Diff: TextDisplay.h

Revision:

19:3f82c1161fd2

Parent:

0:de9d1462a835

Child:

29:422616aa04bd

--- a/TextDisplay.h	Tue Oct 22 20:17:29 2013 +0000
+++ b/TextDisplay.h	Sun Jan 12 17:40:32 2014 +0000
@@ -9,7 +9,7 @@
  * Everything else (locate, printf, putc, cls) will come for free
  *
  * The model is the display will wrap at the right and bottom, so you can
- * keep writing and will always get valid characters. The location is 
+ * keep writing and will always get valid characters. The location is
  * maintained internally to the class to make this easy
  */
 
@@ -18,14 +18,24 @@
 
 #include "mbed.h"
 
-class TextDisplay : public Stream {
+typedef uint16_t color_t;
+
+/// return values from functions
+typedef enum
+{
+    noerror,
+    bad_parameter
+} RetCode_t;
+
+class TextDisplay : public Stream
+{
 public:
 
-  // functions needing implementation in derived implementation class
-  /** Create a TextDisplay interface
-     *
-     * @param name The name used in the path to access the strean through the filesystem
-     */
+    // functions needing implementation in derived implementation class
+    /** Create a TextDisplay interface
+    *
+    * @param name The name used in the path to access the strean through the filesystem
+    */
     TextDisplay(const char *name = NULL);
 
     /** output a character at the given position
@@ -45,7 +55,7 @@
     * @result number of rows
     */
     virtual int columns() = 0;
-    
+
     // functions that come for free, but can be overwritten
 
     /** redirect output from a stream (stoud, sterr) to  display
@@ -55,15 +65,14 @@
 
     /** clear screen
     */
-    virtual void cls();
-    virtual void locate(int column, int row);
-    virtual void foreground(uint16_t colour);
-    virtual void background(uint16_t colour);
+    virtual RetCode_t cls();
+    virtual RetCode_t locate(unsigned int column, unsigned int row) = 0;
+    virtual RetCode_t foreground(uint16_t colour) = 0;
+    virtual RetCode_t background(uint16_t colour) = 0;
     // putc (from Stream)
     // printf (from Stream)
-    
-protected:
 
+protected:    
     virtual int _putc(int value);
     virtual int _getc();