Bitmap bmpSource = new Bitmap(@"c:\1.bmp");
bmpSource.Clone();
Graphics gSource = Graphics.FromImage(bmpSource);


Bitmap bmpDest = new Bitmap(680, 400); // double the size
Graphics gDest = Graphics.FromImage(bmpDest);
IntPtr dcSource = gSource.GetHdc();
IntPtr dcDest = gDest.GetHdc();

GDI32_DLL.StretchBlt(dcDest, 0, 0, bmpDest.Width,
bmpDest.Height, dcSource, 0, 0,
bmpSource.Width, bmpSource.Height,
GDI32_DLL.TernaryRasterOperations.SRCCOPY);

gSource.ReleaseHdc(dcSource);
gDest.ReleaseHdc(dcDest);

bmpDest.Save(@"c:\6.bmp", ImageFormat.Bmp);
MessageBox.Show("Finished Saving Image");

"etjon" <etjon (AT) discussions (DOT) microsoft.com> wrote


I don't know, but if all you're trying to do is resize 1.bmp, why not:

using (Bitmap source = Bitmap.FromFile(@"c:\1.bmp"))
using (Bitmap resized = new Bitmap(source, 640, 400))
{
resized.Save(@"c:\6.bmp", ImageFormat.Bmp);
}

And for reference, the second line of your code:

bmpSource.Clone();

does absolutely nothing. Cloning returns a NEW object; it does not modify an
existing object.

Thank your Reply,

The second line bmpSource.Clone() , It's test code ,sorry ,
I want to resize it and use socket send this picture or show form,
if i write to file and load file from I/O , It's to slow,but i code is
right ,
why not save it is black color ,because i see my picture is black color in
form .
So i write bmpDest.Save(@"c:\6.bmp", ImageFormat.Bmp),is my test code

Ps: My English is to bad...


"Jeff Johnson" wrote:

On 5/11/2010 9:57 PM, etjon wrote:
For optimal speed, you may find using a MemoryStream to save and load
the image will work. I'm not sure if you tried Jeff's code, but it does
work fine for an image here that I tested.

--
Mike