@interface UIImage (Gradient) 为UIImage添加方法
+ (UIImage*)gradientImageFromColors:(NSArray*)colors withSize:(CGSize)size;
#import "UIImage+Gradient.h"
@implementation UIImage (Gradient)
+ (UIImage*)gradientImageFromColors:(NSArray*)colors withSize:(CGSize)size {
if (size.width <= 0 || size.height <= 0) {
return nil;
}
NSMutableArray *ar = [NSMutableArray array];
for(UIColor *c in colors) {
[ar addObject:(id)c.CGColor];
}
UIGraphicsBeginImageContextWithOptions(size, YES, [UIScreen mainScreen].scale);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGColorSpaceRef colorSpace = CGColorGetColorSpace([[colors lastObject] CGColor]);
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (CFArrayRef)ar, NULL);
CGPoint start = CGPointMake(0.0, 0.0);
CGPoint end = CGPointMake(size.width, 0.0);
CGContextDrawLinearGradient(context, gradient, start, end, kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
CGGradientRelease(gradient);
CGContextRestoreGState(context);
CGColorSpaceRelease(colorSpace);
UIGraphicsEndImageContext();
return image;
}
//根据传入的float值实时渐变
- (void)setCurrentProgress:(CGFloat)progress {
[currentProgressView mas_makeConstraints:^(MASConstraintMaker *make) {
make.removeExisting = YES;
make.left.equalTo(backgroundImageView.mas_left);
make.top.equalTo(backgroundImageView.mas_top);
make.height.equalTo(backgroundImageView.mas_height);
make.width.equalTo(backgroundImageView.mas_width).multipliedBy(progress);
}];
currentProgressView.image = [UIImage gradientImageFromColors:[NSArray arrayWithObjects:[UIColor colorWithRed:239.0f / 255.0f green:52.0f / 255.0f blue:40.0f / 255.0f alpha:1.0f], [UIColor colorWithRed:252.0f / 255.0f green:109.0f / 255.0f blue:100.0f / 255.0f alpha:1.0f], nil] withSize:CGSizeMake(size.width * progress, size.height)];
}
progressValueLabel.text = [NSString stringWithFormat:@"%.1f%%", progress * 100];
其中progress是传入的float值 动态获取
