Slider+Settings: Allow sliders to have their baseline at the height of the track.

core/src/main/java/com/github/weisj/darklaf/layout/LayoutHelper.java

@@ -111,7 +111,7 @@ public final class LayoutHelper {
             verticalLabelGroup.addComponent(lComp, p, p, p);
             verticalComponentGroup.addComponent(rComp, p, p, p);
 
-            verticalGroup.addGroup(layout.createParallelGroup(GroupLayout.Alignment.CENTER)
+            verticalGroup.addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
                     .addComponent(lComp, p, p, p)
                     .addComponent(rComp, p, p, p));
         }

core/src/main/java/com/github/weisj/darklaf/settings/ThemeSettingsUI.java

@@ -325,6 +325,7 @@ public class ThemeSettingsUI {
                     return new Rectangle(0, 0, fontSlider.getWidth(), fontSlider.getHeight());
                 });
         fontSlider.putClientProperty(DarkSliderUI.KEY_INSTANT_SCROLL, true);
+        fontSlider.putClientProperty(DarkSliderUI.KEY_USE_TRACK_AS_BASELINE, true);
         fontSlider.putClientProperty(ToolTipConstants.KEY_CONTEXT, context);
         fontSlider.putClientProperty(ToolTipConstants.KEY_STYLE, ToolTipConstants.VARIANT_BALLOON);
         fontSlider.setToolTipText(String.valueOf(fontSlider.getValue()));

core/src/main/java/com/github/weisj/darklaf/ui/slider/DarkSliderUI.java

@@ -50,6 +50,7 @@ public class DarkSliderUI extends BasicSliderUI {
     public static final String KEY_VARIANT = KEY_PREFIX + "variant";
     public static final String KEY_INSTANT_SCROLL = KEY_PREFIX + "instantScrollEnabled";
     public static final String KEY_MANUAL_LABEL_ALIGN = KEY_PREFIX + "manualLabelAlign";
+    public static final String KEY_USE_TRACK_AS_BASELINE = KEY_PREFIX + "useTrackAsBaseline";
     public static final String VARIANT_VOLUME = "volume";
 
     protected final Rectangle iconRect = new Rectangle(0, 0, 0, 0);
@@ -157,6 +158,15 @@ public class DarkSliderUI extends BasicSliderUI {
         sliderListener = null;
     }
 
+    @Override
+    public int getBaseline(JComponent c, int width, int height) {
+        if (isHorizontal() && PropertyUtil.getBooleanProperty(c, KEY_USE_TRACK_AS_BASELINE)) {
+            return trackRect.y + trackRect.height / 2;
+        } else {
+            return super.getBaseline(c, width, height);
+        }
+    }
+
     @Override
     protected void calculateGeometry() {
         // Thumb size should be calculated before content rect.