//
// This code is part of Document Solutions for Imaging demos.
// Copyright (c) MESCIUS 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.Imaging.Skia;
using GCTEXT = GrapeCity.Documents.Text;
using GCDRAW = GrapeCity.Documents.Drawing;

namespace DsImagingWeb.Demos
{
    // Text is always rendered with anti-aliasing in Skia.
    // Graphics rendering on the other hand can be controlled by
    // setting the GcSkiaGraphics.Aliased property.
    // This example shows the difference between shapes drawn
    // with that property set to false (which is the default)
    // and true. Note the more jagged appearance of some lines
    // in the lower part of the image (drawn with Aliased set
    // to false).
    public class SkiaAntialiasing
    {
        public static bool IsSkiaOnly => true;

        private GCTEXT.Font _font = null;

        // Helper method to draw a polygon and a caption beneath it.
        // Can also be used to just calculate the points without actual drawing.
        // startAngle is for the first point, clockwise from (1,0).
        private PointF[] DrawPolygon(GcGraphics g, PointF center, float r, int n, float startAngle, GCDRAW.Pen pen, string caption = null)
        {
            PointF[] pts = new PointF[n];
            for (int i = 0; i < n; ++i)
                pts[i] = new PointF(center.X + (float)(r * Math.Cos(startAngle + 2 * Math.PI * i / n)), center.Y + (float)(r * Math.Sin(startAngle + 2 * Math.PI * i / n)));
            if (pen != null)
                g.DrawPolygon(pts, pen);
            if (!string.IsNullOrEmpty(caption))
                DrawCaption(g, center, r, caption);
            return pts;
        }

        // Helper method to draw a caption beneath a shape:
        private void DrawCaption(GcGraphics g, PointF center, float r, string caption)
        {
            g.DrawString(caption,
                new TextFormat()
                {
                    Font = _font,
                    FontSize = 12,
                },
                new RectangleF(center.X - r, center.Y - r, r * 2, r * 2),
                TextAlignment.Center, ParagraphAlignment.Center, false);
        }

        // Main entry point.
        public Stream GenerateImageStream(string targetMime, Size pixelSize, float dpi, bool opaque, string[] sampleParams = null)
        {
            switch (targetMime)
            {
                case Common.Util.MimeTypes.JPEG:
                case Common.Util.MimeTypes.PNG:
                case Common.Util.MimeTypes.WEBP:
                    break;
                default:
                    throw new Exception("This sample uses Skia to create the image, and only supports JPEG, PNG and WEBP output formats.");
            }

            _font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "times.ttf"));
            var Inch = dpi;
            var bmp = new GcSkiaBitmap(pixelSize.Width, pixelSize.Height, opaque);
            using (var g = bmp.CreateGraphics(Color.White))
            {
                DrawShapes(g, bmp.PixelWidth, bmp.PixelHeight, false);
                DrawShapes(g, bmp.PixelWidth, bmp.PixelHeight, true);
            }
            
            // Done:
            var ms = new MemoryStream();
            switch (targetMime)
            {
                case Common.Util.MimeTypes.JPEG:
                    bmp.SaveAsJpeg(ms);
                    break;
                case Common.Util.MimeTypes.PNG:
                    bmp.SaveAsPng(ms);
                    break;
                case Common.Util.MimeTypes.WEBP:
                    bmp.SaveAsWebp(ms);
                    break;
                default:
                    System.Diagnostics.Debug.Assert(false);
                    break;
            }
            return ms;
        }

        void DrawShapes(GcGraphics g, int pixelWidth, int pixelHeight, bool aliased)
        {
            if (g is GcSkiaGraphics gskia)
                gskia.Aliased = aliased;

            // Set up the helper layout grid:
            var Inch = g.Resolution;
            var grid = new
            {
                Cols = 4,
                Rows = 3,
                MarginX = Inch / 6,
                MarginY = Inch / 4,
                Radius = Inch * 0.6f,
                StepX = (pixelWidth - Inch / 2) / 4,
                StepY = (pixelHeight - Inch / 4) / 7f,
            };

            // Insertion point of the next figure's center:
            PointF startIp = new PointF(grid.MarginX + grid.StepX / 2, grid.MarginY + grid.StepY / 2 + 10);
            if (aliased)
                startIp.Y += pixelHeight / 2;

