8307363: TextFlow.underlineShape()

Reviewed-by: prr, kcr

modules/javafx.graphics/src/main/java/javafx/scene/text/TextFlow.java

@@ -231,6 +231,18 @@ public final PathElement[] rangeShape(int start, int end) {
         return getRange(start, end, TextLayout.TYPE_TEXT);
     }
 
+    /**
+     * Returns the shape for the underline in local coordinates.
+     *
+     * @param start the beginning character index for the range
+     * @param end the end character index (non-inclusive) for the range
+     * @return an array of {@code PathElement} which can be used to create a {@code Shape}
+     * @since 21
+     */
+    public final PathElement[] underlineShape(int start, int end) {
+        return getRange(start, end, TextLayout.TYPE_UNDERLINE);
+    }
+
     @Override
     public boolean usesMirroring() {
         return false;

tests/manual/monkey/src/com/oracle/tools/fx/monkey/pages/TextFlowPage.java

@@ -58,11 +58,13 @@ public class TextFlowPage extends TestPaneBase {
     protected final FontSelector fontSelector;
     protected final CheckBox showChars;
     protected final CheckBox showCaretPath;
+    protected final CheckBox underline;
     protected final TextFlow control;
     protected final Label pickResult;
     protected final Label hitInfo;
     protected final Label hitInfo2;
     protected final Path caretPath;
+    protected final Path underlinePath;
     private static final String INLINE = "$INLINE";
     private static final String RICH_TEXT = "$RICH";
 
@@ -83,6 +85,12 @@ public TextFlowPage() {
         caretPath.setStroke(Color.RED);
         caretPath.setManaged(false);
 
+        underlinePath = new Path();
+        underlinePath.setStrokeWidth(1);
+        underlinePath.setStroke(Color.GREEN);
+        underlinePath.setFill(Color.YELLOW);
+        underlinePath.setManaged(false);
+
         textSelector = TextSelector.fromPairs(
             "textSelector",
             (t) -> updateControl(),
@@ -104,7 +112,13 @@ public TextFlowPage() {
         showCaretPath = new CheckBox("show caret path");
         showCaretPath.setId("showCaretPath");
         showCaretPath.selectedProperty().addListener((p) -> {
-            updateControl();
+            updateCaret();
+        });
+
+        underline = new CheckBox("underline shape");
+        underline.setId("underline");
+        underline.selectedProperty().addListener((p) -> {
+            updateUnderline();
         });
 
         OptionPane p = new OptionPane();
@@ -116,6 +130,7 @@ public TextFlowPage() {
         p.option(fontSelector.sizeNode());
         p.option(showChars);
         p.option(showCaretPath);
+        p.option(underline);
         p.option(new Separator(Orientation.HORIZONTAL));
         p.label("Pick Result:");
         p.option(pickResult);
@@ -142,16 +157,12 @@ protected void updateControl() {
             control.getChildren().add(g);
         }
 
-        if (showCaretPath.isSelected()) {
-            caretPath.getElements().clear();
-            control.getChildren().add(caretPath);
+        caretPath.getElements().clear();
+        underlinePath.getElements().clear();
+        control.getChildren().addAll(underlinePath, caretPath);
 
-            int len = computeTextLength(control);
-            for (int i = 0; i < len; i++) {
-                PathElement[] es = control.caretShape(i, true);
-                caretPath.getElements().addAll(es);
-            }
-        }
+        updateCaret();
+        updateUnderline();
     }
 
     /** TextFlow.getTextLength() */
@@ -160,8 +171,10 @@ private static int computeTextLength(TextFlow f) {
         for (Node n: f.getChildrenUnmodifiable()) {
             if (n instanceof Text t) {
                 len += t.getText().length();
+            } else {
+                // treat any other nodes as having length 1
+                len++;
             }
-            // embedded nodes do not have an associated text
         }
         return len;
     }
@@ -221,4 +234,26 @@ protected void handleMouseEvent(MouseEvent ev) {
         HitInfo h = control.hitTest(p);
         hitInfo.setText(String.valueOf(h));
     }
+
+    protected void updateUnderline() {
+        if (underline.isSelected()) {
+            int len = computeTextLength(control);
+            PathElement[] es = control.underlineShape(0, len);
+            underlinePath.getElements().addAll(es);
+        } else {
+            underlinePath.getElements().clear();
+        }
+    }
+
+    protected void updateCaret() {
+        if (showCaretPath.isSelected()) {
+            int len = computeTextLength(control);
+            for (int i = 0; i < len; i++) {
+                PathElement[] es = control.caretShape(i, true);
+                caretPath.getElements().addAll(es);
+            }
+        } else {
+            caretPath.getElements().clear();
+        }
+    }
 }

tests/system/src/test/java/test/javafx/scene/text/TextFlowNodeTest.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package test.javafx.scene.text;
+
+import java.util.concurrent.CountDownLatch;
+import javafx.geometry.Bounds;
+import javafx.scene.shape.Path;
+import javafx.scene.shape.PathElement;
+import javafx.scene.text.Font;
+import javafx.scene.text.Text;
+import javafx.scene.text.TextFlow;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import test.util.Util;
+
+/**
+ * Tests TextFlow Node
+ */
+public class TextFlowNodeTest {
+    @BeforeClass
+    public static void initFX() {
+        CountDownLatch startupLatch = new CountDownLatch(1);
+        Util.startup(startupLatch, startupLatch::countDown);
+    }
+
+    @Test
+    public void testUnderlineShape() {
+        Text t1 = new Text("one ");
+        t1.setFont(new Font("Monospaced Regular", 16));
+        Text t2 = new Text("two.");
+        TextFlow f = new TextFlow(t1, t2);
+
+        // underline 0,0 must be empty
+        PathElement[] p = f.underlineShape(0, 0);
+        Assert.assertNotNull(p);
+        Assert.assertEquals(0, p.length);
+
+        // underline 1,0 .. 1,len must increase monotonically
+        int len = t1.getText().length() + t2.getText().length();
+        double w = 0.0;
+        for (int i = 1; i < len; i++) {
+            p = f.underlineShape(0, i);
+            Assert.assertNotNull(p);
+
+            // width must increase
+            Bounds b = new Path(p).getBoundsInLocal();
+            Assert.assertTrue(b.getWidth() > w);
+            w = b.getWidth();
+
+            // test height greater than zero
+            Assert.assertTrue(b.getHeight() > 0.0);
+        }
+
+        // 0,1000 same as 0,len
+        Bounds b1 = new Path(f.underlineShape(0, len)).getBoundsInLocal();
+        Bounds b2 = new Path(f.underlineShape(0, 1000)).getBoundsInLocal();
+        Assert.assertEquals(b1, b2);
+        Assert.assertTrue(b1.getHeight() > 0.0);
+    }
+}