<mphillip...@nospam.jun0.c0m> wrote:
> > I would like to draw something into an indexed bitmap. The problem is,
> > that the Graphics object may only be used for non-indexed images.
>
> This is a limitation of gdiplus. =A0You have no limitations, if you use GD=

> I would like to draw something into an indexed bitmap. The problem is,
> that the Graphics object may only be used for non-indexed images.

> My problem is to reconvert the non-indexed image into an indexed
> image. How is it possible?

"Norbert Pürringer" <thalion77@graffiti.net> wrote in message
news:222fad58-2721-4b9a-90c4-5d57d2a396a6@e23g2000prf.googlegroups.com...
> Hello there,
>
> I would like to draw something into an indexed bitmap. The problem is,
> that the Graphics object may only be used for non-indexed images.
>
> So I have to convert my indexed image into an nonindexed image in
> order to be able to manipulate the image and then I have to reconvert
> it to the old indexed format.
>
> My problem is to reconvert the non-indexed image into an indexed
> image. How is it possible?
>
> I use following code:
>
> private Bitmap ConvertToPixelFormat(Bitmap bitmap, PixelFormat
> pixelFormat)
> {
> Rectangle rectangle = new Rectangle(0, 0, bitmap.Width,
> bitmap.Height);
>
> BitmapData bmpData = bitmap.LockBits(rectangle,
> ImageLockMode.ReadWrite, bitmap.PixelFormat);
> int byteCount = bmpData.Stride*bmpData.Height;
> byte[] bytes = new byte[byteCount];
> Marshal.Copy(bmpData.Scan0, bytes, 0, byteCount);
> bitmap.UnlockBits(bmpData);
>
> Bitmap bmpNew = new Bitmap(bitmap.Width, bitmap.Height,
> pixelFormat);
> BitmapData bmpDataNew = bmpNew.LockBits(rectangle,
> ImageLockMode.ReadWrite, pixelFormat);
> Marshal.Copy(bytes, 0, bmpDataNew.Scan0, bytes.Length);
> bmpNew.UnlockBits(bmpDataNew);
> return bmpNew;
> }
>
> The non-indexed image has got the pixel format Format32bppRgb and the
> indexed image is of type Format8bppIndexed. I think, the problem is,
> that the bytes array, which saves 4 bytes for each pixel is too big
> for the indexed image taking only one byte for each pixel.
>
> Any advice for me?
>
> Thanks,
> Norbert

> really? I do not have a lots of experience in gdi. Do you know how to
> draw an subimage at a certain pixel position into an indexed image via
> gdi using C#?

"Norbert Pürringer" <thalion77@graffiti.net> wrote in message
news:cc6d9308-c3f6-4f54-ae91-807fa397214a@e10g2000prf.googlegroups.com...

<mphillip...@nospam.jun0.c0m> wrote:
> > I would like to draw something into an indexed bitmap. The problem is,
> > that the Graphics object may only be used for non-indexed images.
>
> This is a limitation of gdiplus. You have no limitations, if you use GDI.