------------
00028     /** Create a TextDisplay interface
00029     * @param name The name used in the path to access the strean through the filesystem
00030     */
00031     TextDisplay(const char *name = NULL);
00032 
00033     /** output a character at the given position
00034     *
00035     * @param column column where charater must be written
00036     * @param  row where character must be written
00037     * @param c the character to be written to the TextDisplay
00038     * @note this method may be overridden in a derived class.
00039     */
00040     virtual void character(int column, int row, int c) = 0;
00041 
00042     /** return number of rows on TextDisplay
00043     * @result number of rows
00044     * @note this method must be supported in the derived class.
00045     */
00046     virtual int rows() = 0;
00047 
00048     /** return number of columns on TextDisplay
00049     * @result number of columns
00050     * @note this method must be supported in the derived class.
00051     */
00052     virtual int columns() = 0;
00053     
00054     // functions that come for free, but can be overwritten
00055     // ----------------------------------------------------
00056     /** redirect output from a stream (stoud, sterr) to  display
00057     * @param stream stream that shall be redirected to the TextDisplay
00058     * @note this method may be overridden in a derived class.
00059     * @returns true if the claim succeeded.
00060     */
00061     virtual bool claim (FILE *stream);
00062 
00063     /** clear the entire screen
00064     * @note this method may be overridden in a derived class.
00065     */
00066     virtual void cls();
00067 
00068     /** locate the cursor at a character position.
00069     * Based on the currently active font, locate the cursor on screen.
00070     * @note this method may be overridden in a derived class.
00071     * @param column is the horizontal offset from the left side.
00072     * @param row is the vertical offset from the top.
00073     */
00074     virtual void locate(int column, int row);
00075 
00076     /** set the foreground color
00077     * @note this method may be overridden in a derived class.
00078     * @param color is color to use for foreground drawing.
00079     */
00080     virtual void foreground(uint16_t colour);
00081 
00082     /** set the background color
00083     * @note this method may be overridden in a derived class.
00084     * @param color is color to use for background drawing.
00085     */
00086     virtual void background(uint16_t colour);
00087 
00088     // putc (from Stream)
00089     // printf (from Stream)
00090     
00091 protected:
00092 
00093     virtual int _putc(int value);
00094     virtual int _getc();
00095 
00096     // character location
00097     int _column;
00098     int _row;
00099 
00100     // colours
00101     volatile uint16_t _foreground;
00102     volatile uint16_t _background;
00103     char *_path;
00104 };
00105 
00106 #endif