FlatUIUtils: joined the 3 component painting methods (for focus border, border and background) into a single method paintOutlinedComponent()

- this allows optimized painting if focus color and border color are equal
- avoids duplicate code
- support focusWidthFraction for future animations

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

@@ -103,9 +103,11 @@ public class FlatBorder
 			FlatUIUtils.setRenderingHints( g2 );
 
 			float focusWidth = scale( (float) getFocusWidth( c ) );
+			float focusInnerWidth = 0;
 			float borderWidth = scale( (float) getBorderWidth( c ) );
 			float arc = scale( (float) getArc( c ) );
 			Color outlineColor = getOutlineColor( c );
+			Color focusColor = null;
 
 			// paint outer border
 			if( outlineColor != null || isFocused( c ) ) {
@@ -114,15 +116,16 @@ public class FlatBorder
 					: 0;
 
 				if( focusWidth > 0 || innerWidth > 0 ) {
-					g2.setColor( (outlineColor != null) ? outlineColor : getFocusColor( c ) );
-					FlatUIUtils.paintComponentOuterBorder( g2, x, y, width, height,
-						focusWidth, borderWidth + scale( innerWidth ), arc );
+					focusColor = (outlineColor != null) ? outlineColor : getFocusColor( c );
+					focusInnerWidth = borderWidth + scale( innerWidth );
 				}
 			}
 
 			// paint border
-			g2.setPaint( (outlineColor != null) ? outlineColor : getBorderColor( c ) );
-			FlatUIUtils.paintComponentBorder( g2, x, y, width, height, focusWidth, borderWidth, arc );
+			Paint borderColor = (outlineColor != null) ? outlineColor : getBorderColor( c );
+			FlatUIUtils.paintOutlinedComponent( g2, x, y, width, height,
+				focusWidth, 1, focusInnerWidth, borderWidth, arc,
+				focusColor, borderColor, null );
 		} finally {
 			g2.dispose();
 		}

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

@@ -114,9 +114,10 @@ public class FlatButtonBorder
 			width -= spacing.left + spacing.right;
 			height -= spacing.top + spacing.bottom;
 
-			g2.setColor( (outlineColor != null) ? outlineColor : getFocusColor( c ) );
-			// not using paintComponentOuterBorder() here because its round edges look too "thick"
-			FlatUIUtils.paintComponentBorder( g2, x, y, width, height, 0, focusWidth, arc );
+			Color color = (outlineColor != null) ? outlineColor : getFocusColor( c );
+			// not using focus border painting of paintOutlinedComponent() here
+			// because its round edges look too "thick"
+			FlatUIUtils.paintOutlinedComponent( g2, x, y, width, height, 0, 0, 0, focusWidth, arc, null, color, null );
 		} finally {
 			g2.dispose();
 		}

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

@@ -61,8 +61,8 @@ public class FlatLineBorder
 		Graphics2D g2 = (Graphics2D) g.create();
 		try {
 			FlatUIUtils.setRenderingHints( g2 );
-			g2.setColor( getLineColor() );
-			FlatUIUtils.paintComponentBorder( g2, x, y, width, height, 0f, scale( getLineThickness() ), 0f );
+			FlatUIUtils.paintOutlinedComponent( g2, x, y, width, height,
+				0, 0, 0, scale( getLineThickness() ), 0, null, getLineColor(), null );
 		} finally {
 			g2.dispose();
 		}

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

@@ -28,6 +28,7 @@ import java.awt.GraphicsConfiguration;
 import java.awt.GraphicsDevice;
 import java.awt.Insets;
 import java.awt.KeyboardFocusManager;
+import java.awt.Paint;
 import java.awt.Rectangle;
 import java.awt.RenderingHints;
 import java.awt.Shape;
@@ -351,104 +352,6 @@ public class FlatUIUtils
 			: color;
 	}
 
