ComboBox: fixed minimum width if focusWidth > 0 (to be equal with button minimum width)

added some unit tests to compare component sizes

flatlaf-core/build.gradle.kts

@@ -21,6 +21,12 @@ plugins {
 	`flatlaf-publish`
 }
 
+dependencies {
+	testImplementation( "org.junit.jupiter:junit-jupiter-api:5.7.2" )
+	testRuntimeOnly( "org.junit.jupiter:junit-jupiter-engine" )
+	testRuntimeOnly( "org.junit.jupiter:junit-jupiter-params" )
+}
+
 java {
 	withSourcesJar()
 	withJavadocJar()
@@ -52,6 +58,11 @@ tasks {
 	named<Jar>( "javadocJar" ) {
 		archiveBaseName.set( "flatlaf" )
 	}
+
+	test {
+		useJUnitPlatform()
+		testLogging.exceptionFormat = org.gradle.api.tasks.testing.logging.TestExceptionFormat.FULL
+	}
 }
 
 flatlafPublish {

flatlaf-core/src/main/java/com/formdev/flatlaf/LinuxFontPolicy.java

@@ -309,6 +309,9 @@ class LinuxFontPolicy
 	 *   - running on JetBrains Runtime 11 or later and scaling is enabled in system Settings
 	 */
 	private static boolean isSystemScaling() {
+		if( GraphicsEnvironment.isHeadless() )
+			return true;
+
 		GraphicsConfiguration gc = GraphicsEnvironment.getLocalGraphicsEnvironment()
 			.getDefaultScreenDevice().getDefaultConfiguration();
 		return UIScale.getSystemScaleFactor( gc ) > 1;

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java

@@ -501,9 +501,9 @@ public class FlatButtonUI
 			prefSize.width = Math.max( prefSize.width, prefSize.height );
 		} else if( !isIconOnlyOrSingleCharacter && !isToolBarButton( c ) && c.getBorder() instanceof FlatButtonBorder ) {
 			// apply minimum width/height
-			float focusWidth = FlatUIUtils.getBorderFocusWidth( c );
+			int fw = Math.round( FlatUIUtils.getBorderFocusWidth( c ) * 2 );
-			prefSize.width = Math.max( prefSize.width, scale( FlatUIUtils.minimumWidth( c, minimumWidth ) ) + Math.round( focusWidth * 2 ) );
+			prefSize.width = Math.max( prefSize.width, scale( FlatUIUtils.minimumWidth( c, minimumWidth ) ) + fw );
-			prefSize.height = Math.max( prefSize.height, scale( FlatUIUtils.minimumHeight( c, 0 ) ) + Math.round( focusWidth * 2 ) );
+			prefSize.height = Math.max( prefSize.height, scale( FlatUIUtils.minimumHeight( c, 0 ) ) + fw );
 		}
 
 		return prefSize;

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatComboBoxUI.java

@@ -534,7 +534,8 @@ public class FlatComboBoxUI
 	@Override
 	public Dimension getMinimumSize( JComponent c ) {
 		Dimension minimumSize = super.getMinimumSize( c );
-		minimumSize.width = Math.max( minimumSize.width, scale( FlatUIUtils.minimumWidth( c, minimumWidth ) ) );
+		int fw = Math.round( FlatUIUtils.getBorderFocusWidth( c ) * 2 );
+		minimumSize.width = Math.max( minimumSize.width, scale( FlatUIUtils.minimumWidth( c, minimumWidth ) ) + fw );
 		return minimumSize;
 	}
 

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/TestFlatComponentSizes.java

