Android_Graphics学习-Canvas save() restore()的简单理解

很多时候都看到对canvas的save()和restore()运用。

 

从名字上面来看，就是保存canvas和还原canvas，这个俩个在处理图像的平移、旋转、剪切方面使用的比较多。

 /**     * Saves the current matrix and clip onto a private stack. Subsequent     * calls to translate,scale,rotate,skew,concat or clipRect,clipPath     * will all operate as usual, but when the balancing call to restore()     * is made, those calls will be forgotten, and the settings that existed     * before the save() will be reinstated.     *     * @return The value to pass to restoreToCount() to balance this save()     */    public native int save();

SDK如是解释：

 

个人的理解是：保存当前的matrix clip translate等操作。在save()之后的这些操作将保存到画布中去，当调用restore（）的时候，将还原canvas到调用save()之前的状态。

 /**     * This call balances a previous call to save(), and is used to remove all     * modifications to the matrix/clip state since the last save call. It is     * an error to call restore() more times than save() was called.     */    public native void restore();

大致意思应该是：还原canvas的类似matrix/clip 等操作到save（）调用之前的状态。

并且save（）和restore应该是成对的使用的！