GlyphLayoutProcessor for correct glyph layout and support of DIN 91379 (Issue PDFBOX-4951)

examples/src/main/java/org/apache/pdfbox/examples/pdmodel/glyphlayout/DoGlyphLayoutBengali.java

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+/*
+ * 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.
+ */
+
+package org.apache.pdfbox.examples.pdmodel.glyphlayout;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.StringTokenizer;
+
+import org.apache.pdfbox.examples.pdmodel.BengaliPdfGenerationHelloWorld;
+import org.apache.pdfbox.pdmodel.GlyphLayoutProcessor;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.font.PDFont;
+import org.apache.pdfbox.pdmodel.font.PDType0Font;
+
+/**
+ * DoGlyphLayoutBengali
+ *
+ * This class is adapted from:
+ * BengaliPdfGenerationHelloWorld
+ * Inspired from <a href=
+ * "https://svn.apache.org/viewvc/pdfbox/trunk/examples/src/main/java/org/apache/pdfbox/examples/pdmodel/HelloWorldTTF.java?view=markup">PdfBox
+ * Example</a>. This attempts to correctly demonstrate to what extent Bengali text rendering is
+ * supported. We read large amount of text from a file and try to render it properly.
+ *
+ * @author Palash Ray
+ *
+ */
+public class DoGlyphLayoutBengali
+{
+    private static final int LINE_GAP = 5;
+    private static final String LOHIT_BENGALI_TTF = "/org/apache/pdfbox/resources/ttf/Lohit-Bengali.ttf";
+    private static final String TEXT_SOURCE_FILE = "/org/apache/pdfbox/resources/ttf/bengali-samples.txt";
+    private static final int FONT_SIZE = 20;
+    private static final int MARGIN = 20;
+
+    public static void main(String[] args) {
+        try {
+            new DoGlyphLayoutBengali().test();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public void test() throws IOException {
+        String filename = "DoGlyphLayoutBengali.pdf";
+
+        System.out.println("The generated pdf filename is: " + filename);
+
+        try (PDDocument doc = new PDDocument())
+        {
+            // Create GlyphLayoutProcessor load font
+            GlyphLayoutProcessor glyphLayoutProcessor = new GlyphLayoutProcessor();
+            PDType0Font font = glyphLayoutProcessor.loadFont(doc, this.getClass().
+                    getResourceAsStream(LOHIT_BENGALI_TTF));
+
+            PDRectangle rectangle = getPageSize();
+            float workablePageWidth = rectangle.getWidth() - 2 * MARGIN;
+            float workablePageHeight = rectangle.getHeight() - 2 * MARGIN;
+
+            List<List<String>> pagedTexts = getReAlignedTextBasedOnPageHeight(
+                    getReAlignedTextBasedOnPageWidth(getBengaliTextFromFile(), font,
+                            workablePageWidth),
+                    font, workablePageHeight);
+
+            for (List<String> linesForPage : pagedTexts)
+            {
+                PDPage page = new PDPage(getPageSize());
+                doc.addPage(page);
+
+                try (PDPageContentStream contents = new PDPageContentStream(doc, page))
+                {
+                    // set GlyphLayoutProcessor for content stream
+                    contents.setGlyphLayoutProcessor(glyphLayoutProcessor);
+
+                    contents.beginText();
+                    contents.setFont(font, FONT_SIZE);
+                    contents.newLineAtOffset(rectangle.getLowerLeftX() + MARGIN,
+                            rectangle.getUpperRightY() - MARGIN);
+
+                    for (String line : linesForPage)
+                    {
+                        contents.showText(line);
+                        contents.newLineAtOffset(0, -(FONT_SIZE + LINE_GAP));
+                    }
+
+                    contents.endText();
+
+                }
+            }
+
+            doc.save(filename);
+        }
+    }
+
+    private static List<List<String>> getReAlignedTextBasedOnPageHeight(List<String> originalLines,
+                                                                        PDFont font, float workablePageHeight)
+    {
+        final float newLineHeight = font.getFontDescriptor().getFontBoundingBox().getHeight() / 1000
+                * FONT_SIZE + LINE_GAP;
+        List<List<String>> realignedTexts = new ArrayList<>();
+        float consumedHeight = 0;
+        List<String> linesInAPage = new ArrayList<>();
+        for (String line : originalLines)
+        {
+            if (newLineHeight + consumedHeight < workablePageHeight)
+            {
+                consumedHeight += newLineHeight;
+            }
+            else
+            {
+                consumedHeight = newLineHeight;
+                realignedTexts.add(linesInAPage);
+                linesInAPage = new ArrayList<>();
+            }
+
+            linesInAPage.add(line);
+        }
+        realignedTexts.add(linesInAPage);
+        return realignedTexts;
+    }
+
+    private static List<String> getReAlignedTextBasedOnPageWidth(List<String> originalLines,
+                                                                 PDFont font, float workablePageWidth) throws IOException
+    {
+        List<String> uniformlyWideTexts = new ArrayList<>();
+        float consumedWidth = 0;
+        StringBuilder sb = new StringBuilder();
+        for (String line : originalLines)
+        {
+            float newTokenWidth = 0;
+            StringTokenizer st = new StringTokenizer(line, " ", true);
+            while (st.hasMoreElements())
+            {
+                String token = st.nextToken();
+                newTokenWidth = font.getStringWidth(token) / 1000 * FONT_SIZE;
+                if (newTokenWidth + consumedWidth < workablePageWidth)
+                {
+                    consumedWidth += newTokenWidth;
+                }
+                else
+                {
+                    // add a new text chunk
+                    uniformlyWideTexts.add(sb.toString());
+                    consumedWidth = newTokenWidth;
+                    sb = new StringBuilder();
+                }
+
+                sb.append(token);
+            }
+
+            // add a new text chunk
+            uniformlyWideTexts.add(sb.toString());
+            consumedWidth = newTokenWidth;
+            sb = new StringBuilder();
+        }
+
+        return uniformlyWideTexts;
+    }
+
+    private static PDRectangle getPageSize()
+    {
+        return PDRectangle.A4;
+    }
+
+    private static List<String> getBengaliTextFromFile() throws IOException
+    {
+        List<String> lines = new ArrayList<>();
+
+        try (BufferedReader br = new BufferedReader(new InputStreamReader(
+                BengaliPdfGenerationHelloWorld.class.getResourceAsStream(TEXT_SOURCE_FILE), StandardCharsets.UTF_8)))
+        {
+            while (true)
+            {
+                String line = br.readLine();
+
+                if (line == null)
+                {
+                    break;
+                }
+
+                if (!line.startsWith("#"))
+                {
+                    lines.add(line);
+                }
+            }
+        }
+
+        return lines;
+    }
+
+}

