C# Context.Restore方法代码示例

    void Draw(Context cr, int width, int height)
    {
        cr.LineWidth = 1.0;
        cr.Color = new Color(1.0, 1.0, 1.0);
        cr.Rectangle(0, 0, width, height);
        cr.Fill();

        cr.Save();
        cr.Scale(scale_factor, scale_factor);
        try
        {
            if(diagram != null)
            {
                DiagramRenderer dr = new DiagramRenderer(cr, width, height, diagram);
                cr.Color = new Color(0.0, 0.0, 0.0);
                dr.Render();
                dr.Draw();
            }
        }
        catch
        {
            error_counter++;
        }
        cr.Restore();
    }

	void FillChecks (Context cr, int x, int y, int width, int height)
	{
		int CHECK_SIZE = 32;
		
		cr.Save ();
		Surface check = cr.Target.CreateSimilar (Content.Color, 2 * CHECK_SIZE, 2 * CHECK_SIZE);
		
		// draw the check
		using (Context cr2 = new Context (check)) {
			cr2.Operator = Operator.Source;
			cr2.Color = new Color (0.4, 0.4, 0.4);
			cr2.Rectangle (0, 0, 2 * CHECK_SIZE, 2 * CHECK_SIZE);
			cr2.Fill ();

			cr2.Color = new Color (0.7, 0.7, 0.7);
			cr2.Rectangle (x, y, CHECK_SIZE, CHECK_SIZE);
			cr2.Fill ();

			cr2.Rectangle (x + CHECK_SIZE, y + CHECK_SIZE, CHECK_SIZE, CHECK_SIZE);
			cr2.Fill ();
		}

		// Fill the whole surface with the check
		SurfacePattern check_pattern = new SurfacePattern (check);
		check_pattern.Extend = Extend.Repeat;
		cr.Source = check_pattern;
		cr.Rectangle (0, 0, width, height);
		cr.Fill ();

		check_pattern.Destroy ();
		check.Destroy ();
		cr.Restore ();
	}

        public override void Draw(Context context)
        {
            SetupLayout(context);

            RectangleD displayBox = DisplayBox;
            displayBox.OffsetDot5();
            double side = 10.0;

            context.LineWidth = LineWidth;
            context.Save ();
            //Box
            context.MoveTo (displayBox.X, displayBox.Y);
            context.LineTo (displayBox.X, displayBox.Y + displayBox.Height);
            context.LineTo (displayBox.X + displayBox.Width, displayBox.Y + displayBox.Height);
            context.LineTo (displayBox.X + displayBox.Width, displayBox.Y + side);
            context.LineTo (displayBox.X + displayBox.Width - side, displayBox.Y);
            context.LineTo (displayBox.X, displayBox.Y);
            context.Save ();
            //Triangle
            context.MoveTo (displayBox.X + displayBox.Width - side, displayBox.Y);
            context.LineTo (displayBox.X + displayBox.Width - side, displayBox.Y + side);
            context.LineTo (displayBox.X + displayBox.Width, displayBox.Y + side);
            context.LineTo (displayBox.X + displayBox.Width - side, displayBox.Y);
            context.Restore ();

            context.Color = FillColor;
            context.FillPreserve ();
            context.Color = LineColor;
            context.Stroke ();

            DrawText (context);
        }

        public void DrawObject(Context ctx, DrawingObject body)
        {
            if (body == null)
                return;
            ctx.Save ();
            ctx.Color = new Cairo.Color (0, 0, 0);

            ctx.LineWidth = 1;
            foreach (Tuple<PointDouble, PointDouble> line in body.lines) {
                ctx.MoveTo (line.Item1.toPointD());
                ctx.LineTo (line.Item2.toPointD());
            }

            if (body.points.Count > 1)
                ctx.Rectangle(body._centerOfMass.X - 5, body._centerOfMass.Y - 5, 10, 10);
            ctx.Stroke ();

            foreach (PointDouble point in body.points) {
                ctx.Rectangle (point.X - 5, point.Y - 5, 10, 10);
                ctx.Fill ();
            }
            foreach (Tuple<PointDouble, double, double> force in body._forces) {
                DrawForce (ctx, force);
            }

            foreach (Tuple<PointDouble, double> moment in body._moments) {
                DrawMoment (ctx, moment);
            }

            ctx.Restore ();
        }

  protected override FlowReturn OnTransformIp (Gst.Buffer buf) {
    if (!buf.IsWritable)
      return FlowReturn.Error;

