iOS 图片取色器

iOS图片取色计，直接上代码

#import "ViewController.h"@interface ViewController ()@property(nonatomic,strong)UIImageView *imageView;@end@implementation ViewController- (void)viewDidLoad{    [super viewDidLoad];    self.view.backgroundColor=[UIColor whiteColor];        UIImageView *imageView=[[UIImageView alloc]init];        if (fabs(([[UIScreen mainScreen] bounds].size.height - 568)) < 1)    {        // 5 & 5s & 5c        imageView.image=[UIImage imageNamed:@"RGBCircle_5"];        imageView.frame=CGRectMake(54, 44, imageView.image.size.width, imageView.image.size.height);            }    else if (fabs(([[UIScreen mainScreen] bounds].size.height - 667)) < 1)    {        // 6 & 6s        imageView.image=[UIImage imageNamed:@"RGBCircle_6"];        imageView.frame=CGRectMake(57, 44, imageView.image.size.width, imageView.image.size.height);    }    else if (fabs(([[UIScreen mainScreen] bounds].size.height - 736)) < 1)    {        // 6p & 6sp        imageView.image=[UIImage imageNamed:@"RGBCircle_6p"];        imageView.frame=CGRectMake(62, 44, imageView.image.size.width, imageView.image.size.height);            }        NSLog(@"ooooo %f %f",imageView.image.size.width,imageView.image.size.height);    imageView.userInteractionEnabled=YES;    self.imageView=imageView;    [self.view addSubview:imageView];    }-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    //触点对象    UITouch *touch=touches.anyObject;    //触点位置    CGPoint touchLocation=[touch locationInView:self.imageView];    //触点颜色    UIColor *positionColor=[self getPixelColorAtLocation:touchLocation];        const CGFloat *components=CGColorGetComponents(positionColor.CGColor);        NSString *rValue=[NSString stringWithFormat:@"%d",(int)(components[0]*255)];    NSString *gValue=[NSString stringWithFormat:@"%d",(int)(components[1]*255)];    NSString *bValue=[NSString stringWithFormat:@"%d",(int)(components[2]*255)];    NSLog(@"我看看结果:%@ %@ %@",rValue,gValue,bValue);}- (UIColor*) getPixelColorAtLocation:(CGPoint)point{    UIColor* color = nil;    UIImageView *colorImageView=self.imageView;    CGImageRef inImage = colorImageView.image.CGImage;    // Create off screen bitmap context to draw the image into. Format ARGB is 4 bytes for each pixel: Alpa, Red, Green, Blue    CGContextRef cgctx = [self createARGBBitmapContextFromImage:inImage];    if (cgctx == NULL)    {        return nil;    }    size_t w = CGImageGetWidth(inImage);    size_t h = CGImageGetHeight(inImage);    CGRect rect = {{0,0},{w,h}};        // Draw the image to the bitmap context. Once we draw, the memory    // allocated for the context for rendering will then contain the    // raw image data in the specified color space.    CGContextDrawImage(cgctx, rect, inImage);        // Now we can get a pointer to the image data associated with the bitmap    // context.    unsigned char* data = CGBitmapContextGetData (cgctx);    if (data != NULL)    {        //offset locates the pixel in the data from x,y.        //4 for 4 bytes of data per pixel, w is width of one row of data.        @try        {            int offset = 4*((w*round(point.y))+round(point.x));            //NSLog(@"offset: %d", offset);            int alpha =  data[offset];            int red = data[offset+1];            int green = data[offset+2];            int blue = data[offset+3];//            NSLog(@"offset: %i colors: RGB A %i %i %i  %i",offset,red,green,blue,alpha);            color = [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:(blue/255.0f) alpha:(alpha/255.0f)];        }        @catch (NSException * e)        {            NSLog(@"%@",[e reason]);        }        @finally        {                    }            }        // When finished, release the context    CGContextRelease(cgctx);    // Free image data memory for the context    if (data)    {        free(data);    }        return color;}- (CGContextRef) createARGBBitmapContextFromImage:(CGImageRef) inImage{        CGContextRef    context = NULL;    CGColorSpaceRef colorSpace;    void *          bitmapData;    int             bitmapByteCount;    int             bitmapBytesPerRow;        // Get image width, height. We'll use the entire image.    size_t pixelsWide = CGImageGetWidth(inImage);    size_t pixelsHigh = CGImageGetHeight(inImage);        // Declare the number of bytes per row. Each pixel in the bitmap in this    // example is represented by 4 bytes; 8 bits each of red, green, blue, and    // alpha.    bitmapBytesPerRow   = (int)(pixelsWide * 4);    bitmapByteCount     =(int)(bitmapBytesPerRow * pixelsHigh);        // Use the generic RGB color space.    colorSpace = CGColorSpaceCreateDeviceRGB();        if (colorSpace == NULL)    {        fprintf(stderr, "Error allocating color space\n");        return NULL;    }        // Allocate memory for image data. This is the destination in memory    // where any drawing to the bitmap context will be rendered.    bitmapData = malloc( bitmapByteCount );    if (bitmapData == NULL)    {        fprintf (stderr, "Memory not allocated!");        CGColorSpaceRelease( colorSpace );        return NULL;    }        // Create the bitmap context. We want pre-multiplied ARGB, 8-bits    // per component. Regardless of what the source image format is    // (CMYK, Grayscale, and so on) it will be converted over to the format    // specified here by CGBitmapContextCreate.    context = CGBitmapContextCreate (bitmapData,                                     pixelsWide,                                     pixelsHigh,                                     8,      // bits per component                                     bitmapBytesPerRow,                                     colorSpace,                                     kCGImageAlphaPremultipliedFirst);    if (context == NULL)    {        free (bitmapData);        fprintf (stderr, "Context not created!");    }        // Make sure and release colorspace before returning    CGColorSpaceRelease( colorSpace );        return context;}@end

取色的区域要做判断的，非图片区域取色不准。取色会有误差，但人眼感觉不出来，可以使用rgb在线生成器生成颜色。