introduce RendererFactory inside Display which is responsible for creating the renderers

Author: Thomas Singer

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Display.java

@@ -340,6 +340,7 @@ enum APPEARANCE {
 	static Display [] Displays = new Display [1];
 
 	/* Skinning support */
+	private RendererFactory rendererFactory;
 	static final int GROW_SIZE = 1024;
 	Widget [] skinList = new Widget [GROW_SIZE];
 	int skinCount;
@@ -798,6 +799,8 @@ public Display () {
  */
 public Display (DeviceData data) {
 	super (data);
+
+	rendererFactory = new DefaultRendererFactory();
 }
 
 static void checkDisplay (Thread thread, boolean multiple) {
@@ -6867,4 +6870,13 @@ public boolean setRescalingAtRuntime(boolean activate) {
 	// not implemented for Cocoa
 	return false;
 }
+
+public RendererFactory getRendererFactory() {
+	return rendererFactory;
+}
+
+public void setRendererFactory(RendererFactory rendererFactory) {
+	if (rendererFactory == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
+	this.rendererFactory = rendererFactory;
+}
 }

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Button.java

@@ -115,13 +115,14 @@ public Button(Composite parent, int style) {
 		super(parent, checkStyle(style));
 		this.style |= SWT.DOUBLE_BUFFERED;
 
+		final RendererFactory rendererFactory = parent.getDisplay().getRendererFactory();
 		renderer = (this.style & SWT.CHECK) != 0
-				? new DefaultCheckboxRenderer(this)
+				? rendererFactory.createCheckboxRenderer(this)
 				: (this.style & SWT.RADIO) != 0
-				? new DefaultRadioButtonRenderer(this)
+				? rendererFactory.createRadioButtonRenderer(this)
 				: (this.style & SWT.ARROW) != 0
-				? new DefaultArrowButtonRenderer(this)
-				: new DefaultButtonRenderer(this);
+				? rendererFactory.createArrowButtonRenderer(this)
+				: rendererFactory.createPushToggleButtonRenderer(this);
 
 		Listener listener = event -> {
 			switch (event.type) {

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/DefaultRendererFactory.java

@@ -0,0 +1,46 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Syntevo GmbH 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:
+ *     Thomas Singer (Syntevo) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.widgets;
+
+public class DefaultRendererFactory implements RendererFactory {
+	@Override
+	public ButtonRenderer createCheckboxRenderer(Button button) {
+		return new DefaultCheckboxRenderer(button);
+	}
+
+	@Override
+	public ButtonRenderer createRadioButtonRenderer(Button button) {
+		return new DefaultRadioButtonRenderer(button);
+	}
+
+	@Override
+	public ButtonRenderer createArrowButtonRenderer(Button button) {
+		return new DefaultArrowButtonRenderer(button);
+	}
+
+	@Override
+	public ButtonRenderer createPushToggleButtonRenderer(Button button) {
+		return new DefaultButtonRenderer(button);
+	}
+
+	@Override
+	public ScaleRenderer createScaleRenderer(Scale scale) {
+		return new DefaultScaleRenderer(scale);
+	}
+
+	@Override
+	public LabelRenderer createLabelRenderer(Label label) {
+		return new BasicLabelRenderer(label);
+	}
+}

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Label.java

@@ -107,7 +107,8 @@ public Label(Composite parent, int style) {
 			align = SWT.LEFT;
 		}
 
-		renderer = new BasicLabelRenderer(this);
+		final RendererFactory rendererFactory = parent.getDisplay().getRendererFactory();
+		renderer = rendererFactory.createLabelRenderer(this);
 		renderer.setAlign(align);
 		renderer.setForeground(getForeground());
 

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/RendererFactory.java

@@ -0,0 +1,28 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Syntevo GmbH 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:
+ *     Thomas Singer (Syntevo) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.widgets;
+
+public interface RendererFactory {
+	ButtonRenderer createCheckboxRenderer(Button button);
+
+	ButtonRenderer createRadioButtonRenderer(Button button);
+
+	ButtonRenderer createArrowButtonRenderer(Button button);
+
+	ButtonRenderer createPushToggleButtonRenderer(Button button);
+
+	LabelRenderer createLabelRenderer(Label label);
+
+	ScaleRenderer createScaleRenderer(Scale scale);
+}

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/widgets/Scale.java

@@ -126,7 +126,8 @@ public Scale(Composite parent, int style) {
 		// re-add the horizontal/vertical flags
 		super.style |= horizontal ? SWT.HORIZONTAL : SWT.VERTICAL;
 
-		renderer = new DefaultScaleRenderer(this);
+		final RendererFactory rendererFactory = parent.getDisplay().getRendererFactory();
+		renderer = rendererFactory.createScaleRenderer(this);
 	}
 
 

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java

@@ -502,6 +502,7 @@ public void stop() {
 	static Display [] Displays = new Display [1];
 
 	/* Skinning support */
+	private RendererFactory rendererFactory;
 	Widget [] skinList = new Widget [GROW_SIZE];
 	int skinCount;
 
@@ -631,6 +632,8 @@ public Display () {
  */
 public Display (DeviceData data) {
 	super (data);
+
+	rendererFactory = new DefaultRendererFactory();
 }
 
 /**
@@ -6308,4 +6311,12 @@ public boolean setRescalingAtRuntime(boolean activate) {
 	return false;
 }
 
+public RendererFactory getRendererFactory() {
+	return rendererFactory;
+}
+
+public void setRendererFactory(RendererFactory rendererFactory) {
+	if (rendererFactory == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
+	this.rendererFactory = rendererFactory;
+}
 }

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java

@@ -532,6 +532,7 @@ public class Display extends Device implements Executor {
 	static int SWT_OPENDOC;
 
 	/* Skinning support */
+	private RendererFactory rendererFactory;
 	Widget [] skinList = new Widget [GROW_SIZE];
 	int skinCount;
 
@@ -557,7 +558,6 @@ public class Display extends Device implements Executor {
 		CommonWidgetsDPIChangeHandlers.registerCommonHandlers();
 	}
 
-
 /*
 * TEMPORARY CODE.
 */
@@ -595,6 +595,8 @@ public Display () {
  */
 public Display (DeviceData data) {
 	super (data);
+
+	rendererFactory = new DefaultRendererFactory();
 }
 
 Control _getFocusControl () {
@@ -5395,4 +5397,13 @@ private void runWithProperDPIAwareness(Runnable operation) {
 		operation.run();
 	}
 }
+
+public RendererFactory getRendererFactory() {
+	return rendererFactory;
+}
+
+public void setRendererFactory(RendererFactory rendererFactory) {
+	if (rendererFactory == null) SWT.error(SWT.ERROR_NULL_ARGUMENT);
+	this.rendererFactory = rendererFactory;
+}
 }