Add background image support for text elements for layout module

DEVSIX-4142

Author: BezrukovM

layout/src/main/java/com/itextpdf/layout/renderer/AbstractRenderer.java

@@ -506,7 +506,7 @@ public void drawBackground(DrawContext drawContext) {
             if (isTagged) {
                 drawContext.getCanvas().openTag(new CanvasArtifact());
             }
-            Rectangle backgroundArea = applyMargins(bBox, false);
+            Rectangle backgroundArea = getBackgroundArea(applyMargins(bBox, false));
             if (backgroundArea.getWidth() <= 0 || backgroundArea.getHeight() <= 0) {
                 Logger logger = LoggerFactory.getLogger(AbstractRenderer.class);
                 logger.warn(MessageFormatUtil.format(LogMessageConstant.RECTANGLE_HAS_NEGATIVE_OR_ZERO_SIZES, "background"));
@@ -590,6 +590,16 @@ public PdfFormXObject createXObject(AbstractLinearGradientBuilder linearGradient
         return xObject;
     }
 
+    /**
+     * Evaluate the actual background
+     *
+     * @param occupiedAreaWithMargins the current occupied area with applied margins
+     * @return the actual background area
+     */
+    protected Rectangle getBackgroundArea(Rectangle occupiedAreaWithMargins) {
+        return occupiedAreaWithMargins;
+    }
+
     protected boolean clipBorderArea(DrawContext drawContext, Rectangle outerBorderBox) {
         return clipArea(drawContext, outerBorderBox, true, true, false, true);
     }

layout/src/main/java/com/itextpdf/layout/renderer/TextRenderer.java

@@ -856,37 +856,6 @@ public boolean accept(Glyph glyph) {
         }
     }
 
-    @Override
-    public void drawBackground(DrawContext drawContext) {
-        Background background = this.<Background>getProperty(Property.BACKGROUND);
-        Float textRise = this.getPropertyAsFloat(Property.TEXT_RISE);
-        Rectangle bBox = getOccupiedAreaBBox();
-        Rectangle backgroundArea = applyMargins(bBox, false);
-        float bottomBBoxY = backgroundArea.getY();
-        float leftBBoxX = backgroundArea.getX();
-        if (background != null) {
-            boolean isTagged = drawContext.isTaggingEnabled();
-            PdfCanvas canvas = drawContext.getCanvas();
-            if (isTagged) {
-                canvas.openTag(new CanvasArtifact());
-            }
-            boolean backgroundAreaIsClipped = clipBackgroundArea(drawContext, backgroundArea);
-            canvas.saveState().setFillColor(background.getColor());
-            TransparentColor backgroundColor = new TransparentColor(background.getColor(), background.getOpacity());
-            backgroundColor.applyFillTransparency(drawContext.getCanvas());
-            canvas.rectangle(leftBBoxX - background.getExtraLeft(), bottomBBoxY + (float) textRise - background.getExtraBottom(),
-                    backgroundArea.getWidth() + background.getExtraLeft() + background.getExtraRight(),
-                    backgroundArea.getHeight() - (float) textRise + background.getExtraTop() + background.getExtraBottom());
-            canvas.fill().restoreState();
-            if (backgroundAreaIsClipped) {
-                drawContext.getCanvas().restoreState();
-            }
-            if (isTagged) {
-                canvas.closeTag();
-            }
-        }
-    }
-
     /**
      * Trims any whitespace characters from the start of the {@link GlyphLine}
      * to be rendered.
@@ -1116,6 +1085,12 @@ private boolean hasOtfFont() {
         return font instanceof PdfType0Font && font.getFontProgram() instanceof TrueTypeFont;
     }
 
+    @Override
+    protected Rectangle getBackgroundArea(Rectangle occupiedAreaWithMargins) {
+        float textRise = (float) this.getPropertyAsFloat(Property.TEXT_RISE);
+        return occupiedAreaWithMargins.moveUp(textRise).decreaseHeight(textRise);
+    }
+
     @Override
     protected Float getFirstYLineRecursively() {
         return getYLine();

layout/src/test/java/com/itextpdf/layout/BackgroundImageTest.java

@@ -58,11 +58,9 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.utils.CompareTool;
 import com.itextpdf.layout.element.Div;
 import com.itextpdf.layout.element.Paragraph;
+import com.itextpdf.layout.element.Text;
 import com.itextpdf.layout.property.BackgroundImage;
 import com.itextpdf.layout.property.Property;
-import com.itextpdf.layout.property.Transform;
-import com.itextpdf.layout.property.Transform.SingleTransform;
-import com.itextpdf.layout.property.UnitValue;
 import com.itextpdf.test.ExtendedITextTest;
 import com.itextpdf.test.LogLevelConstants;
 import com.itextpdf.test.annotations.LogMessage;
@@ -122,6 +120,34 @@ public void backgroundImageWithLinearGradientAndTransformTest() throws IOExcepti
         backgroundImageGenericTest("backgroundImageWithLinearGradientAndTransform", backgroundImage, Math.PI / 4);
     }
 
+    @Test
+    public void backgroundImageForText() throws IOException, InterruptedException {
+        PdfImageXObject xObject = new PdfImageXObject(ImageDataFactory.create(sourceFolder + "itis.jpg"));
+        BackgroundImage backgroundImage = new BackgroundImage(xObject);
+
+        Assert.assertTrue(backgroundImage.isRepeatX());
+        Assert.assertTrue(backgroundImage.isRepeatY());
+
+        Assert.assertTrue(backgroundImage.isBackgroundSpecified());
+
+        String outFileName = destinationFolder + "backgroundImageForText.pdf";
+        String cmpFileName = sourceFolder + "cmp_backgroundImageForText.pdf";
+
+        try (PdfDocument pdfDocument = new PdfDocument(new PdfWriter(new FileOutputStream(outFileName)))) {
+            Document doc = new Document(pdfDocument);
+
+            Text textElement = new Text("Lorem ipsum dolor sit amet, consectetur adipiscing elit, " +
+                    "sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. ");
+            textElement.setProperty(Property.BACKGROUND_IMAGE, backgroundImage);
+            textElement.setFontSize(50);
+
+            doc.add(new Paragraph(textElement));
+
+        }
+
+        Assert.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
+    }
+
     @Test
     public void backgroundImageWithoutRepeatX() throws IOException, InterruptedException {
         PdfImageXObject xObject = new PdfImageXObject(ImageDataFactory.create(sourceFolder + "itis.jpg"));