Develop Reference

Show Fingerprint in Picturebox

I am developing a functionality that involves saving the fingerprint, for this function I have used the Digital Persona U 4500 reader.
Download and install the personal digital SDK and build a windows form c # application.
I added the control whose name: DigitalPersona Fingerprint Enrollment Control and in effect captures the fingerprint
The objective is to be able to visualize the footprint that has been placed in the reader to see in detail how it has been, for this purpose I added a picturebox to be displayed in it and additionally include the following:
public DPFP.Sample Sample = new DPFP.Sample();// instancia la muestra
DPFP.Capture.SampleConversion Convertor = new DPFP.Capture.SampleConversion();
Bitmap bitmap = null;
Convertor.ConvertToPicture(sample, ref bitmap);
PicBoxHuella.Image = bitmap;
With the previous action it should show the sample in the picture, but it is not. Valid and identified that the sample arrives in null.
I can't understand the Null value, if when putting a footprint I should capture the value, I would appreciate your guidance a bit on the subject.

On the OnCaptured event, you get the image data from the Fiv en Data.Views:
Note: pbFingerprint is an PictureBox where the image will display.
private void enrollment_OnCaptured(EnrollmentControl enrollmentControl, CaptureResult captureResult, int fingerPosition)
{
if (captureResult.ResultCode == Constants.ResultCode.DP_SUCCESS)
{
if (captureResult.Data != null)
{
foreach (Fid.Fiv fiv in captureResult.Data.Views)
{
pbFingerprint.Image = CreateBitmap(fiv.RawImage, fiv.Width, fiv.Height);
}
}
}
}
/// <summary>
/// Create a bitmap from raw data in row/column format.
/// </summary>
/// <param name="bytes"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <returns></returns>
private Bitmap CreateBitmap(byte[] bytes, int width, int height)
{
byte[] rgbBytes = new byte[bytes.Length * 3];
for (int i = 0; i <= bytes.Length - 1; i++)
{
rgbBytes[(i * 3)] = bytes[i];
rgbBytes[(i * 3) + 1] = bytes[i];
rgbBytes[(i * 3) + 2] = bytes[i];
}
Bitmap bmp = new Bitmap(width, height, PixelFormat.Format24bppRgb);
BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
for (int i = 0; i <= bmp.Height - 1; i++)
{
IntPtr p = new IntPtr(data.Scan0.ToInt64() + data.Stride * i);
System.Runtime.InteropServices.Marshal.Copy(rgbBytes, i * bmp.Width * 3, p, bmp.Width * 3);
}
bmp.UnlockBits(data);
return bmp;
}

