Juergen M / RGB_OLED_SSD1331 Featured

Driver for the Seeedstudio RGB OLED module for the xadow M0

Files at this revision

API Documentation at this revision

Revision 10:ef7440718431, committed 2015-11-17

Comitter:
messi1
Date:
Tue Nov 17 21:20:37 2015 +0000
Parent:
9:5a7bf0ce8518
Child:
11:162aa3e801df
Commit message:
Improved the drawString function; Add setFont function

Changed in this revision

include/SGL.h Show annotated file Show diff for this revision Revisions of this file
include/SSD1331.h Show annotated file Show diff for this revision Revisions of this file
include/SimpleFont.h Show annotated file Show diff for this revision Revisions of this file
src/SGL.cpp Show annotated file Show diff for this revision Revisions of this file
src/SSD1331.cpp Show annotated file Show diff for this revision Revisions of this file 
--- a/include/SGL.h	Tue Nov 17 19:45:22 2015 +0000
+++ b/include/SGL.h	Tue Nov 17 21:20:37 2015 +0000
@@ -40,105 +40,7 @@
 #define MIN(a,b) (((a)<(b))?(a):(b))
 #define MAX(a,b) (((a)>(b))?(a):(b))
 
-const unsigned char simpleFont[][8] =
-{
-  {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
-  {0x00,0x00,0x5F,0x00,0x00,0x00,0x00,0x00},
-  {0x00,0x00,0x07,0x00,0x07,0x00,0x00,0x00},
-  {0x00,0x14,0x7F,0x14,0x7F,0x14,0x00,0x00},
-  {0x00,0x24,0x2A,0x7F,0x2A,0x12,0x00,0x00},
-  {0x00,0x23,0x13,0x08,0x64,0x62,0x00,0x00},
-  {0x00,0x36,0x49,0x55,0x22,0x50,0x00,0x00},
-  {0x00,0x00,0x05,0x03,0x00,0x00,0x00,0x00},
-  {0x00,0x1C,0x22,0x41,0x00,0x00,0x00,0x00},
-  {0x00,0x41,0x22,0x1C,0x00,0x00,0x00,0x00},
-  {0x00,0x08,0x2A,0x1C,0x2A,0x08,0x00,0x00},
-  {0x00,0x08,0x08,0x3E,0x08,0x08,0x00,0x00},
-  {0x00,0xA0,0x60,0x00,0x00,0x00,0x00,0x00},
-  {0x00,0x08,0x08,0x08,0x08,0x08,0x00,0x00},
-  {0x00,0x60,0x60,0x00,0x00,0x00,0x00,0x00},
-  {0x00,0x20,0x10,0x08,0x04,0x02,0x00,0x00},
-  {0x00,0x3E,0x51,0x49,0x45,0x3E,0x00,0x00},
-  {0x00,0x00,0x42,0x7F,0x40,0x00,0x00,0x00},
-  {0x00,0x62,0x51,0x49,0x49,0x46,0x00,0x00},
-  {0x00,0x22,0x41,0x49,0x49,0x36,0x00,0x00},
-  {0x00,0x18,0x14,0x12,0x7F,0x10,0x00,0x00},
-  {0x00,0x27,0x45,0x45,0x45,0x39,0x00,0x00},
-  {0x00,0x3C,0x4A,0x49,0x49,0x30,0x00,0x00},
-  {0x00,0x01,0x71,0x09,0x05,0x03,0x00,0x00},
-  {0x00,0x36,0x49,0x49,0x49,0x36,0x00,0x00},
-  {0x00,0x06,0x49,0x49,0x29,0x1E,0x00,0x00},
-  {0x00,0x00,0x36,0x36,0x00,0x00,0x00,0x00},
-  {0x00,0x00,0xAC,0x6C,0x00,0x00,0x00,0x00},
-  {0x00,0x08,0x14,0x22,0x41,0x00,0x00,0x00},
-  {0x00,0x14,0x14,0x14,0x14,0x14,0x00,0x00},
-  {0x00,0x41,0x22,0x14,0x08,0x00,0x00,0x00},
-  {0x00,0x02,0x01,0x51,0x09,0x06,0x00,0x00},
-  {0x00,0x32,0x49,0x79,0x41,0x3E,0x00,0x00},
-  {0x00,0x7E,0x09,0x09,0x09,0x7E,0x00,0x00},
-  {0x00,0x7F,0x49,0x49,0x49,0x36,0x00,0x00},
-  {0x00,0x3E,0x41,0x41,0x41,0x22,0x00,0x00},
-  {0x00,0x7F,0x41,0x41,0x22,0x1C,0x00,0x00},
-  {0x00,0x7F,0x49,0x49,0x49,0x41,0x00,0x00},
-  {0x00,0x7F,0x09,0x09,0x09,0x01,0x00,0x00},
-  {0x00,0x3E,0x41,0x41,0x51,0x72,0x00,0x00},
-  {0x00,0x7F,0x08,0x08,0x08,0x7F,0x00,0x00},
-  {0x00,0x41,0x7F,0x41,0x00,0x00,0x00,0x00},
-  {0x00,0x20,0x40,0x41,0x3F,0x01,0x00,0x00},
-  {0x00,0x7F,0x08,0x14,0x22,0x41,0x00,0x00},
-  {0x00,0x7F,0x40,0x40,0x40,0x40,0x00,0x00},
-  {0x00,0x7F,0x02,0x0C,0x02,0x7F,0x00,0x00},
-  {0x00,0x7F,0x04,0x08,0x10,0x7F,0x00,0x00},
-  {0x00,0x3E,0x41,0x41,0x41,0x3E,0x00,0x00},
-  {0x00,0x7F,0x09,0x09,0x09,0x06,0x00,0x00},
-  {0x00,0x3E,0x41,0x51,0x21,0x5E,0x00,0x00},
-  {0x00,0x7F,0x09,0x19,0x29,0x46,0x00,0x00},
-  {0x00,0x26,0x49,0x49,0x49,0x32,0x00,0x00},
-  {0x00,0x01,0x01,0x7F,0x01,0x01,0x00,0x00},
-  {0x00,0x3F,0x40,0x40,0x40,0x3F,0x00,0x00},
-  {0x00,0x1F,0x20,0x40,0x20,0x1F,0x00,0x00},
-  {0x00,0x3F,0x40,0x38,0x40,0x3F,0x00,0x00},
-  {0x00,0x63,0x14,0x08,0x14,0x63,0x00,0x00},
-  {0x00,0x03,0x04,0x78,0x04,0x03,0x00,0x00},
-  {0x00,0x61,0x51,0x49,0x45,0x43,0x00,0x00},
-  {0x00,0x7F,0x41,0x41,0x00,0x00,0x00,0x00},
-  {0x00,0x02,0x04,0x08,0x10,0x20,0x00,0x00},
-  {0x00,0x41,0x41,0x7F,0x00,0x00,0x00,0x00},
-  {0x00,0x04,0x02,0x01,0x02,0x04,0x00,0x00},
-  {0x00,0x80,0x80,0x80,0x80,0x80,0x00,0x00},
-  {0x00,0x01,0x02,0x04,0x00,0x00,0x00,0x00},
-  {0x00,0x20,0x54,0x54,0x54,0x78,0x00,0x00},
-  {0x00,0x7F,0x48,0x44,0x44,0x38,0x00,0x00},
-  {0x00,0x38,0x44,0x44,0x28,0x00,0x00,0x00},
-  {0x00,0x38,0x44,0x44,0x48,0x7F,0x00,0x00},
-  {0x00,0x38,0x54,0x54,0x54,0x18,0x00,0x00},
-  {0x00,0x08,0x7E,0x09,0x02,0x00,0x00,0x00},
-  {0x00,0x18,0xA4,0xA4,0xA4,0x7C,0x00,0x00},
-  {0x00,0x7F,0x08,0x04,0x04,0x78,0x00,0x00},
-  {0x00,0x00,0x7D,0x00,0x00,0x00,0x00,0x00},
-  {0x00,0x80,0x84,0x7D,0x00,0x00,0x00,0x00},
-  {0x00,0x7F,0x10,0x28,0x44,0x00,0x00,0x00},
-  {0x00,0x41,0x7F,0x40,0x00,0x00,0x00,0x00},
-  {0x00,0x7C,0x04,0x18,0x04,0x78,0x00,0x00},
-  {0x00,0x7C,0x08,0x04,0x7C,0x00,0x00,0x00},
-  {0x00,0x38,0x44,0x44,0x38,0x00,0x00,0x00},
-  {0x00,0xFC,0x24,0x24,0x18,0x00,0x00,0x00},
-  {0x00,0x18,0x24,0x24,0xFC,0x00,0x00,0x00},
-  {0x00,0x00,0x7C,0x08,0x04,0x00,0x00,0x00},
-  {0x00,0x48,0x54,0x54,0x24,0x00,0x00,0x00},
-  {0x00,0x04,0x7F,0x44,0x00,0x00,0x00,0x00},
-  {0x00,0x3C,0x40,0x40,0x7C,0x00,0x00,0x00},
-  {0x00,0x1C,0x20,0x40,0x20,0x1C,0x00,0x00},
-  {0x00,0x3C,0x40,0x30,0x40,0x3C,0x00,0x00},
-  {0x00,0x44,0x28,0x10,0x28,0x44,0x00,0x00},
-  {0x00,0x1C,0xA0,0xA0,0x7C,0x00,0x00,0x00},
-  {0x00,0x44,0x64,0x54,0x4C,0x44,0x00,0x00},
-  {0x00,0x08,0x36,0x41,0x00,0x00,0x00,0x00},
-  {0x00,0x00,0x7F,0x00,0x00,0x00,0x00,0x00},
-  {0x00,0x41,0x36,0x08,0x00,0x00,0x00,0x00},
-  {0x00,0x02,0x01,0x01,0x02,0x01,0x00,0x00},
-  {0x00,0x02,0x05,0x05,0x02,0x00,0x00,0x00} 
-};
+typedef const unsigned char** FontType;
 
