--- rfpdf.orig/lib/rfpdf/fpdf.rb	2009-03-19 01:26:27.437500000 +0900
+++ rfpdf/lib/rfpdf/fpdf.rb	2009-03-19 12:03:28.468750000 +0900
@@ -22,6 +22,7 @@
 
 require 'date'
 require 'zlib'
+require 'stringio'
 
 class FPDF
     FPDF_VERSION = '1.53d'
@@ -60,7 +61,7 @@ class FPDF
         # Initialization of properties
         @page=0
         @n=2
-        @buffer=''
+        @buffer = StringIO::new
         @pages=[]
         @OrientationChanges=[]
         @state=0
@@ -401,7 +402,9 @@ class FPDF
     end
 
     def Circle(mid_x, mid_y, radius, style='')
+      mid_x *= @k
       mid_y = (@h-mid_y)*@k
+      radius *= @k
       out(sprintf("q\n")) # postscript content in pdf
       # init line type etc. with /GSD gs G g (grey) RG rg (RGB) w=line witdh etc. 
       out(sprintf("1 j\n")) # line join
@@ -990,11 +993,11 @@ class FPDF
         
         if file.nil?
             # Return as a string
-            return @buffer
+            return @buffer.string
         else
             # Save file locally
             open(file,'wb') do |f|
-                f.write(@buffer)
+                f.write(@buffer.string)
             end
         end
     end
@@ -1006,7 +1009,7 @@ class FPDF
         unless @AliasNbPages.nil? or @AliasNbPages==''
             # Replace number of pages
             1.upto(nb) do |n|
-                @pages[n].gsub!(@AliasNbPages,nb.to_s)
+                @pages[n].string.gsub!(@AliasNbPages,nb.to_s)
             end
         end
         if @DefOrientation=='P'
@@ -1050,7 +1053,7 @@ class FPDF
             out('/Contents '+(@n+1).to_s+' 0 R>>')
             out('endobj')
             # Page content
-            p=(@compress) ? Zlib::Deflate.deflate(@pages[n]) : @pages[n]
+            p=(@compress) ? Zlib::Deflate.deflate(@pages[n].string) : @pages[n].string
             newobj
             out('<<'+filter+'/Length '+p.length.to_s+'>>')
             putstream(p)
@@ -1344,7 +1347,7 @@ class FPDF
 
     def beginpage(orientation)
         @page=@page+1
-        @pages[@page]=''
+        @pages[@page]=StringIO::new
         @state=2
         @x=@lMargin
         @y=@tMargin
@@ -1536,9 +1539,9 @@ class FPDF
     def out(s)
         # Add a line to the document
         if @state==2
-            @pages[@page]=@pages[@page]+s+"\n"
+            @pages[@page] << s.to_s << "\n"
         else
-            @buffer=@buffer+s.to_s+"\n"
+            @buffer << s.to_s << "\n"
         end
     end