Release memory consumed by images with Twain

Twain scan images to memory and it consumes too much memory. So I scanned images in batch, and compress images in memory. So source images should be released. how can I do it?
protected void OnTwainTransferReady()
{
if (TwainTransferReady == null)
return; // not likely..
List<ImageSource> imageSources = new List<ImageSource>();
ArrayList pics = tw.TransferPictures();
tw.CloseSrc();
EndingScan();
picnumber++;
for (int i = 0; i < pics.Count; i++) {
IntPtr imgHandle = (IntPtr)pics[i];
/*if (i == 0) { // first image only
imageSources.Add(DibToBitmap.FormHDib(imgHandle));
//Refresh(image1); // force a redraw
}*/
ImageSource src = DibToBitmap.FormHDib(imgHandle);
ImageSource temp = ImageHelper.compressImage(src);
src = null;
imageSources.Add(temp);
Win32.GlobalFree(imgHandle);
}
// for some reason the main window does not refresh properly - resizing of the window solves the proble.
// happens only with the Canon LIDE Scanner
// Suspected: some messages where eaten by Twain
TwainTransferReady(this, imageSources);
}
Generate the BitSource
public static BitmapSource FormHDib(IntPtr dibHandle)
{
BitmapSource bs = null;
IntPtr bmpPtr = IntPtr.Zero;
bool flip = true; // vertivcally flip the image
try {
bmpPtr = Win32.GlobalLock(dibHandle);
Win32.BITMAPINFOHEADER bmi = new Win32.BITMAPINFOHEADER();
Marshal.PtrToStructure(bmpPtr, bmi);
if (bmi.biSizeImage == 0)
bmi.biSizeImage = (uint)(((((bmi.biWidth * bmi.biBitCount) + 31) & ~31) >> 3) * bmi.biHeight);
int palettSize = 0;
if (bmi.biClrUsed != 0)
throw new NotSupportedException("DibToBitmap: DIB with pallet is not supported");
// pointer to the beginning of the bitmap bits
IntPtr pixptr = (IntPtr)((int)bmpPtr + bmi.biSize + palettSize);
// Define parameters used to create the BitmapSource.
PixelFormat pf = PixelFormats.Default;
switch (bmi.biBitCount) {
case 32:
pf = PixelFormats.Bgr32;
break;
case 24:
pf = PixelFormats.Bgr24;
break;
case 8:
pf = PixelFormats.Gray8;
break;
case 1:
pf = PixelFormats.BlackWhite;
break;
default: // not supported
throw new NotSupportedException("DibToBitmap: Can't determine picture format (biBitCount=" + bmi.biBitCount + ")");
// break;
}
int width = bmi.biWidth;
int height = bmi.biHeight;
int stride = (int)(bmi.biSizeImage / height);
byte[] imageBytes = new byte[stride * height];
//Debug: Initialize the image with random data.
//Random value = new Random();
//value.NextBytes(rawImage);
if (flip) {
for (int i = 0, j = 0, k = (height - 1) * stride; i < height; i++, j += stride, k -= stride)
Marshal.Copy(((IntPtr)((int)pixptr + j)), imageBytes, k, stride);
} else {
Marshal.Copy(pixptr, imageBytes, 0, imageBytes.Length);
}
int xDpi = (int)Math.Round(bmi.biXPelsPerMeter * 2.54 / 100); // pels per meter to dots per inch
int yDpi = (int)Math.Round(bmi.biYPelsPerMeter * 2.54 / 100);
// Create a BitmapSource.
bs = BitmapSource.Create(width, height, xDpi, yDpi, pf, null, imageBytes, stride);
Win32.GlobalUnlock(pixptr);
Win32.GlobalFree(pixptr);
} catch (Exception ex) {
string msg = ex.Message;
}
finally {
// cleanup
if (bmpPtr != IntPtr.Zero) { // locked sucsessfully
Win32.GlobalUnlock(dibHandle);
}
}
Win32.GlobalUnlock(bmpPtr);
Win32.GlobalFree(bmpPtr);
return bs;
}
Compress Image in Memory
internal static System.Windows.Media.ImageSource compressImage(System.Windows.Media.ImageSource ims)
{
using (MemoryStream stream = new MemoryStream())
{
using (MemoryStream outS = new MemoryStream())
{
BitmapSource bs = ims as BitmapSource;
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
BitmapFrame bf = BitmapFrame.Create(bs);
//encoder.Frames.Add(BitmapFrame.Create(image1.Source));
encoder.Frames.Add(bf);
encoder.Save(stream);
stream.Flush();
try
{
// Read first frame of gif image
using (MagickImage image = new MagickImage(stream))
{
image.Quality = 75;
image.Resize(new Percentage(0.65));
image.Density = new Density(200, DensityUnit.PixelsPerInch);
image.Write(outS);
image.Dispose();
}
stream.Close();
stream.Dispose();
BitmapImage bitmap = new BitmapImage();
bitmap.BeginInit();
bitmap.CacheOption = BitmapCacheOption.OnLoad;
outS.Position = 0;
bitmap.StreamSource = outS;
//
bitmap.EndInit();
//bitmap.Freeze();
outS.Flush();
outS.Close();
outS.Dispose();
ims = null;
return bitmap;
}
catch (Exception e)
{
return null;
}
}
}
}