            PointF ip = startIp;

            // Header:
            var pad = 8;
            var bord = new RectangleF(pad, pad + (aliased ? pixelHeight / 2 : 0), pixelWidth - pad * 2, pixelHeight / 2 - pad * 2);
            g.DrawString($"Shapes (Skia) - Aliased is {aliased}",
                new TextFormat()
                {
                    Font = _font,
                    FontSize = 14,
                },
                bord,
                TextAlignment.Center, ParagraphAlignment.Near);
            g.DrawRoundRect(bord, pad, Color.MediumPurple, 2, DashStyle.DashDot);

            // Pen used to draw shapes:
            var pen = new GCDRAW.Pen(Color.Orange, 1);
            pen.LineJoin = PenLineJoin.Round;
            int fill = 100; // Surfaces fill alpha

            // Circle:
            g.DrawEllipse(new RectangleF(ip.X - grid.Radius, ip.Y - grid.Radius, grid.Radius * 2, grid.Radius * 2), pen);
            DrawCaption(g, ip, grid.Radius, "Circle");
            ip.X += grid.StepX;

            // Ellipse:
            g.DrawEllipse(new RectangleF(ip.X - grid.Radius * 1.4f, ip.Y - grid.Radius / 2, grid.Radius * 2 * 1.4f, grid.Radius), pen);
            DrawCaption(g, ip, grid.Radius, "Ellipse");
            ip.X += grid.StepX;

            // Cylinder:
            float radX = grid.Radius / 1.4f;
            float radY = grid.Radius / 6;
            float height = grid.Radius * 1.8f;
            g.DrawEllipse(new RectangleF(ip.X - radX, ip.Y - height / 2, radX * 2, radY * 2), pen);
            g.FillEllipse(new RectangleF(ip.X - radX, ip.Y + height / 2 - radY * 2, radX * 2, radY * 2), Color.FromArgb(fill, pen.Color));
            g.DrawEllipse(new RectangleF(ip.X - radX, ip.Y + height / 2 - radY * 2, radX * 2, radY * 2), pen);
            g.DrawLine(new PointF(ip.X - radX, ip.Y - height / 2 + radY), new PointF(ip.X - radX, ip.Y + height / 2 - radY), pen);
            g.DrawLine(new PointF(ip.X + radX, ip.Y - height / 2 + radY), new PointF(ip.X + radX, ip.Y + height / 2 - radY), pen);
            DrawCaption(g, ip, grid.Radius, "Cylinder");
            pen.Color = Color.Indigo;
            ip.X += grid.StepX;

            // Cube:
            float cubex = 6;
            var cubePtsFar = DrawPolygon(g, new PointF(ip.X - cubex, ip.Y - cubex), grid.Radius, 4, (float)-Math.PI / 4, pen);
            var cubePtsNear = DrawPolygon(g, new PointF(ip.X + cubex, ip.Y + cubex), grid.Radius, 4, (float)-Math.PI / 4, pen);
            g.DrawLine(cubePtsFar[0], cubePtsNear[0], pen);
            g.DrawLine(cubePtsFar[1], cubePtsNear[1], pen);
            g.DrawLine(cubePtsFar[2], cubePtsNear[2], pen);
            g.DrawLine(cubePtsFar[3], cubePtsNear[3], pen);
            g.FillPolygon(new PointF[] { cubePtsFar[1], cubePtsFar[2], cubePtsNear[2], cubePtsNear[1], }, Color.FromArgb(fill, pen.Color));
            DrawCaption(g, ip, grid.Radius, "Cube");
            pen.Color = Color.DarkGreen;
            ip.X = startIp.X;
            ip.Y += grid.StepY;

            // Pentagon:
            DrawPolygon(g, ip, grid.Radius, 5, (float)-Math.PI / 2, pen, "Pentagon");
            ip.X += grid.StepX;

            // Hexagon:
            // For sample sake, we apply a transform to make the hexagon wider and shorter:
            g.Transform = Matrix3x2.CreateScale(1.4f, 0.8f) * Matrix3x2.CreateTranslation(ip.X, ip.Y);
            DrawPolygon(g, PointF.Empty, grid.Radius, 6, 0, pen, null);
            g.Transform = Matrix3x2.Identity;
            DrawCaption(g, ip, grid.Radius, "Hexagon");
            ip.X += grid.StepX;

