creat a image with a color, such as [UIColor redColor] in ios

Question

How to create a image with a color such as [UIColor redColor].

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

Answer 1

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 2

- (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 3

I have solved this by creating a category of UIImage. And it is better to use the category in such scenarios.

Here is my code:

In UIImage+Customized.h

#import <UIKit/UIKit.h>

@interface UIImage (Customized)

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

In 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;
}

And use it like this. For example, let's assume you want to set background image of button, then use it like:

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

NB: Import the Category in the viewController where you want to use the method.