Resolve CSS color and font definitions without the workbench

bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/css/swt/helpers/CSSSWTColorHelper.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2015 Angelo Zerr and others.
+ * Copyright (c) 2008, 2026 Angelo Zerr and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -96,6 +96,15 @@ public static boolean hasColorDefinitionAsValue(CSSValue value) {
 		return false;
 	}
 
+	/**
+	 * Returns whether the value looks like a color definition reference but
+	 * resolves neither to a color, such as an SWT system color, nor to a definition.
+	 */
+	public static boolean isUnresolvedColorDefinition(CSSValue value) {
+		return hasColorDefinitionAsValue(value) && getRGBA(value) == null
+				&& findColorByDefinition(((CssText) value).value()) == null;
+	}
+
 	public static boolean hasColorDefinitionAsValue(String name) {
 		if (name.startsWith(COLOR_DEFINITION_MARKER)) {
 			return !HEX_COLOR_VALUE_PATTERN.matcher(name).matches();

bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/css/swt/helpers/CSSSWTFontHelper.java

@@ -304,6 +304,44 @@ public static CSS2FontProperties resolveRelativeSize(CSS2FontProperties fontProp
 		return resolved;
 	}
 
+	/**
+	 * Returns the properties unchanged unless the family references an unresolved
+	 * font definition; then returns the font the element had before it was styled,
+	 * with the size, weight and style set in CSS applied on top.
+	 */
+	public static CSS2FontProperties resolveUnresolvedFontDefinition(CSS2FontProperties fontProperties,
+			CSSElementContext context, Widget widget) {
+		if (!hasFontDefinitionAsFamily(fontProperties)
+				|| findFontDataByDefinition((CssText) fontProperties.getFamily()).length > 0) {
+			return fontProperties;
+		}
+		// not the current font, which may carry styling of another state such as :selected
+		FontData baseFontData = getBaseFontData(context);
+		if (baseFontData == null) {
+			baseFontData = getFirstFontData(getFont(widget));
+		}
+		if (baseFontData == null) {
+			return fontProperties;
+		}
+		int baseStyle = baseFontData.getStyle();
+		CSS2FontProperties resolved = new CSS2FontPropertiesImpl();
+		resolved.setFamily(new CssText(CssText.Kind.STRING, baseFontData.getName()));
+		resolved.setSize(new CssDimension(baseFontData.getHeight(), CssUnit.PT));
+		resolved.setSizeFromCSS(true);
+		resolved.setWeight(new CssText(CssText.Kind.IDENT, (baseStyle & SWT.BOLD) != 0 ? "bold" : "normal"));
+		resolved.setStyle(new CssText(CssText.Kind.IDENT, (baseStyle & SWT.ITALIC) != 0 ? "italic" : "normal"));
+		if (fontProperties.isSizeFromCSS()) {
+			resolved.setSize(fontProperties.getSize());
+		}
+		if (fontProperties.getWeight() != null) {
+			resolved.setWeight(fontProperties.getWeight());
+		}
+		if (fontProperties.getStyle() != null) {
+			resolved.setStyle(fontProperties.getStyle());
+		}
+		return resolved;
+	}
+
 	private static boolean isRelativeSize(CssPrimitive size) {
 		if (isKeyword(size, "larger") || isKeyword(size, "smaller")) {
 			return true;

bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/css/swt/properties/converters/CSSValueSWTColorConverterImpl.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2014 Angelo Zerr and others.
+ * Copyright (c) 2008, 2026 Angelo Zerr and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -44,6 +44,10 @@ public CSSValueSWTColorConverterImpl() {
 	@Override
 	public Color convert(CSSValue value, CSSEngine engine, Object context)
 			throws DOMException {
+		if (CSSSWTColorHelper.isUnresolvedColorDefinition(value)) {
+			// treated like unset, so the widget keeps its default color instead of black
+			return null;
+		}
 		Display display = (Display) context;
 		Color color = CSSSWTColorHelper.getSWTColor(value, display);
 		if (color == null) {

bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/css/swt/properties/css2/CSSPropertyBackgroundSWTHandler.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2015 Angelo Zerr and others.
+ * Copyright (c) 2008, 2026 Angelo Zerr and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -86,6 +86,11 @@ public void applyCSSPropertyBackgroundColor(Object element, CSSValue value,
 			if (grad == null) {
 				return; // warn?
 			}
+			if (grad.getRGBs().isEmpty()) {
+				// no stop resolved, treated like unset
+				resetGradient(widget, pseudo);
+				return;
+			}
 			if (widget instanceof CTabItem) {
 				CTabFolder folder = ((CTabItem) widget).getParent();
 				Color[] colors = CSSSWTColorHelper.getSWTColors(grad,
@@ -105,6 +110,20 @@ public void applyCSSPropertyBackgroundColor(Object element, CSSValue value,
 		}
 	}
 
