SVG: support text-decoration attribute

DEVSIX-2270

Author: AnhelinaM

layout/src/main/java/com/itextpdf/layout/ElementPropertyContainer.java

@@ -722,36 +722,53 @@ public T setUnderline(Color color, float thickness, float thicknessMul, float yP
     }
 
     /**
-     * Sets an horizontal line that can be an underline or a strikethrough.
+     * Sets horizontal line that can be an underline or a strikethrough.
      * Actually, the line can be anywhere vertically due to position parameter.
      * Multiple call to this method will produce multiple lines.
+     *
      * <p>
      * The thickness of the line will be {@code thickness + thicknessMul * fontSize}.
      * The position of the line will be {@code baseLine + yPosition + yPositionMul * fontSize}.
      *
      * @param color        the color of the line or <CODE>null</CODE> to follow the
      *                     text color
-     * @param opacity      the opacity of the line; a float between 0 and 1, where 1 stands for fully opaque color and 0 - for fully transparent
+     * @param opacity      the opacity of the line; a float between 0 and 1, where 1 stands for fully opaque color and
+     *                     0 - for fully transparent
      * @param thickness    the absolute thickness of the line
      * @param thicknessMul the thickness multiplication factor with the font size
      * @param yPosition    the absolute y position relative to the baseline
      * @param yPositionMul the position multiplication factor with the font size
      * @param lineCapStyle the end line cap style. Allowed values are enumerated in
      *                     {@link com.itextpdf.kernel.pdf.canvas.PdfCanvasConstants.LineCapStyle}
+     *
+     * @return this element
+     */
+    public T setUnderline(Color color, float opacity, float thickness, float thicknessMul, float yPosition,
+                          float yPositionMul, int lineCapStyle) {
+        return setUnderline(new Underline(color, opacity, thickness, thicknessMul, yPosition,
+                yPositionMul, lineCapStyle));
+    }
+
+    /**
+     * Sets horizontal line that can be an underline, overline or a strikethrough.
+     * Actually, the line can be anywhere vertically due to position parameter.
+     * Multiple call to this method will produce multiple lines.
+     *
+     * @param underline {@link Underline} to set
+     *
      * @return this element
      */
-    public T setUnderline(Color color, float opacity, float thickness, float thicknessMul, float yPosition, float yPositionMul, int lineCapStyle) {
-        Underline newUnderline = new Underline(color, opacity, thickness, thicknessMul, yPosition, yPositionMul, lineCapStyle);
+    public T setUnderline(Underline underline) {
         Object currentProperty = this.<Object>getProperty(Property.UNDERLINE);
         if (currentProperty instanceof List) {
-            ((List) currentProperty).add(newUnderline);
+            ((List) currentProperty).add(underline);
         } else if (currentProperty instanceof Underline) {
             List<Underline> mergedUnderlines = new ArrayList<>();
             mergedUnderlines.add((Underline) currentProperty);
-            mergedUnderlines.add(newUnderline);
+            mergedUnderlines.add(underline);
             setProperty(Property.UNDERLINE, mergedUnderlines);
         } else {
-            setProperty(Property.UNDERLINE, newUnderline);
+            setProperty(Property.UNDERLINE, underline);
         }
         return (T) (Object) this;
     }

layout/src/main/java/com/itextpdf/layout/properties/Underline.java

@@ -29,9 +29,10 @@ This file is part of the iText (R) project.
 
 /**
  * A POJO that describes the underline of a layout element.
- * 
+ *
+ * <p>
  * This class is to be used as a property for an element or renderer,
- * as the value for {@link com.itextpdf.layout.properties.Property#UNDERLINE}
+ * as the value for {@link com.itextpdf.layout.properties.Property#UNDERLINE}.
  */
 public class Underline {
     protected TransparentColor transparentColor;
@@ -41,6 +42,9 @@ public class Underline {
     protected float yPositionMul;
     protected int lineCapStyle = PdfCanvasConstants.LineCapStyle.BUTT;
 
