Bug 546324, Bug 575176: [UI-SWT] Improve AccessibleArrowImage

  - Improve rendering for high dpi devices
  - Improve rendering for dark theme

Change-Id: Ie446fe7101231628c59be97d0931ac723c38d465

6 files changed, 263 insertions, 201 deletions

diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/DropDownButton.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/DropDownButton.java
index 229afa73..443d7f73 100644
--- a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/DropDownButton.java
+++ b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/DropDownButton.java
@@ -33,8 +33,8 @@ import org.eclipse.swt.widgets.Menu;
 
 import org.eclipse.statet.jcommons.collections.CopyOnWriteIdentityListSet;
 
+import org.eclipse.statet.ecommons.ui.swt.AccessibleArrowImage;
 import org.eclipse.statet.ecommons.ui.util.MenuUtils;
-import org.eclipse.statet.internal.ecommons.ui.AccessibleArrowImage;
 import org.eclipse.statet.internal.ecommons.ui.UIMiscellanyPlugin;
 
 
diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/WaCombo.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/WaCombo.java
index a8b6405d..8dcfbd16 100644
--- a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/WaCombo.java
+++ b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/components/WaCombo.java
@@ -51,7 +51,7 @@ import org.eclipse.swt.widgets.TableItem;
 import org.eclipse.swt.widgets.TypedListener;
 import org.eclipse.swt.widgets.Widget;
 
-import org.eclipse.statet.internal.ecommons.ui.AccessibleArrowImage;
+import org.eclipse.statet.ecommons.ui.swt.AccessibleArrowImage;
 import org.eclipse.statet.internal.ecommons.ui.UIMiscellanyPlugin;
 
