PDFsharp & MigraDoc Foundation

Hi,
in the export image example, i only get:
// TODO: You can put the code here that converts vom PDF internal image format to a Windows bitmap

// and use GDI+ to save it in PNG format.

// It is the work of a day or two for the most important formats. Take a look at the file

// PdfSharp.Pdf.Advanced/PdfImage.cs to see how we create the PDF image formats.

// We don't need that feature at the moment and therefore will not implement it.

// If you write the code for exporting images I would be pleased to publish it in a future release

// of PDFsharp.
I want to know how can i convert the /FlateDecode Image to Image object, so I can display it on the picturebox control.
Thanks!

Hi!

"/FlateDecode" gives you a Bitmap in PDF format. Convert it to e.g. a Windows Bitmap and display it.
PDF bitmaps can have 1 bit, 8 bits, 24 bits, 32 bits and other variations.

See also:
viewtopic.php?p=5811#p5811
viewtopic.php?p=5564#p5564

_________________
Regards
Thomas Hoevel
PDFsharp Team

Thomas, Thanks!
If i have other question, I will give you a post.

static Image ExportAsPngImage(PdfDictionary image, ref int count)
{
int width = image.Elements.GetInteger(PdfSharp.Pdf.Advanced.PdfImage.Keys.Width);
int height = image.Elements.GetInteger(PdfSharp.Pdf.Advanced.PdfImage.Keys.Height);
int bitsPerComponent = image.Elements.GetInteger(PdfSharp.Pdf.Advanced.PdfImage.Keys.BitsPerComponent);
System.Drawing.Imaging.PixelFormat pixelFormat = new System.Drawing.Imaging.PixelFormat();

PdfSharp.Pdf.PdfArray arr = image.Elements.GetArray(PdfSharp.Pdf.Advanced.PdfImage.Keys.ColorSpace);
switch (bitsPerComponent)
{
case 1:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format1bppIndexed;
break;
case 8:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format8bppIndexed;
break;
case 24:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format24bppRgb;
break;
default:
throw new Exception("Unknown pixel format " + bitsPerComponent);
}

PdfSharp.Pdf.Filters.FlateDecode fd = new PdfSharp.Pdf.Filters.FlateDecode();

byte[] origineel_byte_boundary = image.Stream.UnfilteredValue;//fd.Decode(image.Stream.Value);
byte[] resultaat_byte_boundary = null;
int new_width = width;
int allignment = 4;

if (new_width % allignment != 0)
//Image data in BMP files always starts at a DWORD boundary, in PDF it starts at a BYTE boundary.
//Most images have a width that is a multiple of 4, so there is no problem with them.
//You must copy the image data line by line and start each line at the DWORD boundary.
{
while (new_width % allignment != 0)
new_width++;
byte[,] copy_dword_boundary = new byte[height, new_width];

for (int y = 0; y < height; y++)
{
for (int x = 0; x < new_width; x++)
{
if (x <= width && (x + (y * width) != origineel_byte_boundary.Length))
// while not at end of line, take orignale array
copy_dword_boundary[y, x] = origineel_byte_boundary[x + (y * width)];
else //fill new array with ending 0
copy_dword_boundary[y, x] = 0;
}
}
resultaat_byte_boundary = new byte[new_width * height];
int counter = 0;
for (int x = 0; x < copy_dword_boundary.GetLength(0); x++)
{
for (int y = 0; y < copy_dword_boundary.GetLength(1); y++)
{ //put 2dim array back in 1dim array
resultaat_byte_boundary[counter] = copy_dword_boundary[x, y];
counter++;
}
}
}
else
{
resultaat_byte_boundary = new byte[new_width * height];
origineel_byte_boundary.CopyTo(resultaat_byte_boundary, 0);
}
Bitmap bmp = new Bitmap(new_width, height, pixelFormat);
System.Drawing.Imaging.BitmapData bmd = bmp.LockBits(new Rectangle(0,0,bmp.Width,bmp.Height),ImageLockMode.WriteOnly,bmp.PixelFormat);
System.Runtime.InteropServices.Marshal.Copy(resultaat_byte_boundary, 0, bmd.Scan0, resultaat_byte_boundary.Length);
bmp.UnlockBits(bmd);
using (FileStream fs = new FileStream("C:\\" + String.Format("Image{0}.bmp", count), FileMode.Create, FileAccess.Write))
{
bmp.Save(fs, ImageFormat.Bmp);
count++;
}
return (Image)bmp;

// TODO: You can put the code here that converts vom PDF internal image format to a Windows bitmap

// and use GDI+ to save it in PNG format.

// It is the work of a day or two for the most important formats. Take a look at the file

// PdfSharp.Pdf.Advanced/PdfImage.cs to see how we create the PDF image formats.

// We don't need that feature at the moment and therefore will not implement it.

// If you write the code for exporting images I would be pleased to publish it in a future release

// of PDFsharp.

}

Hi, Thomas. I get the picture by this functuion. but i get the picture of black background.
Can you give me some help?

Hi，Thomas:
I use the code bellow to create the png file:


but I only get the black-white picutre, how can I get the color picutre?

The color palette is a separate object in the PDF file. The entry for the picture contains a reference to the palette.

_________________
Regards
Thomas Hoevel
PDFsharp Team

Hi Thomas

Could you please supply a working method with the color pallet as I failed to find ref on how to do this.
Currently the image comes out with weird colors instead of the actual correct PDF colors.

Thanks for your help
Shahar

Hi!
The references from Adobe can be found here:
http://www.adobe.com/devnet/pdf/pdf_ref ... chive.html

I cannot help with sample code.

_________________
Best regards
Thomas
(Freelance Software Developer with several years of MigraDoc/PDFsharp experience)