iOS 生成二維碼頭像

簡單的做一張像下圖這樣帶二維碼的頭像

#import "ViewController.h"
#import <CoreImage/CoreImage.h>

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *icon;
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    /*
     二維碼注意點:
     1.二維碼的容錯性很強, 哪怕缺少一部分也可以顯示, 但是不能缺少太多.
     2.二維碼的有些地方是不能覆蓋的, 三個點. 這三個點稱之爲二維碼的定位點
     3.生成二維碼的時候, 切記不要存放太多數據, 數據越多掃描起來就越慢
     */
    // 1.創建濾鏡對象
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 2.還原濾鏡初始化屬性
    [filter setDefaults];
    // 3.將需要生成二維碼的數據轉換成二進制
    NSData *data = [@"My name is Mike" dataUsingEncoding:NSUTF8StringEncoding];
    // 4.給二維碼濾鏡設置數據
    [filter setValue:data forKeyPath:@"inputMessage"];
    // 5.獲取濾鏡生成的圖片
    CIImage *ciImage =  [filter outputImage];
    UIImage *bgImage = [self createNonInterpolatedUIImageFormCIImage:ciImage withSize:200];
    
    UIImage *iconImage = [UIImage imageNamed:@"IMG_5048.JPG"];
    UIImage *newImage = [self createNewImageWithBg:bgImage icon:iconImage];
    
    // 6.設置圖片到控件上
    self.icon.image = newImage;
}

///  生成一張新的圖片
///
///  @param bgImage 圖片的背景
///  @param icon    圖片的圖標
- (UIImage *)createNewImageWithBg:(UIImage *)bgImage icon:(UIImage *)icon{
    // 1.開啓圖片上下文
    UIGraphicsBeginImageContext(bgImage.size);
    
    // 2.繪製背景
    [bgImage drawInRect:CGRectMake(0, 0, bgImage.size.width, bgImage.size.height)];
    
    // 3.繪製圖標
    CGFloat iconW = 50;
    CGFloat iconH = 50;
    CGFloat iconX = (bgImage.size.width - iconW) * 0.5;
    CGFloat iconY = (bgImage.size.height - iconH) * 0.5;
    [icon drawInRect:CGRectMake(iconX, iconY, iconW, iconH)];
    
    // 4.取出繪製好的圖片
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    // 5.關閉上下文
    UIGraphicsEndImageContext();
    // 6.返回生成好得圖片
    return newImage;
}
/**
 *  根據CIImage生成指定大小的UIImage
 *
 *  @param image CIImage
 *  @param size  圖片寬度
 */
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    // 1.創建bitmap;
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
    CGContextScaleCTM(bitmapRef, scale, scale);
    CGContextDrawImage(bitmapRef, extent, bitmapImage);
    // 2.保存bitmap到圖片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}

@end