 
diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/swt/AccessibleArrowImage.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/swt/AccessibleArrowImage.java
new file mode 100644
index 00000000..27703420
--- /dev/null
+++ b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/swt/AccessibleArrowImage.java
@@ -0,0 +1,246 @@
+/*=============================================================================#
+ # Copyright (c) 2012, 2021 Stephan Wahlbrink and others.
+ # 
+ # This program and the accompanying materials are made available under the
+ # terms of the Eclipse Public License 2.0 which is available at
+ # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+ # which is available at https://www.apache.org/licenses/LICENSE-2.0.
+ # 
+ # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+ # 
+ # Contributors:
+ #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
+ #=============================================================================*/
+
+package org.eclipse.statet.ecommons.ui.swt;
+
+import static org.eclipse.statet.jcommons.lang.ObjectUtils.nonNullAssert;
+
+import java.util.Arrays;
+
+import org.eclipse.jface.resource.CompositeImageDescriptor;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.graphics.ImageData;
+import org.eclipse.swt.graphics.ImageDataProvider;
+import org.eclipse.swt.graphics.Point;
+import org.eclipse.swt.graphics.RGB;
+import org.eclipse.swt.widgets.Display;
+
+import org.eclipse.statet.jcommons.lang.NonNullByDefault;
+import org.eclipse.statet.jcommons.lang.Nullable;
+
+
+/**
+ * An arrow image descriptor, e.g. for drop down buttons.
+ * 
+ * <p>Using the foreground and background colors of the widget makes the arrow visible even in high
+ * contrast too.</p>
+ */
+@NonNullByDefault
+public final class AccessibleArrowImage extends CompositeImageDescriptor {
+	
+	
+	public final static int DEFAULT_SIZE= 5;
+	
+	
+	private final int direction;
+	
+	private final int size;
+	
+	private final RGB foregroundColor;
+	private final RGB backgroundColor;
+	
+	
+	public AccessibleArrowImage(final int direction, final int size,
+			final RGB foregroundColor, final RGB backgroundColor) {
+		switch (direction) {
+		case SWT.UP:
+		case SWT.DOWN:
+		case SWT.LEFT:
+		case SWT.RIGHT:
+			this.direction= direction;
+			break;
+		default:
+			throw new IllegalArgumentException("direction: " + direction); //$NON-NLS-1$
+		}
+		
+		this.foregroundColor= nonNullAssert(foregroundColor);
+		this.backgroundColor= nonNullAssert(backgroundColor);
+		this.size= (size == SWT.DEFAULT) ? DEFAULT_SIZE : size;
+	}
+	
+	
+	@Override
+	protected void drawCompositeImage(final int width, final int height) {
+		final int xOffset;
+		final int yOffset;
+		final int imgWidth;
+		final int imgHeight;
+		switch (this.direction) {
+		case SWT.UP:
+			xOffset= 0;
+			yOffset= 0;
+			imgWidth= this.size * 2 - 1;
+			imgHeight= this.size;
+			break;
+		case SWT.DOWN:
+			xOffset= 0;
+			yOffset= this.size % 2;
+			imgWidth= this.size * 2 - 1;
+			imgHeight= this.size;
+			break;
+		case SWT.LEFT:
+			xOffset= 0;
+			yOffset= 0;
+			imgWidth= this.size;
+			imgHeight= this.size * 2 - 1;
+			break;
+		case SWT.RIGHT:
+			xOffset= this.size % 2;
+			yOffset= 0;
+			imgWidth= this.size;
+			imgHeight= this.size * 2 - 1;
+			break;
+		default:
+			throw new IllegalStateException();
+		}
+		
+		final ImageDataProvider imageProvider= (final int zoom) -> {
+			final Display display= Display.getCurrent();
+			
+			final ImageData imageData;
+			final Image image= new Image(display, imgWidth, imgHeight);
+			try {
+				imageData= image.getImageData(zoom);
+			}
+			finally {
+				image.dispose();
+			}
+			
+			if (imageData.alphaData == null) {
+				imageData.alphaData= new byte[imageData.width * imageData.height];
+			}
+			else if (imageData.alphaData[0] != 0) {
+				Arrays.fill(imageData.alphaData, (byte)0);
+			}
+			
+			final int foreground= imageData.palette.getPixel(
+					ColorUtils.blend(this.foregroundColor, this.backgroundColor, 0.80f) );
