Problem Saving .Png Format

Question

User539648229 posted

 Hi

I create a Bitmap and when try to save it in png format there is an error. It says:

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+.

There is no problem saving in gif or jpeg formats.

and my code:

        // Create a new Bitmap object, 50 x 50 pixels in size
        Image canvas = new Bitmap(50, 50);
        // create an object that will do the drawing operations
        Graphics artist = Graphics.FromImage(canvas);
        // draw a few shapes on the canvas picture
        artist.Clear(Color.Lime);
        artist.FillEllipse(Brushes.Red, 3, 30, 30, 30);
        artist.DrawBezier(new Pen(Color.Blue, 3), 0, 0, 40, 15, 10, 35, 50, 50);
        // return the picture
        canvas.Save(Response.OutputStream, ImageFormat.Png);
        // now the drawing is done, we can discard the artist object
        artist.Dispose();
        // also the Bitmap
        canvas.Dispose();

Help please

Thanks

 

 

Answer 1

User1007520750 posted

Hi Iranianboy

The solution is to use a Response.BinaryWrite like this:

MemoryStream io = new MemoryStream();
bmp.Save(io, ImageFormat.Png);
Response.BinaryWrite( io.GetBuffer() );

Found it here: http://www.velocityreviews.com/forums/t78540-generation-of-png-in-aspnet-failed.html

Good luck

Amit

Answer 2

User539648229 posted

 Hi

Reason:The PNG implementation in System.Drawing requires the use of a searchable stream, which Response.OutputStream isn’t.

Thanks