 class SGL {
  
@@ -154,10 +56,14 @@
     virtual void fillCircle(uint8_t x, uint8_t y, uint8_t r, uint16_t color);
     virtual void drawTraingle(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint16_t color);
     virtual void fillTraingle(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint16_t color);    
-    virtual void drawChar(uint8_t ascii, uint8_t x, uint8_t y, uint8_t size, uint16_t color);
-    virtual void drawString(char *string, uint8_t x, uint8_t y, uint8_t size, uint16_t color);
+    
+    // The zoom factor works at the moment only with integer values. Float values will create bad fonts 
+    virtual void drawChar(uint8_t ascii, uint8_t x, uint8_t y, float zoom, uint16_t color);
+    virtual void drawString(const char *string, uint8_t x, uint8_t y, float zoom, uint16_t color, uint8_t fontSpace=6);
+    
     virtual void drawBitMap(uint8_t x, uint8_t y, const uint8_t *bitmap, uint8_t width, uint8_t height, uint16_t color);
     virtual void fillScreen(uint16_t color);
+    virtual void setFont(FontType font, uint8_t width, uint8_t height, uint8_t start, uint8_t stop);
     
 private:
     void swap(uint8_t* a, uint8_t* b){ 
@@ -166,6 +72,11 @@
     
     uint8_t _width;
     uint8_t _height;
+    FontType _currentFont;
+    uint8_t _fontWidth;
+    uint8_t _fontHeight;
+    uint8_t _fontStart;
+    uint8_t _fontStop;
 };
 
 #endif

--- a/include/SSD1331.h	Tue Nov 17 19:45:22 2015 +0000
+++ b/include/SSD1331.h	Tue Nov 17 21:20:37 2015 +0000
@@ -153,7 +153,7 @@
 };
 
