開發(fā)中,可能會使用到圓角圖片,如果直接設置ImageView的layer屬性,會提前開啟屏幕渲染到離屏渲染,消耗性能,通過UIImage分類的方式,實現(xiàn)創(chuàng)建純色圖片、創(chuàng)建帶圓角的純色圖片、設置圓角圖片以及生成帶圓環(huán)的圓角圖片四個方法

.h

#import <UIKit/UIKit.h>

@interface UIImage (Color)

/**
 *  創(chuàng)建純色圖片
 *
 *  @param color     生成純色圖片的顏色
 *  @param imageSize 需要創(chuàng)建純色圖片的尺寸
 *
 *  @return 純色圖片
 */
+ (UIImage *)js_createImageWithColor:(UIColor *)color withSize:(CGSize)imageSize;
/**
 *  創(chuàng)建圓角圖片
 *
 *  @param originalImage 原始圖片
 *
 *  @return 帶圓角的圖片
 */
+ (UIImage *)js_imageWithOriginalImage:(UIImage *)originalImage;
/**
 *  創(chuàng)建圓角純色圖片
 *
 *  @param color     設置圓角純色圖片的顏色
 *  @param imageSize 設置元角純色圖片的尺寸
 *
 *  @return 圓角純色圖片
 */
+ (UIImage *)js_createRoundedImageWithColor:(UIColor *)color withSize:(CGSize)imageSize;
/**
 *  生成帶圓環(huán)的圓角圖片
 *
 *  @param originalImage 原始圖片
 *  @param borderColor   圓環(huán)顏色
 *  @param borderWidth   圓環(huán)寬度
 *
 *  @return 帶圓環(huán)的圓角圖片
 */
+ (UIImage *)js_imageWithOriginalImage:(UIImage *)originalImage withBorderColor:(UIColor *)borderColor withBorderWidth:(CGFloat)borderWidth;
@end

.m

#import "UIImage+Color.h"

@implementation UIImage (Color)

// 生成純色圖片
+ (UIImage *)js_createImageWithColor:(UIColor *)color withSize:(CGSize)imageSize{
    
    CGRect rect = CGRectMake(0.0f, 0.0f, imageSize.width, imageSize.height);
    
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextSetFillColorWithColor(context, color.CGColor);
    
    CGContextFillRect(context, rect);
    
    UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return resultImage;
}

// 生成圓角圖片
+ (UIImage *)js_imageWithOriginalImage:(UIImage *)originalImage{
    
    CGRect rect = CGRectMake(0, 0, originalImage.size.width, originalImage.size.height);
    
    UIGraphicsBeginImageContextWithOptions(originalImage.size, NO, 0.0);
    
    CGFloat cornerRadius = MIN(originalImage.size.width, originalImage.size.height) * 0.5;
    
    [[UIBezierPath bezierPathWithRoundedRect:rect
                                cornerRadius:cornerRadius] addClip];
    
    [originalImage drawInRect:rect];
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return image;
}

// 生成純色圓角圖片
+ (UIImage *)js_createRoundedImageWithColor:(UIColor *)color withSize:(CGSize)imageSize{
    
    UIImage *originalImage = [self js_createImageWithColor:color withSize:imageSize];
    
    return [self js_imageWithOriginalImage:originalImage];
}
// 生成帶圓環(huán)的圓角圖片
+ (UIImage *)js_imageWithOriginalImage:(UIImage *)originalImage withBorderColor:(UIColor *)borderColor withBorderWidth:(CGFloat)borderWidth{
    
    
    CGRect rect = CGRectMake(0, 0, originalImage.size.width, originalImage.size.height);
    
    UIGraphicsBeginImageContextWithOptions(originalImage.size, NO, 0.0);
    
    CGFloat cornerRadius = MIN(originalImage.size.width, originalImage.size.height) * 0.5;
    
    [[UIBezierPath bezierPathWithRoundedRect:rect
                                cornerRadius:cornerRadius] addClip];
    
    
    [originalImage drawInRect:rect];
    
    CGPoint center = CGPointMake(originalImage.size.width * 0.5, originalImage.size.height * 0.5);
    
    UIBezierPath *circlePath = [UIBezierPath bezierPathWithArcCenter:center radius:cornerRadius - borderWidth*0.5 startAngle:0 endAngle:M_PI * 2 clockwise:YES];
    circlePath.lineWidth = borderWidth;
    [borderColor setStroke];
    [circlePath stroke];
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return image;
    
    
}
@end