CGRectXXX笔记

CoreGraphics中有关CGRect相关函数笔记

1、CGRectInset

//该结构体的应用是以原rect为中心，再参考dx，dy，进行缩放或者放大。
CGRect rect = CGRectMake(10.0, 10.0, 100.0, 100.0);
CGRect rectToDraw = CGRectInset(rect, 10.0, 10.0);
NSLog(@"==%@", NSStringFromCGRect(rectToDraw));
//结果为：“=={{20.0, 20.0}, {80.0, 80.0}}”

CGRect rect2 = CGRectMake(10.0, 10.0, 100.0, 100.0);
CGRect rectToDraw2 = CGRectInset(rect2, -10.0, -10.0);
NSLog(@"==%@", NSStringFromCGRect(rectToDraw2));
//结果为：“=={{0.0, 0.0}, {120.0, 120.0}}”

　　

2、CGRectOffset

//相对于源矩形原点rect（左上角的点）沿x轴和y轴偏移, 再rect基础上沿x轴和y轴偏移
CGRect rect3 = CGRectMake(10.0, 10.0, 100.0, 100.0);
CGRect rectToDraw3 = CGRectOffset(rect3, 12.0, 12.0);
NSLog(@"==%@", NSStringFromCGRect(rectToDraw3));
//结果为：“=={{22.0, 22.0}, {100.0, 100.0}}”

CGRect rect4 = CGRectMake(10.0, 10.0, 100.0, 100.0);
CGRect rectToDraw4 = CGRectOffset(rect4, -12.0, -12.0);
NSLog(@"==%@", NSStringFromCGRect(rectToDraw4));
//结果为：“=={{-2.0, -2.0}, {100.0, 100.0}}”