in src/main/java/com/intellij/util/ui/UIUtilities.java [1817:1828]
public static boolean isFloatingPointScale(AffineTransform tx) {
int type = tx.getType() & ~(TYPE_FLIP | TYPE_TRANSLATION);
if (type == 0) {
return false;
} else if ((type & ~TYPE_MASK_SCALE) == 0) {
double scaleX = tx.getScaleX();
double scaleY = tx.getScaleY();
return (scaleX != (int) scaleX) || (scaleY != (int) scaleY);
} else {
return false;
}
}