成长小计-UIImage、UIButton类扩展

最新推荐文章于 2020-06-28 15:01:22 发布

原创最新推荐文章于 2020-06-28 15:01:22 发布 · 560 阅读

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本文介绍了一系列针对 UIKit 的实用扩展方法，包括 UIImage 的压缩、拉伸与圆形裁剪，以及 UIButton 的点击区域扩展，并提供了一个简单的倒计时实现。

一些好的分类利于我们快速开发、今天我将分享一些自己常用的扩展类

UIImage：

1：根据指定大小压缩图片

+(UIImage *)imageByScalingAndCroppingForSize:(CGSize)targetSize forImage:(UIImage *)originImage{
    
    UIImage *sourceImage = originImage;// 原图
    UIImage *newImage = nil;// 新图
    // 原图尺寸
    CGSize imageSize = sourceImage.size;
    CGFloat width = imageSize.width;
    CGFloat height = imageSize.height;
    CGFloat targetWidth = targetSize.width;// 目标宽度
    CGFloat targetHeight = targetSize.height;// 目标高度
    // 伸缩参数初始化
    CGFloat scaleFactor = 0.0;
    CGFloat scaledWidth = targetWidth;
    CGFloat scaledHeight = targetHeight;
    CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
    
    if (CGSizeEqualToSize(imageSize, targetSize) == NO)
    {// 如果原尺寸与目标尺寸不同才执行
        CGFloat widthFactor = targetWidth / width;
        CGFloat heightFactor = targetHeight / height;
        
        if (widthFactor > heightFactor)
            scaleFactor = widthFactor; // 根据宽度伸缩
        else
            scaleFactor = heightFactor; // 根据高度伸缩
        scaledWidth= width * scaleFactor;
        scaledHeight = height * scaleFactor;
        
        // 定位图片的中心点
        if (widthFactor > heightFactor)
        {
            thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
        }
        else if (widthFactor < heightFactor)
        {
            thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
        }
    }
    
    // 创建基于位图的上下文
    UIGraphicsBeginImageContext(targetSize);
    
    // 目标尺寸
    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = thumbnailPoint;
    thumbnailRect.size.width= scaledWidth;
    thumbnailRect.size.height = scaledHeight;
    
    [sourceImage drawInRect:thumbnailRect];
    
    // 新图片
    newImage = UIGraphicsGetImageFromCurrentImageContext();
    if(newImage == nil)
        NSLog(@"could not scale image");
    
    // 退出位图上下文
    UIGraphicsEndImageContext();
    return newImage;
    
}

2：拉伸不变形

// 指定为拉伸模式，伸缩后重新赋值
+ (UIImage *)resizableImage:(NSString *)name
{
    UIImage *normal = [UIImage imageNamed:name];
    CGFloat w = normal.size.width * 0.5;
    CGFloat h = normal.size.height * 0.5;
    return [normal resizableImageWithCapInsets:UIEdgeInsetsMake(h, w, h, w) resizingMode:UIImageResizingModeStretch];
}

3：剪切成圆形

+ (instancetype)circleImageWithName:(NSString *)name borderWidth:(CGFloat)borderWidth borderColor:(UIColor *)borderColor
{
    // 1.加载原图
    UIImage *oldImage = [UIImage imageNamed:name];
    
    // 2.开启上下文
    CGFloat imageW = oldImage.size.width + 2 * borderWidth;
    CGFloat imageH = oldImage.size.height + 2 * borderWidth;
    CGSize imageSize = CGSizeMake(imageW, imageH);
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);
    
    // 3.取得当前的上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    
    // 4.画边框(大圆)
    [borderColor set];
    CGFloat bigRadius = imageW * 0.5; // 大圆半径
    CGFloat centerX = bigRadius; // 圆心
    CGFloat centerY = bigRadius;
    CGContextAddArc(ctx, centerX, centerY, bigRadius, 0, M_PI * 2, 0);
    CGContextFillPath(ctx); // 画圆
    
