diff --git a/PDQ_MinLib/PDQ_GFX.h b/PDQ_MinLib/PDQ_GFX.h
index f2a551e..abc5735 100644
--- a/PDQ_MinLib/PDQ_GFX.h
+++ b/PDQ_MinLib/PDQ_GFX.h
@@ -158,7 +158,7 @@ public:
 	static inline uint8_t getRotation() __attribute__ ((always_inline))		{ return rotation; }
 	static inline coord_t getCursorX() __attribute__ ((always_inline))		{ return cursor_x; }
 	static inline coord_t getCursorY() __attribute__ ((always_inline))		{ return cursor_y; }
-	static inline void getTextBounds(char *string, coord_t x, coord_t y, int16_t *x1, int16_t *y1, uint16_t *w, uint16_t *h, coord_t wi = _width);
+	static inline void getTextBounds(const char *string, coord_t x, coord_t y, int16_t *x1, int16_t *y1, uint16_t *w, uint16_t *h, coord_t wi = _width);
 	static inline void getTextBounds(const __FlashStringHelper *s, coord_t x, coord_t y, int16_t *x1, int16_t *y1, uint16_t *w, uint16_t *h, coord_t wi = _width);
 
 	virtual size_t write(uint8_t);		// used by Arduino "Print.h" (and the one required virtual function)
@@ -1061,7 +1061,7 @@ void PDQ_GFX<HW>::setFont(const GFXfont *f)
 
 // Pass string and a cursor position, returns UL corner and W,H.
 template<class HW>
-void PDQ_GFX<HW>::getTextBounds(char *str, coord_t x, coord_t y, int16_t *x1, int16_t *y1, uint16_t *w, uint16_t *h, coord_t wi)
+void PDQ_GFX<HW>::getTextBounds(const char *str, coord_t x, coord_t y, int16_t *x1, int16_t *y1, uint16_t *w, uint16_t *h, coord_t wi)
 {
 	uint8_t c; // Current character
 
diff --git a/nano_gui.cpp b/nano_gui.cpp
index 92336d1..e6590bb 100644
--- a/nano_gui.cpp
+++ b/nano_gui.cpp
@@ -64,14 +64,14 @@ void displayChar(int16_t x, int16_t y, unsigned char c, uint16_t color, uint16_t
   tft.drawCharGFX(x,y,c,color,bg,1);
 }
 
-void displayRawText(char *text, int x1, int y1, int w, int color, int background){
+void displayRawText(const char *text, int x1, int y1, int w, int color, int background){
   tft.setTextColor(color,background);
   tft.setCursor(x1,y1);
   tft.setBound(x1,x1+w);
   tft.print(text);
 }
 
-void displayText(char *text, int x1, int y1, int w, int h, int color, int background, int border, TextJustification_e justification)
+void displayText(const char *const text, int x1, int y1, int w, int h, int color, int background, int border, TextJustification_e justification)
 {
   displayFillrect(x1, y1, w ,h, background);
   displayRect(x1, y1, w ,h, border);
diff --git a/nano_gui.h b/nano_gui.h
index e35145d..71b2d51 100644
--- a/nano_gui.h
+++ b/nano_gui.h
@@ -16,7 +16,7 @@ void displayVline(unsigned int x, unsigned int y, unsigned int l, unsigned int c
 void displayRect(unsigned int x,unsigned int y,unsigned int w,unsigned int h,unsigned int c);
 void displayFillrect(unsigned int x,unsigned int y,unsigned int w,unsigned int h,unsigned int c);
 void displayChar(int16_t x, int16_t y, unsigned char c, uint16_t color, uint16_t bg);
-void displayText(char *text, int x1, int y1, int w, int h, int color, int background, int border, TextJustification_e justification = TextJustification_e::Center);
+void displayText(const char *const text, int x1, int y1, int w, int h, int color, int background, int border, TextJustification_e justification = TextJustification_e::Center);
 
 #define TEXT_LINE_HEIGHT 18
 #define TEXT_LINE_INDENT 5