Process fillOpacity and strokeOpacity in GraphicsState Processor

DEVSIX-3719

Author: marcoandries

kernel/src/main/java/com/itextpdf/kernel/pdf/canvas/parser/PdfCanvasProcessor.java

@@ -94,19 +94,13 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.colorspace.PdfSpecialCs;
 
 import java.util.Objects;
+import com.itextpdf.kernel.pdf.extgstate.PdfExtGState;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 import java.lang.ref.WeakReference;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.Stack;
+import java.util.*;
 
 import static com.itextpdf.kernel.pdf.canvas.PdfCanvasConstants.FillingRule;
 
@@ -918,7 +912,6 @@ public void invoke(PdfCanvasProcessor processor, PdfLiteral operator, List<PdfOb
                 if (gsDic == null)
                     throw new PdfException(PdfException._1IsAnUnknownGraphicsStateDictionary).setMessageParams(dictionaryName);
             }
-            // at this point, all we care about is the FONT entry in the GS dictionary TODO merge the whole gs dictionary
             PdfArray fontParameter = gsDic.getAsArray(PdfName.Font);
             if (fontParameter != null) {
                 PdfFont font = processor.getFont(fontParameter.getAsDictionary(0));
@@ -927,6 +920,8 @@ public void invoke(PdfCanvasProcessor processor, PdfLiteral operator, List<PdfOb
                 processor.getGraphicsState().setFont(font);
                 processor.getGraphicsState().setFontSize(size);
             }
+            PdfExtGState pdfExtGState = new PdfExtGState(gsDic.clone(Collections.singletonList(PdfName.Font)));
+            processor.getGraphicsState().updateFromExtGState(pdfExtGState);
         }
     }
 

kernel/src/test/java/com/itextpdf/kernel/pdf/canvas/parser/PdfCanvasProcessorTest.java

@@ -70,6 +70,8 @@ This file is part of the iText (R) project.
 import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.HashMap;
 import org.junit.Assert;
 import org.junit.Ignore;
 import org.junit.Rule;
@@ -108,6 +110,34 @@ public void contentStreamProcessorTest() throws IOException {
         Assert.assertEquals(expectedPageEventsLog, pageEventsLog.toString());
     }
 
+    @Test
+    public void processGraphicsStateResourceOperatorFillOpacityTest() throws IOException {
+        PdfDocument document = new PdfDocument(new PdfReader(sourceFolder + "transparentText.pdf"));
+        Float expOpacity = 0.5f;
+
+        Map<String, Object> textRenderInfo = new HashMap<>();
+        for (int i = 1; i <= document.getNumberOfPages(); ++i) {
+            PdfPage page = document.getPage(i);
+            PdfCanvasProcessor processor = new PdfCanvasProcessor(new RecordEveryTextRenderEvent(textRenderInfo));
+            processor.processPageContent(page);
+        }
+        Assert.assertEquals("Expected fill opacity not found", expOpacity, textRenderInfo.get("FillOpacity"));
+    }
+
+    @Test
+    public void processGraphicsStateResourceOperatorStrokeOpacityTest() throws IOException {
+        PdfDocument document = new PdfDocument(new PdfReader(sourceFolder + "hiddenText.pdf"));
+        Float expOpacity = 0.0f;
+
+        Map<String, Object> textRenderInfo = new HashMap<>();
+        for (int i = 1; i <= document.getNumberOfPages(); ++i) {
+            PdfPage page = document.getPage(i);
+            PdfCanvasProcessor processor = new PdfCanvasProcessor(new RecordEveryTextRenderEvent(textRenderInfo));
+            processor.processPageContent(page);
+        }
+        Assert.assertEquals("Expected stroke opacity not found", expOpacity, textRenderInfo.get("StrokeOpacity"));
+    }
+
     @Test
     public void testClosingEmptyPath() throws IOException {
         String fileName = "closingEmptyPath.pdf";
@@ -301,4 +331,25 @@ public Set<EventType> getSupportedEvents() {
             return null;
         }
     }
+
+    private static class RecordEveryTextRenderEvent implements IEventListener {
+        private Map<String, Object> map;
+
+        RecordEveryTextRenderEvent(Map<String, Object> map) {
+            this.map = map;
+        }
+
+        public void eventOccurred(IEventData data, EventType type) {
+            if (data instanceof TextRenderInfo) {
+                TextRenderInfo renderInfo = (TextRenderInfo) data;
+                map.put("String", renderInfo.getPdfString().toUnicodeString());
+                map.put("FillOpacity", renderInfo.getGraphicsState().getFillOpacity());
+                map.put("StrokeOpacity", renderInfo.getGraphicsState().getStrokeOpacity());
+            }
+        }
+
+        public Set<EventType> getSupportedEvents() {
+            return null;
+        }
+    }
 }