I've got a fancy looking chart control I've written, and people will use it to generate plots for Powerpoint presentations, so I need to be able to copy the plots to some fixed size like say 1024x768.
Say I have a button "Copy Plot To Bitmap". Ok my code will look like this:
private BitmapSource RenderToBitmap(double width, double height){
double baseHeight = this.ActualHeight; double baseWidth = this.ActualWidth; this.LayoutTransform = new ScaleTransform(baseWidth/width, baseHeight/height); RenderTargetBitmap rtb = new RenderTargetBitmap(width, height, 96d*width/baseWidth, 96d*height/baseHeight, PixelFormats.Default);rtb.Render(
this); BmpBitmapEncoder encoder = new BmpBitmapEncoder();encoder.Frames.Add(
BitmapFrame.Create(rtb)); FileStream fs = File.Open(@"c:\test.bmp", FileMode.Create);encoder.Save(fs);
fs.Close();
this.LayoutTransform = new ScaleTransform(1, 1); return rtb;}
the problem is, is that the Transform isn't applied until later. So I guess I need to set the tranform, wait until it is rendered, and then copy it to the bitmap. Or is there a better way that someone has come up with
What's a good way to Render to a bitmap that is a different size to the Visual?
psycho_billy
to render just part of an image, try using an ImageBrush and its Viewbox property. the following code sample will render the chunk of the image from 33% to 66% in the horizontal direction and from 25% to 75% in the vertical direction.
you can also add ViewboxUnits="Absolute" to the ImageBrush and work in terms of pixels instead of percentages.
<Rectangle x:Name="image" Margin="0,0,3,0" RadiusX="5" RadiusY="5" HorizontalAlignment="Left" VerticalAlignment="Top" Width="40" Height="40"> <Rectangle.Fill> <ImageBrush AlignmentX="Left" AlignmentY="Center" TileMode="None" Stretch="Uniform" Viewbox="0.3333,0.25,0.3333,0.50" ImageSource="myimage.jpg"/> </Rectangle.Fill> </Rectangle>ispjka
Bigger or smaller, and with a different aspect ratio. But I have it all worked out now. I wanted to change the size of the image, but retain the font size of any text I wanted rendered. I just wasn't aware of the UpdateTranform () method. There's a lot of stuff to discover in this new WPF stuff.
Dinus
Jono378
Got the solution!
After I set the LayoutTransform I need to call
this.UpdateLayout();
Adding that enables you to make the above code render any visual to any size bitmap and save it to disk.
fpsoft
Eric Donoho
Am I getting this right You're tryin to fit a bigger image into a smaller image"box"