Bug 463127 - [Win32] Transparent background not honored on Composite

with Scrollbars on Windows

Change-Id: I015a9271c1b4756c0c151dd1529053ae08cdd701
Signed-off-by: Niraj Modi <niraj.modi@in.ibm.com>

7 files changed, 52 insertions, 29 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
index babd1bc2d4..a50b8f650b 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/SWT.java
@@ -3273,11 +3273,13 @@ public class SWT {
 	 * Current limitations include:
 	 * <ul><li>
 	 * {@link org.eclipse.swt.widgets.Text Text} and {@link org.eclipse.swt.widgets.Combo Combo}
-	 * don't support transparent background and fall back to the default background.
+	 * support transparent background on Windows only and on other platforms fall back to the default background.
 	 * </li>
 	 * <li>
-	 * {@link org.eclipse.swt.widgets.Table Table} and {@link org.eclipse.swt.widgets.Tree Tree}
-	 * support a transparent background on GTK3, but not on other platforms.
+	 * {@link org.eclipse.swt.widgets.Table Table} supports transparent background on GTK3 only.
+	 * </li>
+	 * <li> 
+	 * {@link org.eclipse.swt.widgets.Tree Tree} supports transparent background on GTK3/Windows, but not on other platforms.
 	 * </li>
 	 * </ul>
 	 * 
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Composite.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Composite.java
index b74f39318c..cf479ba12c 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Composite.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Composite.java
@@ -305,7 +305,7 @@ public Point computeSize (int wHint, int hHint, boolean changed) {
 void createHandle () {
 	super.createHandle ();
 	state |= CANVAS;
-	if (applyThemeBackground ()) {
+	if ((style & (SWT.H_SCROLL | SWT.V_SCROLL)) == 0 || findThemeControl () == parent) {
 		state |= THEME_BACKGROUND;
 	}
 	if ((style & SWT.TRANSPARENT) != 0) {
@@ -316,7 +316,7 @@ void createHandle () {
 }
 
 @Override
-boolean applyThemeBackground () {
+int applyThemeBackground () {
 	/*
 	 * Composite with scrollbars would not inherit the theme because it was
 	 * probably being used to implement a control similar to a Text, List,
@@ -329,7 +329,7 @@ boolean applyThemeBackground () {
 	 * enable the THEME_BACKGROUND in 'state' to support background transparent.
 	 * Refer bug 463127 & related bug 234649.
 	 */
-	return (super.applyThemeBackground() || (style & (SWT.H_SCROLL | SWT.V_SCROLL)) == 0 || findThemeControl () == parent);
+	return (backgroundAlpha == 0 || (style & (SWT.H_SCROLL | SWT.V_SCROLL)) == 0 || findThemeControl () == parent) ? 1 : 0;
 }
 
 /** 
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
index 57edfda1f5..7e193cff33 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
@@ -144,19 +144,22 @@ void createWidget () {
 
 @Override
 void updateBackgroundColor () {
-	if (applyThemeBackground ()) {
-		state |= THEME_BACKGROUND;
-	} else {
-		state &= ~THEME_BACKGROUND;
+	switch (applyThemeBackground ()) {
+		case 0: state &= ~THEME_BACKGROUND; break;
+		case 1: state |= THEME_BACKGROUND; break;
+		default: /* No change */
 	}
 	super.updateBackgroundColor ();
 }
 
 /**
-* @return true if THEME_BACKGROUND needs to be applied.
-*/
-boolean applyThemeBackground () {
-	return backgroundAlpha == 0;
+ * @return
+ * 		<li>0 to remove THEME_BACKGROUND</li>
+ *      <li>1 to apply THEME_BACKGROUND</li>
+ *      <li>otherwise don't change THEME_BACKGROUND state</li>
+ */
+int applyThemeBackground () {
+	return (backgroundAlpha == 0) ? 1 : 0;
 }
 
 void destroyScrollBar (int type) {
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java
index f30a6dcb86..f32b253f87 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Table.java
@@ -1629,12 +1629,12 @@ void createHandle () {
 }
 
