[server] Add line start event.

Nibriboard/Client/LineIncubator.cs

@@ -44,6 +44,21 @@ namespace Nibriboard.Client
 			return false;
 		}
 
+		/// <summary>
+		/// Creates a new line in the incubator.
+		/// </summary>
+		/// <param name="lineId">The line id to attach to the new line in the incubator.</param>
+		public void CreateLine(string lineId, string newColour, int newWidth)
+		{
+			if(currentLines.ContainsKey(lineId))
+				throw new InvalidOperationException($"Error: A line with the id {lineId} already exists, so you can't recreate it.");
+			
+			currentLines.Add(lineId, new DrawnLine(lineId) {
+				Colour = newColour,
+				Width = newWidth
+			});
+		}
+
 		/// <summary>
 		/// Adds a series of points to the incomplete line with the specified id.
 		/// </summary>
@@ -53,7 +68,7 @@ namespace Nibriboard.Client
 		{
 			// Create a new line if one doesn't exist already
 			if(!currentLines.ContainsKey(lineId))
-				currentLines.Add(lineId, new DrawnLine(lineId));
+				throw new InvalidOperationException($"Error: A line with the id {lineId} doesn't exist, so you can't add to it.");
 			
 			// Add these points to the line
 			currentLines[lineId].Points.AddRange(points);

Nibriboard/Client/Messages/LineCompleteMessage.cs

@@ -7,14 +7,6 @@ namespace Nibriboard.Client.Messages
 		/// The id of the line to complete
 		/// </summary>
 		public string LineId;
-		/// <summary>
-		/// The colour of the line. May be any valid colour accepted by the HTML5 Canvas API.
-		/// </summary>
-		public string LineColour;
-		/// <summary>
-		/// The width of the line, in pixels.
-		/// </summary>
-		public int LineWidth;
 
 		public LineCompleteMessage()
 		{

Nibriboard/Client/Messages/LineCompleteReflectionMessage.cs

@@ -11,14 +11,6 @@ namespace Nibriboard.Client.Messages
 		/// The id of the line to complete
 		/// </summary>
 		public string LineId;
-		/// <summary>
-		/// The colour of the line. May be any valid colour accepted by the HTML5 Canvas API.
-		/// </summary>
-		public string LineColour;
-		/// <summary>
-		/// The width of the line, in pixels.
-		/// </summary>
-		public int LineWidth;
 
 		public LineCompleteReflectionMessage()
 		{

Nibriboard/Client/Messages/LineStartMessage.cs

@@ -0,0 +1,23 @@
+using System;
+namespace Nibriboard.Client.Messages
+{
+	public class LineStartMessage : Message
+	{
+		/// <summary>
+		/// The id of the line to complete
+		/// </summary>
+		public string LineId;
+		/// <summary>
+		/// The colour of the line. May be any valid colour accepted by the HTML5 Canvas API.
+		/// </summary>
+		public string LineColour;
+		/// <summary>
+		/// The width of the line, in pixels.
+		/// </summary>
+		public int LineWidth;
+
+		public LineStartMessage()
+		{
+		}
+	}
+}

Nibriboard/Client/Messages/LineStartReflectionMessage.cs

@@ -0,0 +1,27 @@
+using System;
+namespace Nibriboard.Client.Messages
+{
+	public class LineStartReflectionMessage : Message
+	{
+		/// <summary>
+		/// The id of the client that has completed drawing a line.
+		/// </summary>
+		public int OtherClientId;
+		/// <summary>
+		/// The id of the line to complete
+		/// </summary>
+		public string LineId;
+		/// <summary>
+		/// The colour of the line. May be any valid colour accepted by the HTML5 Canvas API.
+		/// </summary>
+		public string LineColour;
+		/// <summary>
+		/// The width of the line, in pixels.
+		/// </summary>
+		public int LineWidth;
+
+		public LineStartReflectionMessage()
+		{
+		}
+	}
+}

Nibriboard/Client/NibriClient.cs

@@ -55,6 +55,7 @@ namespace Nibriboard.Client
 			["CursorPosition"] = typeof(CursorPositionMessage),
 			["PlaneChange"] = typeof(PlaneChangeMessage),
 			["ChunkUpdateRequest"] = typeof(ChunkUpdateRequestMessage),
+			["LineStart"] = typeof(LineStartMessage),
 			["LinePart"] = typeof(LinePartMessage),
 			["LineComplete"] = typeof(LineCompleteMessage)
 		};
@@ -384,6 +385,31 @@ namespace Nibriboard.Client
 			return Task.CompletedTask;
 		}
 
+		/// <summary>
+		/// Handles line start events from the client.
+		/// These messages are currently only required to let other clients know about
+		/// lines that are being drawn and their properties for live display.
+		/// </summary>
+		/// <param name="message">The LineStartMessage to process.</param>
+		protected Task handleLineStartMessage(LineStartMessage message)
+		{
+			// Create a new line
+			manager.LineIncubator.CreateLine(
+				message.LineId,
+				message.LineColour,
+				message.LineWidth
+			);
+
+			manager.BroadcastPlane(this, new LineStartReflectionMessage() {
+				OtherClientId = Id,
+				LineId = message.LineId,
+				LineColour = message.LineColour,
+				LineWidth = message.LineWidth
+			});
+
+			return Task.CompletedTask;
+		}
+
 		/// <summary>
 		/// Handles messages containing a fragment of a line from the client.
 		/// </summary>
@@ -421,8 +447,6 @@ namespace Nibriboard.Client
 				return;
 			}
 			DrawnLine line = manager.LineIncubator.CompleteLine(message.LineId);
-			line.Width = message.LineWidth;
-			line.Colour = message.LineColour;
 
 			if(CurrentPlane == null)
 			{
@@ -437,9 +461,7 @@ namespace Nibriboard.Client
 			Log.WriteLine("[NibriClient#{0}] Adding {1}px {2} line", Id, line.Width, line.Colour);
 			manager.BroadcastPlane(this, new LineCompleteReflectionMessage() {
 				OtherClientId = Id,
-				LineId = line.LineId,
-				LineColour = line.Colour,
-				LineWidth = line.Width
+				LineId = line.LineId
 			});
 			await CurrentPlane.AddLine(line);
 		}

Nibriboard/Nibriboard.csproj

@@ -103,6 +103,8 @@
     <Compile Include="Client\RawChunkReference.cs" />
     <Compile Include="Client\Messages\LinePartReflectionMessage.cs" />
     <Compile Include="Client\Messages\LineCompleteReflectionMessage.cs" />
+    <Compile Include="Client\Messages\LineStartMessage.cs" />
+    <Compile Include="Client\Messages\LineStartReflectionMessage.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="ClientFiles\index.html" />