diff --git a/src/gosu.cr b/src/gosu.cr
index fdf2f77..0e4bfbf 100644
--- a/src/gosu.cr
+++ b/src/gosu.cr
@@ -84,6 +84,8 @@ module Gosu
 
     fun clipboard = Gosu_clipboard() : UInt8*
     fun set_clipboard = Gosu_set_clipboard(text : UInt8*)
+
+    fun last_error = Gosu_last_error() : UInt8*
   end
 
   # Returns the current framerate, in frames per second.
@@ -386,4 +388,10 @@ module Gosu
       raise "No such mode: #{mode}"
     end
   end
+
+  def self.check_last_error
+    if (err = GosuC.last_error)
+      raise String.new(err)
+    end
+  end
 end
diff --git a/src/gosu/constants.cr b/src/gosu/constants.cr
index 8e3431c..27d2d3d 100644
--- a/src/gosu/constants.cr
+++ b/src/gosu/constants.cr
@@ -566,4 +566,9 @@ module Gosu
   MS_NUM                  = Gosu::ButtonName::MS_NUM.to_u32
   GP_NUM                  = Gosu::ButtonName::GP_NUM.to_u32
   GP_NUM_PER_GAMEPAD      = Gosu::ButtonName::GP_NUM_PER_GAMEPAD.to_u32
+
+  FF_BOLD = 1_u32
+  FF_ITALIC = 2_u32
+  FF_UNDERLINE = 4_u32
+  FF_COMBINATIONS = 8_u32
 end
diff --git a/src/gosu/font.cr b/src/gosu/font.cr
index 081d652..7664df6 100644
--- a/src/gosu/font.cr
+++ b/src/gosu/font.cr
@@ -4,7 +4,6 @@ module Gosu
 
     fun name = Gosu_Font_name(pointer : UInt8*) : UInt8*
     fun height = Gosu_Font_height(pointer : UInt8*) : Int32
-    fun flags = Gosu_Font_flags(pointer : UInt8*) : UInt32
 
     fun text_width = Gosu_Font_text_width(pointer : UInt8*, text : UInt8*) : Float64
     fun markup_width = Gosu_Font_markup_width(pointer : UInt8*, text : UInt8*) : Float64
@@ -53,11 +52,6 @@ module Gosu
       FontC.height(pointer)
     end
 
-    # Returns the flags passed to `Gosu::Font` as a UInt32
-    def flags : UInt32
-      FontC.flags(pointer)
-    end
-
     # Returns the width of a single line of text, in pixels, if it were drawn.
     def text_width(text) : Float64
       FontC.text_width(pointer, text)
@@ -116,7 +110,10 @@ module Gosu
     #
     # NOTE: For any given character, this method MUST NOT be called more than once, and MUST NOT be called if a string containing the character has already been drawn.
     def []=(codepoint : String, image : Gosu::Image)
-      FontC.set_image(pointer, codepoint, self.flags, image.pointer)
+      Gosu::FF_COMBINATIONS.times do |font_flags|
+        FontC.set_image(pointer, codepoint, font_flags, image.pointer)
+        Gosu.check_last_error
+      end
     end
 
     # :nodoc: