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 #include "Stream.h"
00021 
00022 /** A common base class for Text displays
00023 */
00024 class TextDisplay : public Stream {
00025 public:
00026 
00027     // functions needing implementation in derived implementation class
00028     // ----------------------------------------------------------------
00029     /** Create a TextDisplay interface
00030     * @param name The name used in the path to access the strean through the filesystem
00031     */
00032     TextDisplay(const char *name = NULL);
00033 
00034     /** output a character at the given position
00035     *
00036     * @param column column where charater must be written
00037     * @param  row where character must be written
00038     * @param c the character to be written to the TextDisplay
00039     * @note this method may be overridden in a derived class.
00040     */
00041     virtual void character(int column, int row, int c) = 0;
00042 
00043     /** return number of rows on TextDisplay
00044     * @result number of rows
00045     * @note this method must be supported in the derived class.
00046     */
00047     virtual int rows() = 0;
00048 
00049     /** return number of columns on TextDisplay
00050     * @result number of columns
00051     * @note this method must be supported in the derived class.
00052     */
00053     virtual int columns() = 0;
00054     
00055     // functions that come for free, but can be overwritten
00056     // ----------------------------------------------------
00057     /** redirect output from a stream (stoud, sterr) to  display
00058     * @param stream stream that shall be redirected to the TextDisplay
00059     * @note this method may be overridden in a derived class.
00060     * @returns true if the claim succeeded.
00061     */
00062     virtual bool claim (FILE *stream);
00063 
00064     /** clear the entire screen
00065     * @note this method may be overridden in a derived class.
00066     */
00067     virtual void cls();
00068 
00069     /** locate the cursor at a character position.
00070     * Based on the currently active font, locate the cursor on screen.
00071     * @note this method may be overridden in a derived class.
00072     * @param column is the horizontal offset from the left side.
00073     * @param row is the vertical offset from the top.
00074     */
00075     virtual void locate(int column, int row);
00076 
00077     /** set the foreground color
00078     * @note this method may be overridden in a derived class.
00079     * @param color is color to use for foreground drawing.
00080     */
00081     virtual void foreground(uint16_t colour);
00082 
00083     /** set the background color
00084     * @note this method may be overridden in a derived class.
00085     * @param color is color to use for background drawing.
00086     */
00087     virtual void background(uint16_t colour);
00088 
00089     // putc (from Stream)
00090     // printf (from Stream)
00091     
00092 protected:
00093 
00094     virtual int _putc(int value);
00095     virtual int _getc();
00096 
00097     // character location
00098     int _column;
00099     int _row;
00100 
00101     // colours
00102     volatile uint16_t _foreground;
00103     volatile uint16_t _background;
00104     char *_path;
00105 };
00106 
00107 #endif