GDI+ LockBits flips data

[Peter Krnjevic]

I know I saw something about this but can't find it again. Anybody know why
Bitmap::LockBits is flipping my bitmap upside down? And is there a way to
avoid this?

Peter

[Greg Binkerd [MS]]

Peter,

How are you setting up the "Stride" in your BitmapData Class when defining
your bitmap data?

If the pixel data is stored bottom-up, the Stride data member is negative.
If the pixel data is stored top-down, the Stride data member is positive.

-Greg
Microsoft Developer Support

This posting is provided “AS IS” with no warranties, and confers no rights.

[Peter Krnjevic]

Greg,

I tried that but it causes an exception: Access Violation in GDIPLUS.DLL!
GdipCreateBitmapFromScan0 + 9497 bytes.
I'm preallocating the buffer and everything works fine (only upside down)
when Stride is positive.
Any suggestions?

Thanks,
Peter

"Greg Binkerd [MS]" <GregB...@Microsoft.com> wrote in message
news:ZmdS6kv...@cppssbbsa01.microsoft.com...

[Greg Binkerd [MS]]

scan0 must point to the start of the first scanline of the bitmap (not the
start of the buffer that contains the bitmap bits). It's only for
top-down bitmaps that the first scanline matches the start of the bitmap
bits buffer. It could be that your stride is negative but you are
advancing through the bits as though it were positive.

I don't know if this is the problem in your case. Let me know.

Thanks,

[Peter Krnjevic]

Scan0 points to the start of my bitmap's bits. I'm so used to Windows
top-down bitmaps that anything else almost seems to complicated! <g>

Thanks,
Peter

"Greg Binkerd [MS]" <GregB...@Microsoft.com> wrote in message

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