Bug 435384 - Add support for 'transparent' colors

- Code refactored to remove transparentBackground &
transparentBackgroundImage in Linux & Mac
- Windows refactoring continued for the same.

Change-Id: Ibcdf0dd710cb1a0c7e76ecdce6d7a124ee1316ef
Signed-off-by: Niraj Modi <niraj.modi@in.ibm.com>

4 files changed, 44 insertions, 78 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Control.java
index 07931bdd0d..f99507d4b9 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Control.java
@@ -60,8 +60,8 @@ public abstract class Control extends Widget implements Drawable {
 	Object layoutData;
 	int drawCount, backgroundAlpha = 255;
 	Menu menu;
-	double /*float*/ [] foreground, background, transparentBackground;
-	Image backgroundImage, transparentBackgroundImage;
+	double /*float*/ [] foreground, background;
+	Image backgroundImage;
 	Font font;
 	Cursor cursor;
 	Region region;
@@ -1326,7 +1326,7 @@ Cursor findCursor () {
 }
 
 Control findBackgroundControl () {
-	if (backgroundImage != null || background != null) return this;
+	if ((backgroundImage != null || background != null) && backgroundAlpha > 0) return this;
 	return (!isTransparent() && (state & PARENT_BACKGROUND) != 0) ? parent.findBackgroundControl () : null;
 }
 
@@ -1547,7 +1547,7 @@ public Accessible getAccessible () {
 public Color getBackground () {
 	checkWidget();
 	if (backgroundAlpha == 0) {
-		Color color = Color.cocoa_new (display, transparentBackground, 0);
+		Color color = Color.cocoa_new (display, background, 0);
 		return color;		
 	}
 	else {
@@ -1558,7 +1558,7 @@ public Color getBackground () {
 }
 
 Color getBackgroundColor () {
-	return background != null ? Color.cocoa_new (display, background) : defaultBackground ();
+	return background != null ? Color.cocoa_new (display, background, backgroundAlpha) : defaultBackground ();
 }
 
 /**
@@ -1575,14 +1575,9 @@ Color getBackgroundColor () {
  */
 public Image getBackgroundImage () {
 	checkWidget();
-	if (backgroundAlpha == 0) {
-		return transparentBackgroundImage;
-	}
-	else {
-		Control control = findBackgroundControl ();
-		if (control == null) control = this;
-		return control.backgroundImage;
-	}
+	Control control = findBackgroundControl ();
+	if (control == null) control = this;
+	return control.backgroundImage;
 }
 
 /**
@@ -3488,7 +3483,7 @@ public void setBackground (Color color) {
 	checkWidget ();
 	_setBackground (color);
 	if (color != null) {
-		setBackgroundTransparency (color.getAlpha ());
+		this.updateBackgroundMode ();
 	}
 }
 
@@ -3497,28 +3492,14 @@ private void _setBackground (Color color) {
 		if (color.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT);
 	}
 	double /*float*/ [] background = color != null ? color.handle : null;
-	if (equals (background, this.background)) return;
+	int alpha = color != null ? color.getAlpha() : 255;
+	if (equals (background, this.background) && alpha == this.backgroundAlpha) return;
 	this.background = background;
+	this.backgroundAlpha = alpha;
 	updateBackgroundColor ();
 	redrawWidget(view, true);
 }
 
-private void setBackgroundTransparency (int alpha) {
-	if (alpha == 0) {
-		// clear background
-		if (backgroundImage != null) {
-			transparentBackgroundImage = getBackgroundImage ();
-			setBackgroundImage (null);
-		} 
-		if (getBackground () != null) {
-			transparentBackground = background;
-			_setBackground (null);
-		}
-	} 
-	this.backgroundAlpha = alpha;
-	this.updateBackgroundMode ();
-}
-
 /**
  * Sets the receiver's background image to the image specified
  * by the argument, or to the default system color for the control
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
index b755151ced..135f3b653f 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
@@ -50,8 +50,7 @@ public abstract class Control extends Widget implements Drawable {
 	Composite parent;
 	Cursor cursor;
 	Menu menu;
-	Image backgroundImage, transparentBackgroundImage;
-	GdkColor transparentBackground;
+	Image backgroundImage;
 	Font font;
 	Region region;
 	String toolTipText;
@@ -2392,7 +2391,7 @@ boolean filterKey (int keyval, long /*int*/ event) {
 }
 
 Control findBackgroundControl () {
-	if ((state & BACKGROUND) != 0 || backgroundImage != null) return this;
+	if (((state & BACKGROUND) != 0 || backgroundImage != null) && backgroundAlpha > 0) return this;
 	return (state & PARENT_BACKGROUND) != 0 ? parent.findBackgroundControl () : null;
 }
 
@@ -2495,13 +2494,13 @@ boolean forceFocus (long /*int*/ focusHandle) {
 public Color getBackground () {
 	checkWidget();
 	if (backgroundAlpha == 0) {
-		Color color = Color.gtk_new (display, transparentBackground, 0);
+		Color color = Color.gtk_new (display, this.getBackgroundColor (), 0);
 		return color;
 	}
 	else {
 		Control control = findBackgroundControl ();
 		if (control == null) control = this;
-		return Color.gtk_new (display, control.getBackgroundColor ());
+		return Color.gtk_new (display, control.getBackgroundColor (), backgroundAlpha);
 	}
 }
 
