error when uploading a .gif image

[monfu]

Dear all

 

I have the following code:-

 

System.Drawing.Image src_image = System.Drawing.Image.FromStream(imgStream);

 

Bitmap bitmap = new Bitmap(image_width, image_height, src_image.PixelFormat);

Graphics new_g = Graphics.FromImage(bitmap);

new_g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

new_g.InterpolationMode =

System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

new_g.SmoothingMode = SmoothingMode.HighQuality;

new_g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;

new_g.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;

 

new_g.DrawImage(src_image, 0, 0, bitmap.Width, bitmap.Height);

new_g.Save();

src_image.Dispose();

 

System.Drawing.Imaging.Encoder Enc = System.Drawing.Imaging.Encoder.Transformation;

EncoderParameters EncParms = new EncoderParameters(1);

 

EncParms.Param = new EncoderParameter[]

{

new EncoderParameter(Enc,(long)EncoderValue.CompressionLZW),

new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L)

};

 

ImageCodecInfo ici ;

 

ici = GetProperEncoder(image_name);

 

string newFullPath = path + image_name;

 

bitmap.Save(newFullPath, System.Drawing.Imaging.ImageFormat.Jpeg);

bitmap.Dispose();

new_g.Dispose();

 

which is working fine when i upload a "jpg" image. However, when i tried to upload a ".gif" image, it is not working fine. It is giving me the following error:-

 

"A Graphics object cannot be created from an image that has an indexed pixel format."

 

I am not saving the image prior to uploading, just putting it in a stream and saving the image after the manipulation is done.

 

Thanks for your help and time

 

Johann

[Diesel]

Gif images are 8-bit, 256 color images that contain their own palette.

Use source images that are 16-bits or higher. With that bit depth, each pixel is defined usually by an RGB value, with no need for a custom palette.

 

Just convert the .gif image you are using as the source to a jpg or png.

 

If don't have access to the source image, there might be a way to load in a gif, ask IcePlug.

[monfu]

IcePlug is one of the members right?

 

My problem is that i have a memory stream, and the image is not saved on the server. I will have to save it I guess to manipulate it

[Diesel]

Well yes, but you can't get a graphics object from .gif file to manipulate it, that's the problem.

 

Yes, Iceplug is a member

[monfu]

Hello Diesel

 

I managed to do something like this:-

 

Bitmap org = (Bitmap)Image.FromStream(imgStream);

Bitmap bm=new Bitmap(width, height);

return bm;

 

and this is working fine since i am saving the gif image correctly. However, my problem now is that the background, instead of transparent, is appearing as black. Have any ideas how to solve this?