图片裁剪

图片裁剪

- (void)circleTest2

{

    // 1.加载原图

    UIImage *oldImage = [UIImage imageNamed:@"me"];

    

    // 2.开启上下文

    CGFloat borderW = 2; // 圆环的宽度

    CGFloat imageW = oldImage.size.width + 2 * borderW;

    CGFloat imageH = oldImage.size.height + 2 * borderW;

    CGSize imageSize = CGSizeMake(imageW, imageH);

    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);

    

    // 3.取得当前的上下文

    CGContextRef ctx = UIGraphicsGetCurrentContext();

    

    // 4.画边框(大圆)

    [[UIColor whiteColor] set];

    CGFloat bigRadius = imageW * 0.5; // 大圆半径

    CGFloat centerX = bigRadius; // 圆心

    CGFloat centerY = bigRadius;

    CGContextAddArc(ctx, centerX, centerY, bigRadius, 0, M_PI * 2, 0);

    CGContextFillPath(ctx); // 画圆

    

    // 5.小圆

    CGFloat smallRadius = bigRadius - borderW;

    CGContextAddArc(ctx, centerX, centerY, smallRadius, 0, M_PI * 2, 0);

    // 裁剪(后面画的东西才会受裁剪的影响)

    CGContextClip(ctx);

    

    // 6.画图

    [oldImage drawInRect:CGRectMake(borderW, borderW, oldImage.size.width, oldImage.size.height)];

    

    // 7.取图

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    

    // 8.结束上下文

    UIGraphicsEndImageContext();

    

    // 9.显示图片

    self.iconView.image = newImage;

    

    // 10.写出文件

    NSData *data = UIImagePNGRepresentation(newImage);

    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"new.png"];

    [data writeToFile:path atomically:YES];

}