 enum PowerMode{
-    PM_SleepMode       = 0xAE
+    PM_SleepMode       = 0xAE,
     PM_NormalMode      = 0xAF
 };
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/SimpleFont.h	Tue Nov 17 21:20:37 2015 +0000
@@ -0,0 +1,108 @@
+#ifndef SIMPLE_FONT_H
+#define SIMPLE_FONT_H
+
+#define FONT_SPACE 6
+#define FONT_X 8
+#define FONT_Y 8
+
+const unsigned char simpleFont[][8] =
+{
+  {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
+  {0x00,0x00,0x5F,0x00,0x00,0x00,0x00,0x00},
+  {0x00,0x00,0x07,0x00,0x07,0x00,0x00,0x00},
+  {0x00,0x14,0x7F,0x14,0x7F,0x14,0x00,0x00},
+  {0x00,0x24,0x2A,0x7F,0x2A,0x12,0x00,0x00},
+  {0x00,0x23,0x13,0x08,0x64,0x62,0x00,0x00},
+  {0x00,0x36,0x49,0x55,0x22,0x50,0x00,0x00},
+  {0x00,0x00,0x05,0x03,0x00,0x00,0x00,0x00},
+  {0x00,0x1C,0x22,0x41,0x00,0x00,0x00,0x00},
+  {0x00,0x41,0x22,0x1C,0x00,0x00,0x00,0x00},
+  {0x00,0x08,0x2A,0x1C,0x2A,0x08,0x00,0x00},
+  {0x00,0x08,0x08,0x3E,0x08,0x08,0x00,0x00},
+  {0x00,0xA0,0x60,0x00,0x00,0x00,0x00,0x00},
+  {0x00,0x08,0x08,0x08,0x08,0x08,0x00,0x00},
+  {0x00,0x60,0x60,0x00,0x00,0x00,0x00,0x00},
+  {0x00,0x20,0x10,0x08,0x04,0x02,0x00,0x00},
+  {0x00,0x3E,0x51,0x49,0x45,0x3E,0x00,0x00},
+  {0x00,0x00,0x42,0x7F,0x40,0x00,0x00,0x00},
+  {0x00,0x62,0x51,0x49,0x49,0x46,0x00,0x00},
+  {0x00,0x22,0x41,0x49,0x49,0x36,0x00,0x00},
+  {0x00,0x18,0x14,0x12,0x7F,0x10,0x00,0x00},
+  {0x00,0x27,0x45,0x45,0x45,0x39,0x00,0x00},
+  {0x00,0x3C,0x4A,0x49,0x49,0x30,0x00,0x00},
+  {0x00,0x01,0x71,0x09,0x05,0x03,0x00,0x00},
+  {0x00,0x36,0x49,0x49,0x49,0x36,0x00,0x00},
+  {0x00,0x06,0x49,0x49,0x29,0x1E,0x00,0x00},
+  {0x00,0x00,0x36,0x36,0x00,0x00,0x00,0x00},
+  {0x00,0x00,0xAC,0x6C,0x00,0x00,0x00,0x00},
+  {0x00,0x08,0x14,0x22,0x41,0x00,0x00,0x00},
+  {0x00,0x14,0x14,0x14,0x14,0x14,0x00,0x00},
+  {0x00,0x41,0x22,0x14,0x08,0x00,0x00,0x00},
+  {0x00,0x02,0x01,0x51,0x09,0x06,0x00,0x00},
+  {0x00,0x32,0x49,0x79,0x41,0x3E,0x00,0x00},
+  {0x00,0x7E,0x09,0x09,0x09,0x7E,0x00,0x00},
+  {0x00,0x7F,0x49,0x49,0x49,0x36,0x00,0x00},
+  {0x00,0x3E,0x41,0x41,0x41,0x22,0x00,0x00},
+  {0x00,0x7F,0x41,0x41,0x22,0x1C,0x00,0x00},
+  {0x00,0x7F,0x49,0x49,0x49,0x41,0x00,0x00},
+  {0x00,0x7F,0x09,0x09,0x09,0x01,0x00,0x00},
+  {0x00,0x3E,0x41,0x41,0x51,0x72,0x00,0x00},
+  {0x00,0x7F,0x08,0x08,0x08,0x7F,0x00,0x00},
+  {0x00,0x41,0x7F,0x41,0x00,0x00,0x00,0x00},
+  {0x00,0x20,0x40,0x41,0x3F,0x01,0x00,0x00},
+  {0x00,0x7F,0x08,0x14,0x22,0x41,0x00,0x00},
