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

[Paul Miller]

On 2/13/2012 7:20 PM, Peter Hillman wrote:
> On 14/02/12 11:44, Paul Miller wrote:
> > On 2/13/2012 4:33 PM, Ciaran Wills wrote:
> > > 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));
>
> Shouldn't that be:
>
> pixels = pixels - ( dataWindow.min.x - (dataWindow.min.y * width) ) *
> channels;

Close!! It *was* the missing channels scale. The calculation should be:

pixels -= (dw.min.x + (dw.min.y * width)) * channels;

Sorry for the false alarm (and help!) guys.

(Piotr - your test code you sent worked perfectly, as expected).

Cheers!