+			final int size1;
+			final int size2;
+			switch (this.direction) {
+			case SWT.UP:
+				size1= (imageData.width) / 2 + imageData.width % 2 - 1;
+				size2= size1 * 2;
+				for (int i= 0; i <= size1; i++) {
+					final int fix1= size1 - i;
+					final int last2= size2 - i;
+					imageData.setPixel(i, fix1, foreground);
+					imageData.setAlpha(i, fix1, 191);
+					for (int j= i + 1; j < last2; j++) {
+						imageData.setPixel(j, fix1, foreground);
+						imageData.setAlpha(j, fix1, 255);
+					}
+					imageData.setPixel(last2, fix1, foreground);
+					imageData.setAlpha(last2, fix1, 191);
+				}
+				break;
+			case SWT.DOWN:
+				size1= (imageData.width) / 2 + imageData.width % 2 - 1;
+				size2= size1 * 2;
+				for (int i= 0; i <= size1; i++) {
+					final int fix1= i;
+					final int last2= size2 - i;
+					imageData.setPixel(i, fix1, foreground);
+					imageData.setAlpha(i, fix1, 191);
+					for (int j= i + 1; j < last2; j++) {
+						imageData.setPixel(j, fix1, foreground);
+						imageData.setAlpha(j, fix1, 255);
+					}
+					imageData.setPixel(last2, fix1, foreground);
+					imageData.setAlpha(last2, fix1, 191);
+				}
+				break;
+			case SWT.LEFT:
+				size1= (imageData.height) / 2 + imageData.height % 2 - 1;
+				size2= size1 * 2;
+				for (int i= 0; i <= size1; i++) {
+					final int fix1= size1 - i;
+					final int last2= size2 - i;
+					imageData.setPixel(fix1, i, foreground);
+					imageData.setAlpha(fix1, i, 191);
+					for (int j= i + 1; j < last2; j++) {
+						imageData.setPixel(fix1, j, foreground);
+						imageData.setAlpha(fix1, j, 255);
+					}
+					imageData.setPixel(fix1, last2, foreground);
+					imageData.setAlpha(fix1, last2, 191);
+				}
+				break;
+			case SWT.RIGHT:
+				size1= (imageData.height) / 2 + imageData.height % 2 - 1;
+				size2= size1 * 2;
+				for (int i= 0; i <= size1; i++) {
+					final int fix1= i;
+					final int last2= size2 - i;
+					imageData.setPixel(fix1, i, foreground);
+					imageData.setAlpha(fix1, i, 191);
+					for (int j= i + 1; j < last2; j++) {
+						imageData.setPixel(fix1, j, foreground);
+						imageData.setAlpha(fix1, j, 255);
+					}
+					imageData.setPixel(fix1, last2, foreground);
+					imageData.setAlpha(fix1, last2, 191);
+				}
+				break;
+			}
+			
+			return imageData;
+		};
+		
+		drawImage(imageProvider,
+				xOffset + (width - imgWidth) / 2,
+				yOffset + (height - imgHeight) / 2 );
+	}
+
+	@Override
+	protected Point getSize() {
+		final int corr= ((this.size % 2) == 0) ? -1 : 0;
+		switch (this.direction) {
+		case SWT.UP:
+		case SWT.DOWN:
+			return new Point(this.size * 3 + corr, this.size * 2);
+		case SWT.LEFT:
+		case SWT.RIGHT:
+			return new Point(this.size * 2, this.size * 3 + corr);
+		default:
+			throw new IllegalStateException();
+		}
+	}
+	
+	
+	@Override
+	public int hashCode() {
+		return this.direction * 7
+				+ this.size * 3460
+				+ this.foregroundColor.hashCode() * 343629
+				+ this.backgroundColor.hashCode() * 987972;
+	}
+	
+	@Override
+	public boolean equals(final @Nullable Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj instanceof AccessibleArrowImage) {
+			final AccessibleArrowImage other= (AccessibleArrowImage)obj;
+			return (this.direction == other.direction
+					&& this.size == other.size
+					&& this.foregroundColor.equals(other.foregroundColor)
+					&& this.backgroundColor.equals(other.backgroundColor) );
+		}
+		return false;
+	}
+	
+}
diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/viewers/breadcrumb/BreadcrumbItemDropDown.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/viewers/breadcrumb/BreadcrumbItemDropDown.java
index a1f9985b..17f3df8c 100644
--- a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/viewers/breadcrumb/BreadcrumbItemDropDown.java
+++ b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/ecommons/ui/viewers/breadcrumb/BreadcrumbItemDropDown.java
@@ -67,7 +67,7 @@ import org.eclipse.swt.widgets.Widget;
 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;
 