+	private static void resetGradient(Widget widget, String pseudo) {
+		if (widget instanceof CTabItem item) {
+			if ("selected".equals(pseudo)) {
+				item.getParent().setSelectionBackground(null, null, true);
+			} else {
+				item.getParent().setBackground(null, null, true);
+			}
+		} else if (widget instanceof Control control) {
+			GradientBackgroundListener.remove(control);
+			CSSSWTColorHelper.setBackground(control, null);
+			CompositeElement.setBackgroundOverriddenByCSSMarker(widget);
+		}
+	}
+
 	@Override
 	public void applyCSSPropertyBackgroundImage(Object element, CSSValue value,
 			String pseudo, CSSEngine engine) throws Exception {

bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/css/swt/properties/css2/CSSPropertyFontSWTHandler.java

@@ -74,11 +74,13 @@ private static void setFont(Widget widget, Font font) {
 
 	/**
 	 * Resolves a relative font size against the font the element had before it was
-	 * styled, so that reapplying a style does not scale an already scaled font.
+	 * styled, and an unresolved font definition against the widget's own font.
 	 */
-	private static CSS2FontProperties resolveRelativeSize(CSS2FontProperties fontProperties,
-			CSSElementContext context) {
-		return CSSSWTFontHelper.resolveRelativeSize(fontProperties, CSSSWTFontHelper.getBaseFontData(context));
+	private static CSS2FontProperties resolve(CSS2FontProperties fontProperties, CSSElementContext context,
+			Widget widget) {
+		CSS2FontProperties resolved = CSSSWTFontHelper.resolveRelativeSize(fontProperties,
+				CSSSWTFontHelper.getBaseFontData(context));
+		return CSSSWTFontHelper.resolveUnresolvedFontDefinition(resolved, context, widget);
 	}
 
 	private static void updateChildrenFonts(CTabFolder folder, Font font) {
@@ -234,7 +236,7 @@ public void onAllCSSPropertiesApplied(Object element, CSSEngine engine)
 		if (fontProperties == null) {
 			return;
 		}
-		Font font = (Font) engine.convert(resolveRelativeSize(fontProperties, context), Font.class, widget);
+		Font font = (Font) engine.convert(resolve(fontProperties, context, widget), Font.class, widget);
 		setFont(widget, font);
 	}
 
@@ -323,7 +325,7 @@ private void applyStyles(CSSStyleDeclaration styleDeclaration,
 				try {
 					// set the font
 					Font font = (Font) engine.convert(
-							resolveRelativeSize(fontProperties, engine.getCSSElementContext(item)),
+							resolve(fontProperties, engine.getCSSElementContext(item), item),
 							Font.class, item);
 					setFont(item, font);
 				} catch (Exception e) {

bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/internal/css/swt/ColorAndFontUtil.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- *  Copyright (c) 2010, 2019 IBM Corporation and others.
+ *  Copyright (c) 2010, 2026 IBM Corporation and others.
  *
  *  This program and the accompanying materials
  *  are made available under the terms of the Eclipse Public License 2.0
@@ -14,38 +14,34 @@
 package org.eclipse.e4.ui.internal.css.swt;
 
 import org.eclipse.e4.ui.internal.css.swt.definition.IColorAndFontProvider;
+import org.osgi.framework.BundleContext;
 import org.osgi.framework.FrameworkUtil;
-import org.osgi.framework.ServiceReference;
 import org.osgi.util.tracker.ServiceTracker;
 
 public class ColorAndFontUtil {
 
-	static IColorAndFontProvider colorAndFontProvider = null;
+	private static final IColorAndFontProvider DEFAULT_PROVIDER = new JFaceColorAndFontProvider();
 
