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Last active August 29, 2015 14:10
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QgsMapToPixel / QMatrix4x4
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gistfile1.txt
QgsMapSettings mapSettings = mMapCanvas->mapSettings();
QMatrix4x4 matrix;
float scaleFactor = mMapCanvas->width() / mapSettings.extent().width();
// The following leads to a slight offset depending on the position on the canvas
// float scaleFactor = 1/mapSettings.mapToPixel().mapUnitsPerPixel();
matrix.scale( scaleFactor, -scaleFactor );
matrix.translate( -mapSettings.extent().xMinimum(), -mapSettings.extent().yMaximum() );
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m-kuhn commented Nov 24, 2014

QMatrix4x4 works on qReal (Qt4) and float (Qt5). That introduces unprecise results on large scales. Better to switch it to a double precision matrix instead.

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