SvgGraphicsHtmlId.cs
//
// This code is part of GrapeCity Documents for Imaging samples.
// Copyright (c) GrapeCity, Inc. All rights reserved.
//
using System;
using System.IO;
using System.Drawing;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using GrapeCity.Documents.Drawing;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Imaging;
using GrapeCity.Documents.Svg;
using GcImagingWeb.Samples.Common;

namespace GcImagingWeb.Samples
{
    // This example shows how to create an SVG from scratch,
    // grouping visually related elements and assigning unique
    // HTML IDs to the groups, so that each group can be found
    // and manipulated from JavaScript code (e.g. some elements
    // of a drawing can be hidden or shown in JavaScript, etc).
    // This sample renders an arch similar to that in SvgGraphicsArch,
    // but assigns separate IDs to:
    // - the background;
    // - the arch drawing;
    // - measurements lines.
    public class SvgGraphicsHtmlId
    {
        public string DefaultMime { get => Common.Util.MimeTypes.SVG; }

        public Stream GenerateImageStream(string targetMime, Size pixelSize, float dpi, bool opaque, string[] sampleParams = null)
        {
            if (targetMime != Common.Util.MimeTypes.SVG)
                throw new Exception("This sample only supports SVG output format.");

            Color background = Color.PaleGoldenrod,
                line = Color.FromArgb(11, 83, 69),
                arc = Color.FromArgb(22, 160, 133),
                fill = Color.FromArgb(255, 171, 145),
                marks = Color.DarkGray,
                text = Color.Black,
                textBack = Color.Cornsilk;

            var Inch = dpi;

            // Text format for labels:
            var tf = new TextFormat()
            {
                Font = Font.FromFile(Path.Combine("Resources", "Fonts", "times.ttf")),
                FontSize = Inch / 6,
                ForeColor = text,
            };
            // Arc bounding rectangle:
            var rc = new RectangleF(0, 0, Inch * 4, Inch * 4.8f);
            // Transform to center the drawing:
            var transform = Matrix3x2.CreateTranslation(pixelSize.Width / 2f - rc.Width / 2, pixelSize.Height / 2f - rc.Height / 2);
            // A document for each layer:
            var svgs = new List<GcSvgDocument>();

            // In a loop (from 0 to 2), draw content that belongs to the desired
            // current layer on a graphics, then convert that graphics to a temp GcSvgDocument
            // and save it in a list:
            for (int i = 0; i < 3; ++i)
            {
                using var g = new GcSvgGraphics(pixelSize.Width, pixelSize.Height);
                if (i == 0)
                {
                    // Background:
                    g.FillRectangle(new RectangleF(0, 0, g.Width, g.Height), background);

                }
                else if (i == 1)
                {
                    // Arch and text label:
                    g.Transform = transform;
                    DrawArch(g, rc, rc.Height * 0.3f, rc.Width * 0.08f, line, arc, fill);
                    g.DrawString("ARCH", tf, rc, TextAlignment.Center, ParagraphAlignment.Center, false);
                    g.Transform = Matrix3x2.Identity;
                }
                else if (i == 2)
                {
                    // Measurement lines:
                    g.Transform = transform;
                    var w = Inch / 8;
                    var pen = new Pen(marks);
                    // Width line/label:
                    var txt = $"{(rc.Width / Inch):F}\"";
                    var s = g.MeasureString(txt, tf);
                    var d = s.Height * 1.5f;
                    g.DrawLine(rc.Left, rc.Top - d, rc.Right, rc.Top - d, pen);
                    g.DrawLine(rc.Left, rc.Top - d, rc.Left + w, rc.Top - d - w, pen);
                    g.DrawLine(rc.Left, rc.Top - d, rc.Left + w, rc.Top - d + w, pen);
                    g.DrawLine(rc.Right, rc.Top - d, rc.Right - w, rc.Top - d - w, pen);
                    g.DrawLine(rc.Right, rc.Top - d, rc.Right - w, rc.Top - d + w, pen);
                    var rcTxt = new RectangleF(rc.Left + rc.Width / 2 - s.Width / 2, rc.Top - d - s.Height / 2, s.Width, s.Height);
                    rcTxt.Inflate(2, 2);
                    g.FillRectangle(rcTxt, textBack);
                    g.DrawString(txt, tf, rcTxt, TextAlignment.Center, ParagraphAlignment.Center, false);
                    // Height line/label:
                    txt = $"{(rc.Height / Inch):F}\"";
                    s = g.MeasureString(txt, tf);
                    d = s.Width;
                    g.DrawLine(rc.Left - d, rc.Top, rc.Left - d, rc.Bottom, pen);
                    g.DrawLine(rc.Left - d, rc.Top, rc.Left - d - w, rc.Top + w, pen);
                    g.DrawLine(rc.Left - d, rc.Top, rc.Left - d + w, rc.Top + w, pen);
                    g.DrawLine(rc.Left - d, rc.Bottom, rc.Left - d - w, rc.Bottom - w, pen);
                    g.DrawLine(rc.Left - d, rc.Bottom, rc.Left - d + w, rc.Bottom - w, pen);
                    rcTxt = new RectangleF(rc.Left - d - s.Width / 2, rc.Top + rc.Height / 2 - s.Height / 2, s.Width, s.Height);
                    rcTxt.Inflate(2, 2);
                    g.FillRectangle(rcTxt, textBack);
                    g.DrawString(txt, tf, rcTxt, TextAlignment.Center, ParagraphAlignment.Center, false);
                    g.Transform = Matrix3x2.Identity;
                }
                // Convert the layer to a GcSvgDocument and add it to the list:
                svgs.Add(g.ToSvgDocument());
            }