+  {0x00,0x7F,0x40,0x40,0x40,0x40,0x00,0x00},
+  {0x00,0x7F,0x02,0x0C,0x02,0x7F,0x00,0x00},
+  {0x00,0x7F,0x04,0x08,0x10,0x7F,0x00,0x00},
+  {0x00,0x3E,0x41,0x41,0x41,0x3E,0x00,0x00},
+  {0x00,0x7F,0x09,0x09,0x09,0x06,0x00,0x00},
+  {0x00,0x3E,0x41,0x51,0x21,0x5E,0x00,0x00},
+  {0x00,0x7F,0x09,0x19,0x29,0x46,0x00,0x00},
+  {0x00,0x26,0x49,0x49,0x49,0x32,0x00,0x00},
+  {0x00,0x01,0x01,0x7F,0x01,0x01,0x00,0x00},
+  {0x00,0x3F,0x40,0x40,0x40,0x3F,0x00,0x00},
+  {0x00,0x1F,0x20,0x40,0x20,0x1F,0x00,0x00},
+  {0x00,0x3F,0x40,0x38,0x40,0x3F,0x00,0x00},
+  {0x00,0x63,0x14,0x08,0x14,0x63,0x00,0x00},
+  {0x00,0x03,0x04,0x78,0x04,0x03,0x00,0x00},
+  {0x00,0x61,0x51,0x49,0x45,0x43,0x00,0x00},
+  {0x00,0x7F,0x41,0x41,0x00,0x00,0x00,0x00},
+  {0x00,0x02,0x04,0x08,0x10,0x20,0x00,0x00},
+  {0x00,0x41,0x41,0x7F,0x00,0x00,0x00,0x00},
+  {0x00,0x04,0x02,0x01,0x02,0x04,0x00,0x00},
+  {0x00,0x80,0x80,0x80,0x80,0x80,0x00,0x00},
+  {0x00,0x01,0x02,0x04,0x00,0x00,0x00,0x00},
+  {0x00,0x20,0x54,0x54,0x54,0x78,0x00,0x00},
+  {0x00,0x7F,0x48,0x44,0x44,0x38,0x00,0x00},
+  {0x00,0x38,0x44,0x44,0x28,0x00,0x00,0x00},
+  {0x00,0x38,0x44,0x44,0x48,0x7F,0x00,0x00},
+  {0x00,0x38,0x54,0x54,0x54,0x18,0x00,0x00},
+  {0x00,0x08,0x7E,0x09,0x02,0x00,0x00,0x00},
+  {0x00,0x18,0xA4,0xA4,0xA4,0x7C,0x00,0x00},
+  {0x00,0x7F,0x08,0x04,0x04,0x78,0x00,0x00},
+  {0x00,0x00,0x7D,0x00,0x00,0x00,0x00,0x00},
+  {0x00,0x80,0x84,0x7D,0x00,0x00,0x00,0x00},
+  {0x00,0x7F,0x10,0x28,0x44,0x00,0x00,0x00},
+  {0x00,0x41,0x7F,0x40,0x00,0x00,0x00,0x00},
+  {0x00,0x7C,0x04,0x18,0x04,0x78,0x00,0x00},
+  {0x00,0x7C,0x08,0x04,0x7C,0x00,0x00,0x00},
+  {0x00,0x38,0x44,0x44,0x38,0x00,0x00,0x00},
+  {0x00,0xFC,0x24,0x24,0x18,0x00,0x00,0x00},
+  {0x00,0x18,0x24,0x24,0xFC,0x00,0x00,0x00},
+  {0x00,0x00,0x7C,0x08,0x04,0x00,0x00,0x00},
+  {0x00,0x48,0x54,0x54,0x24,0x00,0x00,0x00},
+  {0x00,0x04,0x7F,0x44,0x00,0x00,0x00,0x00},
+  {0x00,0x3C,0x40,0x40,0x7C,0x00,0x00,0x00},
+  {0x00,0x1C,0x20,0x40,0x20,0x1C,0x00,0x00},
+  {0x00,0x3C,0x40,0x30,0x40,0x3C,0x00,0x00},
+  {0x00,0x44,0x28,0x10,0x28,0x44,0x00,0x00},
+  {0x00,0x1C,0xA0,0xA0,0x7C,0x00,0x00,0x00},
+  {0x00,0x44,0x64,0x54,0x4C,0x44,0x00,0x00},
+  {0x00,0x08,0x36,0x41,0x00,0x00,0x00,0x00},
+  {0x00,0x00,0x7F,0x00,0x00,0x00,0x00,0x00},
+  {0x00,0x41,0x36,0x08,0x00,0x00,0x00,0x00},
+  {0x00,0x02,0x01,0x01,0x02,0x01,0x00,0x00},
+  {0x00,0x02,0x05,0x05,0x02,0x00,0x00,0x00} 
+};
+
+#endif // SIMPLE_FONT_h
\ No newline at end of file

