Ooui-tws-port/Ooui/Canvas.cs

48 lines
1.5 KiB
C#

using System;
namespace Ooui
{
public class Canvas : Element
{
CanvasRenderingContext2D context2d = new CanvasRenderingContext2D ();
int gotContext2d = 0;
public int Width {
get => GetAttribute ("width", 300);
set => SetAttributeProperty ("width", value < 0 ? 0 : value);
}
public int Height {
get => GetAttribute ("height", 150);
set => SetAttributeProperty ("width", value < 0 ? 0 : value);
}
public Canvas ()
: base ("canvas")
{
context2d.MessageSent += Send;
}
public CanvasRenderingContext2D GetContext2D ()
{
if (System.Threading.Interlocked.CompareExchange (ref gotContext2d, 1, 0) == 0) {
var mcall = Message.Call (Id, "getContext", "2d");
mcall.ResultId = context2d.Id;
Send (mcall);
}
return context2d;
}
protected override bool SaveStateMessageIfNeeded (Message message)
{
if (message.TargetId == Id) {
switch (message.MessageType) {
case MessageType.Call when message.Key == "getContext" && message.Value is Array a && a.Length == 1 && "2d".Equals (a.GetValue (0)):
AddStateMessage (message);
break;
}
}
return base.SaveStateMessageIfNeeded (message);
}
}
}