Upload from IOS picture to .net app: Rotate

I have below code for uploading and resize pictures from IOS Devices to my .net application. Users use to take picture in portrait orientation and then all pictures show up in my app with wrong rotation. Any suggestion how to fix this?
string fileName = Server.HtmlEncode(FileUploadFormbilde.FileName);
string extension = System.IO.Path.GetExtension(fileName);
System.Drawing.Image image_file = System.Drawing.Image.FromStream(FileUploadFormbilde.PostedFile.InputStream);
int image_height = image_file.Height;
int image_width = image_file.Width;
int max_height = 300;
int max_width = 300;
image_height = (image_height * max_width) / image_width;
image_width = max_width;
if (image_height > max_height)
{
image_width = (image_width * max_height) / image_height;
image_height = max_height;
}
Bitmap bitmap_file = new Bitmap(image_file, image_width, image_height);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
bitmap_file.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
stream.Position = 0;
byte[] data = new byte[stream.Length + 1];
stream.Read(data, 0, data.Length);

Here you go my friend:
Image originalImage = Image.FromStream(data);
if (originalImage.PropertyIdList.Contains(0x0112))
{
int rotationValue = originalImage.GetPropertyItem(0x0112).Value[0];
switch (rotationValue)
{
case 1: // landscape, do nothing
break;
case 8: // rotated 90 right
// de-rotate:
originalImage.RotateFlip(rotateFlipType: RotateFlipType.Rotate270FlipNone);
break;
case 3: // bottoms up
originalImage.RotateFlip(rotateFlipType: RotateFlipType.Rotate180FlipNone);
break;
case 6: // rotated 90 left
originalImage.RotateFlip(rotateFlipType: RotateFlipType.Rotate90FlipNone);
break;
}
}

You must read the image's Orientation value from the EXIF data in the Image.PropertyItems collection, and rotate it accordingly.

Here is a better solution answer posted Here He wrote a simple helper class that does all that:
you can check the full source code here.
private System.Drawing.Image ResizeAndDraw(System.Drawing.Image objTempImage)
{
// call image helper to fix the orientation issue
var temp = ImageHelper.RotateImageByExifOrientationData(objTempImage, true);
Size objSize = new Size(150, 200);
Bitmap objBmp;
objBmp = new Bitmap(objSize.Width, objSize.Height);
Graphics g = Graphics.FromImage(objBmp);
g.SmoothingMode = SmoothingMode.HighQuality;
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
//Rectangle rect = new Rectangle(x, y, thumbSize.Width, thumbSize.Height);
Rectangle rect = new Rectangle(0,0,150,200);
//g.DrawImage(objTempImage, rect, 0, 0, objTempImage.Width, objTempImage.Height, GraphicsUnit.Pixel);
g.DrawImage(objTempImage, rect);
return objBmp;
}
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
public static class ImageHelper
{
/// <summary>
/// Rotate the given image file according to Exif Orientation data
/// </summary>
/// <param name="sourceFilePath">path of source file</param>
/// <param name="targetFilePath">path of target file</param>
/// <param name="targetFormat">target format</param>
/// <param name="updateExifData">set it to TRUE to update image Exif data after rotation (default is TRUE)</param>
/// <returns>The RotateFlipType value corresponding to the applied rotation. If no rotation occurred, RotateFlipType.RotateNoneFlipNone will be returned.</returns>
public static RotateFlipType RotateImageByExifOrientationData(string sourceFilePath, string targetFilePath, ImageFormat targetFormat, bool updateExifData = true)
{
// Rotate the image according to EXIF data
var bmp = new Bitmap(sourceFilePath);
RotateFlipType fType = RotateImageByExifOrientationData(bmp, updateExifData);
if (fType != RotateFlipType.RotateNoneFlipNone)
{
bmp.Save(targetFilePath, targetFormat);
}
return fType;
}
/// <summary>
/// Rotate the given bitmap according to Exif Orientation data
/// </summary>
/// <param name="img">source image</param>
/// <param name="updateExifData">set it to TRUE to update image Exif data after rotation (default is TRUE)</param>
/// <returns>The RotateFlipType value corresponding to the applied rotation. If no rotation occurred, RotateFlipType.RotateNoneFlipNone will be returned.</returns>
public static RotateFlipType RotateImageByExifOrientationData(Image img, bool updateExifData = true)
{
int orientationId = 0x0112;
var fType = RotateFlipType.RotateNoneFlipNone;
if (img.PropertyIdList.Contains(orientationId))
{
var pItem = img.GetPropertyItem(orientationId);
fType = GetRotateFlipTypeByExifOrientationData(pItem.Value[0]);
if (fType != RotateFlipType.RotateNoneFlipNone)
{
img.RotateFlip(fType);
// Remove Exif orientation tag (if requested)
if (updateExifData) img.RemovePropertyItem(orientationId);
}
}
return fType;
}
/// <summary>
/// Return the proper System.Drawing.RotateFlipType according to given orientation EXIF metadata
/// </summary>
/// <param name="orientation">Exif "Orientation"</param>
/// <returns>the corresponding System.Drawing.RotateFlipType enum value</returns>
public static RotateFlipType GetRotateFlipTypeByExifOrientationData(int orientation)
{
switch (orientation)
{
case 1:
default:
return RotateFlipType.RotateNoneFlipNone;
case 2:
return RotateFlipType.RotateNoneFlipX;
case 3:
return RotateFlipType.Rotate180FlipNone;
case 4:
return RotateFlipType.Rotate180FlipX;
case 5:
return RotateFlipType.Rotate90FlipX;
case 6:
return RotateFlipType.Rotate90FlipNone;
case 7:
return RotateFlipType.Rotate270FlipX;
case 8:
return RotateFlipType.Rotate270FlipNone;
}
}
}

