Quartz2d图片裁剪/加水印/截屏

来源：互联网发布：傻瓜进销存软件编辑：程序博客网时间：2024/05/01 00:17

绘制图片和文字不需要手动获取图形上下文,只要开启图形上下文就获取了.

图片和文字可以直接绘制到图形上下文中,

如果图形上下文中绘制了路径并执行了裁剪,那么只有路径区域会显示图片;

图片的显示形状与路径的形状有关.执行裁剪实际上就是把图形上下文裁剪成了路径的形状.

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//1.加载要裁剪的图片

UIImage * image = [UIImageimageNamed:@"dst2"];

//2.开启一个图形上下文 (bitmap 大小和要裁剪的图片大小一样)

UIGraphicsBeginImageContextWithOptions(image.size,NO,0.0);//参数:上下文区域大小,是否透明,缩放率

//3.获取图形上下文

CGContextRef ctx =UIGraphicsGetCurrentContext();

//4.创建路径

//设置圆心

CGPoint centerP = CGPointMake(image.size.width/2, image.size.height/2);

//设置半径

CGFloat radius = MIN(image.size.width, image.size.height)/2;

UIBezierPath * path = [UIBezierPathbezierPathWithArcCenter:centerPradius:radiusstartAngle:0endAngle:2 *M_PI clockwise:YES];

//5.把路径添加到图形上下文中

CGContextAddPath(ctx, path.CGPath);

//6.执行裁剪

CGContextClip(ctx);

//7.绘制图片

[image drawAtPoint:CGPointZero];

//8.获取图片

UIImage * getImage =UIGraphicsGetImageFromCurrentImageContext();

//8.1 结束图形上下文

UIGraphicsEndImageContext();

// //8.2 裁剪图片

// CGFloat x = 0;

// CGFloat y = (image.size.height - 2 * radius)/2;

// CGFloat w = 2 * radius;

// CGFloat h = w;

// //获取屏幕的缩放比

// CGFloat scale = [UIScreen mainScreen].scale;

// x *= scale;

// y *= scale;

// w *= scale;

// h *= scale;

// CGImageRef imageRef = CGImageCreateWithImageInRect(getImage.CGImage, CGRectMake(x, y, w, h));

//// 获取裁剪后的图片

// getImage = [UIImage imageWithCGImage:imageRef];

self.imageView.image = getImage;

//9.保存

//9.1 保存相册

UIImageWriteToSavedPhotosAlbum(getImage, self, @selector(image:didFinishSavingWithError:contextInfo:),@"hello word");

//9.2 保存沙盒

NSString * documents = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES)lastObject];

//拼接文件名

NSString * fileName = [documents stringByAppendingPathComponent:@"001.png"];

//把UIimage--->NSData

NSData * imageData = UIImagePNGRepresentation(getImage);

[imageData writeToFile:fileName atomically:YES];

NSLog(@"%@",fileName);

}

//保存相册方法

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo

{

NSLog(@"保存完毕 %@",contextInfo);

}

==============================

//1.加载要添加水印图片

UIImage * image = [UIImageimageNamed:@"img05"];

//2.开启和图片大小相同的图形上下文(bitmap)

UIGraphicsBeginImageContextWithOptions(image.size,NO,0.0);

//3.把图片绘制到刚刚开启的图形上下文中

[image drawInRect:CGRectMake(0,0, image.size.width, image.size.height)];

//4.添加文字水印

NSString * text =@"美人你一直是我的春天,你是我的世外桃源";

NSDictionary * attrs =@{NSForegroundColorAttributeName:[UIColorredColor],

NSFontAttributeName:[UIFontsystemFontOfSize:20.f]

};

[text drawInRect:CGRectMake(200,500,300,200)withAttributes:attrs];

//4.1 添加图片水印

//加载水印图片

UIImage * logoImage = [UIImageimageNamed:@"logo"];

[logoImage drawInRect:CGRectMake(300,700,100,38)];

//5.从图形上下文中获取图片

UIImage * getImage =UIGraphicsGetImageFromCurrentImageContext();

//5.1 结束上下文

UIGraphicsEndImageContext();

//6.保存图片到相册

UIImageWriteToSavedPhotosAlbum(getImage,nil,nil,nil);

========================================

截屏

//1.开启一个图形上下文

UIGraphicsBeginImageContextWithOptions(self.view.frame.size,NO,0.0);

//2.获取图形上下文对象

CGContextRef ctx =UIGraphicsGetCurrentContext();

//3.调用view属性layer的方法 renderIncontex 把内容绘制到图形上下文中

[self.view.layerrenderInContext:ctx];

//4.获取图片

UIImage * getImage =UIGraphicsGetImageFromCurrentImageContext();

//5.结束图形上下文

UIGraphicsEndImageContext();

//6.保存图片

UIImageWriteToSavedPhotosAlbum(getImage,nil,nil, nil);

截屏方法二(只能在设备上运行,模拟器会报错):

CGImageRef UIGetScreenImage();
    CGImageRef img = UIGetScreenImage();
    UIImage* scImage=[UIImage imageWithCGImage:img];
    UIImageWriteToSavedPhotosAlbum(scImage, nil, nil, nil);

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