Partially handle screen rotation using remapping

Use row and column remapping to change either row or column addressing
for each orientation.  This removes the need to reverse the drawing
direction of either x or y in the drawing routines.  However in the 90
and 270 case x and y must still be swapped.

Also, rename the SSD1306 remapping command names so they are more
descriptive.

2 files changed, 45 insertions, 48 deletions

diff --git a/drivers/gdisp/SSD1306/SSD1306.h b/drivers/gdisp/SSD1306/SSD1306.h
index d1c59fe4..7d7010e8 100644
--- a/drivers/gdisp/SSD1306/SSD1306.h
+++ b/drivers/gdisp/SSD1306/SSD1306.h
@@ -33,10 +33,11 @@
 #define SSD1306_HV_PAGE_ADDRESS			0x22

 #define SSD1306_PAM_PAGE_START			0xB0

 

-#define SSD1306_COMSCANINC 				0xC0

-#define SSD1306_COMSCANDEC 				0xC8

+#define SSD1306_ROWSCANINC 				0xC0

+#define SSD1306_ROWSCANDEC 				0xC8

 

-#define SSD1306_SEGREMAP 				0xA0

+#define SSD1306_COLSCANINC 				0xA0

+#define SSD1306_COLSCANDEC 				0xA1

 

 #define SSD1306_CHARGEPUMP 				0x8D

 

diff --git a/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c b/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c
index 2386c2d4..713c52bb 100644
--- a/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c
+++ b/drivers/gdisp/SSD1306/gdisp_lld_SSD1306.c
@@ -105,8 +105,8 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 	write_cmd(g, SSD1306_SETSTARTLINE | 0);
 	write_cmd2(g, SSD1306_ENABLE_CHARGE_PUMP, 0x14);
 	write_cmd2(g, SSD1306_MEMORYMODE, 0);
-	write_cmd(g, SSD1306_SEGREMAP+1);
-	write_cmd(g, SSD1306_COMSCANDEC);
+	write_cmd(g, SSD1306_COLSCANDEC);
+	write_cmd(g, SSD1306_ROWSCANDEC);
 	#if GDISP_SCREEN_HEIGHT == 64
 		write_cmd2(g, SSD1306_SETCOMPINS, 0x12);
 	#else
@@ -168,26 +168,11 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 
 #if GDISP_HARDWARE_DRAWPIXEL
 	LLDSPEC void gdisp_lld_draw_pixel(GDisplay *g) {
-		coord_t		x, y;
-
-		switch(g->g.Orientation) {
-		default:
-		case GDISP_ROTATE_0:
-			x = g->p.x;
-			y = g->p.y;
-			break;
-		case GDISP_ROTATE_90:
-			x = g->p.y;
-			y = GDISP_SCREEN_HEIGHT-1 - g->p.x;
-			break;
-		case GDISP_ROTATE_180:
-			x = GDISP_SCREEN_WIDTH-1 - g->p.x;
-			y = GDISP_SCREEN_HEIGHT-1 - g->p.y;
-			break;
-		case GDISP_ROTATE_270:
-			x = GDISP_SCREEN_WIDTH-1 - g->p.y;
-			y = g->p.x;
-			break;
+		coord_t x = g->p.x;
+		coord_t y = g->p.y;
+		if (g->g.Orientation == GDISP_ROTATE_90 || g->g.Orientation == GDISP_ROTATE_270) {
+			coord_t tmp; 
+			tmp = x; x = y; y = tmp;
 		}
 		if (gdispColor2Native(g->p.color) != Black)
 			RAM(g)[xyaddr(x, y)] |= xybit(y);
@@ -199,26 +184,11 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 
 #if GDISP_HARDWARE_PIXELREAD
 	LLDSPEC color_t gdisp_lld_get_pixel_color(GDisplay *g) {
-		coord_t		x, y;
-
-		switch(g->g.Orientation) {
-		default:
-		case GDISP_ROTATE_0:
-			x = g->p.x;
-			y = g->p.y;
-			break;
-		case GDISP_ROTATE_90:
-			x = g->p.y;
-			y = GDISP_SCREEN_HEIGHT-1 - g->p.x;
-			break;
-		case GDISP_ROTATE_180:
-			x = GDISP_SCREEN_WIDTH-1 - g->p.x;
-			y = GDISP_SCREEN_HEIGHT-1 - g->p.y;
-			break;
-		case GDISP_ROTATE_270:
-			x = GDISP_SCREEN_WIDTH-1 - g->p.y;
-			y = g->p.x;
-			break;
+		coord_t x = g->p.x;
+		coord_t y = g->p.y;
+		if (g->g.Orientation == GDISP_ROTATE_90 || g->g.Orientation == GDISP_ROTATE_270) {
+			coord_t tmp; 
+			tmp = x; x = y; y = tmp;
 		}
 		return (RAM(g)[xyaddr(x, y)] & xybit(y)) ? White : Black;
 	}
@@ -252,8 +222,8 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 		case GDISP_CONTROL_ORIENTATION:
 			if (g->g.Orientation == (orientation_t)g->p.ptr)
 				return;
-			switch((orientation_t)g->p.ptr) {
-			/* Rotation is handled by the drawing routines */
+			orientation_t orient = (orientation_t)g->p.ptr;
+			switch(orient) {
 			case GDISP_ROTATE_0:
 			case GDISP_ROTATE_180:
 				g->g.Height = GDISP_SCREEN_HEIGHT;
@@ -267,7 +237,33 @@ LLDSPEC bool_t gdisp_lld_init(GDisplay *g) {
 			default:
 				return;
 			}
-			g->g.Orientation = (orientation_t)g->p.ptr;
+			// Remap the rows and columns according to orientation.  This just
+			// eliminates the need to reverse x or y directions in the drawing
+			// routines.  There is still the need to swap x and y for 90 and 270.
+			// However, without these, the hardware fill routine would be much
+			// more complicated. 
+			acquire_bus(g);
+			switch(orient) {
+			default:
+			case GDISP_ROTATE_0:
+				write_cmd(g, SSD1306_COLSCANDEC);
+				write_cmd(g, SSD1306_ROWSCANDEC);
+				break;
+			case GDISP_ROTATE_180:
+				write_cmd(g, SSD1306_COLSCANINC);
+				write_cmd(g, SSD1306_ROWSCANINC);
+				break;
+			case GDISP_ROTATE_90:
+				write_cmd(g, SSD1306_COLSCANDEC);
+				write_cmd(g, SSD1306_ROWSCANINC);
+				break;
+			case GDISP_ROTATE_270:
+				write_cmd(g, SSD1306_COLSCANINC);
+				write_cmd(g, SSD1306_ROWSCANDEC);
+				break;
+			}
+			release_bus(g);
+			g->g.Orientation = orient;
 			return;
 
 		case GDISP_CONTROL_CONTRAST: