#import <UIKit/UIKit.h>
@interface ViewController : UIViewController
@end
#import "ViewController.h"
@interface ViewController ()
@property (nonatomic)UIImageView *qrcodeImageView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.qrcodeImageView = [[UIImageView alloc]initWithFrame:CGRectMake(40, 60, 220, 220)];
UIImage *qrcode = [self createNonInterpolatedUIImageFormCIImage:[self createQRForString:@"www.baidu.com"] withSize:250.0f];
UIImage *customQrcode = [self imageBlackToTransparent:qrcode withRed:60.0f andGreen:74.0f andBlue:89.0f];
self.qrcodeImageView.image = customQrcode;
// set shadow
//self.qrcodeImageView.layer.shadowOffset = CGSizeMake(0, 0);
self.qrcodeImageView.layer.shadowRadius = 0;
self.qrcodeImageView.layer.shadowColor = [UIColor cyanColor].CGColor;
self.qrcodeImageView.layer.shadowOpacity = 1;
[self.view addSubview:self.qrcodeImageView];
}
#pragma mark - InterpolatedUIImage
//因为生成的二维码是一个CIImage，我们直接转换成UIImage的话大小不好控制，所以使用下面方法返回需要大小的UIImage
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
// create a bitmap image that we‘ll draw into a bitmap context at the desired size; // 创建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);
// Create an image with the contents of our bitmap // 保存bitmap到图片
CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
// Cleanup
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
return [UIImage imageWithCGImage:scaledImage];
}
#pragma mark - QRCodeGenerator
//首先是二维码的生成，使用CIFilter很简单，直接传入生成二维码的字符串即可：
- (CIImage *)createQRForString:(NSString *)qrString {
// Need to convert the string to a UTF-8 encoded NSData object
NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];
// Create the filter 创建filter
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// Set the message content and error-correction level // 设置内容和纠错级别
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];
// Send the image back 返回CIImage
return qrFilter.outputImage;
}
#pragma mark - imageToTransparent
//因为生成的二维码是黑白的，所以还要对二维码进行颜色填充，并转换为透明背景，使用遍历图片像素来更改图片颜色，因为使用的是CGContext，速度非常快：
void ProviderReleaseData (void *info, const void *data, size_t size){
free((void*)data);
}
- (UIImage*)imageBlackToTransparent:(UIImage*)image withRed:(CGFloat)red andGreen:(CGFloat)green andBlue:(CGFloat)blue{
const int imageWidth = image.size.width;
const int imageHeight = image.size.height;
size_t bytesPerRow = imageWidth * 4;
uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight);
// create context
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,
kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);
// traverse pixe // 遍历像素
int pixelNum = imageWidth * imageHeight;
uint32_t* pCurPtr = rgbImageBuf;
for (int i = 0; i < pixelNum; i++, pCurPtr++){
if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){ // 将白色变成透明
// 改成下面的代码，会将图片转成想要的颜色
uint8_t* ptr = (uint8_t*)pCurPtr;
ptr[3] = red; //0~255
ptr[2] = green;
ptr[1] = blue;
}else{
uint8_t* ptr = (uint8_t*)pCurPtr;
ptr[0] = 0;
}
}
// context to image 输出图片
CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);
CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpace,
kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider,
NULL, true, kCGRenderingIntentDefault);
CGDataProviderRelease(dataProvider);
UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef];
// release 清理空间
CGImageRelease(imageRef);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
return resultUIImage;
}