IOS 创建彩色二维码实例详解

ios 创建彩色二维码

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。

#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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