#40: Correctly handle image interpolation and also respect this in t…

…he image cache.

README.md

@@ -14,8 +14,8 @@ pages and change certain aspects. E.g.
 [change the color mapping and perform an overfill](graphics2d/src/test/java/de/rototor/pdfbox/graphics2d/PdfRerenderTest.java).
 Now also it's possible to setup masking of all draw()/fill() calls. Think of this like an
 additional clipping, just that this supports bitmap images and complete complex drawings (XForm's)
-as alpha masks. See 
-[here](https://github.com/rototor/pdfbox-graphics2d/blob/master/graphics2d/src/test/java/de/rototor/pdfbox/graphics2d/TestMaskedDraws.java) 
+as alpha masks. See
+[here](https://github.com/rototor/pdfbox-graphics2d/blob/master/graphics2d/src/test/java/de/rototor/pdfbox/graphics2d/TestMaskedDraws.java)
 how that works.
 
 The following features are supported:
@@ -325,16 +325,26 @@ graphs
 ## Changes
 
 Version 0.42 (not yet released):
+
 - Upgraded PDFBox to 2.0.27
+- [#46](https://github.com/rototor/pdfbox-graphics2d/issues/46): Also override drawRect() and use a
+  Rectangle with drawShape(). Thanks @fransbouwmans for the report.
+- [#40](https://github.com/rototor/pdfbox-graphics2d/issues/40): Correctly implement image
+  interpolation and respect the chosen interpolation when caching an image. NOTE: This is a 
+  API breaking change on the IPdfBoxGraphics2DImageEncoder. So if you have implemeted this interface
+  you need to adapt to the new signature (env parameter).
 
 Version 0.41:
-- #45 Copy & paste error in drawImage() call forwarding. sy1 should be passed for sy1, not sy2... Thanks @fransbouwmans for pointing this out. This affected one 
-  specifc drawImage() overload. 
-
+
+- #45 Copy & paste error in drawImage() call forwarding. sy1 should be passed for sy1, not sy2...
+  Thanks @fransbouwmans for pointing this out. This affected one
+  specifc drawImage() overload.
+
 Version 0.40:
 
-- Messed up the access permissions for `PdfBoxGraphics2DPaintApplier.PaintApplierState::setupLuminosityMasking`. They are
-  now accessible. 
+- Messed up the access permissions
+  for `PdfBoxGraphics2DPaintApplier.PaintApplierState::setupLuminosityMasking`. They are
+  now accessible.
 
 Version 0.39:
 

graphics2d/src/main/java/de/rototor/pdfbox/graphics2d/IPdfBoxGraphics2DImageEncoder.java

@@ -24,17 +24,43 @@
 /**
  * Encode and compress an image as PDImageXObject
  */
-public interface IPdfBoxGraphics2DImageEncoder {
-	/**
-	 * Encode the given image into the a PDImageXObject
-	 * 
-	 * @param document
-	 *            the PDF document
-	 * @param contentStream
-	 *            the content stream of the page
-	 * @param image
-	 *            the image to encode
-	 * @return the encoded image
-	 */
-	PDImageXObject encodeImage(PDDocument document, PDPageContentStream contentStream, Image image);
+public interface IPdfBoxGraphics2DImageEncoder
+{
+    /**
+     * Environment for image encoding
+     */
+    interface IPdfBoxGraphics2DImageEncoderEnv
+    {
+
+        /*
+         * What kind of image interpolations are possible?
+         */
+        enum ImageInterpolation
+        {
+            /*
+             * "Pixel Art" rendering.
+             */
+            NearestNeigbor,  //
+            /*
+             * Interpolate the image. What algorithmus is used depends on the PDF viewer.
+             */
+            Interpolate
+        }
+
+        /**
+         * @return the RenderingHints.KEY_INTERPOLATION value mapped to the Interpolation enum
+         */
+        ImageInterpolation getImageInterpolation();
+    }
+
+    /**
+     * Encode the given image into the a PDImageXObject
+     *
+     * @param document      the PDF document
+     * @param contentStream the content stream of the page
+     * @param image         the image to encode
+     * @return the encoded image
+     */
+    PDImageXObject encodeImage(PDDocument document, PDPageContentStream contentStream, Image image,
+            IPdfBoxGraphics2DImageEncoderEnv env);
 }

graphics2d/src/main/java/de/rototor/pdfbox/graphics2d/PdfBoxGraphics2D.java

@@ -655,6 +655,18 @@ public boolean drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1,
         return drawImage(img, dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, null, observer);
     }
 
+    final IPdfBoxGraphics2DImageEncoder.IPdfBoxGraphics2DImageEncoderEnv imageEncoderEnv = new IPdfBoxGraphics2DImageEncoder.IPdfBoxGraphics2DImageEncoderEnv()
+    {
+        @Override
+        public ImageInterpolation getImageInterpolation()
+        {
+            Object renderingHint = getRenderingHint(RenderingHints.KEY_INTERPOLATION);
+            if (renderingHint == RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR)
+                return ImageInterpolation.NearestNeigbor;
+            return ImageInterpolation.Interpolate;
+        }
+    };
+
     public boolean drawImage(Image img, AffineTransform xform, ImageObserver obs)
     {
         checkNoCopyActive();
@@ -664,7 +676,8 @@ public boolean drawImage(Image img, AffineTransform xform, ImageObserver obs)
         if (xform != null)
             tf.concatenate((AffineTransform) xform.clone());
 
-        PDImageXObject pdImage = imageEncoder.encodeImage(document, contentStream, img);
+        PDImageXObject pdImage = imageEncoder.encodeImage(document, contentStream, img,
+                imageEncoderEnv);
         try
         {
             contentStreamSaveState();
@@ -673,10 +686,6 @@ public boolean drawImage(Image img, AffineTransform xform, ImageObserver obs)
             tf.scale(1, -1);
             contentStream.transform(new Matrix(tf));
 
-            Object keyInterpolation = renderingHints.get(RenderingHints.KEY_INTERPOLATION);
-            if (RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR.equals(keyInterpolation))
-                pdImage.setInterpolate(false);
-
             if (composite != null)
             {
                 // We got an AlphaComposite, we must set the extended graphics dictionary correctly.