-	/**
-	 * Paints an outer border, which is usually a focus border.
-	 * <p>
-	 * The outside bounds of the painted border are {@code x,y,width,height}.
-	 * The line thickness of the painted border is {@code focusWidth + lineWidth}.
-	 * The given arc diameter refers to the inner rectangle ({@code x,y,width,height} minus {@code focusWidth}).
-	 *
-	 * @see #paintComponentBorder
-	 * @see #paintComponentBackground
-	 */
-	public static void paintComponentOuterBorder( Graphics2D g, int x, int y, int width, int height,
-		float focusWidth, float lineWidth, float arc )
-	{
-		if( focusWidth + lineWidth == 0 )
-			return; // nothing to paint
-
-		double systemScaleFactor = UIScale.getSystemScaleFactor( g );
-		if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
-			// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
-			HiDPIUtils.paintAtScale1x( g, x, y, width, height,
-				(g2d, x2, y2, width2, height2, scaleFactor) -> {
-					paintComponentOuterBorderImpl( g2d, x2, y2, width2, height2,
-						(float) (focusWidth * scaleFactor), (float) (lineWidth * scaleFactor), (float) (arc * scaleFactor) );
-				} );
-			return;
-		}
-
-		paintComponentOuterBorderImpl( g, x, y, width, height, focusWidth, lineWidth, arc );
-	}
-
-	private static void paintComponentOuterBorderImpl( Graphics2D g, int x, int y, int width, int height,
-		float focusWidth, float lineWidth, float arc )
-	{
-		float ow = focusWidth + lineWidth;
-		float outerArc = arc + (focusWidth * 2);
-		float innerArc = arc - (lineWidth * 2);
-
-		// reduce outer arc slightly for small arcs to make the curve slightly wider
-		if( focusWidth > 0 && arc > 0 && arc < UIScale.scale( 10 ) )
-			outerArc -= UIScale.scale( 2f );
-
-		Path2D path = new Path2D.Float( Path2D.WIND_EVEN_ODD );
-		path.append( createComponentRectangle( x, y, width, height, outerArc ), false );
-		path.append( createComponentRectangle( x + ow, y + ow, width - (ow * 2), height - (ow * 2), innerArc ), false );
-		g.fill( path );
-	}
-
-	/**
-	 * Draws the border of a component as round rectangle.
-	 * <p>
-	 * The outside bounds of the painted border are
-	 * {@code x + focusWidth, y + focusWidth, width - (focusWidth * 2), height - (focusWidth * 2)}.
-	 * The line thickness of the painted border is {@code lineWidth}.
-	 * The given arc diameter refers to the painted rectangle (and not to {@code x,y,width,height}).
-	 *
-	 * @see #paintComponentOuterBorder
-	 * @see #paintComponentBackground
-	 */
-	public static void paintComponentBorder( Graphics2D g, int x, int y, int width, int height,
-		float focusWidth, float lineWidth, float arc )
-	{
-		if( lineWidth == 0 )
-			return; // nothing to paint
-
-		double systemScaleFactor = UIScale.getSystemScaleFactor( g );
-		if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
-			// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
-			HiDPIUtils.paintAtScale1x( g, x, y, width, height,
-				(g2d, x2, y2, width2, height2, scaleFactor) -> {
-					paintComponentBorderImpl( g2d, x2, y2, width2, height2,
-						(float) (focusWidth * scaleFactor), (float) (lineWidth * scaleFactor), (float) (arc * scaleFactor) );
-				} );
-			return;
-		}
-
-		paintComponentBorderImpl( g, x, y, width, height, focusWidth, lineWidth, arc );
-	}
-
-	private static void paintComponentBorderImpl( Graphics2D g, int x, int y, int width, int height,
-		float focusWidth, float lineWidth, float arc )
-	{
-		float x1 = x + focusWidth;
-		float y1 = y + focusWidth;
-		float width1 = width - focusWidth * 2;
-		float height1 = height - focusWidth * 2;
-		float arc2 = arc - (lineWidth * 2);
-
-		Shape r1 = createComponentRectangle( x1, y1, width1, height1, arc );
-		Shape r2 = createComponentRectangle(
-			x1 + lineWidth, y1 + lineWidth,
-			width1 - lineWidth * 2, height1 - lineWidth * 2, arc2 );
-
-		Path2D border = new Path2D.Float( Path2D.WIND_EVEN_ODD );
-		border.append( r1, false );
-		border.append( r2, false );
-		g.fill( border );
-	}
-
 	/**
 	 * Fills the background of a component with a round rectangle.
 	 * <p>
@@ -456,32 +359,201 @@ public class FlatUIUtils
 	 * {@code x + focusWidth, y + focusWidth, width - (focusWidth * 2), height - (focusWidth * 2)}.
