iOS随机颜色

#import <UIKit/UIKit.h>

@interface UIColor (RandomColor)
+(UIColor *) randomColor;
@end


#import "UIColor+RandomColor.h"

@implementation UIColor (RandomColor)

+(UIColor *) randomColor
{
    <pre name="code" class="objc">//色相, 饱和度, 亮度

CGFloat hue = ( arc4random() % 256 / 256.0 ); //0.0 to 1.0 CGFloat saturation = ( arc4random() % 128 / 256.0 ) + 0.5; // 0.5 to 1.0,away from white CGFloat brightness = ( arc4random() % 128 / 256.0 ) + 0.5; //0.5 to 1.0,away from black return [UIColor colorWithHue:hue saturation:saturation brightness:brightness alpha:1];

//        //RGB
//        CGFloat red = arc4random() % 256 / 255.0;
//        CGFloat green = arc4random() % 256 / 255.0;
//        CGFloat blue = arc4random() % 256 / 255.0;        <pre name="code" class="objc"><pre name="code" class="objc">//        <span style="font-family: Arial, Helvetica, sans-serif;">return </span><span style="font-family: Arial, Helvetica, sans-serif;"> [UIColor colorWithRed:red green:green blue:blue alpha:1];</span>

@end将随机生成的颜色绘制成图片。-(void)createImage{ NSString* path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES) objectAtIndex:0]; path = @"/Users/shouqiangwei/Desktop/未命名目录 2"; NSLog(@"path = %@",path); NSString *imgName; NSString *imgURL; NSString *markNum; UIImage *img; NSData *imgData; NSError *err; int width= 1000, height=1000, fontSize; CGPoint markPoint; int baseLength = 320; NSFileManager *fm = [NSFileManagerdefaultManager]; for (int i=0; i<1000; i++) { UIColor *color = [UIColorrandomColor]; [_currentColorImageViewsetBackgroundColor:color]; imgName = [NSString stringWithFormat:@"%i.jpg", i+1]; _lblCount.text = imgName; imgURL = [path stringByAppendingPathComponent:imgName]; if (![fm fileExistsAtPath:imgURL]) { const CGFloat *colorComps = CGColorGetComponents(color.CGColor); markNum = [NSString stringWithFormat:@"%i", i+1]; fontSize = width / 5; markPoint = CGPointMake(fontSize/2, fontSize/2); UIGraphicsBeginImageContext(CGSizeMake(width, height)); CGContextRef ctx =UIGraphicsGetCurrentContext(); CGContextSetRGBFillColor(ctx, colorComps[0], colorComps[1], colorComps[2], colorComps[3]); CGContextFillRect(ctx, CGRectMake(0, 0, width, height)); CGContextSetRGBFillColor(ctx, 1.0, 1.0, 1.0,1.0); //创建图片上的数字。 [markNum drawAtPoint:markPoint withFont:[UIFont systemFontOfSize:fontSize]]; img = UIGraphicsGetImageFromCurrentImageContext(); self.imageView.image= img; UIGraphicsEndImageContext(); //创建到本地。 imgData = [NSDatadataWithData:UIImageJPEGRepresentation(img,1.0f)]; [imgData writeToFile:imgURLoptions:NSDataWritingAtomicerror:&err]; if (err) { NSLog(@"error: %@\nimage:%@", err.localizedDescription, imgName); } else { NSLog(@"done: %@", imgName); } } }}

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