From 3115ab647033b1a6faa3640c6215613210f8762f Mon Sep 17 00:00:00 2001
From: Omer Goshen <gershon@goosemoose.com>
Date: Sat, 19 Jul 2025 20:12:30 +0300
Subject: [PATCH] Add an abstract base class for chart background

---
 src/background.vala | 16 ++++++++++++----
 src/chart.vala      |  2 +-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/background.vala b/src/background.vala
index c7fc239..27cb47f 100644
--- a/src/background.vala
+++ b/src/background.vala
@@ -1,10 +1,18 @@
 using Cairo;
 
 namespace LiveChart { 
-    public class Background : Drawable, Object {
+
+    public abstract class AbstractBackground : Drawable, Colorable, Object {
+        public abstract bool visible { get; set; default = true; }
+        public abstract Gdk.RGBA main_color { get; set; }
+        public abstract void draw(Context ctx, Config config);
+
+    }
+
+    public class Background : AbstractBackground {
         private BackgroundDrawer drawer = new BackgroundDrawer();
         
-        public bool visible { get; set; default = true; }
+        public override bool visible { get; set; default = true; }
 
         public Gdk.RGBA color { 
             get {
@@ -16,7 +24,7 @@ namespace LiveChart {
         }
 
         [Version (deprecated = true, deprecated_since = "1.8.0", replacement = "Background.color")]
-        public Gdk.RGBA main_color { 
+        public override Gdk.RGBA main_color { 
             get; set; default = Gdk.RGBA() {
                 red = 0.1f,
                 green = 0.1f,
@@ -25,7 +33,7 @@ namespace LiveChart {
             };
         }
 
-        public void draw(Context ctx, Config config) {
+        public override void draw(Context ctx, Config config) {
             if (visible) {
                 drawer.draw(ctx, config, this.color);
             }
diff --git a/src/chart.vala b/src/chart.vala
index 613a7a2..a0194b1 100644
--- a/src/chart.vala
+++ b/src/chart.vala
@@ -12,7 +12,7 @@ namespace LiveChart {
         private Cairo.Context? cairo_context = null;
 
         public Grid grid { get; set; default = new Grid(); }
-        public Background background { get; set; default = new Background(); } 
+        public AbstractBackground background { get; set; default = new Background(); } 
         public Legend legend { get; set; default = new HorizontalLegend(); } 
         public Config config;
         public Series series;