1.将方形图片裁剪成圆形
-(void)testImageClip
{
//加载图片
UIImage *img = [UIImage imageNamed:@"123"];
//开启上下文,跟图片尺寸一样大
UIGraphicsBeginImageContextWithOptions(img.size, NO, 0);
//设置裁剪区域
UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, img.size.width, img.size.height)];
[path addClip];
//绘制图片
[img drawAtPoint:CGPointZero];
//从上下文获取图片
UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();
//关闭上下文
UIGraphicsEndImageContext();
_imageV.image = clipImage;
}
2.给圆形再添加个边框
@implementation UIImage (Clip)
+(UIImage*)imageWithClipImage:(UIImage *)image borderColor:(UIColor *)color borderWidth:(CGFloat)borderWidth
{
CGFloat imageWH = image.size.height;
CGFloat border = borderWidth;
CGFloat ovaWH = imageWH ;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(ovaWH, ovaWH), NO, 0 );
UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, ovaWH, ovaWH)];
[color set];
[path fill];
//设置裁剪区域
UIBezierPath *clipPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(border, border, imageWH - 2*border, imageWH - 2*border)];
[clipPath addClip];
//绘制图片
[image drawAtPoint:CGPointZero];
//从上下文获取图片
UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();
//关闭上下文
UIGraphicsEndImageContext();
return clipImage;
}
@end
将图片按照原来的宽高比例压缩到与窗口合适的大小，然后在设置了_imageView.contentMode = UIViewContentModeCenter; 这个属性的UIImageView中展示压缩后的图片。
//压缩图片
- (UIImage *)image:(UIImage*)image scaledToSize:(CGSize)newSize
{
// Create a graphics image context
UIGraphicsBeginImageContext(newSize);
// Tell the old image to draw in this new context, with the desired
// new size
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
// Get the new image from the context
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
// End the context
UIGraphicsEndImageContext();
// Return the new image.
return newImage;
}
按照窗口宽高比例，将原图横向或者纵向裁剪掉多余的部分，然后不设置UIImageView的contentMode属性，将裁剪后的图片送进去，使其自动适应窗口。
//裁剪图片
- (UIImage *)cutImage:(UIImage*)image
{
//压缩图片
CGSize newSize;
CGImageRef imageRef = nil;
if ((image.size.width / image.size.height) < (bgImgView.size.width / bgImgView.size.height)) {
newSize.width = image.size.width;
newSize.height = image.size.width *bgImgView.size.height /bgImgView.size.width;
imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(0, fabs(image.size.height - newSize.height) / 2, newSize.width, newSize.height));
} else {
newSize.height = image.size.height;
newSize.width = image.size.height *bgImgView.size.width / bgImgView.size.height;
imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(fabs(image.size.width - newSize.width) / 2, 0, newSize.width, newSize.height));
}
return [UIImage imageWithCGImage:imageRef];
}
利用层裁剪
@property (weak, nonatomic) IBOutlet UIImageView *imageV;
_imageV.image = img;
_imageV.layer.masksToBounds = YES;
_imageV.layer.cornerRadius = img.size.width*0.5;
_imageV.layer.borderWidth = 5;
_imageV.layer.borderColor = [[UIColor redColor] CGColor];