From ea4af865f11cd18ac1b3d33fb9951f7527a42ab7 Mon Sep 17 00:00:00 2001
From: inmarket <andrewh@inmarket.com.au>
Date: Mon, 14 Oct 2013 08:55:15 +1000
Subject: [PATCH] Compile time fix to text rendering. Updated gdisp Get/Set
 Display routines to a more logical API.

---
 include/gdisp/gdisp.h | 24 ++++++++++++++++++++----
 src/gdisp/gdisp.c     | 27 ++++++++++++++++++---------
 2 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/include/gdisp/gdisp.h b/include/gdisp/gdisp.h
index 7f0f8012..0c8310bb 100644
--- a/include/gdisp/gdisp.h
+++ b/include/gdisp/gdisp.h
@@ -366,16 +366,32 @@ extern "C" {
 color_t gdispBlendColor(color_t fg, color_t bg, uint8_t alpha);
 
 /**
- * @brief   Set the current default display to the specified display
- * @note	The default display is used for the gdispXxxx functions.
+ * @brief   Get the specified display
+ * @return	The pointer to the display or NULL if the display doesn't exist
+ * @note	The GDISP variable contains the display used by the gdispXxxx routines
+ * 			as opposed to the gdispGXxxx routines which take an explicit display
+ * 			parameter.
  * @note	Displays are numbered from 0 to GDISP_TOTAL_DISPLAYS - 1
- * @note	If an invalid display number is specified the request is ignored.
  *
  * @param[in] display	The display number (0..n)
  *
  * @api
  */
-void gdispSetDisplay(unsigned display);
+GDisplay *gdispGetDisplay(unsigned display);
+
+/**
+ * @brief   Set the current default display to the specified display
+ * @note	The default display is used for the gdispXxxx functions.
+ * @note	The default display is contained in the variable GDISP. Using
+ * 			this function to set it protects against it being set to a NULL
+ * 			value.
+ * @note	If a NULL is passed for the dispay this call is ignored.
+ *
+ * @param[in] display	The display number (0..n)
+ *
+ * @api
+ */
+void gdispSetDisplay(GDisplay *g);
 
 /* Drawing Functions */
 
diff --git a/src/gdisp/gdisp.c b/src/gdisp/gdisp.c
index 41f2f0f9..ca0411e3 100644
--- a/src/gdisp/gdisp.c
+++ b/src/gdisp/gdisp.c
@@ -448,9 +448,14 @@ void _gdispInit(void) {
 	#endif
 }
 
-void gdispSetDisplay(unsigned display) {
-	if (display < GDISP_TOTAL_DISPLAYS)
-		GDISP = &GDisplayArray[display];
+GDisplay *gdispGetDisplay(unsigned display) {
+	if (display >= GDISP_TOTAL_DISPLAYS)
+		return 0;
+	return &GDisplayArray[display];
+}
+
+void gdispSetDisplay(GDisplay *g) {
+	if (g) GDISP = g;
 }
 
 #if GDISP_NEED_STREAMING
@@ -2106,12 +2111,12 @@ void gdispGDrawBox(GDisplay *g, coord_t x, coord_t y, coord_t cx, coord_t cy, co
 			if (y < GD->t.clipy0 || y >= GD->t.clipy1 || x < GD->t.clipx0 || x+count > GD->t.clipx1) return;
 			if (alpha == 255) {
 				GD->p.x = x; GD->p.y = y; GD->p.x1 = x+count-1; GD->p.color = GD->t.color;
-				hline_clip(g);
+				hline_clip(GD);
 			} else {
 				for (; count; count--, x++) {
 					GD->p.x = x; GD->p.y = y;
 					GD->p.color = gdispBlendColor(GD->t.color, gdisp_lld_get_pixel_color(GD), alpha);
-					drawpixel_clip(g);
+					drawpixel_clip(GD);
 				}
 			}
 			#undef GD
@@ -2122,7 +2127,7 @@ void gdispGDrawBox(GDisplay *g, coord_t x, coord_t y, coord_t cx, coord_t cy, co
 			if (y < GD->t.clipy0 || y >= GD->t.clipy1 || x < GD->t.clipx0 || x+count > GD->t.clipx1) return;
 			if (alpha > 0x80) {			// A best approximation when using anti-aliased fonts but we can't actually draw them anti-aliased
 				GD->p.x = x; GD->p.y = y; GD->p.x1 = x+count-1; GD->p.color = GD->t.color;
-				hline_clip(g);
+				hline_clip(GD);
 			}
 			#undef GD
 		}
@@ -2138,7 +2143,7 @@ void gdispGDrawBox(GDisplay *g, coord_t x, coord_t y, coord_t cx, coord_t cy, co
 				GD->p.color = gdispBlendColor(GD->t.color, GD->t.bgcolor, alpha);
 			}
 			GD->p.x = x; GD->p.y = y; GD->p.x1 = x+count-1;
-			hline_clip(g);
+			hline_clip(GD);
 			#undef GD
 		}
 	#else
@@ -2147,12 +2152,16 @@ void gdispGDrawBox(GDisplay *g, coord_t x, coord_t y, coord_t cx, coord_t cy, co
 
 	/* Callback to render characters. */
 	static uint8_t drawcharglyph(int16_t x, int16_t y, mf_char ch, void *state) {
-		return mf_render_character(g->t.font, x, y, ch, drawcharline, state);
+		#define GD	((GDisplay *)state)
+			return mf_render_character(GD->t.font, x, y, ch, drawcharline, state);
+		#undef GD
 	}
 
 	/* Callback to render characters. */
 	static uint8_t fillcharglyph(int16_t x, int16_t y, mf_char ch, void *state) {
-		return mf_render_character(g->t.font, x, y, ch, fillcharline, state);
+		#define GD	((GDisplay *)state)
+			return mf_render_character(GD->t.font, x, y, ch, fillcharline, state);
+		#undef GD
 	}
 
 	void gdispGDrawChar(GDisplay *g, coord_t x, coord_t y, uint16_t c, font_t font, color_t color) {