Draw selection on half-pixels to avoid aliasing.
Draw selection on half-pixels to avoid aliasing.

Adapted from pull request #17.

andig/flot,chiu/flot,cipix2000/flot,cipix2000/flot,gdseller/flot,trask/flot,soenter/flot,chaveiro/flot,ni-kismet/engineering-flot,octavianCraciun/engineering-flot,wet-boew/flot,sedran/flot,saike/flot,kongx73/flot,k-joseph/flot,stanislavdavid/flot,chiu/flot,mlitwiniuk/flot,chaveiro/flot,resnick1223/flot,mlitwiniuk/flot,k-joseph/flot,andig/flot,MAMISHO/flot,stanislavdavid/flot,flot/flot,resnick1223/flot,TrainingPeaks/flot,stanislavdavid/flot,soenter/flot,pepperdata/flot,saike/flot,matong/flot,saike/flot,fashionsun/flot,mlitwiniuk/flot,wet-boew/flot,resnick1223/flot,klarkc/flot,magora-suchkov/flot,cipix2000/engineering-flot,andig/flot,chaveiro/flot,lolifans/flot,colinhunt/flot,chiu/flot,petrvacha/flot,k-joseph/flot,mcanthony/flot,Sensirion/flot