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