FOP-2880 Use soft hyphen for hyphenation

Author: Joao Goncalves

fop-core/src/main/codegen/fonts/encodings.xml

@@ -293,7 +293,7 @@
     <glyph codepoint='aa' name='ordfeminine'/>
     <glyph codepoint='ab' name='guillemotleft'/>
     <glyph codepoint='ac' name='logicalnot'/>
-    <glyph codepoint='ad' name='hyphen'/>
+    <glyph codepoint='ad' name='softhyphen'/>
     <glyph codepoint='ae' name='registered'/>
     <glyph codepoint='af' name='macron'/>
     <glyph codepoint='b0' name='degree'/>
@@ -938,6 +938,7 @@
     <glyph codepoint='aa' name='ordfeminine'/>
     <glyph codepoint='ab' name='guillemotleft'/>
     <glyph codepoint='ac' name='logicalnot'/>
+    <glyph codepoint='ad' name='softhyphen'/>
     <glyph codepoint='ae' name='registered'/>
     <glyph codepoint='af' name='macron'/>
     <glyph codepoint='b0' name='degree'/>

fop-core/src/main/codegen/fonts/glyphlist.xml

@@ -788,7 +788,7 @@
     <glyph codepoint='2302' name='house'/>
     <glyph codepoint='02DD' name='hungarumlaut'/>
     <glyph codepoint='002D' name='hyphen'/>
-    <glyph codepoint='00AD' name='hyphen'/>
+    <glyph codepoint='00AD' name='softhyphen'/>
     <glyph codepoint='F6E5' name='hypheninferior'/>
     <glyph codepoint='F6E6' name='hyphensuperior'/>
     <glyph codepoint='0069' name='i'/>

fop-core/src/main/java/org/apache/fop/render/intermediate/AbstractIFPainter.java

@@ -514,4 +514,8 @@ protected boolean drawSVGText(MultiByteFont multiByteFont, FontTriplet triplet,
         }
         return true;
     }
+
+    public boolean supportsSoftHyphen() {
+        return false;
+    }
 }

fop-core/src/main/java/org/apache/fop/render/intermediate/IFPainter.java

@@ -261,4 +261,10 @@ void drawLine(Point start, Point end, int width, Color color, RuleStyle style)
 
     //etc. etc.
 
+    /**
+     * Allows specific painters to indicate whether a soft hyphen is supported.
+     *
+     * @return true if the painter supports soft hyphens, false otherwise
+     */
+    boolean supportsSoftHyphen();
 }

fop-core/src/main/java/org/apache/fop/render/intermediate/IFParser.java

@@ -66,6 +66,7 @@
 import org.apache.fop.util.ContentHandlerFactoryRegistry;
 import org.apache.fop.util.DOMBuilderContentHandlerFactory;
 import org.apache.fop.util.LanguageTags;
+import org.apache.fop.util.StringUtils;
 import org.apache.fop.util.XMLUtil;
 import org.apache.fop.utils.DefaultErrorListener;
 
@@ -683,7 +684,9 @@ public void endElement() throws IFException {
                     documentHandler.getContext().setHyphenated(isHyphenated);
                 }
                 boolean nextIsSpace = Boolean.valueOf(lastAttributes.getValue("next-is-space"));
-                painter.drawText(x, y, letterSpacing, wordSpacing, dp, content.toString(), nextIsSpace);
+
+                painter.drawText(x, y, letterSpacing, wordSpacing, dp,
+                        StringUtils.processSoftHyphen(content.toString(), painter), nextIsSpace);
                 documentHandler.getContext().setHyphenated(false);
                 resetStructureTreeElement();
             }

fop-core/src/main/java/org/apache/fop/render/intermediate/IFRenderer.java

@@ -98,6 +98,7 @@
 import org.apache.fop.render.intermediate.extensions.URIAction;
 import org.apache.fop.traits.BorderProps;
 import org.apache.fop.traits.RuleStyle;
+import org.apache.fop.util.StringUtils;
 
 /**
  * This renderer implementation is an adapter to the {@link IFPainter} interface. It is used
@@ -1240,8 +1241,8 @@ void flush() {
                         painter.drawText(startx, starty, 0, 0,
                                          trimAdjustments(dp, text.length()), text.toString());
                     } else { */
-                        painter.drawText(startx, starty, tls, tws,
-                                         trimAdjustments(dp, text.length()), text.toString(), nextIsSpace);
+                    painter.drawText(startx, starty, tls, tws, trimAdjustments(dp, text.length()),
+                            StringUtils.processSoftHyphen(text.toString(), painter), nextIsSpace);
                     /* } */
                 } catch (IFException e) {
                     handleIFException(e);
@@ -1252,7 +1253,7 @@ void flush() {
 
         void drawText(int x, int y, int letterSpacing, int wordSpacing, int[][] dx, String text, boolean nextIsSpace)
                 throws IFException {
-            painter.drawText(startx, starty, tls, tws, dx, text, nextIsSpace);
+            painter.drawText(startx, starty, tls, tws, dx, StringUtils.processSoftHyphen(text, painter), nextIsSpace);
         }
 
