This is how i do it. I hope it is what you want:)
GByte *myGdalScanData=(GByte *)
CPLMalloc(theRasterViewport->drawableAreaXDim*theRasterViewport->drawableAreaYDim*4);
if (myGdalScanData == NULL)
{
std::cout<<"scan data is null! ";
}
else
{
CPLErr myErr = GDALRasterIO( myGdalRedBand, GF_Read,
theRasterViewport->rectXOffset,
theRasterViewport->rectYOffset,
theRasterViewport->clippedWidth,
theRasterViewport->clippedHeight,
myGdalScanData+0,
theRasterViewport->drawableAreaXDim,
theRasterViewport->drawableAreaYDim,
GDT_Byte,
4,theRasterViewport->drawableAreaXDim *4 );
myErr = GDALRasterIO( myGdalGreenBand, GF_Read,
theRasterViewport->rectXOffset,
theRasterViewport->rectYOffset,
theRasterViewport->clippedWidth,
theRasterViewport->clippedHeight,
myGdalScanData+1,
theRasterViewport->drawableAreaXDim,
theRasterViewport->drawableAreaYDim,
GDT_Byte,
4,theRasterViewport->drawableAreaXDim* 4 );
myErr = GDALRasterIO( myGdalBlueBand, GF_Read,
theRasterViewport->rectXOffset,
theRasterViewport->rectYOffset,
theRasterViewport->clippedWidth,
theRasterViewport->clippedHeight,
myGdalScanData+2,
theRasterViewport->drawableAreaXDim,
theRasterViewport->drawableAreaYDim,
GDT_Byte,
4,theRasterViewport->drawableAreaXDim * 4 );
myErr = GDALRasterIO( myGdalBlueBand, GF_Read,
theRasterViewport->rectXOffset,
theRasterViewport->rectYOffset,
theRasterViewport->clippedWidth,
theRasterViewport->clippedHeight,
myGdalScanData+3,
theRasterViewport->drawableAreaXDim,
theRasterViewport->drawableAreaYDim,
GDT_Byte,
4,theRasterViewport->drawableAreaXDim * 4 );
if (myErr != CPLE_None)
{
std::cout<< "RaterIO error: " << CPLGetLastErrorMsg();
}
}
2008/10/19 <[EMAIL PROTECTED]>
> I have a BGRA buffer in memory, and a multi-band RGBA TIF image. Is it
> possible to use RasterIO to read in values from each band and neatly
> interleave them in my buffer.
>
> For example if I was loading an RGBA image I am hoping to be able to make 4
> separate RasterIO calls.
>
> Assuming a BGRA image looks like:
>
> 0 - blue byte
> 8 - green byte
> 16 - red byte
> 24 - alpha byte
> 32 - blue byte
> 40 - green byte
> 48 - red byte
> 56 - alpha byte
> 64 - ....
>
> The first RasterIO call would read in the blue values and insert them at 0,
> 32, 64, etc making it look like:
>
> 0 - blue byte
> 8 -
> 16 -
> 24 -
> 32 - blue byte
> 40 -
> 48 -
> 56 -
> 64 - ....
>
> The second RasterIO call would read the green values and insert them at 8,
> 40, etc making it look like:
>
> 0 - blue byte
> 8 - green byte
> 16 -
> 24 -
> 32 - blue byte
> 40 - green byte
> 48 -
> 56 -
> 64 - ....
>
> Rinse and repeat for red and alpha.
>
> Is this possible, or is there a much much simpler way that I'm
> overlooking? I've been looking at the paramaters for RasterIO but can't
> seem to get it to work. I do understand that I can just read the values
> into a separate buffer and memcpy them over to my image buffer. I was
> trying to minimize the total number of times the same data has to be copied.
>
> Thanks for the help.
>
> Craig
>
>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
_______________________________________________
gdal-dev mailing list
gdal-dev@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/gdal-dev
