[Oiio-dev] "ImageBufAlgo::resize" and "ImageBufAlgo::resample" cropsimage instead of scaling down to new size

[talonrenaud at me.com]

I understand why I’m getting a silence treatment. I was reading the pixels from my source image instead of my resized (resampled) image.
I waited half a day on a stupid typo. See working code below:

Code:
ImageBuf srcImageBuf("C:/someImage.dpx”);

int thumbWidth = 480;
int thumbHeight = 270;
int thumbChans = 3;

ImageSpec thumbSpecSpec( thumbWidth, thumbHeight, thumbChans, TypeDesc::UINT8 );
ImageBuf resizedBuf( thumbSpecSpec );
ImageBufAlgo::resample ( resizedBuf, srcImageBuf );

unsigned char* myBuffer = (unsigned char*)malloc(thumbSpecSpec.width*thumbSpecSpec.height*thumbSpecSpec.nchannels );
resizedBuf.get_pixels(resizedBuf.roi_full(), TypeDesc::UINT8, myBuffer);

// Create QImage
QImage::Format QIFormat = QImage::Format_RGB888;
QImage *newQImage = new QImage(myBuffer, resizedBuf.spec().width, resizedBuf.spec().height, QIFormat);

Renaud


From: talonrenaud at me.com
Sent: Sunday, March 5, 2017 1:09 AM
To: OpenImageIO developers
Subject: [Oiio-dev] "ImageBufAlgo::resize" and "ImageBufAlgo::resample" cropsimage instead of scaling down to new size

Hi !

I was able to get my get my image loaded and converted to a QImage using code that Larry and Peter Black helped with a little while back, that said for some reason when I try to scale down my image (to generate a thumbnail) both ImageBufAlgo::resize and ImageBufAlgo::resample crop the original image (using a portion of the source image from what seems to be a roi of 0, 480, 0, 270) instead of using the full ROI from the source and scaling it down into a smaller thumbnail ImgBuf.
I am pulling my hair off on this. I have used both resize and resample with pyOpenImageIO with no issue, it’s pretty much the same code here so I’m not sure what I am doing wrong.
As usual, any help would be greatly appreciated. (I’m using OIIO 1.7 on Windows 10, compiled with VS2015)

Thanks,

Renaud

Code:
ImageBuf srcImageBuf("C:/someImage.dpx”);

int thumbWidth = 480;
int thumbHeight = 270;
int thumbChans = 3;

ImageSpec thumbSpecSpec( thumbWidth, thumbHeight, thumbChans, TypeDesc::UINT8 );
ImageBuf resizedBuf( thumbSpecSpec );
ImageBufAlgo::resample ( resizedBuf, srcImageBuf );

unsigned char* myBuffer = (unsigned char*)malloc(thumbSpecSpec.width*thumbSpecSpec.height*thumbSpecSpec.nchannels );
srcImageBuf.get_pixels(resizedBuf.roi_full(), TypeDesc::UINT8, myBuffer);

// Create QImage
QImage::Format QIFormat = QImage::Format_RGB888;
QImage *newQImage = new QImage(myBuffer, resizedBuf.spec().width, resizedBuf.spec().height, QIFormat);

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