Save canvas to SVG

Question

simple question for you all (hopefully). I made a canvas in C#, this canvas has shapes in it. Now I want to save this canvas with the shapes in it to a .svg to use it for other things. So, how can I save this canvas to a svg file?

Hope you can help.

Answer 1

You can not do this directly and with Microsoft classes. you should create Your own class for doing this.

this is only an example and is not usable for you but is good for your example:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Windows;
using System.IO;
using System.Windows.Media;

namespace Render
{
    public class SVGRenderer : IRenderContext
    {
        public bool Absolute { get { return true; } }
        public double Width { get; private set; }
        public double Height { get; private set; }

        public MemoryStream SVGDocument { get; private set; }
        private XmlTextWriter Writer { get { return m_writer; } }

        private XmlTextWriter m_writer;

        /// <summary>
        /// Creates a new SVGRenderer, which will produce an output SVG with the specified width and height.
        /// </summary>
        /// <param name="width">Width of the output SVG.</param>
        /// <param name="height">Height of the output SVG.</param>
        public SVGRenderer(double width, double height)
        {
            SVGDocument = new MemoryStream();
            m_writer = new XmlTextWriter(SVGDocument, Encoding.UTF8);
            m_writer.Formatting = Formatting.Indented;
            this.Width = width;
            this.Height = height;
        }

        public void Begin()
        {
            string cdlibraryVersion = System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString();

            Writer.WriteStartDocument();
            Writer.WriteComment(" Generator: " + (IO.ApplicationInfo.FullName != null ? IO.ApplicationInfo.FullName : "") + ", cdlibrary.dll " + cdlibraryVersion + " ");
            Writer.WriteDocType("svg", "-//W3C//DTD SVG 1.1//EN", "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd", null);
            Writer.WriteStartElement("svg", "http://www.w3.org/2000/svg");
            Writer.WriteAttributeString("version", "1.1");
            Writer.WriteAttributeString("width", this.Width.ToString());
            Writer.WriteAttributeString("height", this.Height.ToString());
        }

        public void End()
        {
            Writer.WriteEndDocument();
            Writer.Flush();
        }

        public void StartSection(object tag)
        {
            // Do nothing.
        }

        public void DrawLine(Point start, Point end, double thickness)
        {
            m_writer.WriteStartElement("line");
            m_writer.WriteAttributeString("x1", start.X.ToString());
            m_writer.WriteAttributeString("y1", start.Y.ToString());
            m_writer.WriteAttributeString("x2", end.X.ToString());
            m_writer.WriteAttributeString("y2", end.Y.ToString());
            m_writer.WriteAttributeString("style", "stroke:rgb(0,0,0);stroke-linecap:square;stroke-width:" + thickness.ToString());
            m_writer.WriteEndElement();
        }

        public void DrawRectangle(Point start, Size size, double thickness, bool fill = false)
        {
            m_writer.WriteStartElement("rect");
            m_writer.WriteAttributeString("x", start.X.ToString());
            m_writer.WriteAttributeString("y", start.Y.ToString());
            m_writer.WriteAttributeString("width", size.Width.ToString());
            m_writer.WriteAttributeString("height", size.Height.ToString());
            m_writer.WriteAttributeString("style", "fill-opacity:0;stroke:rgb(0,0,0);stroke-width:" + thickness.ToString());
            m_writer.WriteEndElement();
        }

        public void DrawEllipse(Point centre, double radiusX, double radiusY, double thickness, bool fill = false)
        {
            string fillOpacity = ((fill ? 255f : 0f) / 255f).ToString();

            m_writer.WriteStartElement("ellipse");
            m_writer.WriteAttributeString("cx", centre.X.ToString());
            m_writer.WriteAttributeString("cy", centre.Y.ToString());
            m_writer.WriteAttributeString("rx", radiusX.ToString());
            m_writer.WriteAttributeString("ry", radiusY.ToString());
            m_writer.WriteAttributeString("style", String.Format("fill-opacity:" + fillOpacity + ";fill:rgb({0},{1},{2});stroke:rgb(0,0,0);stroke-width:" + thickness.ToString(), 0, 0, 0));
            m_writer.WriteEndElement();
        }

        public void DrawPath(Point start, IList<IPathCommand> commands, double thickness, bool fill = false)
        {
            string data = "M " + start.X.ToString() + "," + start.Y.ToString();
            Point last = new Point(0, 0);
            foreach (IPathCommand pathCommand in commands)
            {
                data += " " + pathCommand.Shorthand(start, last);
                last = new Point(pathCommand.End.X, pathCommand.End.Y);
            }

            string fillOpacity = ((fill ? 255f : 0f) / 255f).ToString();

            m_writer.WriteStartElement("path");
            m_writer.WriteAttributeString("d", data);
            m_writer.WriteAttributeString("style", "fill-opacity:" + fillOpacity + ";fill:rgb(0,0,0);stroke:rgb(0,0,0);stroke-width:" + thickness.ToString());
            m_writer.WriteEndElement();
        }

        public void DrawText(Point anchor, TextAlignment alignment, IEnumerable<TextRun> textRuns, Brush bru = null)
        {
            m_writer.WriteStartElement("text");
            m_writer.WriteAttributeString("x", anchor.X.ToString());
            m_writer.WriteAttributeString("y", anchor.Y.ToString());

            string textAnchor = "start";
            if (alignment == TextAlignment.BottomCentre  || alignment == TextAlignment.CentreCentre || alignment == Render.TextAlignment.TopCentre)
                textAnchor = "middle";
            else if (alignment == TextAlignment.BottomRight || alignment == TextAlignment.CentreRight || alignment == Render.TextAlignment.TopRight)
                textAnchor = "end";

            string dy = "-0.3em";
            if (alignment == TextAlignment.CentreCentre || alignment == TextAlignment.CentreLeft || alignment == TextAlignment.CentreRight)
                dy = ".3em";
            else if (alignment == TextAlignment.TopCentre || alignment == TextAlignment.TopLeft || alignment == TextAlignment.TopRight)
                dy = "1em";

            m_writer.WriteAttributeString("style", "font-family:Arial;font-size:" + textRuns.FirstOrDefault().Formatting.Size.ToString() + ";text-anchor:" + textAnchor);
            m_writer.WriteAttributeString("dy", dy);

            foreach (TextRun run in textRuns)
            {
                if (run.Formatting.FormattingType != TextRunFormattingType.Normal)
                    m_writer.WriteStartElement("tspan");
                if (run.Formatting.FormattingType == TextRunFormattingType.Subscript)
                {
                    m_writer.WriteAttributeString("baseline-shift", "sub");
                    m_writer.WriteAttributeString("style", "font-size:0.8em");
                }
                else if (run.Formatting.FormattingType == TextRunFormattingType.Superscript)
                {
                    m_writer.WriteAttributeString("baseline-shift", "super");
                    m_writer.WriteAttributeString("style", "font-size:0.8em");
                }
                m_writer.WriteString(run.Text);
                if (run.Formatting.FormattingType != TextRunFormattingType.Normal)
                    m_writer.WriteEndElement();
            }

            m_writer.WriteEndElement();
        }
    }
}

Hope Helps You