diff --git a/src/clj_htmltopdf/core.clj b/src/clj_htmltopdf/core.clj
index 9b991a9..1aa1504 100644
--- a/src/clj_htmltopdf/core.clj
+++ b/src/clj_htmltopdf/core.clj
@@ -4,12 +4,14 @@
     [hiccup.page :as h]
     [clj-htmltopdf.options :as o])
   (:import
+    [java.awt.geom Point2D$Float]
     [java.io InputStream OutputStream PipedInputStream PipedOutputStream]
     [com.openhtmltopdf DOMBuilder]
     [com.openhtmltopdf.pdfboxout PdfRendererBuilder]
     [com.openhtmltopdf.util XRLog]
     [org.apache.pdfbox.pdmodel PDDocument PDPage PDPageContentStream PDPageContentStream$AppendMode]
-    [org.apache.pdfbox.pdmodel.font PDType1Font]
+    [org.apache.pdfbox.pdmodel.common PDRectangle]
+    [org.apache.pdfbox.pdmodel.font PDType1Font PDFont]
     [org.apache.pdfbox.pdmodel.graphics.state PDExtendedGraphicsState]
     [org.apache.pdfbox.util Matrix]
     [org.jsoup Jsoup]
@@ -61,13 +63,59 @@
           (.run builder)))
       piped-in)))
 
+(def watermark-fonts
+  {"times-roman"           PDType1Font/TIMES_ROMAN
+   "times-bold"            PDType1Font/TIMES_BOLD
+   "times-italic"          PDType1Font/TIMES_ITALIC
+   "times-bolditalic"      PDType1Font/TIMES_BOLD_ITALIC
+   "helvetica"             PDType1Font/HELVETICA
+   "helvetica-bold"        PDType1Font/HELVETICA_BOLD
+   "helvetica-oblique"     PDType1Font/HELVETICA_OBLIQUE
+   "helvetica-boldoblique" PDType1Font/HELVETICA_BOLD_OBLIQUE
+   "courier"               PDType1Font/COURIER
+   "courier-bold"          PDType1Font/COURIER_BOLD
+   "courier-oblique"       PDType1Font/COURIER_OBLIQUE
+   "courier-boldoblique"   PDType1Font/COURIER_BOLD_OBLIQUE})
+
+(defn render-watermark!
+  [^PDPage page ^PDPageContentStream cs options]
+  (let [font          (or (get watermark-fonts (:font options))
+                          (get watermark-fonts "helvetica-bold"))
+        font-size     (float (or (:font-size options) 36.0))
+        font-color    (or (:color options) [0 0 0])
+        text          (:text options)
+        text-width    (/ (* (.getStringWidth font text) font-size) 1000.0)
+        text-height   (/ (* (.getHeight (.getFontBoundingBox (.getFontDescriptor ^PDFont font))) font-size) 1000.0)
+        rotation      (float (or (:rotation options) 0))
+        page-size     (.getMediaBox page)
+        page-width    (.getWidth page-size)
+        page-height   (.getHeight page-size)
+        x             (if (= :center (:x options)) (/ page-width 2) (float (:x options)))
+        y             (if (= :center (:y options)) (/ page-height 2) (float (:y options)))
+        transform     (doto (Matrix.)
+                        (.translate x y)
+                        (.rotate (Math/toRadians rotation))
+                        (.translate (- (/ text-width 2)) (- (/ text-height 2))))]
+    (when (:opacity options)
+      (let [r0 (PDExtendedGraphicsState.)]
+        (.setNonStrokingAlphaConstant r0 (float (:opacity options)))
+        (.setGraphicsStateParameters cs r0)))
+    (.beginText cs)
+    (.setFont cs font font-size)
+    (.setNonStrokingColor cs (int (nth font-color 0)) (int (nth font-color 1)) (int (nth font-color 2)))
+    (.setTextMatrix cs transform)
+    (.showText cs text)
+    (.endText cs)))
+
 (defn write-watermark!
   [^InputStream pdf ^OutputStream out {:keys [watermark] :as options}]
   (with-open [doc (PDDocument/load pdf)]
     (doseq [^PDPage page (.getPages doc)]
       (let [cs (PDPageContentStream. doc page PDPageContentStream$AppendMode/APPEND true true)]
         (with-open [cs cs]
-          (watermark page cs))))
+          (if (map? watermark)
+            (render-watermark! page cs watermark)
+            (watermark page cs)))))
     (.save doc out)
     out))