Re: [Openexr-devel] how to properly save with data window?

[Paul Miller]

On 2/13/2012 4:33 PM, Ciaran Wills wrote:
> On Feb 13, 2012, at 1:16 PM, Paul Miller wrote:
>
> > When I specify for example a data window such as (-70,-154)-(649,331) for a 
> > 720x486 image and then call writePixels(486), the library is crashing down in 
> > copyFromFrameBuffer().
> >
> > Perhaps this is the way I am adding Slices to my frame-buffer?
> >
> > for (int i = 0; i<  channels; i++)
> > {
> >         const half *pixels = pixPtr + i;
> >         frameBuffer.insert(chanName, Slice(HALF, (char *)(pixels), sizeof(half) 
> > * channels, sizeof(half) * width * channels));
> > }
> >
> > I am basing this on "3.2 Writing a Cropped Image" in the reading/writing 
> > document. Though my RGBA pixels are packed into a single buffer.
> >
> > What am I doing wrong?
>
> I think you probably need to offset the pixel pointer to point at where pixel 
> (0, 0) would be - section 2.2 explains the pixel pointer math a bit clearer.

I tried that as well:

const half *pixels = pixPtr + chan_index;
pixels = pixels - dataWindow.min.x - (dataWindow.min.y * width);
fb.insert(chanName, Slice(HALF, (char *)(pixels), sizeof(half) * 
channels, sizeof(half) * width * channels));

But I got the same crash in the same place.

Thus my confusion.