//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System;using System.IO;using System.Drawing;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Text;using GrapeCity.Documents.Drawing;using GCTEXT = GrapeCity.Documents.Text;using GCDRAW = GrapeCity.Documents.Drawing;
namespace DsPdfWeb.Demos{    // This sample demonstrates the effects of different blend modes    // when drawing on a GcPdfGraphics. Note that the current blend mode    // set on an instance of GcGraphics (including GcPdfGraphics)    // affects not only images but all drawing operations.    // In this sample it is demonstrated by rendering the blend mode    // names on the second page.    public class AllBlendModes    {        public int CreatePDF(Stream stream)        {            var doc = new GcPdfDocument();            var page = doc.NewPage();            var g = page.Graphics;
            var iorchid = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "orchid.jpg"));            var ispectr = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "spectrum-pastel-500x500.png"));
            const int margin = 36;            const int NCOLS = 4;            var w = (int)((page.Size.Width - margin * 2) / NCOLS);            var h = (int)((iorchid.Height * w) / iorchid.Width);
            // Text layout for captions:            var tl = g.CreateTextLayout();            tl.DefaultFormat.Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "NotoSansMono-Regular.ttf"));            tl.DefaultFormat.FontSize = 12;            tl.ParagraphAlignment = ParagraphAlignment.Center;            tl.TextAlignment = TextAlignment.Center;            tl.MaxWidth = w;            tl.MaxHeight = h;            tl.MarginTop = h - g.MeasureString("QWERTY", tl.DefaultFormat).Height * 1.4f;
            int row = 0, col, dy;            // Render all blending modes in a grid:            var modes = Enum.GetValues(typeof(BlendMode));            for (int i = 0; i < 2; ++i)            {                row = col = 0;                GCDRAW.Image iback, ifore;                if (i == 0)                {                    iback = ispectr;                    ifore = iorchid;                    var trc1 = Common.Util.AddNote(                        "Below are tiles drawn by composing two images (a spectrum and an orchid) using the " +                        "different blend modes supported by DsPdf. " +                        "First the spectrum image is drawn normally, then it is overlaid by the orchid image " +                        "drawn in a supported blend mode. The blend mode name is shown below each tile." +                        "\n" +                        "Tiles on the second page are composed of the same images but drawn in reverse order: " +                        "the orchid is drawn normally, the spectrum is blended with it using the different modes." +                        "\n" +                        "Note that the current blend mode affects not only images but any drawing on a GcGraphics. " +                        "The blend mode names on the 2nd page illustrate this.",                        page);                    dy = (int)trc1.Bottom;                }                else // i == 1                {                    iback = iorchid;                    ifore = ispectr;                    page = doc.Pages.Add();                    g = page.Graphics;                    dy = 0;                }                foreach (var mode in modes)                {                    var blendMode = (BlendMode)mode;                    if (!g.IsBlendModeSupported(blendMode))                        continue;
                    int x = margin + w * col;                    int y = margin + h * row + dy;                    var r = new RectangleF(x, y, w, h);
                    g.BlendMode = BlendMode.Normal;                    g.DrawImage(iback, r, null, ImageAlign.StretchImage);                    g.BlendMode = blendMode;                    g.DrawImage(ifore, r, null, ImageAlign.StretchImage);                    g.BlendMode = BlendMode.Normal;
                    // Caption:                    tl.Clear();                    tl.Append(blendMode.ToString());                    tl.PerformLayout(true);                    var rc = tl.ContentRectangle;                    rc.Offset(x, y);                    rc.Inflate(4, 2);                    g.FillRectangle(rc, Color.White);                    g.DrawTextLayout(tl, new PointF(x, y));                    nextRowCol();                }            }            // Text blends:            page = doc.Pages[1];            g = page.Graphics;            var trc = Common.Util.AddNote(                "Below are supported blend mode names rendered into rectangles using the corresponding blend mode. " +                "Each rectangle is first filled by the spectrum image using BlendMode.Normal, " +                "then black and white texts are drawn using the current blend mode, " +                "finally the same spectrum image is drawn using BlendMode.Difference to black out the background. " +                "Names prefixed with 'B:' are drawn in black, " +                "while names prefixed with 'W:' are drawn in white. " +                "Most combinations yield rather colorful results, but for some the results are invisible.",                page,                new RectangleF(margin, margin + h * row + 12, page.Bounds.Width - margin * 2, 0));
            var yoff = (int)trc.Bottom + 12;            tl.DefaultFormat.FontBold = true;            tl.DefaultFormat.FontSize = 16;            h = (int)(g.MeasureString("QWERTY", tl.DefaultFormat).Height * 1.4f) * 2;            tl.MaxWidth = w;            tl.MaxHeight = h;            tl.MarginTop = (h - h / 1.4f) / 2;
            tl.DefaultFormat.ForeColor = Color.Black;            var tfWhite = new TextFormat(tl.DefaultFormat) { ForeColor = Color.White };
            row = col = 0;            foreach (var mode in modes)            {                var blendMode = (BlendMode)mode;                if (!g.IsBlendModeSupported(blendMode))                    continue;
                int x = margin + w * col;                int y = yoff + h * row;                var r = new RectangleF(x, y, w, h);
                // Draw spectrum image normally:                g.BlendMode = BlendMode.Normal;                g.DrawImage(ispectr, r, null, ImageAlign.StretchImage);                // Draw blend mode name using the current blend mode:                tl.Clear();                tl.AppendLine($"B: {blendMode}");                tl.Append($"W: {blendMode}", tfWhite);                tl.PerformLayout(true);                var rc = tl.ContentRectangle;                rc.Offset(x, y);                rc.Inflate(4, 2);                // Current blend mode:                g.BlendMode = blendMode;                g.DrawTextLayout(tl, new PointF(x, y));                // Draw spectrum image again using BlendMode.Difference                // to produce (mostly) colorful text on black background:                g.BlendMode = BlendMode.Difference;                g.DrawImage(ispectr, r, null, ImageAlign.StretchImage);                // Draw a rectangle to mark the current area:                g.BlendMode = BlendMode.Normal;                g.DrawRectangle(r, Color.Gray);                nextRowCol();            }            // Done:            doc.Save(stream);            return doc.Pages.Count;
            //            void nextRowCol()            {                if (++col == NCOLS)                {                    col = 0;                    ++row;                }            }        }    }}