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Merged r6372 from 0.8 release branch to head

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git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@6373 c8812cc2-4d05-0410-92ff-de0c093fc19c
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g_j_m 2007-01-01 22:47:22 +00:00
parent 7ae236e2b5
commit a8673c3b90
1 changed files with 15 additions and 10 deletions
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25
src/raster/qgsrasterlayer.cpp
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@ -1133,16 +1133,21 @@ __FUNCTION__, __LINE__);
myRasterViewPort->clippedYMinDouble = (myRasterExtent.yMin() - adfGeoTransform[3]) / adfGeoTransform[5];
myRasterViewPort->clippedYMaxDouble = (myRasterExtent.yMax() - adfGeoTransform[3]) / adfGeoTransform[5];
// We do a "+2" for each of the 2 assignments below because:
// + 1 to simulate a ceil() out of static_cast<int> which otherwise is just a truncation.
// + 1 to allow for the fact that the left hand source pixel may be mostly scrolled out of view
// and therefore a fraction of a pixel would "leak" in the right hand side.
// (we could test for this case more explicitly if we wanted to be pedantic, but
// it's easier to just add one pixel "just in case")
myRasterViewPort->clippedWidthInt =
abs(static_cast < int >(myRasterViewPort->clippedXMaxDouble - myRasterViewPort->clippedXMinDouble)) + 2;
myRasterViewPort->clippedHeightInt =
abs(static_cast < int >(myRasterViewPort->clippedYMaxDouble - myRasterViewPort->clippedYMinDouble)) + 2;
// Sometimes the Ymin/Ymax are reversed.
if (myRasterViewPort->clippedYMinDouble > myRasterViewPort->clippedYMaxDouble)
{
double t = myRasterViewPort->clippedYMinDouble;
myRasterViewPort->clippedYMinDouble = myRasterViewPort->clippedYMaxDouble;
myRasterViewPort->clippedYMaxDouble = t;
}
// Set the clipped width and height to encompass all of the source pixels
// that could end up being displayed.
myRasterViewPort->clippedWidthInt =
static_cast<int>(ceil(myRasterViewPort->clippedXMaxDouble) - floor(myRasterViewPort->clippedXMinDouble));
myRasterViewPort->clippedHeightInt =
static_cast<int>(ceil(myRasterViewPort->clippedYMaxDouble) - floor(myRasterViewPort->clippedYMinDouble));
// but make sure the intended SE corner extent doesn't exceed the SE corner
// of the source raster, otherwise GDAL's RasterIO gives an error and returns nothing.