examples/src/main/java/org/apache/pdfbox/examples/pdmodel/glyphlayout/DoGlyphLayoutBidi.java

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+/*
+ * 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.
+ */
+
+package org.apache.pdfbox.examples.pdmodel.glyphlayout;
+
+import org.apache.pdfbox.pdmodel.GlyphLayoutProcessor;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.font.PDType0Font;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Examples for bidirectional text with GlyphLayoutProcessor
+ *
+ * @author Volker Kunert
+ * @version 2026-05
+ */
+public class DoGlyphLayoutBidi {
+    public static final String TEXT1 = "نحن الآن في شهر رمضان 1447 هجري";
+    public static final String TEXT2 = "Guten Tag ";
+    public static final String TEXT3 = "السلام عليكم";
+    public static final String TEXT4 = " Good afternoon";
+
+    /*
+     * Main
+     */
+    public static void main(String[] args) {
+        new DoGlyphLayoutBidi().test();
+    }
+
+    /*
+     * show one line
+     */
+    public static float showLine(PDPageContentStream cs, PDType0Font font, float fontSize,
+                                 float x, float y, String text) throws IOException {
+        return showLine(cs, new PDType0Font[]{font}, fontSize, x, y, new String[]{text});
+    }
+
+    /*
+     * show one line
+     */
+    public static float showLine(PDPageContentStream cs, PDType0Font[] fonts, float fontSize,
+                                 float x, float y, String[] texts) throws IOException {
+        cs.beginText();
+        cs.newLineAtOffset(x, y);
+
+        if (fonts.length != texts.length) {
+            throw new IllegalArgumentException("Size of fonts and texts is different");
+        }
+        for (int i = 0; i < texts.length; i++) {
+            cs.setFont(fonts[i], fontSize);
+            cs.showText(texts[i]);
+        }
+        cs.endText();
+
+        float height = fonts[0].getBoundingBox().getHeight();
+        y -= height / 1000f * fontSize;
+        return y;
+    }
+
+    /**
+     * Start the example
+     */
+    public void test() {
+        try {
+            GlyphLayoutProcessor glyphLayoutProcessor = new GlyphLayoutProcessor();
+
+            String outputFilename = "DoGlyphLayoutBidi.pdf";
+            String arabicPath = "/org/apache/pdfbox/examples/glyphlayout/noto/NotoSansArabic-Regular.ttf";
+            String lgcPath = "/org/apache/pdfbox/examples/glyphlayout/noto/NotoSans-Regular.ttf";
+
+            float fontSize = 12.0f;
+
+            PDDocument pdDocument = new PDDocument();
+
+            PDType0Font arabicFont = createPdType0Font(glyphLayoutProcessor, pdDocument, arabicPath);
+            PDType0Font lgcFont = createPdType0Font(glyphLayoutProcessor, pdDocument, lgcPath);
+
+            PDPage blankPage = new PDPage();
+            pdDocument.addPage(blankPage);
+            PDPageContentStream cs = new PDPageContentStream(pdDocument, pdDocument.getPage(0),
+                    PDPageContentStream.AppendMode.APPEND, true);
+            cs.setGlyphLayoutProcessor(glyphLayoutProcessor);
+
+            float x = blankPage.getBBox().getLowerLeftX() + fontSize;
+            float y = blankPage.getBBox().getUpperRightY() - fontSize;
+
+            y = showLine(cs, arabicFont, fontSize, x, y, TEXT1);
+            showLine(cs, new PDType0Font[]{lgcFont, arabicFont, lgcFont}, fontSize, x, y, new String[]{TEXT2, TEXT3, TEXT4});
+            cs.close();
+            pdDocument.save(outputFilename);
+            pdDocument.close();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    /*
+     * Create the PDType0Font font
+     */
+    private PDType0Font createPdType0Font(GlyphLayoutProcessor glyphLayoutProcessor, PDDocument pdDocument,
+                                          String fontPath) {
+        InputStream fontStream = this.getClass().
+                getResourceAsStream(fontPath);
+        PDType0Font font = glyphLayoutProcessor.loadFont(pdDocument, fontStream);
+        return font;
+    }
+}