    // 5.小圆
    CGFloat smallRadius = bigRadius - borderWidth;
    CGContextAddArc(ctx, centerX, centerY, smallRadius, 0, M_PI * 2, 0);
    // 裁剪(后面画的东西才会受裁剪的影响)
    CGContextClip(ctx);
    
    // 6.画图
    [oldImage drawInRect:CGRectMake(borderWidth, borderWidth, oldImage.size.width, oldImage.size.height)];
    
    // 7.取图
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // 8.结束上下文
    UIGraphicsEndImageContext();
    
    return newImage;
}

UIButton:

1:扩大按钮的点击返回用到了runtime机制，只需要调用setEnlargeEdgeWithTop方法即可

#import <objc/runtime.h>

@implementation UIButton (EnlargeTouchArea)
static char topNameKey;
static char rightNameKey;
static char bottomNameKey;
static char leftNameKey;

- (void) setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left
{
    objc_setAssociatedObject(self, &topNameKey, [NSNumber numberWithFloat:top], OBJC_ASSOCIATION_COPY_NONATOMIC);
    objc_setAssociatedObject(self, &rightNameKey, [NSNumber numberWithFloat:right], OBJC_ASSOCIATION_COPY_NONATOMIC);
    objc_setAssociatedObject(self, &bottomNameKey, [NSNumber numberWithFloat:bottom], OBJC_ASSOCIATION_COPY_NONATOMIC);
    objc_setAssociatedObject(self, &leftNameKey, [NSNumber numberWithFloat:left], OBJC_ASSOCIATION_COPY_NONATOMIC);
}

- (CGRect) enlargedRect
{
    NSNumber* topEdge = objc_getAssociatedObject(self, &topNameKey);
    NSNumber* rightEdge = objc_getAssociatedObject(self, &rightNameKey);
    NSNumber* bottomEdge = objc_getAssociatedObject(self, &bottomNameKey);
    NSNumber* leftEdge = objc_getAssociatedObject(self, &leftNameKey);
    if (topEdge && rightEdge && bottomEdge && leftEdge)
    {
        return CGRectMake(self.bounds.origin.x - leftEdge.floatValue,
                          self.bounds.origin.y - topEdge.floatValue,
                          self.bounds.size.width + leftEdge.floatValue + rightEdge.floatValue,
                          self.bounds.size.height + topEdge.floatValue + bottomEdge.floatValue);
    }
    else
    {
        return self.bounds;
    }
}

- (UIView*) hitTest:(CGPoint) point withEvent:(UIEvent*) event
{
    CGRect rect = [self enlargedRect];
    if (CGRectEqualToRect(rect, self.bounds))
    {
        return [super hitTest:point withEvent:event];
    }
    return CGRectContainsPoint(rect, point) ? self : nil;
}
@end

2：60秒倒计时

//获取验证码倒计时
-(void)addTimer
{
    __block int timeout= 60;//倒计时时间
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    dispatch_source_t _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
    dispatch_source_set_timer(_timer, DISPATCH_TIME_NOW, 1.0 * NSEC_PER_SEC, 0);//每秒执行
    dispatch_source_set_event_handler(_timer, ^{
        if (timeout<=0) {//倒计时结束,关闭
            dispatch_source_cancel(_timer);
            dispatch_async(dispatch_get_main_queue(),^{
                ;
                self.userInteractionEnabled=YES;
                //设置界面的按钮显示 根据自己需求设置;
                [self setTitle:@"获取" forState:UIControlStateNormal];
                
            });
        }else{
            NSString *strTime = [NSString stringWithFormat:@"获取中 %d",timeout];
            
            dispatch_async(dispatch_get_main_queue(), ^{
                //设置按钮显示;
                self.userInteractionEnabled=NO;
                [self setTitle:strTime forState:UIControlStateNormal];
                
            });
            timeout--;
        }
    });
    
    dispatch_resume(_timer);
}