-	static {
-		if (FrameworkUtil.getBundle(ColorAndFontUtil.class).getBundleContext() != null) {
-			ServiceTracker<IColorAndFontProvider, IColorAndFontProvider> colorAndFontProviderTracker = new ServiceTracker<>(
-					FrameworkUtil.getBundle(ColorAndFontUtil.class).getBundleContext(),
-					IColorAndFontProvider.class.getName(), null) {
-				@Override
-				public IColorAndFontProvider addingService(ServiceReference<IColorAndFontProvider> reference) {
-					// this is needed so that the unit test can exchange the color and font provider
-					// with a mocked version
-					colorAndFontProvider = super.addingService(reference);
-					return colorAndFontProvider;
-				}
-			};
-			colorAndFontProviderTracker.open();
+	private static final ServiceTracker<IColorAndFontProvider, IColorAndFontProvider> TRACKER = openTracker();
+
+	private static ServiceTracker<IColorAndFontProvider, IColorAndFontProvider> openTracker() {
+		BundleContext context = FrameworkUtil.getBundle(ColorAndFontUtil.class).getBundleContext();
+		if (context == null) {
+			return null;
 		}
+		ServiceTracker<IColorAndFontProvider, IColorAndFontProvider> tracker = new ServiceTracker<>(context,
+				IColorAndFontProvider.class, null);
+		tracker.open();
+		return tracker;
 	}
 
 	/**
-	 * Util method to access the OSGI immediate component IColorAndFontProvider
-	 * defined in the same bundle as we do life in the same bundle we do not track
-	 * its life-cycle (as it is the same as our life-cycle)
+	 * Returns the registered {@link IColorAndFontProvider} service, or a provider
+	 * backed by the JFace registries if none is registered.
 	 */
 	public static IColorAndFontProvider getColorAndFontProvider() {
-		return colorAndFontProvider;
+		IColorAndFontProvider provider = TRACKER != null ? TRACKER.getService() : null;
+		return provider != null ? provider : DEFAULT_PROVIDER;
 	}
 
 }

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/themes/ColorAndFontProviderImpl.java → bundles/org.eclipse.e4.ui.css.swt/src/org/eclipse/e4/ui/internal/css/swt/JFaceColorAndFontProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2013, 2016 IBM Corporation and others.
+ * Copyright (c) 2013, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,34 +10,30 @@
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
- ******************************************************************************/
-
-package org.eclipse.ui.internal.themes;
+ *******************************************************************************/
+package org.eclipse.e4.ui.internal.css.swt;
 
 import org.eclipse.e4.ui.internal.css.swt.definition.IColorAndFontProvider;
+import org.eclipse.jface.resource.FontRegistry;
+import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.swt.graphics.FontData;
 import org.eclipse.swt.graphics.RGB;
-import org.eclipse.ui.internal.Workbench;
-import org.eclipse.ui.themes.ITheme;
-import org.osgi.service.component.annotations.Component;
 
 /**
- * @since 3.5
+ * Resolves color and font definitions from the JFace registries, which the
+ * workbench keeps in sync with its current theme.
  */
-@Component
-public class ColorAndFontProviderImpl implements IColorAndFontProvider {
+class JFaceColorAndFontProvider implements IColorAndFontProvider {
 
 	@Override
 	public FontData[] getFont(String symbolicName) {
-		return getCurrentTheme().getFontRegistry().getFontData(symbolicName);
+		FontRegistry registry = JFaceResources.getFontRegistry();
+		// getFontData returns the default font for unknown keys
+		return registry.hasValueFor(symbolicName) ? registry.getFontData(symbolicName) : null;
 	}
 
 	@Override
 	public RGB getColor(String symbolicName) {
-		return getCurrentTheme().getColorRegistry().getRGB(symbolicName);
-	}
-
-	private ITheme getCurrentTheme() {
-		return Workbench.getInstance().getThemeManager().getCurrentTheme();
+		return JFaceResources.getColorRegistry().getRGB(symbolicName);
 	}
 }

bundles/org.eclipse.ui.workbench/META-INF/MANIFEST.MF

@@ -139,5 +139,4 @@ Automatic-Module-Name: org.eclipse.ui.workbench
 Service-Component: OSGI-INF/org.eclipse.ui.internal.BindingToModelProcessor.xml,
  OSGI-INF/org.eclipse.ui.internal.CommandToModelProcessor.xml,
  OSGI-INF/org.eclipse.ui.internal.ContextToModelProcessor.xml,
- OSGI-INF/org.eclipse.ui.internal.WindowsDefenderConfigurator.xml,
- OSGI-INF/org.eclipse.ui.internal.themes.ColorAndFontProviderImpl.xml
+ OSGI-INF/org.eclipse.ui.internal.WindowsDefenderConfigurator.xml

