Convert iTextSharp.text.Image back to System.Drawing.Image

Question

I am trying to convert an object of type iTextSharp.text.Image back to System.Drawing.Image. Here is a piece of code that does not work:

System.Drawing.Image img = System.Drawing.Image.FromStream(new MemoryStream(itextImg.RawData)); 

I could make all this mistakes, but I won’t know if I don’t consult with experts, and after two hours of fruitless searches on the Internet, I finally send it myself as a question.

Answer 1

I’m sure it will work sometimes, but in the general case it won’t succeed ... it depends on what kind of compression filters the image uses.

I believe that JPEG image streams are exactly what you will see in the .jpeg file ... but for most (all?) Other types of compression, image information (height, width, bit per component, number of components, etc.) d.) is vital.

So it will be possible, but not so.

PS: There is at least one image format that iText cannot unpack, CITTFAXDecode (JBIG2, possibly others). In such cases, you will need other software that will deliver the raw pixel data so you can wrap it in Drawing.Image .

Answer 2

Yes, I found a solution by rewriting the BarcodeQRCode class ITextSharp and GetImageMethod (), as described below:

 using System; using System.Collections.Generic; using System.Drawing; using iTextSharp.text; using iTextSharp.text.pdf.qrcode; using iTextSharp.text.pdf.codec; /* Class rewritted to Convert ByteMatrix to BMP image by rewritting GetImage method from ITextSharp author: Luis Claudio Souza */ namespace iTextSharp.text.pdf{ /** * A QRCode implementation based on the zxing code. * @author Paulo Soares * @since 5.0.2 */ public class BarcodeQRCode { ByteMatrix bm; /** * Creates the QR barcode. The barcode is always created with the smallest possible size and is then stretched * to the width and height given. Set the width and height to 1 to get an unscaled barcode. * @param content the text to be encoded * @param width the barcode width * @param height the barcode height * @param hints modifiers to change the way the barcode is create. They can be EncodeHintType.ERROR_CORRECTION * and EncodeHintType.CHARACTER_SET. For EncodeHintType.ERROR_CORRECTION the values can be ErrorCorrectionLevel.L, M, Q, H. * For EncodeHintType.CHARACTER_SET the values are strings and can be Cp437, Shift_JIS and ISO-8859-1 to ISO-8859-16. The default value is * ISO-8859-1. * @throws WriterException */ public BarcodeQRCode(String content, int width, int height, IDictionary<EncodeHintType, Object> hints) { QRCodeWriter qc = new QRCodeWriter(); bm = qc.Encode(content, width, height, hints); } private byte[] GetBitMatrix() { int width = bm.GetWidth(); int height = bm.GetHeight(); int stride = (width + 7) / 8; byte[] b = new byte[stride * height]; sbyte[][] mt = bm.GetArray(); for (int y = 0; y < height; ++y) { sbyte[] line = mt[y]; for (int x = 0; x < width; ++x) { if (line[x] != 0) { int offset = stride * y + x / 8; b[offset] |= (byte)(0x80 >> (x % 8)); } } } return b; } /** Gets an <CODE>Image</CODE> with the barcode. * @return the barcode <CODE>Image</CODE> * @throws BadElementException on error */ public void GetImage() { sbyte[][] imgNew = bm.GetArray(); Bitmap bmp1 = new Bitmap(bm.GetWidth(), bm.GetHeight()); Graphics g1 = Graphics.FromImage(bmp1); g1.Clear(Color.White); for (int i = 0; i <= imgNew.Length - 1; i++) { for (int j = 0; j <= imgNew[i].Length - 1; j++) { if (imgNew[j][i] == 0) { g1.FillRectangle(Brushes.Black, i, j, 1, 1); } else { g1.FillRectangle(Brushes.White, i, j, 1, 1); } } } bmp1.Save("D:\\QREncode.jpg", System.Drawing.Imaging.ImageFormat.Jpeg); } } } 

After that, I used this code to call the method:

  var hints = new Dictionary<EncodeHintType, object>(); hints.Add(EncodeHintType.ERROR_CORRECTION, iTextSharp.text.pdf.qrcode.ErrorCorrectionLevel.H); BarcodeQRCode code = new BarcodeQRCode("98134979213479523874952873", 100, 100, hints); code.GetImage(); 

In the new GetImage method, you can choose what to do with the bmp class. In this case, it saves the JPEG image file, but the method can either return the storage stream that will be used by the caller.