@@ -2523,14 +2522,9 @@ GdkColor getBackgroundColor () {
  */
 public Image getBackgroundImage () {
 	checkWidget ();
-	if (backgroundAlpha == 0) {
-		return transparentBackgroundImage;
-	}
-	else {
-		Control control = findBackgroundControl ();
-		if (control == null) control = this;
-		return control.backgroundImage;
-	}
+	Control control = findBackgroundControl ();
+	if (control == null) control = this;
+	return control.backgroundImage;
 }
 
 GdkColor getContextBackground () {
@@ -4016,7 +4010,7 @@ public void setBackground (Color color) {
 	checkWidget ();
 	_setBackground (color);
 	if (color != null) {
-		setBackgroundTransparency (color.getAlpha ());
+		this.updateBackgroundMode ();
 	}
 }
 
@@ -4026,6 +4020,7 @@ private void _setBackground (Color color) {
 	if (color != null) {
 		if (color.isDisposed ()) error(SWT.ERROR_INVALID_ARGUMENT);
 		gdkColor = color.handle;
+		backgroundAlpha = color.getAlpha ();
 	}
 	boolean set = false;
 	if (OS.GTK3) {
@@ -4054,22 +4049,6 @@ private void _setBackground (Color color) {
 	}
 }
 
-private void setBackgroundTransparency (int alpha) {
-	if (alpha == 0) {
-		// clear background
-		if (backgroundImage != null) {
-			transparentBackgroundImage = getBackgroundImage ();
-			setBackgroundImage (null);
-		} 
-		if (getBackground () != null) {
-			transparentBackground = getBackground ().handle;
-			_setBackground (null);
-		}
-	} 
-	this.backgroundAlpha = alpha;
-	this.updateBackgroundMode ();
-}
-
 void setBackgroundColor (long /*int*/ context, long /*int*/ handle, GdkRGBA rgba) {
 	OS.gtk_widget_override_background_color (handle, OS.GTK_STATE_FLAG_NORMAL, rgba);
 }
@@ -4101,9 +4080,12 @@ void setBackgroundColor (long /*int*/ handle, GdkColor color) {
 				color = control.getBackgroundColor();
 			}
 		}
+		else {
+			alpha = backgroundAlpha;
+		}
 		if (color != null) {
 			rgba = new GdkRGBA ();
-			rgba.alpha = alpha;
+			rgba.alpha = alpha / (float)255;
 			rgba.red = (color.red & 0xFFFF) / (float)0xFFFF;
 			rgba.green = (color.green & 0xFFFF) / (float)0xFFFF;
 			rgba.blue = (color.blue & 0xFFFF) / (float)0xFFFF;
@@ -4171,7 +4153,8 @@ void setBackgroundColor (GdkColor color) {
 public void setBackgroundImage (Image image) {
 	checkWidget ();
 	if (image != null && image.isDisposed ()) error(SWT.ERROR_INVALID_ARGUMENT);
-	if (image == backgroundImage) return;
+	if (image == backgroundImage && backgroundAlpha > 0) return;
+	backgroundAlpha = 255;
 	this.backgroundImage = image;
 	if (backgroundImage != null) {
 		setBackgroundPixmap (backgroundImage);
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
index b76c2393a3..92c78d2133 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
@@ -1166,9 +1166,15 @@ public Accessible getAccessible () {
  */
 public Color getBackground () {
 	checkWidget ();
-	Control control = findBackgroundControl ();
-	if (control == null) control = this;
-	return Color.win32_new (display, control.getBackgroundPixel (), backgroundAlpha);
+	if (backgroundAlpha == 0) {
+		Color color =  Color.win32_new (display, background, 0);
+		return color;
+	}
+	else {
+		Control control = findBackgroundControl ();
+		if (control == null) control = this;
+		return Color.win32_new (display, control.getBackgroundPixel (), backgroundAlpha);
+	}
 }
 
 /**
@@ -3010,25 +3016,24 @@ public void setBackground (Color color) {
 	checkWidget ();
 	_setBackground (color);
 	if (color != null) {
-		setBackgroundTransparency (color.getAlpha());
+		this.updateBackgroundMode ();
 	}
 }
 
 private void _setBackground (Color color) {
 	int pixel = -1;
+	int alpha = 255;
 	if (color != null) {
 		if (color.isDisposed ()) error (SWT.ERROR_INVALID_ARGUMENT);
 		pixel = color.handle;
+		alpha = color.getAlpha();
 	}
-	if (pixel == background) return;
+	if (pixel == background && alpha == backgroundAlpha) return;
 	background = pixel;
+	backgroundAlpha = alpha;
 	updateBackgroundColor ();
 }
 
-private void setBackgroundTransparency (int alpha) {
-	this.backgroundAlpha = alpha;
-	this.updateBackgroundMode ();
-}
 
 /**
  * Sets the receiver's background image to the image specified
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 d3a73745ee..950e6dd13d 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
@@ -75,22 +75,19 @@ public class Snippet365 {
 			@Override

 			public void widgetSelected(SelectionEvent e) {

 				boolean transparent = ((Button) e.getSource()).getSelection();

-				int alpha = transparent ? 0 : 255;

 				if (transparent){

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

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

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

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

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

-					// radio widget have custom background

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

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

-//					check.setBackgroundImage(getBackgroundImage(display));

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

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

 				}

 				else {

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

+					buttonCheckBox.setBackground(null);

+					bar.setBackground(null);

+					label.setBackground(null);

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

 					check.setBackgroundImage(getBackgroundImage(display));

 				}