-import org.eclipse.statet.internal.ecommons.ui.AccessibleArrowImage;
+import org.eclipse.statet.ecommons.ui.swt.AccessibleArrowImage;
 
 
 /**
diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImage.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImage.java
deleted file mode 100644
index 1c362ab5..00000000
--- a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImage.java
+++ /dev/null
@@ -1,190 +0,0 @@
-/*=============================================================================#
- # Copyright (c) 2012, 2021 Stephan Wahlbrink and others.
- # 
- # This program and the accompanying materials are made available under the
- # terms of the Eclipse Public License 2.0 which is available at
- # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
- # which is available at https://www.apache.org/licenses/LICENSE-2.0.
- # 
- # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
- # 
- # Contributors:
- #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
- #=============================================================================*/
-
-package org.eclipse.statet.internal.ecommons.ui;
-
-import org.eclipse.jface.resource.CompositeImageDescriptor;
-import org.eclipse.swt.SWT;
-import org.eclipse.swt.graphics.Image;
-import org.eclipse.swt.graphics.ImageData;
-import org.eclipse.swt.graphics.Point;
-import org.eclipse.swt.graphics.RGB;
-import org.eclipse.swt.widgets.Display;
-
-import org.eclipse.statet.ecommons.ui.swt.ColorUtils;
-
-
-/**
- * An arrow image descriptor, e.g. for drop down buttons.
- * Using the foreground and background colors of the widget makes the arrow visible even in high 
- * contrast too.
- */
-public class AccessibleArrowImage extends CompositeImageDescriptor {
-	
-	
-	public final static int DEFAULT_SIZE= 5;
-	
-	
-	private final int fDirection;
-	
-	private final RGB fForegroundColor;
-	private final RGB fBackgroundColor;
-	
-	private final int fSize;
-	
-	
-	public AccessibleArrowImage(final int direction, final int size,
-			final RGB foregroundColor, final RGB backgroundColor) {
-		switch (direction) {
-		case SWT.UP:
-		case SWT.DOWN:
-		case SWT.LEFT:
-		case SWT.RIGHT:
-			break;
-		default:
-			throw new IllegalArgumentException("direction: " + direction); //$NON-NLS-1$
-		}
-		if (foregroundColor == null) {
-			throw new NullPointerException("foregroundColor");
-		}
-		if (backgroundColor == null) {
-			throw new NullPointerException("backgroundColor");
-		}
-		fDirection = direction;
-		fForegroundColor = foregroundColor;
-		fBackgroundColor = backgroundColor;
-		fSize = (size == -1) ? DEFAULT_SIZE : size;
-	}
-	
-	
-	@Override
-	protected void drawCompositeImage(final int width, final int height) {
-		final Display display= Display.getCurrent();
-		
-		final Image image= (fDirection == SWT.LEFT || fDirection == SWT.RIGHT) ?
-				new Image(display, fSize, fSize * 2 - 1) :
-				new Image(display, fSize * 2 - 1, fSize);
-		
-		final ImageData imageData= image.getImageData();
-		final int foreground = imageData.palette.getPixel(
-				ColorUtils.blend(fForegroundColor, fBackgroundColor, 0.80f) );
-		final int aliasing = imageData.palette.getPixel(
-				ColorUtils.blend(fForegroundColor, fBackgroundColor, 0.60f) );
-		
-		final int size1 = fSize - 1;
-		int xOffset = 0;
-		int yOffset = 0;
-		switch (fDirection) {
-		case SWT.UP:
-			for (int i = 0; i <= size1; i++) {
-				final int last = size1 * 2 - i;
-				imageData.setPixel(i, size1 - i, aliasing);
-				imageData.setAlpha(i, size1 - i, 255);
-				imageData.setPixel(last, size1 - i, aliasing);
-				imageData.setAlpha(last, size1 - i, 255);
-				for (int j = i + 1; j < last; j++) {
-					imageData.setPixel(j, size1 - i, foreground);
-					imageData.setAlpha(j, size1 - i, 255);
-				}
-			}
-			break;
-		case SWT.DOWN:
-			for (int i = 0; i <= size1; i++) {
-				final int last = size1 * 2 - i;
-				imageData.setPixel(i, i, aliasing);
-				imageData.setAlpha(i, i, 255);
-				imageData.setPixel(last, i, aliasing);
-				imageData.setAlpha(last, i, 255);
-				for (int j = i + 1; j < last; j++) {
-					imageData.setPixel(j, i, foreground);
-					imageData.setAlpha(j, i, 255);
-				}
-			}
-			yOffset = 1;
-			break;
-		case SWT.LEFT:
-			for (int i = 0; i <= size1; i++) {
-				final int last = size1 * 2 - i;
-				imageData.setPixel(size1 - i, i, aliasing);
-				imageData.setAlpha(size1 - i, i, 255);
-				imageData.setPixel(size1 - i, last, aliasing);
-				imageData.setAlpha(size1 - i, last, 255);
-				for (int j = i + 1; j < last; j++) {
-					imageData.setPixel(size1 - i, j, foreground);
-					imageData.setAlpha(size1 - i, j, 255);
-				}
-			}
-			break;
-		case SWT.RIGHT:
-			for (int i = 0; i <= size1; i++) {
-				final int last = size1 * 2 - i;
-				imageData.setPixel(i, i, aliasing);
-				imageData.setAlpha(i, i, 255);
-				imageData.setPixel(i, last, aliasing);
-				imageData.setAlpha(i, last, 255);
-				for (int j = i + 1; j < last; j++) {
-					imageData.setPixel(i, j, foreground);
-					imageData.setAlpha(i, j, 255);
-				}
-			}
-			xOffset = 1;
-			break;
-		}
-		
-		drawImage(imageData,
-				(width - imageData.width) / 2 + xOffset,
-				(height - imageData.height) / 2 + yOffset);
-		
-		image.dispose();
-	}
-	
-	@Override
-	protected Point getSize() {
-		final int corr = ((fSize % 2) == 0) ? -1 : 0;
-		switch (fDirection) {
-		case SWT.UP:
-		case SWT.DOWN:
-			return new Point(fSize * 3 + corr, fSize * 2);
-		case SWT.LEFT:
-		case SWT.RIGHT:
-			return new Point(fSize * 2, fSize * 3 + corr);
-		default:
-			throw new IllegalStateException();
-		}
-	}
-	
-	
-	@Override
-	public int hashCode() {
-		return fDirection * 7 + fSize * 3460
-				+ fForegroundColor.hashCode() * 343629
-				+ fBackgroundColor.hashCode() * 987972;
-	}
-	
-	@Override
-	public boolean equals(final Object obj) {
-		if (this == obj) {
-			return true;
-		}
-		if (getClass() != obj.getClass()) {
-			return false;
-		}
-		final AccessibleArrowImage other = (AccessibleArrowImage) obj;
-		return (fDirection == other.fDirection
-				&& fSize == other.fSize
-				&& fForegroundColor.equals(other.fForegroundColor)
-				&& fBackgroundColor.equals(other.fBackgroundColor) );
-	}
-	
-}
diff --git a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImageTest.java b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImageTest.java
index e6c7506a..a18df004 100644
--- a/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImageTest.java
+++ b/ecommons/org.eclipse.statet.ecommons.uimisc/src/org/eclipse/statet/internal/ecommons/ui/AccessibleArrowImageTest.java
@@ -20,26 +20,32 @@ import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Shell;
 
