Android 学习 之 Canvas (一)

1.官方API文档中对save()方法的解释：

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public class Canvas { /** * Saves the current matrix and clip onto a private stack. Subsequent * calls to translate,scale,rotate,skew,concat or clip Rect,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. */ /** * 保存当前的矩阵和剪裁到一个私有的堆栈，其实矩阵和剪裁就是当前Canvas的状态State 接着调用位置，缩放，选择，倾斜，concat或者剪辑矩形，剪辑区域等将被正常操作，但是 当restore()被调用，恢复时，这些操作都将被放弃，并且刚才调用save()之前被保存的状态将被重新恢复。 */ public native int save();}public class Canvas { /** * 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. */ /** * 移除自上次保存操作后所做的修改，恢复到之前的状态，因为是堆栈实现，所以pull操作不能不等于push操作， save()和restore()应该成对使用，否则恢复的状态就很有可能是错误的 */ public native void restore();}

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