--- a/src/SGL.cpp	Tue Nov 17 19:45:22 2015 +0000
+++ b/src/SGL.cpp	Tue Nov 17 21:20:37 2015 +0000
@@ -29,23 +29,28 @@
 */
 #include <stdlib.h>
 #include "SGL.h"
+#include "SimpleFont.h"
 
 //---------------------------------------------------------------------------------------
-SGL::SGL(uint8_t width, uint8_t height)
-{
-    _width  = width;
-    _height = height;
-}
+SGL::SGL(uint8_t width, uint8_t height):
+    _width(width), _height(height),
+    _currentFont(0),     
+    _fontWidth(0),
+    _fontHeight(0),
+    _fontStart(0),
+    _fontStop(0)
+{}
 
 //---------------------------------------------------------------------------------------
 void SGL::drawLine(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1, uint16_t color)
 {
     uint8_t x   = x1-x0;
     uint8_t y   = y1-y0;
-    uint8_t dx  = abs(x), sx = x0<x1 ? 1 : -1;
+    uint8_t dx  = abs(x),  sx = x0<x1 ? 1 : -1;
     uint8_t dy  = -abs(y), sy = y0<y1 ? 1 : -1;
     uint8_t err = dx+dy, e2;
-    for (;;){
+    for (;;)
+    {
         drawPixel(x0, y0,color);
         e2 = 2*err;
         if (e2 >= dy) {
@@ -63,7 +68,8 @@
 void SGL::drawVLine(uint8_t x, uint8_t y, uint8_t length,uint16_t color)
 {
     uint8_t y1 = MIN(y+length,_height-1);
-    for(uint8_t i = y; i < y1; ++i){
+    for(uint8_t i = y; i < y1; ++i)
+    {
         drawPixel(x, i, color);
     }
 }
@@ -72,7 +78,8 @@
 void SGL::drawHLine(uint8_t x, uint8_t y, uint8_t length, uint16_t color)
 {
     uint8_t x1 = MIN(x+length,_width-1);
-    for(uint8_t i = x; i < x1; ++i){
+    for(uint8_t i = x; i < x1; ++i)
+    {
         drawPixel(i, y, color);
     }
 }
@@ -89,8 +96,10 @@
 //---------------------------------------------------------------------------------------
 void SGL::fillRect(uint8_t x, uint8_t y, uint8_t width, uint8_t height, uint16_t color)
 {
-    for(uint8_t i = 0; i < height; ++i){
-        for(uint8_t j = 0; j < width; ++j){
+    for(uint8_t i = 0; i < height; ++i)
+    {
+        for(uint8_t j = 0; j < width; ++j)
+        {
             drawPixel( x+j, y+i, color);
         }
     }
@@ -100,13 +109,15 @@
 void SGL::drawCircle(uint8_t poX, uint8_t poY, uint8_t r, uint16_t color)
 {
     int x = -r, y = 0, err = 2-2*r, e2;
-    do{
+    do
+    {
         drawPixel(poX-x, poY+y,color);
         drawPixel(poX+x, poY+y,color);
         drawPixel(poX+x, poY-y,color);
         drawPixel(poX-x, poY-y,color);
         e2 = err;
-        if(e2 <= y) {
+        if(e2 <= y)
+        {
             err += ++y*2+1;
             if(-x == y && e2 <= x) e2 = 0;
         }
@@ -118,11 +129,13 @@
 void SGL::fillCircle(uint8_t poX, uint8_t poY, uint8_t r, uint16_t color)
 {
     int x = -r, y = 0, err = 2-2*r, e2;
-    do{
+    do
+    {
         drawVLine(poX-x, poY-y, 2*y, color);
         drawVLine(poX+x, poY-y, 2*y, color);
         e2 = err;
-        if(e2 <= y){
+        if(e2 <= y)
+        {
             err += ++y*2+1;
             if(-x == y && e2 <= x) e2 = 0;
         }
@@ -164,7 +177,8 @@
     else 
         last = y1-1;
 
-    for(y=y0; y<=last; ++y) {
+    for(y = y0; y <= last; ++y) 
+    {
         a = x0 + sa / dy01;
         b = x0 + sb / dy02;
         sa += dx01;
@@ -175,7 +189,8 @@
 
     sa = dx12 * (y - y1);
     sb = dx02 * (y - y0);
-    for(; y<=y2; ++y) {
+    for(; y<=y2; ++y)
+    {
         a = x1 + sa / dy12;
         b = x0 + sb / dy02;
         sa += dx12;
@@ -186,31 +201,41 @@
 }
 
