add object drawer support

src/clj_htmltopdf/core.clj

@@ -2,6 +2,7 @@
   (:require
     [clojure.java.io :as io]
     [hiccup.page :as h]
+    [clj-htmltopdf.objects :as obj]
     [clj-htmltopdf.options :as o]
     [clj-htmltopdf.watermark :as w])
   (:import
@@ -45,15 +46,20 @@
     html-doc))
 
 (defn write-pdf!
-  ^InputStream [^Document html-doc ^String base-uri]
-  (let [builder (PdfRendererBuilder.)]
+  ^InputStream [^Document html-doc options]
+  (let [builder  (PdfRendererBuilder.)
+        base-uri (o/->base-uri options)]
+    (obj/set-object-drawer-factory builder options)
     (.withW3cDocument builder (DOMBuilder/jsoup2DOM html-doc) base-uri)
     (let [piped-in  (PipedInputStream.)
           piped-out (PipedOutputStream. piped-in)]
       (future
-        (with-open [os piped-out]
-          (.toStream builder os)
-          (.run builder)))
+        (try
+          (with-open [os piped-out]
+            (.toStream builder os)
+            (.run builder))
+          (catch Exception ex
+            (println "Exception while rendering PDF" ex))))
       piped-in)))
 
 (defn ->pdf
@@ -61,7 +67,7 @@
   (let [options  (o/get-final-options options)
         html-doc (prepare-html in options)]
     (configure-logging! options)
-    (let [pdf (write-pdf! html-doc (o/->base-uri options))
+    (let [pdf (write-pdf! html-doc options)
           out (->output-stream out)]
       (if (:watermark options)
         (w/write-watermark! pdf out options)

src/clj_htmltopdf/objects.clj

@@ -0,0 +1,47 @@
+(ns clj-htmltopdf.objects
+  (:require
+    [clojure.string :as string])
+  (:import
+    [com.openhtmltopdf.extend FSObjectDrawer FSObjectDrawerFactory OutputDevice OutputDeviceGraphicsDrawer]
+    [com.openhtmltopdf.pdfboxout PdfRendererBuilder]
+    [org.w3c.dom Element NamedNodeMap]))
+
+(defn element-attrs->map
+  [^Element element]
+  (let [attributes (.getAttributes element)]
+    (reduce
+      (fn [m idx]
+        (let [node  (.item attributes (int idx))
+              name  (.getNodeName node)
+              value (.getNodeValue node)]
+          (assoc m (keyword name) value)))
+      {}
+      (range (.getLength attributes)))))
+
+(defn ->object-drawer-by-id
+  ^FSObjectDrawer [f]
+  (reify FSObjectDrawer
+    (drawObject [_ element x y width height output-device rendering-context dots-per-pixel]
+      (.drawWithGraphics
+        ^OutputDevice output-device
+        (float x)
+        (float y)
+        (float (/ width dots-per-pixel))
+        (float (/ height dots-per-pixel))
+        (reify OutputDeviceGraphicsDrawer
+          (render [_ graphics2d]
+            (f (element-attrs->map element) graphics2d)))))))
+
+(defn ->object-drawer-by-id-factory
+  ^FSObjectDrawerFactory [options]
+  (reify FSObjectDrawerFactory
+    (^FSObjectDrawer createDrawer [_ ^Element element]
+      (if (.hasAttribute element "id")
+        (let [element-id (.getAttribute element "id")]
+          (if-let [f (get-in options [:objects :by-id element-id])]
+            (->object-drawer-by-id f)))))))
+
+(defn set-object-drawer-factory
+  [^PdfRendererBuilder builder options]
+  (let [factory (->object-drawer-by-id-factory options)]
+    (.useObjectDrawerFactory builder factory)))