@@ -0,0 +1,209 @@
+/*
+ * Copyright 2021 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.ui;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import java.awt.Color;
+import java.awt.Component;
+import java.awt.Dimension;
+import java.awt.Graphics;
+import java.awt.Insets;
+import javax.swing.*;
+import javax.swing.border.Border;
+import javax.swing.border.LineBorder;
+import javax.swing.plaf.basic.BasicComboBoxEditor;
+import javax.swing.plaf.basic.BasicComboBoxRenderer;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+import com.formdev.flatlaf.util.UIScale;
+
+/**
+ * @author Karl Tauber
+ */
+public class TestFlatComponentSizes
+{
+	@BeforeAll
+	static void setup() {
+		TestUtils.setup( false );
+	}
+
+	@AfterAll
+	static void cleanup() {
+		TestUtils.cleanup();
+	}
+
+	static float[] factors() {
+		return new float[] { 1f, 1.25f, 1.5f, 1.75f, 2f, 2.25f, 2.5f, 3f, 4f };
+	}
+
+	@ParameterizedTest
+	@MethodSource( "factors" )
+	void sizes( float factor ) {
+		TestUtils.scaleFont( factor );
+
+		// TODO on some scale factors the combobox/spinner sizes are slightly different
+		//      because different size calculation methods and rounding
+		boolean testComboBoxAndSpinner = (UIManager.getInt( "Component.focusWidth" ) > 0)
+			? (factor != 1.25 && factor != 2.25)
+			: (factor != 1.75);
+
+
+		// should have same default size (minimumWidth is 64)
+		JTextField textField = new JTextField();
+		JFormattedTextField formattedTextField = new JFormattedTextField();
+		JPasswordField passwordField = new JPasswordField();
+		JSpinner spinner = new JSpinner();
+
+		Dimension textFieldSize = textField.getPreferredSize();
+		assertEquals( textFieldSize, formattedTextField.getPreferredSize() );
+		assertEquals( textFieldSize, passwordField.getPreferredSize() );
+		if( testComboBoxAndSpinner )
+			assertEquals( textFieldSize, spinner.getPreferredSize() );
+
+
+		// should have same default size (minimumWidth is 72)
+		JButton button = new JButton( "text" );
+		JComboBox<String> comboBox = new JComboBox<>();
+		JComboBox<String> comboBoxEditable = new JComboBox<>();
+		comboBoxEditable.setEditable( true );
+
+		Dimension buttonSize = button.getPreferredSize();
+		if( testComboBoxAndSpinner ) {
+			assertEquals( buttonSize, comboBox.getPreferredSize() );
+			assertEquals( buttonSize, comboBoxEditable.getPreferredSize() );
+		}
+
+
+		// should have same height
+		JToggleButton toggleButton = new JToggleButton( "text" );
+
+		assertEquals( textFieldSize.height, button.getPreferredSize().height );
+		assertEquals( textFieldSize.height, toggleButton.getPreferredSize().height );
+
+
+		// should have same size
+		JCheckBox checkBox = new JCheckBox( "text" );
+		JRadioButton radioButton = new JRadioButton( "text" );
+		assertEquals( checkBox.getPreferredSize(), radioButton.getPreferredSize() );
+
+
+		// should have same size
+		JMenu menu = new JMenu( "text" );
+		JMenuItem menuItem = new JMenuItem( "text" );
+		JCheckBoxMenuItem checkBoxMenuItem = new JCheckBoxMenuItem( "text" );
+		JRadioButtonMenuItem radioButtonMenuItem = new JRadioButtonMenuItem( "text" );
+
+		Dimension menuSize = menu.getPreferredSize();
+		assertEquals( menuSize, menuItem.getPreferredSize() );
+		assertEquals( menuSize, checkBoxMenuItem.getPreferredSize() );
+		assertEquals( menuSize, radioButtonMenuItem.getPreferredSize() );
+
+
+		TestUtils.resetFont();
+	}
+
+	@ParameterizedTest
+	@MethodSource( "factors" )
+	void comboBox( float factor ) {
+		TestUtils.scaleFont( factor );
+
+		JComboBox<String> comboBox = new JComboBox<>();
+		JComboBox<String> comboBox2 = new JComboBox<>();
+		JComboBox<String> comboBox3 = new JComboBox<>();
+		JComboBox<String> comboBox4 = new JComboBox<>();
+
+		applyCustomComboBoxRendererBorder( comboBox2, new LineBorder( Color.orange, UIScale.scale( 3 ) ) );
+		applyCustomComboBoxRendererBorder( comboBox3, new BorderWithIcon() );
+		applyCustomComboBoxRendererBorder( comboBox4, null );
+
+		Dimension size = comboBox.getPreferredSize();
+		assertEquals( size, comboBox2.getPreferredSize() );
+		assertEquals( size, comboBox3.getPreferredSize() );
+		assertEquals( size, comboBox4.getPreferredSize() );
+
+		TestUtils.resetFont();
+	}
+
+	@SuppressWarnings( "unchecked" )
+	private void applyCustomComboBoxRendererBorder( JComboBox<String> comboBox, Border border ) {
+		BasicComboBoxRenderer customRenderer = new BasicComboBoxRenderer();
+		customRenderer.setBorder( border );
+		comboBox.setRenderer( customRenderer );
+	}
+
+	@ParameterizedTest
+	@MethodSource( "factors" )
+	void comboBoxEditable( float factor ) {
+		TestUtils.scaleFont( factor );
+
+		JComboBox<String> comboBox = new JComboBox<>();
+		JComboBox<String> comboBox2 = new JComboBox<>();
+		JComboBox<String> comboBox3 = new JComboBox<>();
+		JComboBox<String> comboBox4 = new JComboBox<>();
+
+		comboBox.setEditable( true );
+		comboBox2.setEditable( true );
+		comboBox3.setEditable( true );
+		comboBox4.setEditable( true );
+
+		applyCustomComboBoxEditorBorder( comboBox2, new LineBorder( Color.orange, UIScale.scale( 3 ) ) );
+		applyCustomComboBoxEditorBorder( comboBox3, new BorderWithIcon() );
+		applyCustomComboBoxEditorBorder( comboBox4, null );
+
+		Dimension size = comboBox.getPreferredSize();
+		assertEquals( size.width, comboBox2.getPreferredSize().width );
+		assertEquals( size.height + (2 * UIScale.scale( 3 )), comboBox2.getPreferredSize().height );
+		assertEquals( size, comboBox3.getPreferredSize() );
+		assertEquals( size, comboBox4.getPreferredSize() );
+
+		TestUtils.resetFont();
+	}
+
+	private void applyCustomComboBoxEditorBorder( JComboBox<String> comboBox, Border border ) {
+		JTextField customTextField = new JTextField();
+		if( border != null )
+			customTextField.setBorder( border );
+		comboBox.setEditor( new BasicComboBoxEditor() {
+			@Override
+			protected JTextField createEditorComponent() {
+				return customTextField;
+			}
+		} );
+	}
+
+	//---- class BorderWithIcon -----------------------------------------------
+
+	private static class BorderWithIcon
+		implements Border
+	{
+		@Override
+		public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+		}
+
+		@Override
+		public boolean isBorderOpaque() {
+			return false;
+		}
+
+		@Override
+		public Insets getBorderInsets( Component c ) {
+			return new Insets( 0, 0, 0, UIScale.scale( 16 ) + 4 );
+		}
+	}
+}

