diff --git a/zahnrad.c b/zahnrad.c
index 597199c..cbf54d7 100644
--- a/zahnrad.c
+++ b/zahnrad.c
@@ -1309,11 +1309,11 @@ static zr_size
 zr_use_font_glyph_clamp(const struct zr_user_font *font, const char *text,
     zr_size text_len, float space, zr_size *glyphs, float *text_width)
 {
-    zr_size len = 0;
-    zr_size glyph_len;
-    float width = 0;
+    zr_size glyph_len = 0;
     float last_width = 0;
-    zr_rune unicode;
+    zr_rune unicode = 0;
+    float width = 0;
+    zr_size len = 0;
     zr_size g = 0;
 
     glyph_len = zr_utf_decode(text, &unicode, text_len);
@@ -1321,6 +1321,7 @@ zr_use_font_glyph_clamp(const struct zr_user_font *font, const char *text,
         zr_size s;
         len += glyph_len;
         s = font->width(font->userdata, font->height, text, len);
+
         last_width = width;
         width = (float)s;
         glyph_len = zr_utf_decode(&text[len], &unicode, text_len - len);
@@ -2893,13 +2894,13 @@ zr__draw_next(const struct zr_draw_command *cmd,
 #pragma warning (disable: 4456)
 #endif
 
-#ifndef ZR_DISABLE_STB_RECT_PACK_IMPLEMENTATION
+#if !ZR_DISABLE_STB_RECT_PACK_IMPLEMENTATION
 #define STBRP_STATIC
 #define STB_RECT_PACK_IMPLEMENTATION
 #endif
 #include "stb_rect_pack.h"
 
-#ifndef ZR_DISABLE_STB_TRUETYPE_IMPLEMENTATION
+#if !ZR_DISABLE_STB_TRUETYPE_IMPLEMENTATION
 #define STBTT_STATIC
 #define STB_TRUETYPE_IMPLEMENTATION
 #endif
diff --git a/zahnrad.h b/zahnrad.h
index 98af585..1133b57 100644
--- a/zahnrad.h
+++ b/zahnrad.h
@@ -68,6 +68,14 @@ extern "C" {
  If you already have font handling or do not want to use this font handler
  you can just set this define to zero and the font module will not be compiled
  and the two headers will not be needed. */
+#define ZR_DISABLE_STB_RECT_PACK_IMPLEMENTATION 0
+/* If you already provide the implementation for stb_rect_pack.h in one of your
+ files you have to define this as 1 to prevent another implementation and the
+ resulting symbol collision. */
+#define ZR_DISABLE_STB_TRUETYPE_IMPLEMENTATION 0
+/* If you already provide the implementation for stb_truetype.h in one of your
+ files you have to define this as 1 to prevent another implementation and the
+ resulting symbol collision. */
 /*
  * ===============================================================
  *