         /**

fop-core/src/main/java/org/apache/fop/render/intermediate/IFSerializer.java

@@ -523,6 +523,11 @@ public void drawImage(Document doc, Rectangle rect) throws IFException {
         }
     }
 
+    @Override
+    public boolean supportsSoftHyphen() {
+        return false;
+    }
+
     private static String toString(Paint paint) {
         if (paint instanceof Color) {
             return ColorUtil.colorToString((Color)paint);

fop-core/src/main/java/org/apache/fop/render/pdf/PDFPainter.java

@@ -649,4 +649,9 @@ private int selectAndMapSingleByteFont(Typeface tf, String fontName, float fontS
         return ch;
     }
 
+    @Override
+    public boolean supportsSoftHyphen() {
+        return true;
+    }
+
 }

fop-core/src/main/java/org/apache/fop/util/StringUtils.java

@@ -0,0 +1,36 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.util;
+
+import org.apache.fop.render.intermediate.IFPainter;
+
+public final class StringUtils {
+
+    private StringUtils() {
+    }
+
+    public static String processSoftHyphen(String text, IFPainter painter) {
+        if (!painter.supportsSoftHyphen()) {
+            return text.replace(CharUtilities.SOFT_HYPHEN, '-');
+        }
+        return text;
+    }
+
+}

fop-core/src/test/java/org/apache/fop/render/intermediate/IFRendererTestCase.java

@@ -33,15 +33,18 @@
 import javax.xml.transform.sax.SAXResult;
 import javax.xml.transform.stream.StreamSource;
 
-import org.junit.Assert;
 import org.junit.Test;
 
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.apps.Fop;
 import org.apache.fop.apps.FopFactory;
 import org.apache.fop.apps.FopFactoryBuilder;
 import org.apache.fop.area.inline.WordArea;
+import org.apache.fop.util.CharUtilities;
 
 public class IFRendererTestCase {
     private List<WordArea> wordAreas = new ArrayList<WordArea>();
@@ -80,7 +83,46 @@ public void testWordSpace() throws FOPException, TransformerException {
                 + "  </fo:page-sequence>\n"
                 + "</fo:root>";
         foToOutput(new ByteArrayInputStream(fo.getBytes()));
-        Assert.assertTrue(wordAreas.get(0).isNextIsSpace());
-        Assert.assertFalse(wordAreas.get(1).isNextIsSpace());
+        assertTrue(wordAreas.get(0).isNextIsSpace());
+        assertFalse(wordAreas.get(1).isNextIsSpace());
+    }
+
+    @Test
+    public void testSoftHyphen() throws FOPException, TransformerException {
+        String fo = getSoftHyphenTestFO("&#x00AD;");
+        foToOutput(new ByteArrayInputStream(fo.getBytes()));
+        assertTrue("PDF files are able to handle the soft hyphen, so must not replace with normal hyphen",
+                wordAreas.get(1).getWord().endsWith(String.valueOf(CharUtilities.SOFT_HYPHEN)));
+
+
+        wordAreas = new ArrayList<>();
+        fo = getSoftHyphenTestFO("-");
+        foToOutput(new ByteArrayInputStream(fo.getBytes()));
+        assertTrue("Must not replace the hyphenation character", wordAreas.get(1).getWord().endsWith("-"));
+
+        wordAreas = new ArrayList<>();
+        fo = getSoftHyphenTestFO("/");
+        foToOutput(new ByteArrayInputStream(fo.getBytes()));
+        assertTrue("Must not replace the hyphenation character", wordAreas.get(1).getWord().endsWith("/"));
+    }
+
+    private String getSoftHyphenTestFO(String hyphenationCharacter) {
+        return "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+                + "<fo:root xmlns:fo=\"http://www.w3.org/1999/XSL/Format\" "
+                + "xmlns:fox=\"http://xmlgraphics.apache.org/fop/extensions\">\n"
+                + "\t<fo:layout-master-set>\n"
+                + "\t\t<fo:simple-page-master master-name=\"mainPage\" page-width=\"90pt\">\n"
+                + "\t\t\t<fo:region-body/>\n"
+                + "\t\t</fo:simple-page-master>\n"
+                + "\t</fo:layout-master-set>\n"
+                + "\t<fo:page-sequence master-reference=\"mainPage\">\n"
+                + "\t\t<fo:flow flow-name=\"xsl-region-body\">\n"
+                + "\t\t\t<fo:block language=\"en\" country=\"GB\" hyphenate=\"true\" page-break-inside=\"auto\" "
+                + "hyphenation-character=\"" + hyphenationCharacter + "\">\n"
+                + "\t\t\t\tcomputer computer computer computer computer computer computer computer\n"
+                + "\t\t\t</fo:block>\n"
+                + "\t\t</fo:flow>\n"
+                + "\t</fo:page-sequence>\n"
+                + "</fo:root>";
     }
 }