+import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 
+import org.eclipse.statet.ecommons.ui.swt.AccessibleArrowImage;
+
+
+@NonNullByDefault
 public class AccessibleArrowImageTest {
 	
 	
 	public static void main(final String[] args) {
-		final int[] directions = new int[] { SWT.UP, SWT.DOWN, SWT.LEFT, SWT.RIGHT };
-		final int size = 4;
+		final int[] directions= new int[] { SWT.UP, SWT.DOWN, SWT.LEFT, SWT.RIGHT };
+		final int size= AccessibleArrowImage.DEFAULT_SIZE;
 		
-		final Display display = new Display();
-		final Shell shell = new Shell(display);
+		final Display display= new Display();
+		final Shell shell= new Shell(display);
 		shell.setLayout (new GridLayout(directions.length, false));
 		
-		for (int i = 0; i < directions.length; i++) {
-			final AccessibleArrowImage image = new AccessibleArrowImage(directions[i], size,
+		for (int i= 0; i < directions.length; i++) {
+			final AccessibleArrowImage image= new AccessibleArrowImage(directions[i], size,
 					display.getSystemColor(SWT.COLOR_WIDGET_FOREGROUND).getRGB(),
 					display.getSystemColor(SWT.COLOR_WIDGET_BACKGROUND).getRGB() );
-			final Button button = new Button(shell, SWT.PUSH);
+			final Button button= new Button(shell, SWT.PUSH);
+			button.setBackground(display.getSystemColor(SWT.COLOR_GREEN));
 			button.setImage(image.createImage());
 		}
-		shell.setSize(300, 300);
+		shell.setSize((size + 8) * 8 + 100, (size + 8) * 2 + 100);
 		shell.open();
 		while (!shell.isDisposed ()) {
 			if (!display.readAndDispatch ()) {