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/themes/WorkbenchThemeManager.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2004, 2017 IBM Corporation and others.
+ * Copyright (c) 2004, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -96,12 +96,13 @@ public static synchronized void disposeManager() {
 	private ITheme currentTheme;
 
 	private final IPropertyChangeListener currentThemeListener = event -> {
-		firePropertyChange(event);
+		// JFace first, as the CSS engine resolves definitions from the JFace registries
 		if (event.getSource() instanceof FontRegistry) {
 			JFaceResources.getFontRegistry().put(event.getProperty(), (FontData[]) event.getNewValue());
 		} else if (event.getSource() instanceof ColorRegistry) {
 			JFaceResources.getColorRegistry().put(event.getProperty(), (RGB) event.getNewValue());
 		}
+		firePropertyChange(event);
 	};
 
 	private ColorRegistry defaultThemeColorRegistry;
@@ -337,7 +338,6 @@ public void setCurrentTheme(String id) {
 		init();
 		ITheme oldTheme = currentTheme;
 		if (WorkbenchThemeManager.getInstance().doSetCurrentTheme(id)) {
-			firePropertyChange(CHANGE_CURRENT_THEME, oldTheme, getCurrentTheme());
 			if (oldTheme != null) {
 				oldTheme.removePropertyChangeListener(currentThemeListener);
 			}
@@ -361,6 +361,7 @@ public void setCurrentTheme(String id) {
 			for (String key : themeFonts.getKeySet()) {
 				jfaceFonts.put(key, themeFonts.getFontData(key));
 			}
+			firePropertyChange(CHANGE_CURRENT_THEME, oldTheme, getCurrentTheme());
 			if (oldTheme != null && eventBroker != null) {
 				eventBroker.send(UIEvents.UILifeCycle.THEME_CHANGED, null);
 				eventBroker.send(UIEvents.UILifeCycle.THEME_DEFINITION_CHANGED, context.get(MApplication.class));

tests/org.eclipse.e4.ui.tests.css.swt/src/org/eclipse/e4/ui/css/swt/helpers/CSSSWTHelperTestCase.java

@@ -19,6 +19,7 @@
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import org.eclipse.e4.ui.css.core.css2.CSS2FontHelper;
@@ -32,13 +33,22 @@
 import org.eclipse.e4.ui.internal.css.swt.definition.IColorAndFontProvider;
 import org.eclipse.swt.graphics.FontData;
 import org.eclipse.swt.graphics.RGB;
+import org.junit.jupiter.api.AfterEach;
 import org.osgi.framework.FrameworkUtil;
+import org.osgi.framework.ServiceRegistration;
 
 public abstract class CSSSWTHelperTestCase {
 
 	protected static final String CSS_ITALIC = CSS2FontHelper.getFontStyle(true);
 	protected static final String CSS_BOLD = CSS2FontHelper.getFontWeight(true);
 
+	private final List<ServiceRegistration<IColorAndFontProvider>> registrations = new ArrayList<>();
+
+	@AfterEach
+	void unregisterProviders() {
+		registrations.forEach(ServiceRegistration::unregister);
+	}
+
 	protected void registerFontProviderWith(String expectedSymbolicName, String family, int size, int style) {
 		IColorAndFontProvider provider = mock(IColorAndFontProvider.class);
 		doReturn(new FontData[] { new FontData(family, size, style) }).when(provider).getFont(expectedSymbolicName);
@@ -49,12 +59,11 @@ protected void registerColorProviderWith(String expectedSymbolicName, RGB rgb) {
 		IColorAndFontProvider provider = mock(IColorAndFontProvider.class);
 		doReturn(rgb).when(provider).getColor(expectedSymbolicName);
 		registerProvider(provider);
-
 	}
 
 	private void registerProvider(final IColorAndFontProvider provider) {
-		FrameworkUtil.getBundle(getClass()).getBundleContext().registerService(IColorAndFontProvider.class, provider,
-				null);
+		registrations.add(FrameworkUtil.getBundle(getClass()).getBundleContext()
+				.registerService(IColorAndFontProvider.class, provider, null));
 	}
 
 	protected CSS2FontProperties fontProperties(String family) {