+    private TransparentColor strokeColor;
+    private float strokeWidth = 0f;
+
     /**
      * Creates an Underline. Both the thickness and vertical positioning under
      * the text element's base line can be set to a fixed value, or a variable
@@ -137,4 +141,46 @@ public float getYPositionMul() {
     public int getLineCapStyle() {
         return lineCapStyle;
     }
+
+    /**
+     * Gets the color of the underline stroke.
+     *
+     * @return {@link TransparentColor} stroke color
+     */
+    public TransparentColor getStrokeColor() {
+        return strokeColor;
+    }
+
+    /**
+     * Sets the stroke color of the underline.
+     *
+     * @param strokeColor {@link TransparentColor} stroke color
+     *
+     * @return this {@link Underline} instance
+     */
+    public Underline setStrokeColor(TransparentColor strokeColor) {
+        this.strokeColor = strokeColor;
+        return this;
+    }
+
+    /**
+     * Gets the thickness of the underline stroke.
+     *
+     * @return float value of the stroke width
+     */
+    public float getStrokeWidth() {
+        return strokeWidth;
+    }
+
+    /**
+     * Sets the thickness of the underline stroke.
+     *
+     * @param strokeWidth float value of the stroke width
+     *
+     * @return this {@link Underline} instance
+     */
+    public Underline setStrokeWidth(float strokeWidth) {
+        this.strokeWidth = strokeWidth;
+        return this;
+    }
 }

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

@@ -1489,27 +1489,57 @@ protected TextRenderer[] split(int initialOverflowTextPos) {
         return new TextRenderer[]{splitRenderer, overflowRenderer};
     }
 
-    protected void drawSingleUnderline(Underline underline, TransparentColor fontStrokeColor, PdfCanvas canvas, float fontSize, float italicAngleTan) {
-        TransparentColor underlineColor = underline.getColor() != null ? new TransparentColor(underline.getColor(), underline.getOpacity()) : fontStrokeColor;
-        canvas.saveState();
+    protected void drawSingleUnderline(Underline underline, TransparentColor fontColor, PdfCanvas canvas,
+                                       float fontSize, float italicAngleTan) {
+        TransparentColor underlineFillColor = underline.getColor() != null ?
+                new TransparentColor(underline.getColor(), underline.getOpacity()) : null;
+        TransparentColor underlineStrokeColor = underline.getStrokeColor();
+
+        boolean doStroke = underlineStrokeColor != null;
+        RenderingMode mode = this.<RenderingMode>getProperty(Property.RENDERING_MODE);
+        // In SVG mode we should always use underline color, it is not related to the font color of the current text,
+        // but to the font color of the text element where text-decoration has been declared. In case of none value
+        // for fill and stroke in SVG mode, underline shouldn't be drawn at all.
+        if (underlineFillColor == null && !doStroke) {
+            if (RenderingMode.SVG_MODE == mode) {
+                return;
+            }
+            underlineFillColor = fontColor;
+        }
+        boolean doFill = underlineFillColor != null;
 
-        if (underlineColor != null) {
-            canvas.setStrokeColor(underlineColor.getColor());
-            underlineColor.applyStrokeTransparency(canvas);
+        canvas.saveState();
+        if (doFill) {
+            canvas.setFillColor(underlineFillColor.getColor());
+            underlineFillColor.applyFillTransparency(canvas);
+        }
+        if (doStroke) {
+            canvas.setStrokeColor(underlineStrokeColor.getColor());
+            underlineStrokeColor.applyStrokeTransparency(canvas);
         }
         canvas.setLineCapStyle(underline.getLineCapStyle());
         float underlineThickness = underline.getThickness(fontSize);
         if (underlineThickness != 0) {
-            canvas.setLineWidth(underlineThickness);
+            if (doStroke) {
+                canvas.setLineWidth(underline.getStrokeWidth());
+            }
             float yLine = getYLine();
             float underlineYPosition = underline.getYPosition(fontSize) + yLine;
             float italicWidthSubstraction = .5f * fontSize * italicAngleTan;
             Rectangle innerAreaBbox = getInnerAreaBBox();
-            canvas.moveTo(innerAreaBbox.getX(), underlineYPosition).
-                    lineTo(innerAreaBbox.getX() + innerAreaBbox.getWidth() - italicWidthSubstraction, underlineYPosition).
-                    stroke();
+            Rectangle underlineBBox = new Rectangle(innerAreaBbox.getX(), underlineYPosition - underlineThickness / 2,
+                    innerAreaBbox.getWidth() - italicWidthSubstraction, underlineThickness);
+            canvas.rectangle(underlineBBox);
+            if (doFill && doStroke) {
+                canvas.fillStroke();
+            } else if (doStroke) {
+                canvas.stroke();
+            } else {
+                // In layout/html we should use default color in case underline and fontColor are null
+                // and still draw underline.
+                canvas.fill();
+            }
         }
-
         canvas.restoreState();
     }
 

