Bug 570208 - Rendering/Scroll issue with vertical indent

Change-Id: I291c0a242a17b3ec76d13b7a061ddcd3d0775383
Signed-off-by: Mickael Istria <mistria@redhat.com>

3 files changed, 47 insertions, 9 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledText.java b/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledText.java
index 986c4fc54d..e6b827f407 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledText.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledText.java
@@ -9449,15 +9449,18 @@ public void setLineVerticalIndent(int lineIndex, int verticalLineIndent) {
 	}
 	int initialTopPixel = getTopPixel();
 	int initialTopIndex = getPartialTopIndex();
-	int initialBottonIndex = getPartialBottomIndex();
+	int initialBottomIndex = getPartialBottomIndex();
 	int verticalIndentDiff = verticalLineIndent - previousVerticalIndent;
 	renderer.setLineVerticalIndent(lineIndex, verticalLineIndent);
 	this.hasVerticalIndent = verticalLineIndent != 0 || renderer.hasVerticalIndent();
 	resetCache(lineIndex, 1);
-	if (lineIndex < initialTopIndex || lineIndex > getPartialBottomIndex()) {
+	if (lineIndex < initialTopIndex) {
+		verticalScrollOffset += verticalIndentDiff; // just change value, don't actually scroll/redraw
+		setScrollBars(true);
+	} else if (lineIndex > initialBottomIndex) {
 		setScrollBars(true);
 	} else {
-		if (getCaretLine() >= initialTopIndex && getCaretLine() <= initialBottonIndex) { // caret line with caret mustn't move
+		if (getCaretLine() >= initialTopIndex && getCaretLine() <= initialBottomIndex) { // caret line with caret mustn't move
 			if (getCaretLine() < lineIndex) {
 				redrawLines(lineIndex, getPartialBottomIndex() - lineIndex + 1, true);
 			} else {
@@ -9471,6 +9474,7 @@ public void setLineVerticalIndent(int lineIndex, int verticalLineIndent) {
 				redrawLines(lineIndex, getPartialBottomIndex() - lineIndex + 1, true);
 			}
 		}
+		setScrollBars(true);
 	}
 }
 
diff --git a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_custom_StyledText.java b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_custom_StyledText.java
index c9c3994a2a..6706c94458 100644
--- a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_custom_StyledText.java
+++ b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_custom_StyledText.java
@@ -4925,10 +4925,11 @@ public void test_verticalIndent_changeRelativeBounds() {
 }
 
 @Test
-public void test_verticalIndent_keepsCurrentCaretAndLinePosition() throws InterruptedException {
+public void test_verticalIndent_keepsCurrentCaretAndLinePosition() {
 	String _50lines = IntStream.range(1, 50).mapToObj(Integer::toString).collect(Collectors.joining("\n"));
 	text.setText(_50lines);
 	text.setSize(500, 200);
+	final int INDENT = 34;
 	int line = 30;
 	int offset = text.getOffsetAtLine(line);
 	text.setSelection(offset);
@@ -4937,49 +4938,62 @@ public void test_verticalIndent_keepsCurrentCaretAndLinePosition() throws Interr
 	line = text.getLineIndex(text.getClientArea().height / 2);
 	offset = text.getOffsetAtLine(line);
 	text.setSelection(offset);
+	int initialTopPixel = text.getTopPixel();
 	Point caretLocation = text.getCaret().getLocation();
 	Point offsetLocation = text.getLocationAtOffset(offset);
 
 	// on active line
-	text.setLineVerticalIndent(line, 34);
+	text.setLineVerticalIndent(line, INDENT);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("vertical scroll should have been updated", initialTopPixel + INDENT, text.getTopPixel());
 	text.setLineVerticalIndent(line, 0);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("vertical scroll should have been restored", initialTopPixel, text.getTopPixel());
 
 	// above visible area
-	text.setLineVerticalIndent(0, 34);
+	//render(shell, 5000);
+	text.setLineVerticalIndent(0, INDENT);
+	//render(shell, 5000);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("vertical scroll should have been updated", initialTopPixel + INDENT, text.getTopPixel());
 	text.setLineVerticalIndent(0, 0);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("vertical scroll should have been updated", initialTopPixel, text.getTopPixel());
 
 	//below visible area
 	int nextInvisibleLine = text.getLineIndex(text.getClientArea().height - 1) + 1;
-	text.setLineVerticalIndent(nextInvisibleLine, 34);
+	text.setLineVerticalIndent(nextInvisibleLine, INDENT);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("Vertical scroll shouldn't be modified",initialTopPixel, text.getTopPixel());
 	text.setLineVerticalIndent(nextInvisibleLine, 0);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("Vertical scroll shouldn't be modified",initialTopPixel, text.getTopPixel());
 
 	// above active line, in visible area
-	text.setLineVerticalIndent(line - 2, 34);
+	text.setLineVerticalIndent(line - 2, INDENT);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("Vertical scroll should have been updated",initialTopPixel + INDENT, text.getTopPixel());
 	text.setLineVerticalIndent(line - 2, 0);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("Vertical scroll should have been restored",initialTopPixel, text.getTopPixel());
 
 	// below active line, in visible area
-	text.setLineVerticalIndent(line + 2, 34);
+	text.setLineVerticalIndent(line + 2, INDENT);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("Vertical scroll shouldn't be modified",initialTopPixel, text.getTopPixel());
 	text.setLineVerticalIndent(line + 2, 0);
 	assertEquals(caretLocation, text.getCaret().getLocation());
 	assertEquals(offsetLocation, text.getLocationAtOffset(offset));
+	assertEquals("Vertical scroll shouldn't be modified",initialTopPixel, text.getTopPixel());
 }
 
 @Test
diff --git a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Widget.java b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Widget.java
index 8fdcaad62f..9dcab165c3 100644
--- a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Widget.java
+++ b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Widget.java
@@ -251,6 +251,26 @@ protected void processEvents(int timeoutMs, BooleanSupplier breakCondition) thro
 	}
 }
 
+/**
+ * Renders the shell and process events for duration.
+ * Convenience method for debugging tests, ⚠️ should not be
+ * called for headless tests!
+ * @param shell The shell to render.
+ * @param durationMs duration in milliseconds. Method exits after duration.
+ * @throws InterruptedException
+ */
+protected void render(Shell shell, int durationMs) throws InterruptedException {
+	long timestamp = System.currentTimeMillis();
+	shell.pack();
+	shell.layout();
+	shell.setVisible(true);
+	while (System.currentTimeMillis() - timestamp < durationMs) {
+		if (!shell.getDisplay().readAndDispatch()) {
+			Thread.sleep(50);
+		}
+	}
+}
+
 protected void assertNotExists(Widget[] widgetTable, Widget w) {
 	for (Widget widget : widgetTable) {
 		if(widget == w) {