void QgsMapToPixel::updateMatrix()
{
double rotation = mapRotation();
#if 0 // debugging
QgsDebugMsg( QString( "XXX %7 -- xCent:%1 yCent:%2 mWidth:%3 mHeight:%4 uPP:%5 rot:%6" )
.arg( xCenter ).arg( yCenter ).arg( mWidth ).arg( mHeight )
.arg( mMapUnitsPerPixel ).arg( rotation ).arg(( quintptr )this, QT_POINTER_SIZE *2, 15, QChar( '0' ) ) );
#endif
// NOTE: operations are done in the reverse order in which
// they are configured, so translation to geographical
// center happens first, then scaling, then rotation
// and finally translation to output viewport center
if ( qgsDoubleNear( rotation, 0.0 ) )
{
//no rotation, return a simplified matrix
mMatrix = QTransform::fromScale( 1.0 / mMapUnitsPerPixel, -1.0 / mMapUnitsPerPixel )
.translate( -xMin, - ( yMin + mHeight * mMapUnitsPerPixel ) );
return;
}
double cy = mapHeight() / 2.0;
double cx = mapWidth() / 2.0;
mMatrix = QTransform::fromTranslate( cx, cy )
.rotate( rotation )
.scale( 1 / mMapUnitsPerPixel, -1 / mMapUnitsPerPixel )
.translate( -xCenter, -yCenter )
;
}
QTransform QgsMapToPixel::transform() const
{
// NOTE: operations are done in the reverse order in which
// they are configured, so translation to geographical
// center happens first, then scaling, then rotation
// and finally translation to output viewport center
double rotation = mapRotation();
if ( qgsDoubleNear( rotation, 0.0 ) )
{
//no rotation, return a simplified matrix
return QTransform::fromScale( 1.0 / mMapUnitsPerPixel, -1.0 / mMapUnitsPerPixel )
.translate( -xMin, - ( yMin + mHeight * mMapUnitsPerPixel ) );
}
else
{
double cy = mapHeight() / 2.0;
double cx = mapWidth() / 2.0;
return QTransform::fromTranslate( cx, cy )
.rotate( rotation )
.scale( 1 / mMapUnitsPerPixel, -1 / mMapUnitsPerPixel )
.translate( -xCenter, -yCenter );
}
}
