如何创建尺寸恒定、清晰可读的 PDF417 位图？

如何创建尺寸恒定、清晰可读的 PDF417 位图？

以下 C# ASP .NET 示例代码生成了一个尺寸恒定的 PDF417 图像。

//PDF417
Barcode barcode = new Barcode();
barcode.Data = strMyData;
barcode.BarcodeType = BarcodeType.Pdf417;
barcode.Pdf417.EncodingMode = PdfEncodingMode.Binary;

// with dpi = 100 we get 1 Pixel = 0.254 mms
barcode.Dpi = 100;

 // we should specify the number of horizontal data columns
 // this inhibits the symbol to change its horizontal size regardless of data
 barcode.Pdf417.NumberOfColumns = 16; // use a value, which fits to your available space !!

 // now calculate optimal bitmap size for the bar code
 barcode.SizeMode = SizeMode.FitToBoundingRectangle;
 Size optimalSize = barcode.CalculateOptimalBitmapSize(null, 1, 1);

 // we already could use this optimal Size for saving the image
 // barcode.BoundingRectangle = new Rectangle(0, 0, optimalSize.Width,  optimalSize.Height);
 // barcode.Draw(filename, ImageType.Jpg);

 // but we want a constant bitmap size,
 // which fits exactly into your predefined space

 Size finalSize = new Size(350, 200); // final bitmap size in Pixel

 // so we have to add empty spaces around the symbol via adding a quiet zone
 barcode.QuietZoneUnit = QuietZoneUnit.Pixel;

 // calculate the required empty quiet zone we have to add

if (finalSize.Width > optimalSize.Width)
  barcode.QuietZoneRight = finalSize.Width - optimalSize.Width;
else
  // should not occur!! Reduce the Pdf417.NumberOfColumns
  finalSize.Width = optimalSize.Width;

if (finalSize.Height > optimalSize.Height)
  barcode.QuietZoneBottom = finalSize.Height - optimalSize.Height;
else
  // should not occur!! Increase final bitmap size
  finalSize.Height = optimalSize.Height;

barcode.BoundingRectangle = new Rectangle(0, 0, finalSize.Width, finalSize.Height);
barcode.Draw(filename, ImageType.Jpg);