How to extract FlateDecoded Images from PDF with PDFSharp

how do I extract Images, which are FlateDecoded (such like PNG) out of a PDF-Document with PDFSharp?
I found that comment in a Sample of PDFSharp:
// 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.
// [...]
// Take a look at the file
// PdfSharp.Pdf.Advanced/PdfImage.cs to see how we create the PDF image formats.
Does anyone have a solution for this problem?
Thanks for your replies.
EDIT: Because I'm not able to answer on my own Question within 8 hours, I do it on that way:
Thanks for your very fast reply.
I added some Code to the Method "ExportAsPngImage", but I didn't get the wanted results. It is just extracting a few more Images (png) and they don't have the right colors and are distorted.
Here's my actual Code:
PdfSharp.Pdf.Filters.FlateDecode flate = new PdfSharp.Pdf.Filters.FlateDecode();
byte[] decodedBytes = flate.Decode(bytes);
System.Drawing.Imaging.PixelFormat pixelFormat;
switch (bitsPerComponent)
{
case 1:
pixelFormat = PixelFormat.Format1bppIndexed;
break;
case 8:
pixelFormat = PixelFormat.Format8bppIndexed;
break;
case 24:
pixelFormat = PixelFormat.Format24bppRgb;
break;
default:
throw new Exception("Unknown pixel format " + bitsPerComponent);
}
Bitmap bmp = new Bitmap(width, height, pixelFormat);
var bmpData = bmp.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, pixelFormat);
int length = (int)Math.Ceiling(width * bitsPerComponent / 8.0);
for (int i = 0; i < height; i++)
{
int offset = i * length;
int scanOffset = i * bmpData.Stride;
Marshal.Copy(decodedBytes, offset, new IntPtr(bmpData.Scan0.ToInt32() + scanOffset), length);
}
bmp.UnlockBits(bmpData);
using (FileStream fs = new FileStream(#"C:\Export\PdfSharp\" + String.Format("Image{0}.png", count), FileMode.Create, FileAccess.Write))
{
bmp.Save(fs, System.Drawing.Imaging.ImageFormat.Png);
}
Is that the right way? Or should I choose another way? Thanks a lot!

