diff -r b3c9090d1120 SDL_ttf.c
--- a/SDL_ttf.c	Sun Sep 10 00:41:53 2017 -0700
+++ b/SDL_ttf.c	Sun Sep 10 14:04:15 2017 +0200
@@ -1480,6 +1480,11 @@
             dst = (Uint8*) textbuf->pixels +
                 (row+glyph->yoffset) * textbuf->pitch +
                 xstart + glyph->minx;
+
+            if (dst < (Uint8*) textbuf->pixels) {
+                dst = textbuf->pixels;
+            }
+
             src = current->buffer + row * current->pitch;
 
             for (col=width; col>0 && dst < dst_check; --col) {
@@ -1676,6 +1681,11 @@
             dst = (Uint8*) textbuf->pixels +
                 (row+glyph->yoffset) * textbuf->pitch +
                 xstart + glyph->minx;
+
+            if (dst < (Uint8*) textbuf->pixels) {
+                dst = textbuf->pixels;
+            }
+
             src = current->buffer + row * current->pitch;
             for (col=width; col>0 && dst < dst_check; --col) {
                 *dst++ |= *src++;
@@ -1864,6 +1874,10 @@
                 (row+glyph->yoffset) * textbuf->pitch/4 +
                 xstart + glyph->minx;
 
+            if (dst < (Uint8*) textbuf->pixels) {
+                dst = textbuf->pixels;
+            }
+
             /* Added code to adjust src pointer for pixmaps to
              * account for pitch.
              * */
@@ -2168,6 +2182,10 @@
                 (row+glyph->yoffset) * textbuf->pitch/4 +
                 xstart + glyph->minx;
 
+                if (dst < (Uint8*) textbuf->pixels) {
+                    dst = textbuf->pixels;
+                }
+
                 /* Added code to adjust src pointer for pixmaps to
                  * account for pitch.
                  * */