Implement basic layout

osu.Game/Graphics/UserInterface/PageSelector.cs

@@ -0,0 +1,100 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Framework.Bindables;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public class PageSelector : CompositeDrawable
+    {
+        private BindableInt currentPage = new BindableInt(1);
+
+        private readonly int maxPages;
+        private readonly FillFlowContainer pillsFlow;
+
+        public PageSelector(int maxPages)
+        {
+            this.maxPages = maxPages;
+
+            AutoSizeAxes = Axes.Both;
+            InternalChild = pillsFlow = new FillFlowContainer
+            {
+                AutoSizeAxes = Axes.X,
+                RelativeSizeAxes = Axes.Y,
+                Direction = FillDirection.Horizontal,
+            };
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            currentPage.BindValueChanged(page => redraw(page.NewValue), true);
+        }
+
+        private void redraw(int newPage)
+        {
+            pillsFlow.Clear();
+
+            for (int i = 0; i < maxPages; i++)
+            {
+                addPagePill(i);
+            }
+        }
+
+        private void addPagePill(int page)
+        {
+            var pill = new Pill(page);
+
+            if (page != currentPage.Value)
+                pill.Action = () => currentPage.Value = page;
+
+            pillsFlow.Add(pill);
+        }
+
+        private class Pill : OsuClickableContainer
+        {
+            private const int height = 20;
+
+            private readonly Box background;
+
+            public Pill(int page)
+            {
+                AutoSizeAxes = Axes.X;
+                Height = height;
+                Child = new CircularContainer
+                {
+                    AutoSizeAxes = Axes.X,
+                    RelativeSizeAxes = Axes.Y,
+                    Masking = true,
+                    Children = new Drawable[]
+                    {
+                        background = new Box
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                        },
+                        new SpriteText
+                        {
+                            Anchor = Anchor.Centre,
+                            Origin = Anchor.Centre,
+                            Text = page.ToString(),
+                            Margin = new MarginPadding { Horizontal = 8 }
+                        }
+                    }
+                };
+            }
+
+            [BackgroundDependencyLoader]
+            private void load(OsuColour colours)
+            {
+                background.Colour = colours.Seafoam;
+            }
+        }
+    }
+}