            // Create the resulting SVG, add each of the temp documents
            // into a separate group with unique ID that can be used
            // to find and manipulate it:
            var svg = new GcSvgDocument();
            for (int i = 0; i < svgs.Count; ++i)
            {
                var tsvg = svgs[i];
                var group = new SvgGroupElement()
                {
                    ID = $"myId{i}",
                };
                while (tsvg.RootSvg.Children.Count > 0)
                {
                    var e = tsvg.RootSvg.Children[0];
                    tsvg.RootSvg.Children.RemoveAt(0);
                    group.Children.Add(e);
                }
                svg.RootSvg.Children.Add(group);
            }
            svg.RootSvg.ViewBox = new SvgViewBox(0, 0, pixelSize.Width, pixelSize.Height);

            // When the resulting SVG is shown in a browser, any of the three layers
            // can be found and manipulated in JavaScript using the unique ID of its group.
            // For example, if you download the resulting SVG and open it in a browser,
            // you can hide the background and measurement lines by running the following
            // commands in the browser's console:
            // document.getElementById("myId0").style.display= 'none' 
            // document.getElementById("myId2").style.display= 'none' 

            // Done:
            var ms = new MemoryStream();
            svg.Save(ms);
            ms.Seek(0, SeekOrigin.Begin);
            return ms;
        }

        private void DrawArch(GcGraphics g, RectangleF rc, float harc, float wd, Color line, Color arch, Color fill)
        {
            var path = g.CreatePath();
            // Insides filler (start from bottom left, to clockwise):
            path.BeginFigure(rc.Left + wd, rc.Bottom - wd);
            path.AddLine(rc.Left + wd, rc.Top + harc);
            path.AddArc(new ArcSegment()
            {
                ArcSize = ArcSize.Small,
                Point = new PointF(rc.Right - wd, rc.Top + harc),
                RotationAngle = 0,
                Size = new SizeF(rc.Width / 2f - wd, harc - wd),
                SweepDirection = SweepDirection.Clockwise
            });
            path.AddLine(rc.Right - wd, rc.Bottom - wd);
            path.EndFigure(FigureEnd.Closed);
            g.FillPath(path, fill);
            path.Dispose();

            // Arc outlines (start from bottom left, to clockwise):
            path = g.CreatePath();
            path.BeginFigure(rc.Left, rc.Bottom);
            path.AddLine(rc.Left, rc.Top + harc);
            path.AddLine(rc.Left + wd, rc.Top + harc);
            path.AddLine(rc.Left + wd, rc.Bottom - wd);
            path.EndFigure(FigureEnd.Closed);
            path.BeginFigure(rc.Left, rc.Top + harc);
            path.AddArc(new ArcSegment()
            {
                ArcSize = ArcSize.Small,
                Point = new PointF(rc.Right, rc.Top + harc),
                RotationAngle = 0,
                Size = new SizeF(rc.Width / 2f, harc),
                SweepDirection = SweepDirection.Clockwise
            });
            path.AddLine(rc.Right - wd, rc.Top + harc);
            path.AddArc(new ArcSegment()
            {
                ArcSize = ArcSize.Small,
                Point = new PointF(rc.Left + wd, rc.Top + harc),
                RotationAngle = 0,
                Size = new SizeF(rc.Width / 2f - wd, harc - wd),
                SweepDirection = SweepDirection.CounterClockwise
            });
            path.EndFigure(FigureEnd.Closed);
            path.BeginFigure(rc.Right, rc.Top + harc);
            path.AddLine(rc.Right, rc.Bottom);
            path.AddLine(rc.Right - wd, rc.Bottom - wd);
            path.AddLine(rc.Right - wd, rc.Top + harc);
            path.EndFigure(FigureEnd.Closed);
            path.BeginFigure(rc.Right, rc.Bottom);
            path.AddLine(rc.Left, rc.Bottom);
            path.AddLine(rc.Left + wd, rc.Bottom - wd);
            path.AddLine(rc.Right - wd, rc.Bottom - wd);
            path.EndFigure(FigureEnd.Closed);

            g.FillPath(path, arch);
            g.DrawPath(path, new Pen(line, 2));

            path.Dispose();
        }
    }
}