C# 動的に画像生成 – テックメモ

System.Drawing

        public async Task<IActionResult> CreateImage()
        {
            using (System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(500, 80))
            {
                using (System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap))
                {
                    //背景描画
                    using (SolidBrush solidBrush = new SolidBrush(Color.White))
                    {
                        //graphics.FillRectangle(solidBrush, new Rectangle(0, 0, 200, 200));
                        graphics.FillRectangle(solidBrush, graphics.VisibleClipBounds);
                    }

                    // 図形描画
                    using (SolidBrush solidBrush = new SolidBrush(Color.Blue))
                    {
                        graphics.DrawPie(Pens.Red, 0, 0, 80, 80, 300, 300);
                    }

                    // 文字描画
                    string serial = "管理番号：0001";

                    using (System.Drawing.Font font = new System.Drawing.Font("メイリオ", 36))
                    using (SolidBrush solidBrush = new SolidBrush(Color.Black))
                    {
                        graphics.TextRenderingHint = TextRenderingHint.AntiAlias;
                        graphics.DrawString(serial, font, solidBrush, new System.Drawing.Point(0, 0));
                    }

                    // Controllerで実行する場合(ASP.NET)
                    var ms = new MemoryStream();
                    bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
                    ms.Position = 0;
                    return new FileStreamResult(ms, "image/png");

                    // PictureBoxの場合
                    // PictureBox1.Image = bitmap;
                }
            }
        }

public async Task<IActionResult> CreateImage()

{

using (System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(500, 80))

{

using (System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap))

{

//背景描画

using (SolidBrush solidBrush = new SolidBrush(Color.White))

{

//graphics.FillRectangle(solidBrush, new Rectangle(0, 0, 200, 200));

graphics.FillRectangle(solidBrush, graphics.VisibleClipBounds);

}

// 図形描画

using (SolidBrush solidBrush = new SolidBrush(Color.Blue))

{

graphics.DrawPie(Pens.Red, 0, 0, 80, 80, 300, 300);

}

// 文字描画

string serial = "管理番号：0001";

using (System.Drawing.Font font = new System.Drawing.Font("メイリオ", 36))

using (SolidBrush solidBrush = new SolidBrush(Color.Black))

{

graphics.TextRenderingHint = TextRenderingHint.AntiAlias;

graphics.DrawString(serial, font, solidBrush, new System.Drawing.Point(0, 0));

}

// Controllerで実行する場合(ASP.NET)

var ms = new MemoryStream();

bitmap.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

ms.Position = 0;

return new FileStreamResult(ms, "image/png");

// PictureBoxの場合

// PictureBox1.Image = bitmap;

}

QRコードの場合(ZXing.SkiaSharp)

        public async Task<IActionResult> CreateImage(string? id)
        {
            using System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(500, 70);
            using System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap);

            using (SolidBrush solidBrush = new SolidBrush(Color.White))
            {
                graphics.FillRectangle(solidBrush, graphics.VisibleClipBounds);
            }

            var writer = new BarcodeWriter
            {
                Format = ZXing.BarcodeFormat.QR_CODE,
                Options = new ZXing.Common.EncodingOptions
                {
                    Width = 200,
                    Height = 200,
                    Margin = 2,
                }
            };

            var ms = new MemoryStream();
            var bmp = writer.Write("abcabc");
            bmp.Encode(ms, SKEncodedImageFormat.Png, 100);
            ms.Position = 0;

            return new FileStreamResult(ms, "image/png");
        }

public async Task<IActionResult> CreateImage(string? id)

{

using System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(500, 70);

using System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap);

using (SolidBrush solidBrush = new SolidBrush(Color.White))

{

graphics.FillRectangle(solidBrush, graphics.VisibleClipBounds);