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

@@ -39,6 +39,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.layout.properties.FloatPropertyValue;
 import com.itextpdf.layout.properties.OverflowPropertyValue;
 import com.itextpdf.layout.properties.Property;
+import com.itextpdf.layout.properties.TransparentColor;
+import com.itextpdf.layout.properties.Underline;
 import com.itextpdf.test.ExtendedITextTest;
 
 import java.io.IOException;
@@ -340,6 +342,47 @@ public void underlineTest() throws IOException, InterruptedException {
         Assertions.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
     }
 
+    @Test
+    public void strokedUnderlineTest() throws IOException, InterruptedException {
+        String outFileName = destinationFolder + "strokedUnderline.pdf";
+        String cmpFileName = sourceFolder + "cmp_strokedUnderline.pdf";
+        try (PdfDocument pdfDocument = new PdfDocument(new PdfWriter(outFileName));
+             Document document = new Document(pdfDocument)) {
+
+            Paragraph p = new Paragraph("Yellow text with pink stroked underline.")
+                    .setFontSize(50).setFontColor(ColorConstants.YELLOW);
+            Underline underline = new Underline(null, 0, 0.1f, 0, -0.1f, PdfCanvasConstants.LineCapStyle.BUTT)
+                    .setStrokeWidth(2).setStrokeColor(new TransparentColor(ColorConstants.PINK, 0.5f));
+            p.setUnderline(underline);
+
+            Paragraph p2 = new Paragraph("Text with line-through and default underline.")
+                    .setFontSize(50).setStrokeWidth(1).setFontColor(ColorConstants.DARK_GRAY)
+                    .setStrokeColor(ColorConstants.GREEN);
+            Underline underline2 = new Underline(ColorConstants.DARK_GRAY, 0, 0.1f, 0, 0.3f,
+                    PdfCanvasConstants.LineCapStyle.BUTT)
+                    .setStrokeWidth(1).setStrokeColor(new TransparentColor(ColorConstants.GREEN));
+            p2.setUnderline(underline2);
+            p2.setUnderline();
+
+            Paragraph p3 = new Paragraph("Text with transparent font color and default overline.").setFontSize(50)
+                    .setFontColor(new TransparentColor(ColorConstants.BLUE, 0));
+            Underline underline3 = new Underline(null, 0, 0.1f, 0, 0.9f, PdfCanvasConstants.LineCapStyle.BUTT);
+            p3.setUnderline(underline3);
+            p3.setBackgroundColor(ColorConstants.PINK);
+
+            Paragraph p4 = new Paragraph("Text with null font color and default overline.").setFontSize(50)
+                    .setFontColor((TransparentColor) null);
+            p4.setUnderline(underline3);
+
+            document.add(p);
+            document.add(p2);
+            document.add(p3);
+            document.add(p4);
+        }
+
+        Assertions.assertNull(new CompareTool().compareByContent(outFileName, cmpFileName, destinationFolder, "diff"));
+    }
+
     @Test
     public void lineThroughTest() throws IOException, InterruptedException {
         //TODO: update after DEVSIX-2623 fix