函数求解paint(QPainter *painter,const QStyleOptionGraphicsItem *option, QWidget *widget) [复制链接]

图元项的该函数第二个参数option->levelOfDetail这个字段 为什么无论怎么缩放它的值仍然为1呢  求大侠解答！

levelOfDetail ?
存在这个东东？那个版本的Qt？

QT 4啊 好像4.2就有了把 QStyleOptionGraphicsItem这个类的一个成员

能多贴些代码吗 好分析

顶起来

By default, if no transformations are applied, its value is 1. If zoomed out 1:2, the level of detail will be 0.5, and if zoomed in 2:1, its value is 2.
This function was introduced in Qt 4.6.
也只能帮你这么多了，我的是Qt 4.7.0

qreal QStyleOptionGraphicsItem::levelOfDetailFromTransform ( const QTransform & worldTransform ) [static]
Returns the level of detail from the worldTransform.
Its value represents the maximum value of the height and width of a unity rectangle, mapped using the worldTransform of the painter used to draw the item. By default, if no transformations are applied, its value is 1. If zoomed out 1:2, the level of detail will be 0.5, and if zoomed in 2:1, its value is 2.
This function was introduced in Qt 4.6.

The option parameter provides style options for the item, such as its state, exposed area and its level-of-detail hints.