I know this answer might be a few years to late, but maybe it will help others.
The disortion occurs in my case because image.Elements.GetInteger(PdfImage.Keys.BitsPerComponent) seems to not return the correct value. As Vive la déraison pointed out under your question, you get the BGR Format for using Marshal.Copy. So reversing the Bytes and rotating the Bitmap after executing Marshal.Copy will do the job.
The resulting code looks like this:
private static void ExportAsPngImage(PdfDictionary image, ref int count)
{
int width = image.Elements.GetInteger(PdfImage.Keys.Width);
int height = image.Elements.GetInteger(PdfImage.Keys.Height);
var canUnfilter = image.Stream.TryUnfilter();
byte[] decodedBytes;
if (canUnfilter)
{
decodedBytes = image.Stream.Value;
}
else
{
PdfSharp.Pdf.Filters.FlateDecode flate = new PdfSharp.Pdf.Filters.FlateDecode();
decodedBytes = flate.Decode(image.Stream.Value);
}
int bitsPerComponent = 0;
while (decodedBytes.Length - ((width * height) * bitsPerComponent / 8) != 0)
{
bitsPerComponent++;
}
System.Drawing.Imaging.PixelFormat pixelFormat;
switch (bitsPerComponent)
{
case 1:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format1bppIndexed;
break;
case 8:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format8bppIndexed;
break;
case 16:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format16bppArgb1555;
break;
case 24:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format24bppRgb;
break;
case 32:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format32bppArgb;
break;
case 64:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format64bppArgb;
break;
default:
throw new Exception("Unknown pixel format " + bitsPerComponent);
}
decodedBytes = decodedBytes.Reverse().ToArray();
Bitmap bmp = new Bitmap(width, height, pixelFormat);
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.WriteOnly, bmp.PixelFormat);
int length = (int)Math.Ceiling(width * (bitsPerComponent / 8.0));
for (int i = 0; i < height; i++)
{
int offset = i * length;
int scanOffset = i * bmpData.Stride;
Marshal.Copy(decodedBytes, offset, new IntPtr(bmpData.Scan0.ToInt32() + scanOffset), length);
}
bmp.UnlockBits(bmpData);
bmp.RotateFlip(RotateFlipType.Rotate180FlipNone);
bmp.Save(String.Format("exported_Images\\Image{0}.png", count++), System.Drawing.Imaging.ImageFormat.Png);
}
The code might need some optimisation, but it did export FlateDecoded Images correctly in my case.

To get a Windows BMP, you just have to create a Bitmap header and then copy the image data into the bitmap. PDF images are byte aligned (every new line starts on a byte boundary) while Windows BMPs are DWORD aligned (every new line starts on a DWORD boundary (a DWORD is 4 bytes for historical reasons)).
All information you need for the Bitmap header can be found in the filter parameters or can be calculated.
The color palette is another FlateEncoded object in the PDF. You also copy that into the BMP.
This must be done for several formats (1 bit per pixel, 8 bpp, 24 bpp, 32 bpp).

Here's my full code for doing this.
I'm extracting a UPS shipping label from a PDF so I know the format in advance. If your extracted image is of an unknown type then you'll need to check the bitsPerComponent and handle it accordingly. I also only handle the first image here on the first page.
Note: I'm using TryUnfilter to 'deflate' which uses whatever filter is applied and decodes the data in-place for me. No need to call 'Deflate' explicitly.
var file = #"c:\temp\PackageLabels.pdf";
var doc = PdfReader.Open(file);
var page = doc.Pages[0];
{
// Get resources dictionary
PdfDictionary resources = page.Elements.GetDictionary("/Resources");
if (resources != null)
{
// Get external objects dictionary
PdfDictionary xObjects = resources.Elements.GetDictionary("/XObject");
if (xObjects != null)
{
ICollection<PdfItem> items = xObjects.Elements.Values;
// Iterate references to external objects
foreach (PdfItem item in items)
{
PdfReference reference = item as PdfReference;
if (reference != null)
{
PdfDictionary xObject = reference.Value as PdfDictionary;
// Is external object an image?
if (xObject != null && xObject.Elements.GetString("/Subtype") == "/Image")
{
// do something with your image here
// only the first image is handled here
var bitmap = ExportImage(xObject);
bmp.Save(#"c:\temp\exported.png", System.Drawing.Imaging.ImageFormat.Bmp);
}
}
}
}
}
}
Using these helper functions
private static Bitmap ExportImage(PdfDictionary image)
{
string filter = image.Elements.GetName("/Filter");
switch (filter)
{
case "/FlateDecode":
return ExportAsPngImage(image);
default:
throw new ApplicationException(filter + " filter not implemented");
}
}
private static Bitmap ExportAsPngImage(PdfDictionary image)
{
int width = image.Elements.GetInteger(PdfImage.Keys.Width);
int height = image.Elements.GetInteger(PdfImage.Keys.Height);
int bitsPerComponent = image.Elements.GetInteger(PdfImage.Keys.BitsPerComponent);
var canUnfilter = image.Stream.TryUnfilter();
var decoded = image.Stream.Value;
Bitmap bmp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format8bppIndexed);
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.WriteOnly, bmp.PixelFormat);
Marshal.Copy(decoded, 0, bmpData.Scan0, decoded.Length);
bmp.UnlockBits(bmpData);
return bmp;
}

