#344 - Pixel perfect sizing for PDF pages embedded from img tag.

Turns out the problem was prematurely casting our width and height to ints and thus getting incorrect scale factors. Test now passing.
danfickle · Jul 16, 2019 · f3f5c81 · f3f5c81
1 parent 0887f7f
commit f3f5c81
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Showing 6 changed files with 24 additions and 17 deletions.
diff --git a/...ltopdf-core/src/main/java/com/openhtmltopdf/simple/extend/ReplacedElementScaleHelper.java b/...ltopdf-core/src/main/java/com/openhtmltopdf/simple/extend/ReplacedElementScaleHelper.java
@@ -14,11 +14,11 @@ public class ReplacedElementScaleHelper {
      * @return AffineTransform or null if not available.
      */
     public static AffineTransform createScaleTransform(double dotsPerPixel, Rectangle contentBounds, float width, float height) {
-        int intrinsicWidth = (int) width;
-        int intrinsicHeight = (int) height;
+        double intrinsicWidth = width;
+        double intrinsicHeight = height;
 
-        int desiredWidth = (int) (contentBounds.getWidth() / dotsPerPixel);
-        int desiredHeight = (int) (contentBounds.getHeight() / dotsPerPixel);
+        double desiredWidth = (contentBounds.getWidth() / dotsPerPixel);
+        double desiredHeight = (contentBounds.getHeight() / dotsPerPixel);
 
         AffineTransform scale = null;
 
@@ -28,15 +28,15 @@ public static AffineTransform createScaleTransform(double dotsPerPixel, Rectangl
         else if (desiredWidth > intrinsicWidth ||
                  desiredHeight > intrinsicHeight) {
 
-            double rw = (double) desiredWidth / width;
-            double rh = (double) desiredHeight / height;
+            double rw = desiredWidth / width;
+            double rh = desiredHeight / height;
 
             double factor = Math.min(rw, rh);
             scale = AffineTransform.getScaleInstance(factor, factor);
         } else if (desiredWidth < intrinsicWidth &&
                    desiredHeight < intrinsicHeight) {
-            double rw = (double) desiredWidth / width;
-            double rh = (double) desiredHeight / height;
+            double rw = desiredWidth / width;
+            double rh = desiredHeight / height;
 
             double factor = Math.max(rw, rh);
             scale = AffineTransform.getScaleInstance(factor, factor);

diff --git a/openhtmltopdf-examples/src/main/resources/visualtest/expected/pdf-linked-from-img-tag.pdf b/openhtmltopdf-examples/src/main/resources/visualtest/expected/pdf-linked-from-img-tag.pdf
diff --git a/openhtmltopdf-examples/src/main/resources/visualtest/html/pdf-linked-from-img-tag.html b/openhtmltopdf-examples/src/main/resources/visualtest/html/pdf-linked-from-img-tag.html
@@ -2,13 +2,17 @@
 <head>
 <style>
 @page {
-
+  margin: 0;
 }
 img {
   margin-top: 5px;
   display: block;
   box-sizing: border-box;
-  border: 1px solid red;
+  border: 2px solid red;
+}
+body {
+  margin: 0;
+  padding: 0;
 }
 </style>
 </head>

diff --git a/...-examples/src/test/java/com/openhtmltopdf/visualregressiontests/VisualRegressionTest.java b/...-examples/src/test/java/com/openhtmltopdf/visualregressiontests/VisualRegressionTest.java
@@ -838,8 +838,11 @@ public void testSvgLinkedFromImgTag() throws IOException {
         assertTrue(vt.runTest("svg-linked-from-img-tag", WITH_SVG));
     }
 
+    /**
+     * Tests that we correctly render PDF pages in the img tag at 
+     * the correct CSS specified sizing. Issue 344.
+     */
     @Test
-    @Ignore // Still a couple of pixels off with width (noticeable when there is a border).
     public void testPdfLinkedFromImgTag() throws IOException {
         assertTrue(vt.runTest("pdf-linked-from-img-tag"));
     }

diff --git a/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxFastOutputDevice.java b/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxFastOutputDevice.java
@@ -854,17 +854,16 @@ public void drawPdfAsImage(PDFormXObject _srcObject, Rectangle contentBounds, fl
         // Then the x and y of this object...
         af.translate(contentBounds.getX() / _dotsPerPoint, -(contentBounds.getY() / _dotsPerPoint));
 
-        float conversion = 96f / 72f;
-
         // Scale to the desired height and width...
-        AffineTransform scale = ReplacedElementScaleHelper.createScaleTransform(_dotsPerPoint, contentBounds, intrinsicWidth / _dotsPerPoint * conversion, intrinsicHeight / _dotsPerPoint * conversion);
+        AffineTransform scale = ReplacedElementScaleHelper.createScaleTransform(_dotsPerPoint, contentBounds, intrinsicWidth / _dotsPerPoint, intrinsicHeight / _dotsPerPoint);
+
         if (scale != null) {
             af.concatenate(scale);
         }
 
         // And take into account the height of the drawn feature...
         // And yes these transforms were all determined by trial and error!
-        af.translate(0, -((intrinsicHeight / _dotsPerPoint) * conversion));
+        af.translate(0, -((intrinsicHeight / _dotsPerPoint)));
 
         _cp.saveGraphics();
         _cp.applyPdfMatrix(af);

diff --git a/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxPDFReplacedElement.java b/openhtmltopdf-pdfbox/src/main/java/com/openhtmltopdf/pdfboxout/PdfBoxPDFReplacedElement.java
@@ -80,8 +80,9 @@ public static PdfBoxPDFReplacedElement create(PDDocument target, byte[] pdfBytes
             }
 
             PDPage page = srcDocument.getPage(pageNo);
-            float width = page.getMediaBox().getWidth() * shared.getDotsPerPixel();
-            float height = page.getMediaBox().getHeight() * shared.getDotsPerPixel();
+            float conversion = 96f / 72f;
+            float width = page.getMediaBox().getWidth() * shared.getDotsPerPixel() * conversion;
+            float height = page.getMediaBox().getHeight() * shared.getDotsPerPixel() * conversion;
 
             LayerUtility util = new LayerUtility(target);
             PDFormXObject formXObject = util.importPageAsForm(srcDocument, page);