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/TestFlatComponentSizesWithFocus.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.ui;
+
+import org.junit.jupiter.api.BeforeAll;
+
+/**
+ * @author Karl Tauber
+ */
+public class TestFlatComponentSizesWithFocus
+	extends TestFlatComponentSizes
+{
+	@BeforeAll
+	static void setup() {
+		TestUtils.setup( true );
+	}
+}

flatlaf-core/src/test/java/com/formdev/flatlaf/ui/TestUtils.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2021 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.ui;
+
+import java.awt.Font;
+import javax.swing.UIManager;
+import com.formdev.flatlaf.FlatIntelliJLaf;
+import com.formdev.flatlaf.FlatLightLaf;
+import com.formdev.flatlaf.FlatSystemProperties;
+
+/**
+ * @author Karl Tauber
+ */
+public class TestUtils
+{
+	public static void setup( boolean withFocus ) {
+		System.setProperty( FlatSystemProperties.UI_SCALE, "1x" );
+		if( withFocus )
+			FlatIntelliJLaf.setup();
+		else
+			FlatLightLaf.setup();
+		System.clearProperty( FlatSystemProperties.UI_SCALE );
+	}
+
+	public static void cleanup() {
+		UIManager.put( "defaultFont", null );
+	}
+
+	public static void scaleFont( float factor ) {
+		Font defaultFont = UIManager.getLookAndFeelDefaults().getFont( "defaultFont" );
+		UIManager.put( "defaultFont", defaultFont.deriveFont( (float) Math.round( defaultFont.getSize() * factor ) ) );
+	}
+
+	public static void resetFont() {
+		UIManager.put( "defaultFont", null );
+	}
+}