    Cairo.ImageSurface img = new Cairo.ImageSurface (buf.Data, Cairo.Format.Rgb24, width, height, width*4);

    using (Cairo.Context context = new Cairo.Context (img)) {
      double dx = (double) ( (buf.Timestamp / Clock.MSecond) % 2180) / 5;
      context.Save ();
      context.Scale (width / 640.0, height / 480.0);
      context.MoveTo (300, 10 + dx);
      context.LineTo (500 - dx, 400);
      context.LineWidth = 4.0;
      context.Color = new Color (0, 0, 1.0);
      context.Stroke();
      context.Restore ();

      if (lastX != -1 && lastY != -1) {
        context.Color = new Color (1.0, 0, 0);
        context.Translate (lastX, lastY);
        context.Scale (Math.Min (width / 640.0, height / 480.0), Math.Min (width / 640.0, height / 480.0));
        context.Arc (0, 0, 10.0, 0.0, 2 * Math.PI);
        context.Fill();
      }
    }

    img.Destroy ();
    return base.OnTransformIp (buf);
  }

 public override void Run()
 {
     ICollection<double> chapters = this.Theory.Chapters;
     StripCanvasSize scs = this.Manager.GenerateStripCanvasSize (chapters.Count);
     double dw = scs.CanvasSize.Width;
     double dh = scs.CanvasSize.Height;
     using (PdfSurface surface = new PdfSurface (this.Manager.OutputFile, scs.TotalWidth, scs.TotalHeight)) {
         using (Context ctx = new Context (surface)) {
             int index = 0x00;
             IPoint3 p;
             foreach (double chapter in chapters) {
                 p = scs.GetCanvasOffset (index);
                 ctx.Save ();
                 ctx.Translate (p.X, p.Y);
                 ctx.Rectangle (0.0d, 0.0d, dw, dh);
                 ctx.Stroke ();
                 this.Theory.Time = chapter;
                 CairoEngine engine = new CairoEngine (this.Theory);
                 engine.Context = ctx;
                 engine.Process ();
                 ctx.Restore ();
                 index++;
             }
         }
     }
 }

        protected override void Draw(Context cr, Pixbuf prev, Pixbuf next, int width, int height, double progress)
        {
            cr.Color = new Color (0, 0, 0, progress);
            if (next != null) {
                double scale = Math.Min ((double)width/(double)next.Width, (double)height/(double)next.Height);
                cr.Save ();

                cr.Rectangle (0, 0, width, .5 * (height - scale*next.Height));
                cr.Fill ();

                cr.Rectangle (0, height - .5 * (height - scale*next.Height), width, .5 * (height - scale*next.Height));
                cr.Fill ();

                cr.Rectangle (0, 0, .5 * (width - scale*next.Width), height);
                cr.Fill ();

                cr.Rectangle (width - .5 * (width - scale*next.Width), 0, .5 * (width - scale*next.Width), height);
                cr.Fill ();

                cr.Rectangle (0, 0, width, height);
                cr.Scale (scale, scale);
                CairoHelper.SetSourcePixbuf (cr, next, .5 * ((double)width/scale - next.Width), .5 * ((double)height/scale - next.Height));
                cr.PaintWithAlpha (progress);
                cr.Restore ();
            }
        }

 protected void OnRender(Context cr, int width, int height)
 {
     cr.Save();
     cr.SetSourceRGBA(1, 0, 0, mTick*0.1);
     cr.Rectangle(0, 0, width, height);
     cr.Fill();
     cr.Restore();
 }

        /// <summary>
        /// Erase the handle that was drawn in a previous call to Render ().
        /// </summary>
        public void Clear (Context g)
        {
            g.Save ();

            var rect = GetHandleRect ().Inflate (2, 2);
            using (var path = g.CreateRectanglePath (rect))
                g.AppendPath (path);
            g.Operator = Operator.Clear;
            g.Fill ();

            g.Restore ();
        }

		public override void BasicDraw (Context context) {
			RectangleD displayBox = DisplayBox;

			context.LineWidth = LineWidth;
			context.Save ();
			displayBox.OffsetDot5 ();
			context.Rectangle (GdkCairoHelper.CairoRectangle(displayBox));
			context.Restore ();
			context.Color = FillColor;
			context.FillPreserve ();
			context.Color = LineColor;
			context.Stroke ();
		}

		protected override void DrawBackground (Context context, Gdk.Rectangle region)
		{
			LayoutRoundedRectangle (context, region);
			context.Clip ();

			context.SetSourceColor (CairoExtensions.ParseColor ("D3E6FF"));
			context.Paint ();

			context.Save ();
			context.Translate (region.X + region.Width / 2.0, region.Y + region.Height);

			using (var rg = new RadialGradient (0, 0, 0, 0, 0, region.Height * 1.2)) {
				var color = CairoExtensions.ParseColor ("E5F0FF");
				rg.AddColorStop (0, color);
				color.A = 0;
				rg.AddColorStop (1, color);

				context.Scale (region.Width / (double)region.Height, 1.0);
				context.SetSource (rg);
				context.Paint ();
			}

			context.Restore ();

