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

[Piotr Stanczyk]

Hi Paul

hmm - that sounds about right. let me take a closer look in a mo  ...

Piotr


________________________________________
From: address@hidden address@hidden on behalf of Paul Miller address@hidden
Sent: 13 February 2012 14:44
To: Ciaran Wills
Cc: address@hidden
Subject: Re: [Openexr-devel] how to properly save with data window?

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.

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