So far... my code... it works with many png files, but not the one that comes from adobe photoshop with colorspace indexed:
private bool ExportAsPngImage(PdfDictionary image, string SaveAsName)
{
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);
var ColorSpace = image.Elements.GetArray(PdfImage.Keys.ColorSpace);
System.Drawing.Imaging.PixelFormat pixelFormat= System.Drawing.Imaging.PixelFormat.Format24bppRgb; //24 just for initalize
if (ColorSpace is null) //no colorspace.. bufferedimage?? is in BGR order instead of RGB so change the byte order. Right now it works
{
byte[] origineel_byte_boundary = image.Stream.UnfilteredValue;
bitsPerComponent = (origineel_byte_boundary.Length) / (width * height);
switch (bitsPerComponent)
{
case 4:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format32bppPArgb;
break;
case 3:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format24bppRgb;
break;
default:
{
MessageBox.Show("Unknown pixel format " + bitsPerComponent, "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return false;
}
break;
}
Bitmap bmp = new Bitmap(width, height, pixelFormat); //copy raw bytes to "master" bitmap so we are out of pdf format to work with
System.Drawing.Imaging.BitmapData bmd = bmp.LockBits(new Rectangle(0, 0, width, height), System.Drawing.Imaging.ImageLockMode.WriteOnly, pixelFormat);
System.Runtime.InteropServices.Marshal.Copy(origineel_byte_boundary, 0, bmd.Scan0, origineel_byte_boundary.Length);
bmp.UnlockBits(bmd);
Bitmap bmp2 = new Bitmap(width, height, pixelFormat);
for (int indicex = 0; indicex < bmp.Width; indicex++)
{
for (int indicey = 0; indicey < bmp.Height; indicey++)
{
Color nuevocolor = bmp.GetPixel(indicex, indicey);
Color colorintercambiado = Color.FromArgb(nuevocolor.A, nuevocolor.B, nuevocolor.G, nuevocolor.R);
bmp2.SetPixel(indicex, indicey, colorintercambiado);
}
}
using (FileStream fs = new FileStream(SaveAsName, FileMode.Create, FileAccess.Write))
{
bmp2.Save(fs, System.Drawing.Imaging.ImageFormat.Png);
}
bmp2.Dispose();
bmp.Dispose();
}
else
{
// this is the case of photoshop... work needs to be done here. I ´m able to get the color palette but no idea how to put it back or create the png file...
switch (bitsPerComponent)
{
case 4:
pixelFormat = System.Drawing.Imaging.PixelFormat.Format32bppArgb;
break;
default:
{
MessageBox.Show("Unknown pixel format " + bitsPerComponent, "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return false;
}
break;
}
if ((ColorSpace.Elements.GetName(0) == "/Indexed") && (ColorSpace.Elements.GetName(1) == "/DeviceRGB"))
{
//we need to create the palette
int paletteColorCount = ColorSpace.Elements.GetInteger(2);
List<System.Drawing.Color> paletteList = new List<Color>();
//Color[] palette = new Color[paletteColorCount+1]; // no idea why but it seams that there´s always 1 color more. ¿transparency?
PdfObject paletteObj = ColorSpace.Elements.GetObject(3);
PdfDictionary paletteReference = (PdfDictionary)paletteObj;
byte[] palettevalues = paletteReference.Stream.Value;
for (int index = 0; index < (paletteColorCount + 1); index++)
{
//palette[index] = Color.FromArgb(1, palettevalues[(index*3)], palettevalues[(index*3)+1], palettevalues[(index*3)+2]); // RGB
paletteList.Add(Color.FromArgb(1, palettevalues[(index * 3)], palettevalues[(index * 3) + 1], palettevalues[(index * 3) + 2])); // RGB
}
}
}
return true;
}