 	 * The given arc diameter refers to the painted rectangle (and not to {@code x,y,width,height}).
 	 *
-	 * @see #paintComponentOuterBorder
-	 * @see #paintComponentBorder
+	 * @see #paintOutlinedComponent
 	 */
 	public static void paintComponentBackground( Graphics2D g, int x, int y, int width, int height,
 		float focusWidth, float arc )
+	{
+		paintOutlinedComponent( g, x, y, width, height, focusWidth, 0, 0, 0, arc, null, null, g.getPaint() );
+	}
+
+	/**
+	 * Paints an outlined component with rounded corners, consisting of following parts:
+	 * <ul>
+	 * <li>an (optional) outer border, which is usually a focus indicator
+	 * <li>an (optional) component border
+	 * <li>the (optional) component background
+	 * </ul>
+	 * Each part is painted only if the corresponding part color is not {@code null}.
+	 * The parts are painted in this order:
+	 * <p>
+	 * <ol>
+	 * <li>background
+	 * <li>focus border
+	 * <li>border
+	 * </ol>
+	 *
+	 * <strong>Background</strong>:
+	 * The bounds of the filled round rectangle are
+	 * {@code [x + focusWidth, y + focusWidth, width - (focusWidth * 2), height - (focusWidth * 2)]}.
+	 * The focus border and the border may paint over the background.
+	 * <p>
+	 *
+	 * <strong>Focus border</strong>:
+	 * The outside bounds of the painted focus border are {@code [x, y, width, height]}.
+	 * The thickness of the painted focus border is {@code (focusWidth * focusWidthFraction) + focusInnerWidth}.
+	 * The border may paint over the focus border if {@code focusInnerWidth > 0}.
+	 * <p>
+	 *
+	 * <strong>Border</strong>:
+	 * The outside bounds of the painted border are
+	 * {@code [x + focusWidth, y + focusWidth, width - (focusWidth * 2), height - (focusWidth * 2)]}.
+	 * The thickness of the painted border is {@code lineWidth}.
+	 *
+	 * @param g the graphics context used for painting
+	 * @param x the x coordinate of the component
+	 * @param y the y coordinate of the component
+	 * @param width the width of the component
+	 * @param height the height of the component
+	 * @param focusWidth the width of the focus border, or {@code 0}
+	 * @param focusWidthFraction specified how much of the focus border is painted (in range 0 - 1);
+	 *                           can be used for animation;
+	 *                           the painted thickness of the focus border is {@code (focusWidth * focusWidthFraction) + focusInnerWidth}
+	 * @param focusInnerWidth the inner width of the focus border, or {@code 0};
+	 *                        if a border is painted then {@code focusInnerWidth} needs to be larger
+	 *                        than {@code lineWidth} to be not hidden by the border
+	 * @param borderWidth the width of the border, or {@code 0}
+	 * @param arc the arc diameter used for the outside shape of the component border;
+	 *            the other needed arc diameters are computed from this arc diameter
+	 * @param focusColor the color of the focus border, or {@code null}
+	 * @param borderColor the color of the border, or {@code null}
+	 * @param background the background color of the component, or {@code null}
+	 *
+	 * @since 2
+	 */
+	public static void paintOutlinedComponent( Graphics2D g, int x, int y, int width, int height,
+		float focusWidth, float focusWidthFraction, float focusInnerWidth, float borderWidth, float arc,
+		Paint focusColor, Paint borderColor, Paint background )
 	{
 		double systemScaleFactor = UIScale.getSystemScaleFactor( g );
 		if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
 			// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
 			HiDPIUtils.paintAtScale1x( g, x, y, width, height,
 				(g2d, x2, y2, width2, height2, scaleFactor) -> {
-					paintComponentBackgroundImpl( g2d, x2, y2, width2, height2,
-						(float) (focusWidth * scaleFactor), (float) (arc * scaleFactor) );
+					paintOutlinedComponentImpl( g2d, x2, y2, width2, height2,
+						(float) (focusWidth * scaleFactor), focusWidthFraction, (float) (focusInnerWidth * scaleFactor),
+						(float) (borderWidth * scaleFactor), (float) (arc * scaleFactor),
+						focusColor, borderColor, background );
 				} );
 			return;
 		}
 