}

var writer = new BarcodeWriter

{

Format = ZXing.BarcodeFormat.QR_CODE,

Options = new ZXing.Common.EncodingOptions

{

Width = 200,

Height = 200,

Margin = 2,

}

};

var ms = new MemoryStream();

var bmp = writer.Write("abcabc");

bmp.Encode(ms, SKEncodedImageFormat.Png, 100);

ms.Position = 0;

return new FileStreamResult(ms, "image/png");

}

SkiaSharp+ZXing.SkiaSharpを利用し1つの画像として生成

        public async Task<IActionResult> CreateImage(string? id)
        {
            using SkiaSharp.SKBitmap bitmap = new SkiaSharp.SKBitmap(500, 70);
            using SkiaSharp.SKCanvas canvas = new SkiaSharp.SKCanvas(bitmap);

            //背景描画1
            canvas.Clear(SKColors.White);

            //背景描画2
            SkiaSharp.SKPaint paint1 = new SkiaSharp.SKPaint();
            paint1.Style = SkiaSharp.SKPaintStyle.Fill;
            paint1.Color = SkiaSharp.SKColors.Blue;
            //canvas.DrawRect (canvas.LocalClipBounds, paint1);

            // 文字描画
            SkiaSharp.SKPaint paint2 = new SkiaSharp.SKPaint();
            paint2.Style = SkiaSharp.SKPaintStyle.Fill;
            paint2.Color = SkiaSharp.SKColors.Black ;
            paint2.TextSize = 36;
            paint2.Typeface = SkiaSharp.SKTypeface.FromFamilyName("Yu Gothic UI");
            paint2.IsAntialias = true;
            canvas.DrawText("管理番号：" + id, 70, 48, paint2);

            //QRコード描画
            var writer = new BarcodeWriter
            {
                Format = ZXing.BarcodeFormat.QR_CODE,
                Options = new ZXing.Common.EncodingOptions
                {
                    Width = 70,
                    Height = 70,
                    Margin = 0,
                }
            };

            var ms = new MemoryStream();
            var qr = writer.Write(Url.Content("/TestTable33/Details/" + id));
            canvas.DrawImage(SkiaSharp.SKImage.FromBitmap(qr), new SkiaSharp.SKPoint(0,0));
            bitmap.Encode(ms, SKEncodedImageFormat.Png, 100);
            ms.Position = 0;
            return new FileStreamResult(ms, "image/png");
        }

public async Task<IActionResult> CreateImage(string? id)

{

using SkiaSharp.SKBitmap bitmap = new SkiaSharp.SKBitmap(500, 70);

using SkiaSharp.SKCanvas canvas = new SkiaSharp.SKCanvas(bitmap);

//背景描画1

canvas.Clear(SKColors.White);

//背景描画2

SkiaSharp.SKPaint paint1 = new SkiaSharp.SKPaint();

paint1.Style = SkiaSharp.SKPaintStyle.Fill;

paint1.Color = SkiaSharp.SKColors.Blue;

//canvas.DrawRect (canvas.LocalClipBounds, paint1);

// 文字描画

SkiaSharp.SKPaint paint2 = new SkiaSharp.SKPaint();

paint2.Style = SkiaSharp.SKPaintStyle.Fill;

paint2.Color = SkiaSharp.SKColors.Black ;

paint2.TextSize = 36;

paint2.Typeface = SkiaSharp.SKTypeface.FromFamilyName("Yu Gothic UI");

paint2.IsAntialias = true;

canvas.DrawText("管理番号：" + id, 70, 48, paint2);

//QRコード描画

var writer = new BarcodeWriter

{

Format = ZXing.BarcodeFormat.QR_CODE,

Options = new ZXing.Common.EncodingOptions

{

Width = 70,

Height = 70,

Margin = 0,

}

};

var ms = new MemoryStream();

var qr = writer.Write(Url.Content("/TestTable33/Details/" + id));

canvas.DrawImage(SkiaSharp.SKImage.FromBitmap(qr), new SkiaSharp.SKPoint(0,0));

bitmap.Encode(ms, SKEncodedImageFormat.Png, 100);

ms.Position = 0;

return new FileStreamResult(ms, "image/png");

}