PDF may contain images with masks and with different colorspace options that is why simply decoding an image object may not work properly in some cases.
So the code also needs to check for image masks (/ImageMask) and other properties of image objects (to see if image should also use inverted colors or uses indexed colors) inside PDF to recreate the image similar to how it is displayed in PDF. See Image object, /ImageMask and /Decode dictionaries in the official PDF Reference.
Not sure if PDFSharp is capable of finding Image Mask objects inside PDF but iTextSharp is able to access image mask objects (see PdfName.MASK object types).
Commercial tools like PDF Extractor SDK are able to extract images in both original form and in "as rendered" form.
I work for ByteScout, maker of PDF Extractor SDK

Maybe not directly answer the question but another option to extract images from PDF is to use FreeSpire.PDF which can extract the image from pdf easily. It is available as Nuget package https://www.nuget.org/packages/FreeSpire.PDF/. They handle all the image format and can export as PNG. Their sample code is
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using Spire.Pdf;
namespace ExtractImagesFromPDF
{
class Program
{
static void Main(string[] args)
{
//Instantiate an object of Spire.Pdf.PdfDocument
PdfDocument doc = new PdfDocument();
//Load a PDF file
doc.LoadFromFile("sample.pdf");
List<Image> ListImage = new List<Image>();
for (int i = 0; i < doc.Pages.Count; i++)
{
// Get an object of Spire.Pdf.PdfPageBase
PdfPageBase page = doc.Pages[i];
// Extract images from Spire.Pdf.PdfPageBase
Image[] images = page.ExtractImages();
if (images != null && images.Length > 0)
{
ListImage.AddRange(images);
}
}
if (ListImage.Count > 0)
{
for (int i = 0; i < ListImage.Count; i++)
{
Image image = ListImage[i];
image.Save("image" + (i + 1).ToString() + ".png", System.Drawing.Imaging.ImageFormat.Png);
}
System.Diagnostics.Process.Start("image1.png");
}
}
}
}
(code taken from https://www.e-iceblue.com/Tutorials/Spire.PDF/Spire.PDF-Program-Guide/How-to-Extract-Image-From-PDF-in-C.html)

Directshow & .Net - Bitmap shows stripe from right on left side of image?

Sample Image:
I'm using DirectShow.net to get webcam footage into my program.
To accomplish this, I'm adding the source camera to the graph, and a VideoMixingRenderer9.
That part is all working swimmingly, but the part where I extract a frame using GetCurrentImage(out lpDib) is having what I can only describe as an odd issue.
What I am doing is using Marshal.PtrToSTructure to create a BitmapInfoHeader from lpDib, then calculating the width / height / stride / & pixel format.
The problem comes when I look at the image stored in bitmap - It has a 10 px wide line down the left side that came from what is actually the right!
It is worth noting that the data I am getting from the GetCurrentImage call is actually upside down - note the call to Cap.RotateFlip.
IntPtr lpDib;
windowlessCtrl.GetCurrentImage(out lpDib);
BitmapInfoHeader head;
head = (BitmapInfoHeader)Marshal.PtrToStructure(lpDib, typeof(BitmapInfoHeader));
int width = head.Width;
int height = head.Height;
int stride = width * (head.BitCount / 8);
PixelFormat pixelFormat = PixelFormat.Format24bppRgb;
switch (head.BitCount)
{
case 24: pixelFormat = PixelFormat.Format24bppRgb; break;
case 32: pixelFormat = PixelFormat.Format32bppRgb; break;
case 48: pixelFormat = PixelFormat.Format48bppRgb; break;
default: throw new Exception("Unknown BitCount");
}
Cap = new Bitmap(width, height, stride, pixelFormat, lpDib);
Cap.RotateFlip(RotateFlipType.RotateNoneFlipY);
//if we examine Cap here (Cap.Save, for example) I'm seeing the odd stripe.
I'm completely lost here. Seems like some sort of offset issue, and I've tried tweaking with stride some, but to no avail (just creates odd diagonal look).

