Creating tiff image at runtime in WPF - wpf

Question

I'm trying to generate a simple tiff image at runtime. This image consists of white background and image downloaded from remote server.
Here's the code I've written for reaching that goal:
const string url = "http://localhost/barcode.gif";
var size = new Size(794, 1123);
var drawingVisual = new DrawingVisual();
using (var drawingContext = drawingVisual.RenderOpen())
{
drawingContext.DrawRectangle(new SolidColorBrush(Colors.White), null, new Rect(size));
var image = new BitmapImage(new Uri(url));
drawingContext.DrawImage(image, new Rect(0, 0, 180, 120));
}
var targetBitmap = new RenderTargetBitmap((int)size.Width, (int)size.Height, 96, 96, PixelFormats.Default);
targetBitmap.Render(drawingVisual);
var convertedBitmap = new FormatConvertedBitmap(targetBitmap, PixelFormats.BlackWhite, null, 0);
var encoder = new TiffBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(convertedBitmap));
using (var fs = new FileStream("out.tif", FileMode.Create))
{
encoder.Save(fs);
}
The code works and generates "out.tif" file. But the output file has just a white background, without image received from remote server.
What can be the problem? I have tried the following code in a variety of ways, but everytime with no luck.

Answer 1

I found this reading about the FormatConvertedBitmap class. Maybe give it a shot
FormatConvertedBitmap newFormatedBitmapSource = new FormatConvertedBitmap();
// BitmapSource objects like FormatConvertedBitmap can only have their properties
// changed within a BeginInit/EndInit block.
newFormatedBitmapSource.BeginInit();
// Use the BitmapSource object defined above as the source for this new
// BitmapSource (chain the BitmapSource objects together).
newFormatedBitmapSource.Source = targetBitmap;
// Set the new format to BlackWhite.
newFormatedBitmapSource.DestinationFormat = PixelFormats.BlackWhite;
newFormatedBitmapSource.EndInit();