 @Override
-boolean applyThemeBackground () {
+int applyThemeBackground () {
 	/*
 	 * Just inheriting the THEME_BACKGROUND doesn't turn complete Table
 	 * background transparent, TableItem background remains as-is.
 	 */
-	return false;
+	return -1; /* No Change */
 }
 
 void createHeaderToolTips () {
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java
index aa13243d0b..a788ce5caf 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Text.java
@@ -275,15 +275,15 @@ void createHandle () {
 	super.createHandle ();
 	OS.SendMessage (handle, OS.EM_LIMITTEXT, 0, 0);
 	if ((style & SWT.READ_ONLY) != 0) {
-		if (applyThemeBackground ()) {
+		if (applyThemeBackground () == 1) {
 			state |= THEME_BACKGROUND;
 		}
 	}
 }
 
 @Override
-boolean applyThemeBackground () {
-	return (super.applyThemeBackground() || (style & (SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL)) == 0);
+int applyThemeBackground () {
+	return (backgroundAlpha == 0 || (style & (SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL)) == 0) ? 1 : 0;
 }
 
 /**
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/ToolBar.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/ToolBar.java
index 1abd14583c..9b1ea0db98 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/ToolBar.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/ToolBar.java
@@ -402,6 +402,11 @@ void createWidget () {
 	lastFocusId = lastArrowId = lastHotId = -1;
 }
 
+@Override
+int applyThemeBackground () {
+	return -1; /* No Change */
+}
+
 int defaultBackground () {
 	if (OS.IsWinCE) return OS.GetSysColor (OS.COLOR_BTNFACE);
 	return super.defaultBackground ();
diff --git a/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet365.java b/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet365.java
index 1b96765b01..b9be917c52 100644
--- a/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet365.java
+++ b/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet365.java
@@ -37,7 +37,8 @@ public class Snippet365 {
 	// Native

 	static Group nativeGroup;

 	static Button buttonCheckBox;

-	static ToolBar bar;

+	static ToolBar toolBar;

+	static CoolBar coolBar;

 	static Label label;

 	static Link link;

 	static Scale scale;

@@ -121,7 +122,8 @@ public class Snippet365 {
 					

 					// Native

 					nativeGroup.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

-					bar.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

+					toolBar.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

+					coolBar.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

 					label.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

 					link.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

 					scale.setBackground(display.getSystemColor(SWT.COLOR_TRANSPARENT));

@@ -159,7 +161,8 @@ public class Snippet365 {
 				} else {

 					// Native

 					nativeGroup.setBackground(display.getSystemColor(SWT.COLOR_WIDGET_BACKGROUND));

-					bar.setBackground(null);

+					toolBar.setBackground(null);

+					coolBar.setBackground(null);

 					label.setBackground(null);

 					link.setBackground(null);

 					scale.setBackground(null);

@@ -276,11 +279,21 @@ public class Snippet365 {
 		push.setText("Push Button");

 		

 		// Toolbar

-		bar = new ToolBar(nativeGroup, SWT.FLAT);

-		bar.pack();

-		ToolItem item = new ToolItem(bar, SWT.PUSH);

+		toolBar = new ToolBar(nativeGroup, SWT.FLAT);

+		toolBar.pack();

+		ToolItem item = new ToolItem(toolBar, SWT.PUSH);

 		item.setText("ToolBar_Item");

 

+		// Coolbar

+		coolBar = new CoolBar(nativeGroup, SWT.BORDER);

+		for (int i=0; i<2; i++) {

+			CoolItem item2 = new CoolItem (coolBar, SWT.NONE);

+			Button button = new Button (coolBar, SWT.PUSH);

+			button.setText ("Button " + i);

+			Point size = button.computeSize (SWT.DEFAULT, SWT.DEFAULT);

+			item2.setPreferredSize (item2.computeSize (size.x, size.y));

+			item2.setControl (button);

+		}

 		// Scale

 		scale = new Scale(nativeGroup, SWT.None);

 		scale.setMaximum(100);

@@ -293,10 +306,10 @@ public class Snippet365 {
 		// List

 		list = new List(nativeGroup, SWT.BORDER);

 		list.setBackground(display.getSystemColor(SWT.COLOR_CYAN));

-		list.add("one");

-		list.add("two");

-		list.add("three");

-		list.add("four");

+		list.add("List_one");

+		list.add("List_two");

+		list.add("List_three");

+		list.add("List_four");

 		

 		// Canvas

 		canvas = new Canvas (containerGroup, SWT.NONE);