This code is made using the DirectShowLib samples and it works:
public Bitmap GetCurrentImage()
{
Bitmap bmp = null;
if (windowlessCtrl != null)
{
IntPtr currentImage = IntPtr.Zero;
try
{
int hr = windowlessCtrl.GetCurrentImage(out currentImage);
DsError.ThrowExceptionForHR(hr);
if (currentImage != IntPtr.Zero)
{
BitmapInfoHeader structure = new BitmapInfoHeader();
Marshal.PtrToStructure(currentImage, structure);
PixelFormat pixelFormat = PixelFormat.Format24bppRgb;
switch (structure.BitCount)
{
case 24:
pixelFormat = PixelFormat.Format24bppRgb;
break;
case 32:
pixelFormat = PixelFormat.Format32bppRgb;
break;
case 48:
pixelFormat = PixelFormat.Format48bppRgb;
break;
default:
throw new Exception("BitCount desconhecido");
}
// este trecho: new IntPtr(currentImage.ToInt64() + 40), é o que resolve o problema da faixa (strip) da direita na esquerda.
bmp = new Bitmap(structure.Width, structure.Height, (structure.BitCount / 8) * structure.Width, pixelFormat, new IntPtr(currentImage.ToInt64() + 40));
bmp.RotateFlip(RotateFlipType.RotateNoneFlipY);
}
}
catch (Exception anyException)
{
MessageBox.Show("Falha gravando imagem da Webcam: " + anyException.ToString());
}
finally
{
Marshal.FreeCoTaskMem(currentImage);
}
}
return bmp;
}

The video renderer is extending the bitmap to suit its own memory alignment needs, but it will have adjusted the media type to match. The VIDEOINFOHEADER (or VIDEOINFOHEADER2 structure) in the media type will have an rcTarget rectangle that defines the valid area within the larger bitmap. You can query the current media type on the input pin and get hold of this information.
You will find that the renderer only needs this extended stride for some formats, so perhaps your simplest approach is to force a different capture format. An alternative is to use the sample grabber filter instead of the VMR.
G

For those who want to avoid using SampleGrabber. The "stripe" issue can be fixed by adding the offset of the bitmap header to the IntPtr. However this requires unsafe code
IntPtr pBuffer = IntPtr.Zero;
int xBufferSize = 0;
int xWidth, xHeight;
basicVideo.get_VideoWidth(out xWidth);
basicVideo.get_VideoHeight(out xHeight);
int hr = basicVideo.GetCurrentImage(ref xBufferSize, IntPtr.Zero);
pBuffer = Marshal.AllocCoTaskMem(xBufferSize);
// Get the pixel buffer for the thumbnail
hr = basicVideo.GetCurrentImage(ref xBufferSize, pBuffer);
// Offset for BitmapHeader info
var bitmapHeader = (BitmapInfoHeader)Marshal.PtrToStructure(pBuffer, typeof(BitmapInfoHeader));
var pBitmapData = (byte*)pBuffer.ToPointer();
pBitmapData += bitmapHeader.Size;
// This will be the pointer to the bitmap pixels
var bitmapData = new IntPtr(pBitmapData);
//Change for your format type!
System.Drawing.Imaging.PixelFormat xFormat = (System.Drawing.Imaging.PixelFormat.Format32bppRgb);
int bitsPerPixel = ((int)xFormat & 0xff00) >> 8;
int bytesPerPixel = (bitsPerPixel + 7) / 8;
int stride = 4 * ((xWidth * bytesPerPixel + 3) / 4);
Bitmap image = new Bitmap(xWidth, xHeight, stride, xFormat, bitmapData);
image.RotateFlip(RotateFlipType.RotateNoneFlipY);
return image;
Calculation for Stride can be found here.