TextField: support adding extra padding

(for #172, #173 and #330)

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

@@ -733,6 +733,18 @@ public interface FlatClientProperties
 	 */
 	String PLACEHOLDER_TEXT = "JTextField.placeholderText";
 
+	/**
+	 * Specifies the padding of the text.
+	 * This changes the location and size of the text view within the component bounds,
+	 * but does not affect the size of the component.
+	 * <p>
+	 * <strong>Component</strong> {@link javax.swing.JTextField} (and subclasses)<br>
+	 * <strong>Value type</strong> {@link java.awt.Insets}
+	 *
+	 * @since 1.4
+	 */
+	String TEXT_FIELD_PADDING = "JTextField.padding";
+
 	//---- JToggleButton ------------------------------------------------------
 
 	/**

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

@@ -18,6 +18,8 @@ package com.formdev.flatlaf.ui;
 
 import static com.formdev.flatlaf.FlatClientProperties.*;
 import java.awt.EventQueue;
+import java.awt.Insets;
+import java.awt.Rectangle;
 import java.awt.event.FocusEvent;
 import java.awt.event.MouseEvent;
 import javax.swing.JFormattedTextField;
@@ -61,6 +63,19 @@ public class FlatCaret
 		}
 	}
 
+	@Override
+	protected void adjustVisibility( Rectangle nloc ) {
+		JTextComponent c = getComponent();
+		if( c != null && c.getUI() instanceof FlatTextFieldUI ) {
+			Insets padding = ((FlatTextFieldUI)c.getUI()).getPadding();
+			if( padding != null ) {
+				nloc.x -= padding.left;
+				nloc.y -= padding.top;
+			}
+		}
+		super.adjustVisibility( nloc );
+	}
+
 	@Override
 	public void focusGained( FocusEvent e ) {
 		if( !wasTemporaryLost && (!isMousePressed || selectAllOnMouseClick) )

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

@@ -24,6 +24,7 @@ import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Insets;
+import java.awt.Rectangle;
 import java.awt.event.FocusListener;
 import java.beans.PropertyChangeEvent;
 import javax.swing.JComboBox;
@@ -40,6 +41,7 @@ import javax.swing.text.JTextComponent;
 import com.formdev.flatlaf.FlatClientProperties;
 import com.formdev.flatlaf.util.HiDPIUtils;
 import com.formdev.flatlaf.util.JavaCompatibility;
+import com.formdev.flatlaf.util.UIScale;
 
 /**
  * Provides the Flat LaF UI delegate for {@link javax.swing.JTextField}.
@@ -142,6 +144,7 @@ public class FlatTextFieldUI
 		switch( e.getPropertyName() ) {
 			case FlatClientProperties.PLACEHOLDER_TEXT:
 			case FlatClientProperties.COMPONENT_ROUND_RECT:
+			case FlatClientProperties.TEXT_FIELD_PADDING:
 				c.repaint();
 				break;
 
@@ -264,4 +267,27 @@ public class FlatTextFieldUI
 		size.width = Math.max( size.width, scale( minimumWidth ) + Math.round( focusWidth * 2 ) );
 		return size;
 	}
+
+	@Override
+	protected Rectangle getVisibleEditorRect() {
+		Rectangle r = super.getVisibleEditorRect();
+		if( r != null ) {
+			// remove padding
+			Insets padding = getPadding();
+			if( padding != null ) {
+				r = FlatUIUtils.subtractInsets( r, padding );
+				r.width = Math.max( r.width, 0 );
+				r.height = Math.max( r.height, 0 );
+			}
+		}
+		return r;
+	}
+
+	/**
+	 * @since 1.4
+	 */
+	protected Insets getPadding() {
+		Object padding = getComponent().getClientProperty( FlatClientProperties.TEXT_FIELD_PADDING );
+		return (padding instanceof Insets) ? UIScale.scale( (Insets) padding ) : null;
+	}
 }