iOS 生成二维码

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

@end

#import "AppDelegate.h"
#import "RootViewController.h"
@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.window.backgroundColor = [UIColor whiteColor];

self.window.rootViewController = [[RootViewController alloc] init];

[self.window makeKeyAndVisible];
return YES;
}

@end

#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController

@end

#import "RootViewController.h"

@interface RootViewController ()

@property (nonatomic , strong) UIImageView *imgView;

@end

@implementation RootViewController

- (void)viewDidLoad {
[super viewDidLoad];

CGFloat width = 200;
CGFloat height = 200;
self.imgView = [[UIImageView alloc] initWithFrame:CGRectMake(self.view.center.x - width/2.0, self.view.center.y - height/2.0, width, height)];
[self.view addSubview:self.imgView];

[self productImageView];
}

- (void)productImageView{

CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

[filter setDefaults];
NSString *string = @"想择一人，一城；终老";
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
[filter setValue:data forKey:@"inputMessage"];
CIImage *outputImage = [filter outputImage];

self.imgView.image = [self createUIImageFromCIImage:outputImage withSize:100.0];
}

- (UIImage *)createUIImageFromCIImage:(CIImage *)image withSize:(CGFloat)size{
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

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);

CGImageRef scaleImage = CGBitmapContextCreateImage(bitmapRef);

CGContextRelease(bitmapRef);

CGImageRelease(bitmapImage);

return [UIImage imageWithCGImage:scaleImage];
}

@end