feat: add new ImGui windowing system

Dalamud/Interface/Windowing/Window.cs

@@ -0,0 +1,144 @@
+using System.Numerics;
+
+using ImGuiNET;
+
+namespace Dalamud.Interface.Windowing
+{
+    /// <summary>
+    /// Base class you can use to implement an ImGui window for use with the built-in <see cref="WindowSystem"/>.
+    /// </summary>
+    public abstract class Window
+    {
+        private bool internalIsOpen;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Window"/> class.
+        /// </summary>
+        /// <param name="name">The name/ID of this window.
+        /// If you have multiple windows with the same name, you will need to
+        /// append an unique ID to it by specifying it after "###" behind the window title.
+        /// </param>
+        /// <param name="flags">The <see cref="ImGuiWindowFlags"/> of this window.</param>
+        /// <param name="forceMainWindow">Whether or not this window should be limited to the main game window.</param>
+        protected Window(string name, ImGuiWindowFlags flags, bool forceMainWindow = false)
+        {
+            this.WindowName = name;
+            this.Flags = flags;
+            this.ForceMainWindow = forceMainWindow;
+        }
+
+        /// <summary>
+        /// Gets or sets the name of the window.
+        /// If you have multiple windows with the same name, you will need to
+        /// append an unique ID to it by specifying it after "###" behind the window title.
+        /// </summary>
+        public string WindowName { get; set; }
+
+        /// <summary>
+        /// Gets or sets the position of this window.
+        /// </summary>
+        public Vector2? Position { get; set; }
+
+        /// <summary>
+        /// Gets or sets the condition that defines when the position of this window is set.
+        /// </summary>
+        public ImGuiCond PositionCondition { get; set; }
+
+        /// <summary>
+        /// Gets or sets the size of the window.
+        /// </summary>
+        public Vector2? Size { get; set; }
+
+        /// <summary>
+        /// Gets or sets the condition that defines when the size of this window is set.
+        /// </summary>
+        public ImGuiCond SizeCondition { get; set; }
+
+        /// <summary>
+        /// Gets or sets the minimum size of this window.
+        /// </summary>
+        public Vector2? SizeConstraintsMin { get; set; }
+
+        /// <summary>
+        /// Gets or sets the maximum size of this window.
+        /// </summary>
+        public Vector2? SizeConstraintsMax { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not this window is collapsed.
+        /// </summary>
+        public bool? Collapsed { get; set; }
+
+        /// <summary>
+        /// Gets or sets the condition that defines when the collapsed state of this window is set.
+        /// </summary>
+        public ImGuiCond CollapsedCondition { get; set; }
+
+        /// <summary>
+        /// Gets or sets the window flags.
+        /// </summary>
+        public ImGuiWindowFlags Flags { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not this ImGui window will be forced to stay inside the main game window.
+        /// </summary>
+        public bool ForceMainWindow { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not this window will stay open.
+        /// </summary>
+        public bool IsOpen
+        {
+            get => this.internalIsOpen;
+            set => this.internalIsOpen = value;
+        }
+
+        /// <summary>
+        /// In this method, implement your drawing code.
+        /// You do NOT need to ImGui.Begin your window.
+        /// </summary>
+        public abstract void Draw();
+
+        /// <summary>
+        /// Draw the window via ImGui.
+        /// </summary>
+        internal void DrawInternal()
+        {
+            this.ApplyConditionals();
+
+            if (this.ForceMainWindow)
+                ImGuiHelpers.ForceMainWindow();
+
+            if (ImGui.Begin(this.WindowName, ref this.internalIsOpen, this.Flags))
+            {
+                // Draw the actual window contents
+                this.Draw();
+
+                ImGui.End();
+            }
+        }
+
+        private void ApplyConditionals()
+        {
+            if (this.Position.HasValue)
+            {
+                ImGui.SetNextWindowPos(this.Position.Value, this.PositionCondition);
+            }
+
+            if (this.Size.HasValue)
+            {
+                ImGui.SetNextWindowPos(this.Size.Value, this.SizeCondition);
+            }
+
+            if (this.Collapsed.HasValue)
+            {
+                ImGui.SetNextWindowCollapsed(this.Collapsed.Value, this.CollapsedCondition);
+            }
+
+            if (this.SizeConstraintsMin.HasValue && this.SizeConstraintsMax.HasValue)
+            {
+                ImGui.SetNextWindowSizeConstraints(this.SizeConstraintsMin.Value, this.SizeConstraintsMax.Value);
+            }
+        }
+    }
+}

Dalamud/Interface/Windowing/WindowSystem.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+using ImGuiNET;
+
+namespace Dalamud.Interface.Windowing
+{
+    /// <summary>
+    /// Class running a WindowSystem using <see cref="Window"/> implementations to simplify ImGui windowing.
+    /// </summary>
+    public class WindowSystem
+    {
+        private readonly List<Window> windows = new List<Window>();
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="WindowSystem"/> class.
+        /// </summary>
+        /// <param name="imNamespace">The name/ID-space of this <see cref="WindowSystem"/>.</param>
+        public WindowSystem(string imNamespace = null)
+        {
+            this.Namespace = imNamespace;
+        }
+
+        /// <summary>
+        /// Gets or sets the name/ID-space of this <see cref="WindowSystem"/>.
+        /// </summary>
+        public string Namespace { get; set; }
+
+        /// <summary>
+        /// Add a window to this <see cref="WindowSystem"/>.
+        /// </summary>
+        /// <param name="window">The window to add.</param>
+        public void AddWindow(Window window)
+        {
+            if (this.windows.Any(x => x.WindowName == window.WindowName))
+                throw new ArgumentException("A window with this name/ID already exists.");
+
+            this.windows.Add(window);
+        }
+
+        /// <summary>
+        /// Remove a window from this <see cref="WindowSystem"/>.
+        /// </summary>
+        /// <param name="window">The window to remove.</param>
+        public void RemoveWindow(Window window)
+        {
+            if (!this.windows.Contains(window))
+                throw new ArgumentException("This window is not registered on this WindowSystem.");
+
+            this.windows.Remove(window);
+        }
+
+        /// <summary>
+        /// Draw all registered windows using ImGui.
+        /// </summary>
+        public void Draw()
+        {
+            var hasNamespace = !string.IsNullOrEmpty(this.Namespace);
+
+            if (hasNamespace)
+                ImGui.PushID(this.Namespace);
+
+            foreach (var window in this.windows)
+            {
+                window.DrawInternal();
+            }
+
+            if (hasNamespace)
+                ImGui.PopID();
+        }
+    }
+}