iOS图形动画笔记

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1，填充背景色：

[[UIColorpurpleColor]setFill];

UIRectFill(rect);//填充背景色：

2,设置边框颜色

[[UIColorredColor]setFill];

CGRect frame =CGRectMake(20,30,100,300);

UIRectFrame(frame);//设置边框颜色

3,给图片上面增加水印或文字

重写UIView的- (void)drawRect:(CGRect)rect方法，然后将图形绘制到view上面，然后再增加文字或其他图层，如:

- (void)drawRect:(CGRect)rect

{

NSString* imagePath = [[NSBundlemainBundle]pathForResource:@"dog"ofType:@"png"];//rabbit

UIImage* myImageObj = [[UIImagealloc]initWithContentsOfFile:imagePath];

[myImageObjdrawInRect:CGRectMake(0,40,200,300)];

[myImageObjdrawAsPatternInRect:CGRectMake(0,0,320,400)];

NSString *s =@"我的小狗";

UIFont *font = [UIFontsystemFontOfSize:34];

NSDictionary *attr =@{NSFontAttributeName:font};

［drawAtPoint:CGPointMake(100,300)withAttributes:attr];

}

＊，绘制曲线:

- (void)drawRect:(CGRect)rect

{

CGContextRef cgContext =UIGraphicsGetCurrentContext();//坐标

CGContextMoveToPoint(cgContext, 333, 0);

/*绘制曲线

void CGContextAddArcToPoint (

CGContextRef c,

CGFloat x1, //端点1的x坐标

CGFloat y1, //端点1的y坐标

CGFloat x2, //端点2的x坐标

CGFloat y2, //端点2的y坐标

CGFloat radius //半径

);

原理：首先画两条线，这两条线分别是 current point to (x1,y1) 和(x1,y1) to (x2,y2).

这样就是出现一个以(x1,y1)为顶点的两条射线，

然后定义半径长度，这个半径是垂直于两条射线的，这样就能决定一个圆了，更好的理解看下图，不过个人认为下图所标的 tangent point 1的位置是错误的。

最后，函数执行完后，current point就被重置为(x2,y2).

还有一点要注意的是，假如当前path已经存在一个subpath，那么这个函数执行的另外一个效果是

会有一条直线，从current point到(x1,y1)

详见:http://blog.sina.com.cn/s/blog_9a7e29220101bwlu.html

CGContextAddCurveToPoint(cgContext, 333, 0, 332, 26, 330, 26);

CGContextAddCurveToPoint(cgContext, 330, 26, 299, 20, 299, 17);

CGContextAddLineToPoint(cgContext, 296, 17);

CGContextAddCurveToPoint(cgContext, 296, 17, 296, 19, 291, 19);

CGContextAddLineToPoint(cgContext, 250, 19);

CGContextAddCurveToPoint(cgContext, 250, 19, 241, 24, 238, 19);

CGContextAddCurveToPoint(cgContext, 236, 20, 234, 24, 227, 24);

CGContextAddCurveToPoint(cgContext, 220, 24, 217, 19, 216, 19);

CGContextAddCurveToPoint(cgContext, 214, 20, 211, 22, 207, 20);

CGContextAddCurveToPoint(cgContext, 207, 20, 187, 20, 182, 21);

CGContextAddLineToPoint(cgContext, 100, 45);

CGContextAddLineToPoint(cgContext, 97, 46);

CGContextAddCurveToPoint(cgContext, 97, 46, 86, 71, 64, 72);

CGContextAddCurveToPoint(cgContext, 42, 74, 26, 56, 23, 48);

CGContextAddLineToPoint(cgContext, 9, 47);

CGContextAddCurveToPoint(cgContext, 9, 47, 0, 31, 0, 0);

CGContextStrokePath(cgContext);

}

＊，图片的缩放，平移，旋转示例

- (void)drawRect:(CGRect)rect

{

NSString *path = [[NSBundlemainBundle]pathForResource:@"cat"ofType:@"png"];

UIImage *img = [UIImageimageWithContentsOfFile:path];

CGImageRef image = img.CGImage;

CGContextRef context =UIGraphicsGetCurrentContext();

CGContextSaveGState(context);

CGContextTranslateCTM (context,150,200);//平移

CGContextScaleCTM (context, 1.0, .75);//缩放

CGContextRotateCTM (context, radians(275.));//旋转

CGRect touchRect = CGRectMake(0, 0, img.size.width, img.size.height);

CGContextDrawImage(context, touchRect, image);

CGContextRestoreGState(context);

}

还可以得用图层来平称图片:如：

CGAffineTransform moveTransform =CGAffineTransformMakeTranslation(180,400);

[myImageView.layersetAffineTransform:moveTransform];//平移

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