            // Octagon:
            DrawPolygon(g, ip, grid.Radius, 8, (float)-Math.PI / 8, pen, "Octagon");
            pen.Color = Color.DarkRed;
            ip.X += grid.StepX;

            // Triangle:
            DrawPolygon(g, ip, grid.Radius, 3, (float)-Math.PI / 2, pen, "Triangle");
            ip.X = startIp.X;
            ip.Y += grid.StepY;

            // Filled pentagram:
            var pts = DrawPolygon(g, ip, grid.Radius, 5, (float)-Math.PI / 2, pen, "Pentagram");
            pts = new PointF[] { pts[0], pts[2], pts[4], pts[1], pts[3], };
            g.FillPolygon(pts, Color.FromArgb(fill, pen.Color));
            g.DrawPolygon(pts, pen);
            ip.X += grid.StepX;

            // Set up a simple kind of oblique projection to draw a pyramid:
            var angle = Math.PI / 6;
            float s = (float)Math.Sin(angle);
            float c = (float)Math.Cos(angle);
            Func<float, float, float, PointF> project = (x_, y_, z_) => new PointF(x_ - c * y_ * 0.5f, -(z_ - s * y_ * 0.5f));
            Func<Vector3, PointF> p3d = v_ => project(v_.X, v_.Y, v_.Z);
            float hedge = grid.Radius; // 1/2 edge
                                       // Debug - draw the 3 axis:
                                       // g.DrawLine(project(0, 0, 0), project(100, 0, 0), Color.Red);
                                       // g.DrawLine(project(0, 0, 0), project(0, 100, 0), Color.Green);
                                       // g.DrawLine(project(0, 0, 0), project(0, 0, 100), Color.Blue);
                                       // 3d points forming a square pyramid:
            var pts3d = new Vector3[]
            {
                new Vector3(-hedge, -hedge, 0),
                new Vector3(hedge, -hedge, 0),
                new Vector3(hedge, hedge, 0),
                new Vector3(-hedge, hedge, 0),
                new Vector3(0, 0, hedge * 2),
            };
            // project the points to draw the pyramid:
            pts = pts3d.Select(v_ => p3d(v_)).ToArray();
            g.Transform = Matrix3x2.CreateTranslation(ip.X, ip.Y + hedge * 0.7f);
            // Visible edges:
            g.DrawPolygon(new PointF[] { pts[4], pts[1], pts[2], pts[3], pts[4], pts[2] }, pen);
            // Invisible edges:
            pen.Width /= 2;
            pen.Color = Color.FromArgb(fill, pen.Color);
            g.DrawLine(pts[0], pts[4], pen);
            g.DrawLine(pts[0], pts[1], pen);
            g.DrawLine(pts[0], pts[3], pen);
            g.FillPolygon(pts.Take(4).ToArray(), pen.Color);
            //
            g.Transform = Matrix3x2.Identity;
            DrawCaption(g, ip, grid.Radius, "Pyramid");
            ip.X += grid.StepX;
            pen.Width *= 2;
            pen.Color = Color.Green;

            // Cone:
            float baseh = grid.Radius * 0.3f;
            pts = DrawPolygon(g, ip, grid.Radius, 3, (float)-Math.PI / 2, null, "Cone");
            g.DrawLines(new PointF[] { pts[2], pts[0], pts[1] }, pen);
            var rect = new RectangleF(pts[2].X, pts[2].Y - baseh / 2, pts[1].X - pts[2].X, baseh);
            g.FillEllipse(rect, Color.FromArgb(fill, pen.Color));
            g.DrawEllipse(rect, pen);
            ip.X += grid.StepX;

            // Trapezoid (use DrawPolygon to just get the points of the square):
            float dx = 10;
            pts = DrawPolygon(g, ip, grid.Radius, 4, (float)-Math.PI / 4, null, "Trapezoid");
            pts[0].X -= dx;
            pts[1].X += dx;
            pts[2].X -= dx;
            pts[3].X += dx;
            g.DrawPolygon(pts, pen);
        }
    }
}