From 8b8ed0b9ff0e67bead982c387c56449008dc3a99 Mon Sep 17 00:00:00 2001
From: Karl Tauber <karl@jformdesigner.com>
Date: Wed, 18 Nov 2020 18:26:30 +0100
Subject: [PATCH] Slider: - compute useful baseline for horizontal orientation
 so that the track is vertically centered - no baseline for vertical
 orientation

---
 .../com/formdev/flatlaf/ui/FlatSliderUI.java    | 17 +++++++++++++++++
 .../flatlaf/jideoss/ui/FlatRangeSliderUI.java   | 17 +++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSliderUI.java b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSliderUI.java
index 25901e4f..bc503667 100644
--- a/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSliderUI.java
+++ b/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatSliderUI.java
@@ -18,6 +18,7 @@ package com.formdev.flatlaf.ui;
 
 import java.awt.Color;
 import java.awt.Dimension;
+import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Rectangle;
@@ -143,6 +144,22 @@ public class FlatSliderUI
 		return new FlatTrackListener();
 	}
 
+	@Override
+	public int getBaseline( JComponent c, int width, int height ) {
+		if( c == null )
+			throw new NullPointerException();
+		if( width < 0 || height < 0 )
+			throw new IllegalArgumentException();
+
+		// no baseline for vertical orientation
+		if( slider.getOrientation() == JSlider.VERTICAL )
+			return -1;
+
+		// compute a baseline so that the track is vertically centered
+		FontMetrics fm = slider.getFontMetrics( slider.getFont() );
+		return trackRect.y + Math.round( (trackRect.height - fm.getHeight()) / 2f ) + fm.getAscent() - 1;
+	}
+
 	@Override
 	public Dimension getPreferredHorizontalSize() {
 		return UIScale.scale( super.getPreferredHorizontalSize() );
diff --git a/flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatRangeSliderUI.java b/flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatRangeSliderUI.java
index 9bbd1c36..34c7a6d1 100644
--- a/flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatRangeSliderUI.java
+++ b/flatlaf-jide-oss/src/main/java/com/formdev/flatlaf/jideoss/ui/FlatRangeSliderUI.java
@@ -18,6 +18,7 @@ package com.formdev.flatlaf.jideoss.ui;
 
 import java.awt.Color;
 import java.awt.Dimension;
+import java.awt.FontMetrics;
 import java.awt.Graphics;
 import java.awt.Graphics2D;
 import java.awt.Point;
@@ -141,6 +142,22 @@ public class FlatRangeSliderUI
 		disabledThumbBorderColor = null;
 	}
 
+	@Override
+	public int getBaseline( JComponent c, int width, int height ) {
+		if( c == null )
+			throw new NullPointerException();
+		if( width < 0 || height < 0 )
+			throw new IllegalArgumentException();
+
+		// no baseline for vertical orientation
+		if( slider.getOrientation() == JSlider.VERTICAL )
+			return -1;
+
+		// compute a baseline so that the track is vertically centered
+		FontMetrics fm = slider.getFontMetrics( slider.getFont() );
+		return trackRect.y + Math.round( (trackRect.height - fm.getHeight()) / 2f ) + fm.getAscent() - 1;
+	}
+
 	@Override
 	public Dimension getPreferredHorizontalSize() {
 		return UIScale.scale( super.getPreferredHorizontalSize() );