图片的裁剪

最新推荐文章于 2025-05-22 21:00:45 发布

转载最新推荐文章于 2025-05-22 21:00:45 发布 · 128 阅读

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原文链接：http://www.cnblogs.com/PJXWang/p/5623616.html

本文详细介绍了在iOS开发中如何使用Objective-C进行图片裁剪，包括将方形图片裁剪为圆形，给圆形图片添加边框，以及按窗口大小比例压缩和裁剪图片的方法。通过具体的代码实现，展示了如何利用Core Graphics进行图像处理，适用于需要定制化图片显示效果的场景。

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];

转载于:https://www.cnblogs.com/PJXWang/p/5623616.html