POC PDFBox line wrapping

Author: fugerit79

CHANGELOG.md

@@ -9,7 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Test for pdfbox special characters : U+2002 ('enspace')
+- POC PDFBox line wrapping
+- POC PDFBox special characters : U+2002 ('enspace')
 - Module pdfbox 
 - AgeCheck with tests
 

code-samples-pdfbox2/src/main/java/org/fugerit/java/code/samples/pdfbox2/LineWrapping.java

@@ -0,0 +1,76 @@
+package org.fugerit.java.code.samples.pdfbox2;
+
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.font.PDFont;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Line wrapping test.
+ *
+ * This code will wrap text on more lines if it is longer than maximum page width.
+ */
+public class LineWrapping {
+
+    private void handleLine( String l, List<String> list, int maxSize ) {
+        String[] splits = l.split( " " );
+        StringBuilder builder = new StringBuilder();
+        for ( int i=0; i<splits.length; i++ ) {
+            String s = splits[i];
+            if ( builder.length() + s.length() > maxSize ) {
+                list.add( builder.toString() );
+                builder = new StringBuilder();
+            }
+            builder.append( s );
+            if ( i != splits.length - 1 ) {
+                builder.append( " " );
+            }
+        }
+        list.add( builder.toString() );
+    }
+
+    private List<String> splitLines( String[] lines, int maxSize ) {
+        List<String> list = new ArrayList<>();
+        for ( String l : lines ) {
+            if ( l.length() > maxSize ) {
+                this.handleLine( l, list, maxSize );
+            } else {
+                list.add( l );
+            }
+        }
+        return list;
+    }
+
+    public void generatePDF(OutputStream os, PDFont font, String[] lines) throws IOException {
+        try (PDDocument document = new PDDocument()) {
+            PDPage currentPage = new PDPage();
+            PDPageContentStream cs = new PDPageContentStream( document, currentPage );
+            float fontSize = 14;
+            float leading = 12;
+            cs.setFont( font, fontSize );
+            cs.setLeading( leading );
+            float baseX = 25;
+            float baseY = 750;
+            float offsetY = 0;
+            float maxPageWidth = 1400;
+            int maxLineLength = (int)(maxPageWidth/fontSize);  // actual formula can be different depending on font
+            List<String> list = splitLines( lines, maxLineLength );
+            for ( String s : list ) {
+                cs.beginText();
+                cs.newLineAtOffset( baseX, baseY+offsetY );
+                cs.showText( s );
+                cs.endText();
+                offsetY-= fontSize;
+            }
+            cs.stroke();
+            cs.close();
+            document.addPage( currentPage );
+            document.save( os );
+        }
+    }
+
+}

code-samples-pdfbox2/src/test/java/test/org/fugerit/java/code/samples/pdfbox2/TestLineWrapping.java

@@ -0,0 +1,39 @@
+package test.org.fugerit.java.code.samples.pdfbox2;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.pdfbox.pdmodel.font.PDType1Font;
+import org.fugerit.java.code.samples.pdfbox2.LineWrapping;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+
+/*
+ * Proof of Concept to handle PDFBox line wrapping.
+ *
+ * PDFBox is a low level library and does not wrap text OOTB.
+ *
+ *
+ */
+@Slf4j
+class TestLineWrapping {
+
+    private static final String[] LINES = {
+            "Row 1 test",
+            "Row 2 test, this is a long line that needs line wrapping, let's see how it works. Hopefully this line will show up on two lines.",
+            "Row 3 test",
+    };
+
+    @Test
+    void testLineWrapping() throws IOException {
+        LineWrapping handler = new LineWrapping();
+        File pdfFile = new File( "target/test_line_wrapping.pdf" );
+        log.info( "pdfFile: {}, delete: {}", pdfFile, pdfFile.delete() );
+        Assertions.assertFalse( pdfFile.exists() );
+        try (OutputStream os = new FileOutputStream( pdfFile ) ) {
+            handler.generatePDF(os, PDType1Font.HELVETICA, LINES );
+        }
+        Assertions.assertTrue( pdfFile.exists() );
+    }
+
+}