Make canvas buffers protected instead of private members

A use case came up where it was helpful to be able to alter the buffer pointer in a subclass. This is esoteric and should be used with care.

Adafruit_GFX.h

@@ -328,10 +328,9 @@ class GFXcanvas1 : public Adafruit_GFX {
   bool getRawPixel(int16_t x, int16_t y) const;
   void drawFastRawVLine(int16_t x, int16_t y, int16_t h, uint16_t color);
   void drawFastRawHLine(int16_t x, int16_t y, int16_t w, uint16_t color);
+  uint8_t *buffer; // protected (no longer private) for subclass flexibility
 
 private:
-  uint8_t *buffer;
-
 #ifdef __AVR__
   // Bitmask tables of 0x80>>X and ~(0x80>>X), because X>>Y is slow on AVR
   static const uint8_t PROGMEM GFXsetBit[], GFXclrBit[];
@@ -360,9 +359,7 @@ class GFXcanvas8 : public Adafruit_GFX {
   uint8_t getRawPixel(int16_t x, int16_t y) const;
   void drawFastRawVLine(int16_t x, int16_t y, int16_t h, uint16_t color);
   void drawFastRawHLine(int16_t x, int16_t y, int16_t w, uint16_t color);
-
-private:
-  uint8_t *buffer;
+  uint8_t *buffer; // protected (no longer private) for subclass flexibility
 };
 
 ///  A GFX 16-bit canvas context for graphics
@@ -388,9 +385,7 @@ class GFXcanvas16 : public Adafruit_GFX {
   uint16_t getRawPixel(int16_t x, int16_t y) const;
   void drawFastRawVLine(int16_t x, int16_t y, int16_t h, uint16_t color);
   void drawFastRawHLine(int16_t x, int16_t y, int16_t w, uint16_t color);
-
-private:
-  uint16_t *buffer;
+  uint16_t *buffer; // protected (no longer private) for subclass flexibility
 };
 
 #endif // _ADAFRUIT_GFX_H

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit GFX Library
-version=1.11.3
+version=1.11.4
 author=Adafruit
 maintainer=Adafruit <[email protected]>
 sentence=Adafruit GFX graphics core library, this is the 'core' class that all our other graphics libraries derive from.