			LayoutRoundedRectangle (context, region, -3, -3, 2);
			context.SetSourceRGBA (1, 1, 1, 0.4);
			context.LineWidth = 1;
			context.StrokePreserve ();

			context.Clip ();

			int boxSize = 11;
			int x = region.Left + (region.Width % boxSize) / 2;
			for (; x < region.Right; x += boxSize) {
				context.MoveTo (x + 0.5, region.Top);
				context.LineTo (x + 0.5, region.Bottom);
			}

			int y = region.Top + (region.Height % boxSize) / 2;
			y += boxSize / 2;
			for (; y < region.Bottom; y += boxSize) {
				context.MoveTo (region.Left, y + 0.5);
				context.LineTo (region.Right, y + 0.5);
			}

			context.SetSourceRGBA (1, 1, 1, 0.2);
			context.Stroke ();

			context.ResetClip ();
		}

        protected override void Draw(Context cr, Pixbuf prev, Pixbuf next, int width, int height, double progress)
        {
            cr.SetSourceColor (new Color (0, 0, 0));
            if (prev != null) {
                double scale = Math.Min ((double)width/(double)prev.Width, (double)height/(double)prev.Height);
                cr.Save ();
                cr.Translate (-progress * width, 0);

                cr.Rectangle (0, 0, width, .5 * (height - scale*prev.Height));
                cr.Fill ();

                cr.Rectangle (0, height - .5 * (height - scale*prev.Height), width, .5 * (height - scale*prev.Height));
                cr.Fill ();

                cr.Rectangle (0, 0, .5 * (width - scale*prev.Width), height);
                cr.Fill ();

                cr.Rectangle (width - .5 * (width - scale*prev.Width), 0, .5 * (width - scale*prev.Width), height);
                cr.Fill ();

                cr.Rectangle (0, 0, width, height);
                cr.Scale (scale, scale);
                CairoHelper.SetSourcePixbuf (cr, prev, .5 * ((double)width/scale - prev.Width), .5 * ((double)height/scale - prev.Height));
                cr.Fill ();
                cr.Restore ();
            }
            if (next != null) {
                double scale = Math.Min ((double)width/(double)next.Width, (double)height/(double)next.Height);
                cr.Save ();
                cr.Translate (width * (1.0 - progress), 0);

                cr.Rectangle (0, 0, width, .5 * (height - scale*next.Height));
                cr.Fill ();

                cr.Rectangle (0, height - .5 * (height - scale*next.Height), width, .5 * (height - scale*next.Height));
                cr.Fill ();

                cr.Rectangle (0, 0, .5 * (width - scale*next.Width), height);
                cr.Fill ();

                cr.Rectangle (width - .5 * (width - scale*next.Width), 0, .5 * (width - scale*next.Width), height);
                cr.Fill ();

                cr.Rectangle (0, 0, width, height);
                cr.Scale (scale, scale);
                CairoHelper.SetSourcePixbuf (cr, next, .5 * ((double)width/scale - next.Width), .5 * ((double)height/scale - next.Height));
                cr.Fill ();
                cr.Restore ();
            }
        }

        public override void Draw(Context context)
        {
            double middle = DisplayBox.Width / 2.0;

            context.LineWidth = LineWidth;
            context.Save ();
            context.Translate (DisplayBox.X + middle, DisplayBox.Y + middle);
            context.Arc (0.0, 0.0, middle, 0.0, 2.0 * Math.PI);
            context.Restore ();
            context.Color = new Cairo.Color (1.0, 1.0, 0.2, 0.2);
            context.FillPreserve ();
            context.Color = new Cairo.Color (0.0, 0.0, 0.0, 1.0);
            context.Stroke ();
        }

		public override void Draw (Context context, IDrawingView view) {
			RectangleD rect = ViewDisplayBox(view);
			
			double middle = rect.Width / 2.0;

			context.LineWidth = LineWidth;
			context.Save ();
			context.Translate (rect.X + middle, rect.Y + middle);
			context.Arc (0.0, 0.0, middle, 0.0, 2.0 * Math.PI);
			context.Restore ();
			context.Color = new Cairo.Color (0.2, 0.2, 1.0, 0.5);
			context.FillPreserve ();
			context.Color = new Cairo.Color (0.0, 0.0, 0.0, 1.0);
			context.Stroke ();
		}

		public override void BasicDraw (Context context) {
			double midwidth  = DisplayBox.Width / 2.0;
			double midheight = DisplayBox.Height / 2.0;

			context.LineWidth = LineWidth;
			context.Save ();
			context.Translate (DisplayBox.X + midwidth, DisplayBox.Y + midheight);
			context.Scale (midwidth - 1.0, midheight - 1.0);
			context.Arc (0.0, 0.0, 1.0, 0.0, 2.0 * Math.PI);
			context.Restore ();
			context.Color = FillColor;
			context.FillPreserve ();
			context.Color = LineColor;
			context.Stroke ();
		}