FOP-3139: Add support for font-selection-strategy=character-by-character

fop-core/src/main/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java

@@ -781,6 +781,8 @@ public class TextLayoutManager extends LeafNodeLayoutManager {
         int level = -1;
         int prevLevel = -1;
         boolean retainControls = false;
+        Font lastFont = null;
+        int lastFontPos = -1;
         while (nextStart < foText.length()) {
             ch = foText.charAt(nextStart);
             level = foText.bidiLevelAt(nextStart);
@@ -813,10 +815,22 @@ public class TextLayoutManager extends LeafNodeLayoutManager {
                             + "}");
             }
             if (inWord) {
-                if (breakOpportunity
-                     || GlyphMapping.isSpace(ch)
-                     || CharUtilities.isExplicitBreak(ch)
-                     || ((prevLevel != -1) && (level != prevLevel))) {
+                boolean processWord = breakOpportunity
+                        || GlyphMapping.isSpace(ch)
+                        || CharUtilities.isExplicitBreak(ch)
+                        || ((prevLevel != -1) && (level != prevLevel));
+                if (!processWord && foText.getCommonFont().getFontSelectionStrategy() == EN_CHARACTER_BY_CHARACTER) {
+                    if (lastFont == null || lastFontPos != nextStart - 1) {
+                        lastFont = FontSelector.selectFontForCharactersInText(
+                                foText, nextStart - 1, nextStart, foText, this);
+                    }
+                    Font font = FontSelector.selectFontForCharactersInText(
+                            foText, nextStart, nextStart + 1, foText, this);
+                    processWord = font != lastFont;
+                    lastFont = font;
+                    lastFontPos = nextStart;
+                }
+                if (processWord) {
                     // this.foText.charAt(lastIndex) == CharUtilities.SOFT_HYPHEN
                     prevMapping = processWord(alignment, sequence, prevMapping, ch,
                         breakOpportunity, true, prevLevel, retainControls);

fop/test/layoutengine/standard-testcases/block_font-character-by-character.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  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.
+-->
+<!-- $Id$ -->
+<testcase>
+  <info>
+    <p>
+      This test checks the font character-by-character selection.
+    </p>
+  </info>
+  <fo>
+    <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
+      <fo:layout-master-set>
+        <fo:simple-page-master master-name="normal" page-width="210mm" page-height="297mm">
+          <fo:region-body/>
+        </fo:simple-page-master>
+      </fo:layout-master-set>
+      <fo:page-sequence master-reference="normal" white-space-collapse="true">
+        <fo:flow flow-name="xsl-region-body" font-selection-strategy="character-by-character">
+          <fo:block>font-family not given</fo:block>
+          <fo:block>this text contains a &#x2211; symbol in the middle</fo:block>
+          <fo:block>mixed contents should be</fo:block>
+          <fo:block>&#x2211;&#x2211;text</fo:block>
+          <fo:block>&#x2211;&#x2211;&#x2211;&#x2211;text</fo:block>
+          <fo:block>&#x2211;&#x2211;&#x2211;&#x2211;sym</fo:block>
+        </fo:flow>
+      </fo:page-sequence>
+    </fo:root>
+  </fo>
+  <checks>
+    <eval expected="sans-serif" xpath="//flow/block[1]/lineArea/text/@font-name"/>
+    <eval expected="sans-serif" xpath="//flow/block[2]/lineArea/text[1]/@font-name"/>
+    <eval expected="Symbol" xpath="//flow/block[2]/lineArea/text[2]/@font-name"/>
+    <eval expected="sans-serif" xpath="//flow/block[2]/lineArea/text[3]/@font-name"/>
+    <eval expected="sans-serif" xpath="//flow/block[3]/lineArea/text[1]/@font-name"/>
+    <eval expected="Symbol" xpath="//flow/block[4]/lineArea/text[1]/@font-name"/>
+    <eval expected="sans-serif" xpath="//flow/block[4]/lineArea/text[2]/@font-name"/>
+    <eval expected="Symbol" xpath="//flow/block[5]/lineArea/text[1]/@font-name"/>
+    <eval expected="sans-serif" xpath="//flow/block[5]/lineArea/text[2]/@font-name"/>
+    <eval expected="Symbol" xpath="//flow/block[6]/lineArea/text[1]/@font-name"/>
+    <eval expected="sans-serif" xpath="//flow/block[6]/lineArea/text[2]/@font-name"/>
+  </checks>
+</testcase>