diff --git a/src/cguittfont/CGUITTFont.cpp b/src/cguittfont/CGUITTFont.cpp
index f6606996e..2342eb748 100644
--- a/src/cguittfont/CGUITTFont.cpp
+++ b/src/cguittfont/CGUITTFont.cpp
@@ -29,6 +29,7 @@
 */
 
 #include <irrlicht.h>
+#include <iostream>
 #include "CGUITTFont.h"
 
 namespace irr
@@ -64,8 +65,24 @@ scene::SMesh CGUITTFont::shared_plane_;
 
 //
 
+/** Checks that no dimension of the FT_BitMap object is negative.  If either is
+ * negative, abort execution.
+ */
+inline void checkFontBitmapSize(const FT_Bitmap &bits)
+{
+	if ((s32)bits.rows < 0 || (s32)bits.width < 0) {
+		std::cout << "Insane font glyph size. File: "
+		          << __FILE__ << " Line " << __LINE__
+		          << std::endl;
+		abort();
+	}
+}
+
 video::IImage* SGUITTGlyph::createGlyphImage(const FT_Bitmap& bits, video::IVideoDriver* driver) const
 {
+	// Make sure our casts to s32 in the loops below will not cause problems
+	checkFontBitmapSize(bits);
+
 	// Determine what our texture size should be.
 	// Add 1 because textures are inclusive-exclusive.
 	core::dimension2du d(bits.width + 1, bits.rows + 1);
@@ -87,10 +104,11 @@ video::IImage* SGUITTGlyph::createGlyphImage(const FT_Bitmap& bits, video::IVide
 			const u32 image_pitch = image->getPitch() / sizeof(u16);
 			u16* image_data = (u16*)image->lock();
 			u8* glyph_data = bits.buffer;
-			for (int y = 0; y < bits.rows; ++y)
+
+			for (s32 y = 0; y < (s32)bits.rows; ++y)
 			{
 				u16* row = image_data;
-				for (int x = 0; x < bits.width; ++x)
+				for (s32 x = 0; x < (s32)bits.width; ++x)
 				{
 					// Monochrome bitmaps store 8 pixels per byte.  The left-most pixel is the bit 0x80.
 					// So, we go through the data each bit at a time.
@@ -116,10 +134,10 @@ video::IImage* SGUITTGlyph::createGlyphImage(const FT_Bitmap& bits, video::IVide
 			const u32 image_pitch = image->getPitch() / sizeof(u32);
 			u32* image_data = (u32*)image->lock();
 			u8* glyph_data = bits.buffer;
-			for (int y = 0; y < bits.rows; ++y)
+			for (s32 y = 0; y < (s32)bits.rows; ++y)
 			{
 				u8* row = glyph_data;
-				for (int x = 0; x < bits.width; ++x)
+				for (s32 x = 0; x < (s32)bits.width; ++x)
 				{
 					image_data[y * image_pitch + x] |= static_cast<u32>(255.0f * (static_cast<float>(*row++) / gray_count)) << 24;
 					//data[y * image_pitch + x] |= ((u32)(*bitsdata++) << 24);