Fix to gImage BMP handling where the system pixel size is less than a byte

changelog.txt

@@ -4,6 +4,8 @@
 
 *** After Release 2.9 ***
 CHANGE:		Added type gImage          to replace V2.x gdispImage
+FIX:		Fixed GWIN console widget scroll
+FIX:		A warning and adjusted is made if GDISP_IMAGE_BMP_BLIT_BUFFER_SIZE is less than 40 bytes.
 
 
 *** Release 2.9 ***

src/gdisp/gdisp_image_bmp.c

@@ -11,6 +11,16 @@
 
 #include "gdisp_image_support.h"
 
+#if GDISP_IMAGE_BMP_BLIT_BUFFER_SIZE * (COLOR_TYPE_BITS/8) < 40
+		#if GFX_COMPILER_WARNING_TYPE == GFX_COMPILER_WARNING_DIRECT
+			#warning "GDISP: GDISP_IMAGE_BMP_BLIT_BUFFER_SIZE must be at least 40 bytes. It has been adjusted for you."
+		#elif GFX_COMPILER_WARNING_TYPE == GFX_COMPILER_WARNING_MACRO
+			COMPILER_WARNING("GDISP: GDISP_IMAGE_BMP_BLIT_BUFFER_SIZE must be at least 40 bytes. It has been adjusted for you.")
+		#endif
+	#undef GDISP_IMAGE_BMP_BLIT_BUFFER_SIZE
+	#define GDISP_IMAGE_BMP_BLIT_BUFFER_SIZE	((40 + (COLOR_TYPE_BITS/8) - 1) / (COLOR_TYPE_BITS/8))
+#endif
+
 typedef struct gdispImagePrivate_BMP {
 	gU8		bmpflags;
 		#define BMP_V2				0x01		// Version 2 (old) header format

src/gdisp/gdisp_options.h

@@ -389,8 +389,8 @@
 		#define GDISP_NEED_IMAGE_BMP_32		GFXON
 	#endif
 	/**
-	 * @brief   The BMP blit buffer size.
-	 * @details	Defaults to 32
+	 * @brief   The BMP blit buffer size in pixels.
+	 * @details	Defaults to 32 pixels
 	 * @note 	Bigger is faster but requires more RAM.
 	 * @note 	This must be greater than 40 bytes and 32 pixels as we read our headers into this space as well.
 	 */