Bug 564162 - [Win] Disabled Checkbox with set foreground color is drawn slightly left compared to an enabled one

The problem was caused by a hardcoded value of 16.

Change-Id: I173c7d324704b78c8b8259b44144ff03ecba5e60
Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>

2 files changed, 76 insertions, 8 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java
index 25efa6873f..1e13f27a95 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Button.java
@@ -60,6 +60,7 @@ public class Button extends Control {
 	static final int CHECK_WIDTH, CHECK_HEIGHT;
 	static final int ICON_WIDTH = 128, ICON_HEIGHT = 128;
 	static /*final*/ boolean COMMAND_LINK = false;
+	static final char[] STRING_WITH_ZERO_CHAR = new char[] {'0'};
 	static final long ButtonProc;
 	static final TCHAR ButtonClass = new TCHAR (0, "BUTTON", true);
 	static {
@@ -1290,6 +1291,25 @@ LRESULT wmCommandChild (long wParam, long lParam) {
 	return super.wmCommandChild (wParam, lParam);
 }
 
+private int getCheckboxTextOffset(long hdc) {
+	int result = 0;
+
+	SIZE size = new SIZE();
+
+	if (OS.IsAppThemed ()) {
+		OS.GetThemePartSize(display.hButtonTheme(), hdc, OS.BP_CHECKBOX, OS.CBS_UNCHECKEDNORMAL, null, OS.TS_TRUE, size);
+		result += size.cx;
+	} else {
+		result += DPIUtil.autoScaleUpUsingNativeDPI(13);
+	}
+
+	// Windows uses half width of '0' as checkbox-to-text distance.
+	OS.GetTextExtentPoint32(hdc, STRING_WITH_ZERO_CHAR, 1, size);
+	result += size.cx / 2;
+
+	return result;
+}
+
 @Override
 LRESULT wmNotifyChild (NMHDR hdr, long wParam, long lParam) {
 	switch (hdr.code) {
@@ -1319,14 +1339,7 @@ LRESULT wmNotifyChild (NMHDR hdr, long wParam, long lParam) {
 						OS.DeleteObject(brush);
 					}
 					if (customForegroundDrawing()) {
-						/*
-						 * Check-box/Radio buttons are native widget which honors
-						 * the Win OS zoom level for both 'Square' and 'Text' part
-						 * [Note: By-design SWT doesn't control native auto-scaling]
-						 * Hence, custom fore-ground draw logic should auto-scale
-						 * text-padding as per OS Native DPI level to fix bug 506371
-						 */
-						int radioOrCheckTextPadding = DPIUtil.autoScaleUpUsingNativeDPI(16);
+						int radioOrCheckTextPadding = getCheckboxTextOffset(nmcd.hdc);
 						int border = isRadioOrCheck() ? 0 : 3;
 						int left = nmcd.left + border;
 						int right = nmcd.right - border;
diff --git a/tests/org.eclipse.swt.tests/ManualTests/org/eclipse/swt/tests/manual/Bug564162_OwnerdrawCheckboxLayout.java b/tests/org.eclipse.swt.tests/ManualTests/org/eclipse/swt/tests/manual/Bug564162_OwnerdrawCheckboxLayout.java
new file mode 100644
index 0000000000..ea4eeb97a3
--- /dev/null
+++ b/tests/org.eclipse.swt.tests/ManualTests/org/eclipse/swt/tests/manual/Bug564162_OwnerdrawCheckboxLayout.java
@@ -0,0 +1,55 @@
+/*******************************************************************************
+ * Copyright (c) 2020 Syntevo and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Syntevo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.tests.manual;
+
+import org.eclipse.swt.*;
+import org.eclipse.swt.graphics.Font;
+import org.eclipse.swt.layout.*;
+import org.eclipse.swt.widgets.*;
+
+public class Bug564162_OwnerdrawCheckboxLayout {
+	public static void main(String[] args) {
+		Display display = new Display();
+		Shell shell = new Shell(display);
+		shell.setLayout(new RowLayout(SWT.VERTICAL));
+
+		Font biggerFont = new Font(display, "Courier new", 15, SWT.NONE);
+
+		for (int iFont      = 0; iFont < 2;      iFont++)
+		for (int iCheckbox  = 0; iCheckbox < 2;  iCheckbox++)
+		for (int iBackColor = 0; iBackColor < 2; iBackColor++)
+		for (int iDisabled  = 0; iDisabled < 2;  iDisabled++)
+		{
+			Button button = new Button(shell, (iCheckbox == 0) ? SWT.RADIO : SWT.CHECK);
+			button.setText("000 Every control with same font shall have same text position");
+
+			if (iFont != 0)
+				button.setFont(biggerFont);
+
+			if (iBackColor != 0)
+				button.setForeground(shell.getForeground());
+
+			if (iDisabled != 0)
+				button.setEnabled(false);
+		}
+
+		shell.pack();
+		shell.open();
+		while (!shell.isDisposed()) {
+			if (!display.readAndDispatch())
+				display.sleep();
+		}
+		display.dispose();
+	}
+}