 //---------------------------------------------------------------------------------------
-void SGL::drawChar(uint8_t ascii, uint8_t x, uint8_t y, uint8_t size, uint16_t color)
+void SGL::drawChar(uint8_t ascii, uint8_t x, uint8_t y, float zoom, uint16_t color)
 {
-    if((ascii<32)||(ascii>=127)){
+    if(!_currentFont && !*_currentFont)
+        return;
+        
+    if((ascii < _fontStart)||(ascii > _fontStop)){
         return;
     }
 
-    for (uint8_t i = 0; i < FONT_X; ++i ) {
-        uint8_t temp = simpleFont[ascii-0x20][i];
-        uint8_t inrun = 0;
+    for(uint8_t i = 0; i < _fontWidth; ++i )
+    {
+        uint8_t temp   = simpleFont[ascii-0x20][i];
+        uint8_t inrun  = 0;
         uint8_t runlen = 0;
         uint8_t endrun = 0;
 
-        for(uint8_t f = 0; f < FONT_Y; f++){
-            if((temp>>f)&0x01){
+        for(uint8_t f = 0; f < _fontHeight; ++f)
+        {
+            if((temp>>f)&0x01)
+            {
                 if (inrun) runlen += 1;
-                else {
-                    inrun = 1;
+                else 
+                {
+                    inrun  = 1;
                     runlen = 1;
                 }
-            } else if (inrun) {
+            }
+            else if (inrun) 
+            {
                 endrun = 1;
-                inrun = 0;
+                inrun  = 0;
             }
 
-            if (f == FONT_Y - 1 && inrun) {
+            if (f == _fontHeight - 1 && inrun) 
+            {
                 endrun = 1;
                 // need the +1 b/c we this code is normally
                 // only triggered  when f == FONT_Y, due to the
@@ -218,8 +243,9 @@
                 f += 1;
             }
             
-            if (endrun) {
-                fillRect(x+i*size, y+(f-runlen)*size, size, runlen*size, color);
+            if (endrun) 
+            {
+                fillRect(x+i*zoom, y+(f-runlen)*zoom, zoom, runlen*zoom, color);
                 inrun = 0;
                 runlen = 0;
                 endrun = 0;
@@ -229,14 +255,19 @@
 }
 
 //---------------------------------------------------------------------------------------
-void SGL::drawString(char *string, uint8_t x, uint8_t y, uint8_t size, uint16_t color)
+void SGL::drawString(const char *string, uint8_t x, uint8_t y, float zoom, uint16_t color, uint8_t fontSpace)
 {
-    while(*string){
-        drawChar(*string, x, y, size, color);
+    if(!_currentFont && !*_currentFont)
+        return;
+        
+    while(*string)
+    {
+        drawChar(*string, x, y, zoom, color);
         *string++;
-        x += FONT_SPACE*size;
-        if(x >= _width-1){
-            y += FONT_Y*size;
+        x += fontSpace*zoom;
+        if(x >= _width-1)
+        {
+            y += _fontHeight*zoom;
             x = 0;
         }
     }
@@ -263,4 +294,17 @@
 void SGL::fillScreen(uint16_t color)
 {
     fillRect(0, 0, _width, _height, color);
+}
+
+//---------------------------------------------------------------------------------------
+void SGL::setFont(FontType font, uint8_t width, uint8_t height, uint8_t start, uint8_t stop)
+{
+    if(!font && !*font)
+        return;
+    
+    _currentFont= font;
+    _fontWidth  = width;
+    _fontHeight = height;
+    _fontStart  = start;
+    _fontStop   = stop;    
 }
\ No newline at end of file

--- a/src/SSD1331.cpp	Tue Nov 17 19:45:22 2015 +0000
+++ b/src/SSD1331.cpp	Tue Nov 17 21:20:37 2015 +0000
@@ -62,7 +62,10 @@
 #include "wait_api.h"
 
 SSD1331::SSD1331(PinName cs, PinName rst, PinName dc, PinName mosi, PinName miso, PinName sclk)
-:SGL(RGB_OLED_WIDTH, RGB_OLED_HEIGHT), _cs(cs), _dc(dc), _spiPort(mosi, miso, sclk)
+    :SGL(RGB_OLED_WIDTH, RGB_OLED_HEIGHT), 
+    _cs(cs), 
+    _dc(dc),
+    _spiPort(mosi, miso, sclk)
 {
     _spiPort.format(8,3); //8bit frame and POL=1 /PHA=1(UpEdge Sampled)
     _spiPort.frequency(25000000); // modify later