-		paintComponentBackgroundImpl( g, x, y, width, height, focusWidth, arc );
+		paintOutlinedComponentImpl( g, x, y, width, height, focusWidth, focusWidthFraction, focusInnerWidth,
+			borderWidth, arc, focusColor, borderColor, background );
 	}
 
-	private static void paintComponentBackgroundImpl( Graphics2D g, int x, int y, int width, int height,
-		float focusWidth, float arc )
+	private static void paintOutlinedComponentImpl( Graphics2D g, int x, int y, int width, int height,
+		float focusWidth, float focusWidthFraction, float focusInnerWidth, float borderWidth, float arc,
+		Paint focusColor, Paint borderColor, Paint background )
 	{
-		g.fill( createComponentRectangle(
-			x + focusWidth, y + focusWidth,
-			width - focusWidth * 2, height - focusWidth * 2, arc ) );
+		// outside bounds of the border and the background
+		float x1 = x + focusWidth;
+		float y1 = y + focusWidth;
+		float w1 = width - focusWidth * 2;
+		float h1 = height - focusWidth * 2;
+
+		// fill background
+		//   bounds: x + focusWidth, y + focusWidth, width - (focusWidth * 2), height - (focusWidth * 2)
+		//   arc diameter: arc
+		if( background != null ) {
+			g.setPaint( background );
+			g.fill( createComponentRectangle( x1, y1, w1, h1, arc ) );
+		}
+
+		// optimization: paint focus border and border in single operation if colors are equal
+		if( borderColor != null && borderColor.equals( focusColor ) ) {
+			borderColor = null;
+			focusInnerWidth = Math.max( focusInnerWidth, borderWidth );
+		}
+
+		// paint focus border
+		//   outer bounds: x, y, width, height
+		//   thickness: focusWidth + focusInnerWidth
+		//   outer arc diameter: arc + (focusWidth * 2)
+		//   inner arc diameter: arc - (focusInnerWidth * 2)
+		float paintedFocusWidth = (focusWidth * focusWidthFraction) + focusInnerWidth;
+		if( focusColor != null && paintedFocusWidth != 0 ) {
+			// outside bounds of the focus border
+			float inset = focusWidth - (focusWidth * focusWidthFraction);
+			float x2 = x + inset;
+			float y2 = y + inset;
+			float w2 = width - (inset * 2);
+			float h2 = height - (inset * 2);
+
+			float outerArc = arc + (focusWidth * 2);
+			float innerArc = arc - (focusInnerWidth * 2);
+
+			// reduce outer arc slightly for small arcs to make the curve slightly wider
+			if( focusWidth > 0 && arc > 0 && arc < UIScale.scale( 10 ) )
+				outerArc -= UIScale.scale( 2f );
+
+			// consider focus width fraction
+			if( focusWidthFraction != 1 )
+				outerArc = arc + ((outerArc - arc) * focusWidthFraction);
+
+			g.setPaint( focusColor );
+			paintOutline( g, x2, y2, w2, h2, paintedFocusWidth, outerArc, innerArc );
+		}
+
+		// paint border
+		//   outer bounds: x + focusWidth, y + focusWidth, width - (focusWidth * 2), height - (focusWidth * 2)
+		//   thickness: borderWidth
+		//   outer arc diameter: arc
+		//   inner arc diameter: arc - (borderWidth * 2)
+		if( borderColor != null && borderWidth != 0 ) {
+			g.setPaint( borderColor );
+			paintOutline( g, x1, y1, w1, h1, borderWidth, arc );
+		}
+	}
+
+	/**
+	 * Paints an outline at the given bounds using the given line width.
+	 * Depending on the given arc, a rectangle, rounded rectangle or circle (if w == h) is painted.
+	 *
+	 * @param g the graphics context used for painting
+	 * @param x the x coordinate of the outline
+	 * @param y the y coordinate of the outline
+	 * @param w the width of the outline
+	 * @param h the height of the outline
+	 * @param lineWidth the width of the outline
+	 * @param arc the arc diameter used for the outside shape of the outline
+	 *
+	 * @since 2
+	 */
+	public static void paintOutline( Graphics2D g, float x, float y, float w, float h,
+		float lineWidth, float arc )
+	{
+		paintOutline( g, x, y, w, h, lineWidth, arc, arc - (lineWidth * 2) );
+	}
+
+	/**
+	 * Paints an outline at the given bounds using the given line width.
+	 * Depending on the given arc, a rectangle, rounded rectangle or circle (if w == h) is painted.
+	 *
+	 * @param g the graphics context used for painting
+	 * @param x the x coordinate of the outline
+	 * @param y the y coordinate of the outline
+	 * @param w the width of the outline
+	 * @param h the height of the outline
+	 * @param lineWidth the width of the outline
+	 * @param arc the arc diameter used for the outside shape of the outline
+	 * @param innerArc the arc diameter used for the inside shape of the outline
+	 *
+	 * @since 2
+	 */
+	public static void paintOutline( Graphics2D g, float x, float y, float w, float h,
+		float lineWidth, float arc, float innerArc )
+	{
+		if( lineWidth == 0 || w <= 0 || h <= 0 )
+			return;
+
+		float t = lineWidth;
+		float t2x = t * 2;
+
+		Path2D border = new Path2D.Float( Path2D.WIND_EVEN_ODD );
+		border.append( createComponentRectangle( x, y, w, h, arc ), false );
+		border.append( createComponentRectangle( x + t, y + t, w - t2x, h - t2x, innerArc ), false );
+		g.fill( border );
 	}
 
 	/**
@@ -492,6 +564,9 @@ public class FlatUIUtils
 		if( arc <= 0 )
 			return new Rectangle2D.Float( x, y, w, h );
 
+		if( w == h && arc >= w )
+			return new Ellipse2D.Float( x, y, w, h );
+
 		arc = Math.min( arc, Math.min( w, h ) );
 		return new RoundRectangle2D.Float( x, y, w, h, arc, arc );
 	}