使用quartz2D绘制阴影的代码

void
MyDrawWithShadows (CGContextRef myContext, // 1

float wd, float ht);

{

CGSize myShadowOffset = CGSizeMake (-15, 20);// 2

float myColorValues[] = {1.0, 1.0, 1.0, .6};// 3 (White shadow colour)

CGColorRef myColor;// 4

CGColorSpaceRef myColorSpace;// 5

CGContextSaveGState(myContext);// 6

CGContextSetShadow (myContext, myShadowOffset, 5); // 7

// Your drawing code here!!!!!!!!!!!!!!!! // 8

CGContextSetRGBFillColor (myContext, 0, 1, 0, 1);

CGContextFillRect (myContext, CGRectMake (wd/3 + 75, ht/2 , wd/4, ht/4));

myColorSpace = CGColorSpaceCreateDeviceRGB ();// 9

myColor = CGColorCreate (myColorSpace, myColorValues);// 10

CGContextSetShadowWithColor (myContext, myShadowOffset, 5, myColor);// 11

// Your drawing code here// 12

CGContextSetRGBFillColor (myContext, 0, 0, 1, 1);

CGContextFillRect (myContext, CGRectMake (wd/3-75,ht/2-100,wd/4,ht/4));

CGColorRelease (myColor);// 13

CGColorSpaceRelease (myColorSpace); // 14

CGContextRestoreGState(myContext);// 15

}

取获到绘图的context,就可以绘制阴影效果了。