IOS圖片上添加浮水印文字（微博上圖片上得浮水印文字）

標籤：ios   圖片   微博   繪圖   

建一個類目（不知道怎麼建的可以去百度一下） UIImage的類目

類目的.h檔案  檔案名稱為UIImage+watermark

#import <UIKit/UIKit.h>

@interface UIImage (watermark)

//定義一個方法

- (UIImage *)watermarkImage:(NSString *)text;

@end

.m檔案的實現

#import "UIImage+watermark.h"

@implementation UIImage (watermark)

- (UIImage *)watermarkImage:(NSString *)text{

    //1.擷取上下文

    UIGraphicsBeginImageContext(self.size);

    

    //2.繪製圖片

    [selfdrawInRect:CGRectMake(0,0, self.size.width,self.size.height)];

    

    //3.繪製浮水印文字

   CGRect rect = CGRectMake(0,self.size.height-20,self.size.width,20);

    

    NSMutableParagraphStyle *style = [[NSMutableParagraphStyledefaultParagraphStyle]mutableCopy];

    style.alignment =NSTextAlignmentCenter;

    //文字的屬性

   NSDictionary *dic = @{

                         NSFontAttributeName:[UIFontsystemFontOfSize:13],

                         NSParagraphStyleAttributeName:style,

                          NSForegroundColorAttributeName:[UIColorwhiteColor]

                         };

    //將文字繪製上去

    [text drawInRect:rectwithAttributes:dic];

    //4.擷取繪製到得圖片

    UIImage *watermarkImage =UIGraphicsGetImageFromCurrentImageContext();

    

    //5.結束圖片的繪製

    UIGraphicsEndImageContext();

    

   return watermarkImage;

}

@end

然後再viewController 的視圖上添加一個UIImageView 匯入類目（UIImage+watermark）檔案

#import "ViewController.h"

#import "UIImage+watermark.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

    [superviewDidLoad];

    

   UIImage *image = [UIImageimageNamed:@"baymax.jpg"];

//調用類目的方法實現功能

   UIImage *img = [image watermarkImage:@"@大白"];

    

   UIImageView *imageView = [[UIImageViewalloc] initWithImage:img];

//    imageView.frame = self.view.bounds;

    

    [self.viewaddSubview:imageView];

}

- (void)didReceiveMemoryWarning {

    [superdidReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end

IOS圖片上添加浮水印文字（微博片上得浮水印文字）