因为系统创建的二维码默认都是黑色的，所以突然想改变一下二维码颜色，具体操作有点复杂，而且其中用到了好多C语言的语法，Swift不好写，所以默认用了OC。只贴了.m文件的代码，.h文件就是几个类函数的声明。
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#import "UIImage+CreateQRCode.h"
@implementation UIImage (CreateQRCode)
+ (UIImage *)createQRCode:(NSString *)string andSize:(CGSize)size andColor:(UIColor *)color {
UIImage *qrcode = [self createNonInterpolatedUIImageFormCIImage:[self createQRForString:string] withSize:size];
const CGFloat *_components = CGColorGetComponents(color.CGColor);
CGFloat red = _components[0] * 255.f;
CGFloat green = _components[1] * 255.f;
CGFloat blue = _components[2] * 255.f;
return [self imageBlackToTransparent:qrcode withRed:red andGreen:green andBlue:blue];
}
+ (void)setImageViewShadow:(UIImageView *)view {
view.layer.shadowOffset = CGSizeMake(0, 2);
view.layer.shadowRadius = 2;
view.layer.shadowColor = [UIColor blackColor].CGColor;
view.layer.shadowOpacity = 0.5;
view.backgroundColor = [UIColor clearColor];
}
#pragma mark - 创建灰度图，只有灰度图才能改变颜色
+ (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGSize)size {
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size.width/CGRectGetWidth(extent), size.height/CGRectGetHeight(extent));
size_t width = CGRectGetWidth(extent) * scale;
size_t height = CGRectGetHeight(extent) * scale;
// iOS不支持设备依赖颜色空间或通用颜色空间。iOS应用程序必须使用设备颜色空间
// 设备颜色空间主要用于IOS应用程序，因为其它颜色空间无法在IOS上使用。大多数情况下，Mac OS X应用程序应使用通用颜色空间，而不使用设备颜色空间。
// CGColorSpaceCreateDeviceGray：创建设备依赖灰度颜色空间
// CGColorSpaceCreateDeviceRGB：创建设备依赖RGB颜色空间
// CGColorSpaceCreateDeviceCMYK：创建设备依赖CMYK颜色空间
CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();//这个是改变二维码颜色的主要属性，必须是灰度空间，作用是将UIImage转变成了灰度图
CGContextRef bitmapRef = CGBitmapContextCreate(NULL, width, height, 8, 0, cs, kCGImageAlphaNone);
CIContext * context = [CIContext contextWithOptions:NULL];
CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationHigh);
CGContextScaleCTM(bitmapRef, scale, scale);
CGContextDrawImage(bitmapRef, extent, bitmapImage);
CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
return [UIImage imageWithCGImage:scaledImage];
}
#pragma mark - 创建二维码的主要代码
+ (CIImage *)createQRForString:(NSString *)qrString {
NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];
return qrFilter.outputImage;
}
#pragma mark - 改变二维码的颜色
void ProviderReleaseData (voidvoid *info, const voidvoid *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);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,
kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);
int pixelNum = imageWidth * imageHeight;
uint32_t* pCurPtr = rgbImageBuf;
for (int i = 0; i < pixelNum; i++, pCurPtr++){
if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){
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;
}
}
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];
CGImageRelease(imageRef);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
return resultUIImage;
}
@end
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感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！
原文链接：http://blog.csdn.net/youshaoduo/article/details/53286153