C# Context.FixedStrokeExtents方法代码示例

		protected override Gdk.Rectangle OnMouseMove (Context g, Color strokeColor, ImageSurface surface,
		                                              int x, int y, int lastX, int lastY)
		{
			// Cairo does not support a single-pixel-long single-pixel-wide line
			if (x == lastX && y == lastY && g.LineWidth == 1 &&
			    PintaCore.Workspace.ActiveWorkspace.PointInCanvas (new PointD(x,y))) {
				surface.Flush ();

				ColorBgra source = surface.GetColorBgraUnchecked (x, y);
				source = UserBlendOps.NormalBlendOp.ApplyStatic (source, strokeColor.ToColorBgra ());
				surface.SetColorBgra (source, x, y);
				surface.MarkDirty ();

				return new Gdk.Rectangle (x - 1, y - 1, 3, 3);
			}

			g.MoveTo (lastX + 0.5, lastY + 0.5);
			g.LineTo (x + 0.5, y + 0.5);
			g.StrokePreserve ();

			Gdk.Rectangle dirty = g.FixedStrokeExtents ().ToGdkRectangle ();

			// For some reason (?!) we need to inflate the dirty
			// rectangle for small brush widths in zoomed images
			dirty.Inflate (1, 1);

			return dirty;
		}

		protected override Gdk.Rectangle OnMouseMove (Context g, Color strokeColor, ImageSurface surface,
		                                              int x, int y, int lastX, int lastY)
		{
			int dx = x - lastX;
			int dy = y - lastY;
			double px = Math.Cos (theta) * dx - Math.Sin (theta) * dy;
			double py = Math.Sin (theta) * dx + Math.Cos (theta) * dy;

			g.MoveTo (lastX - px, lastY - py);
			g.LineTo (lastX + px, lastY + py);
			g.LineTo (x + px, y + py);
			g.LineTo (x - px, y - py);
			g.LineTo (lastX - px, lastY - py);

			g.StrokePreserve ();

			return g.FixedStrokeExtents ().ToGdkRectangle ();
		}

		protected override Gdk.Rectangle OnMouseMove (Context g, Color strokeColor, ImageSurface surface,
		                                              int x, int y, int lastX, int lastY)
		{
			int line_width = (int)g.LineWidth;
			int size;

			// we want a minimum size of 2 for the splatter (except for when the brush width is 1), since a splatter of size 1 is very small
			if (line_width == 1)
			{
				size = 1;
			}
			else
			{
				size = Random.Next (2, line_width);
			}

			Rectangle r = new Rectangle (x - Random.Next (-15, 15), y - Random.Next (-15, 15), size, size);

			double rx = r.Width / 2;
			double ry = r.Height / 2;
			double cx = r.X + rx;
			double cy = r.Y + ry;
			double c1 = 0.552285;

			g.Save ();

			g.MoveTo (cx + rx, cy);

			g.CurveTo (cx + rx, cy - c1 * ry, cx + c1 * rx, cy - ry, cx, cy - ry);
			g.CurveTo (cx - c1 * rx, cy - ry, cx - rx, cy - c1 * ry, cx - rx, cy);
			g.CurveTo (cx - rx, cy + c1 * ry, cx - c1 * rx, cy + ry, cx, cy + ry);
			g.CurveTo (cx + c1 * rx, cy + ry, cx + rx, cy + c1 * ry, cx + rx, cy);

			g.ClosePath ();

			Rectangle dirty = g.FixedStrokeExtents ();

			g.Fill ();
			g.Restore ();

			return dirty.ToGdkRectangle ();
		}

        public static Gdk.Rectangle GetBounds(this Path path)
        {
            Rectangle rect;

            using (Context g = new Context (PintaCore.Layers.CurrentLayer.Surface)) {
                g.AppendPath (path);

                // We don't want the bounding box to include a stroke width
                // of 1, but setting it to 0 returns an empty rectangle.  Set
                // it to a sufficiently small width and rounding takes care of it
                g.LineWidth = .01;
                rect = g.FixedStrokeExtents ();
            }

            int x = (int)Math.Round (rect.X);
            int y = (int)Math.Round (rect.Y);
            int w = (int)Math.Round (rect.Width);
            int h = (int)Math.Round (rect.Height);

            return new Gdk.Rectangle (x, y, w, h);
        }