使用顏色創建圖像，如ios中的[UIColor redColor]

Question

如何使用[UIColor redColor]等顏色創建圖像。

UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); 

Answer 1

- (void)setBackgroundColor:(UIColor *)backgroundColor forState:(UIControlState)state { 
    [self setBackgroundImage:[UIButton imageFromColor:backgroundColor] forState:state]; 
} 

+ (UIImage *)imageFromColor:(UIColor *)color { 
    CGRect rect = CGRectMake(0, 0, 1, 1); 
    UIGraphicsBeginImageContext(rect.size); 
    CGContextRef context = UIGraphicsGetCurrentContext(); 
    CGContextSetFillColorWithColor(context, [color CGColor]); 
    CGContextFillRect(context, rect); 
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 
    return image; 
} 

Answer 2

CIImage* outputImage = nil; 
CIFilter* blueGenerator = [CIFilter filterWithName:@"CIConstantColorGenerator"]; 
CIColor* blue = [CIColor colorWithString:@"0.1 0.5 0.8 1.0"]; 
[blueGenerator setValue:blue forKey:@"inputColor"]; 
CIImage* blueImage = [blueGenerator valueForKey:@"outputImage"]; 

Answer 3

我已經通過創建的UIImage 的類別來解決這一點，它是更好地使用該類別中這樣的場景。

這裏是我的代碼：

在的UIImage + Customized.h

#import <UIKit/UIKit.h> 

@interface UIImage (Customized) 

/** 
*Return the image from Color given 
*/ 
+ (UIImage *)imageWithColor:(UIColor *)color; 
@end 

在的UIImage + Customized.m

#import "UIImage+Customized.h" 

@implementation UIImage (Customized) 

+ (UIImage *)imageWithColor:(UIColor *)color 
{ 
    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f); 
    UIGraphicsBeginImageContext(rect.size); 
    CGContextRef context = UIGraphicsGetCurrentContext(); 

    CGContextSetFillColorWithColor(context, [color CGColor]); 
    CGContextFillRect(context, rect); 

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 

    return image; 
} 

，並使用它像這樣 對於例如，讓我們假設你想要設置按鈕的地面圖像，然後使用它

USE： [btnDone了setBackgroundImage：[UIImage的imageWithColor：的UIColor redColor] forState：UIControlStateNormal];

注意：在要使用該方法的viewController中導入類別。

希望它有幫助。

快樂編碼...