LPLevelView

类似AppStore评分等级条

下载地址：https://github.com/SwiftLiu/LPLevelView.git

####1.支持打分手动评级，点击即可打分，同时回调打分完成block：

@property (strong, nonatomic) void (^scoreBlock)(float level);

####2.采用绘图渲染界面，高效流畅，可自定义图标和尺寸等：

///整星图标，半星和空星尺寸以整星为准
@property (strong, nonatomic) UIImage *iconFull;
///半星图标
@property (strong, nonatomic) UIImage *iconHalf;
///空星图标
@property (strong, nonatomic) UIImage *iconEmpty;
///图片尺寸，默认为iconFull图标的尺寸，同时自适应self尺寸
@property (assign, nonatomic) CGSize iconSize;

*绘制图标到画布

- (void)drawIcons
{
    //计算绘制的图标尺寸
    CGSize size = [self sizeOfIcon];
    //纵坐标
    CGFloat y = (self.bounds.size.height - size.height) / 2.l;
    //图标间距
    CGFloat spacing = (self.bounds.size.width - size.width*_maxLevel)/(CGFloat)_maxLevel;
    //横坐标
    CGFloat x = spacing/2.l;
        
    for (int i=1; i<=_maxLevel; i++) {
        //①获取图标
        UIImage *iconImg;
        if (i <= _level) {//整星
            iconImg = _iconFull;
        }else if (i-_level < 1 && !_levelInt) {//半星
            if (_iconHalf) iconImg = _iconHalf;
            else return;
        }else if (_iconHalf) {//空星
            iconImg = _iconEmpty;
        }
        
        //③绘制
        [iconImg drawInRect:CGRectMake(x, y, size.width, size.height)];
        
        //④横坐标右移，以便绘制下一个图标
        x += size.width + spacing;
    }
}

*计算绘制的图标尺寸

- (CGSize)sizeOfIcon
{
    //最大宽度
    CGFloat width = self.bounds.size.width/(CGFloat)_maxLevel;
    width = MIN(width, _iconFull.size.width);
    if (_iconSize.width != 0) width = MIN(width, _iconSize.width);
    //宽度伸缩比
    CGFloat wScale = width / _iconFull.size.width;
    //最大高度
    CGFloat height = self.bounds.size.height;
    height = MIN(height, _iconFull.size.height);
    if (_iconSize.height != 0) height = MIN(height, _iconSize.height);
    //高度伸缩比
    CGFloat hScale = height / _iconFull.size.height;
    
    //实际伸缩比
    CGFloat scale = MIN(wScale, hScale);
    //实际尺寸
    CGSize size = CGSizeMake(_iconFull.size.width * scale, _iconFull.size.height * scale);
    return size;
}

####3.蒙版剪切自定义图标颜色：

@property (strong, nonatomic) UIColor *iconColor;

*剪切

- (void)drawRect:(CGRect)rect
{
    //绘制默认图标
    if (_iconColor) {
        CGContextRef context = UIGraphicsGetCurrentContext();
        CGContextSaveGState(context);
        CGContextClipToMask(context, rect, [self clipPathImage]);//按蒙版图像路径剪切
        CGContextSetFillColorWithColor(context, _iconColor.CGColor);
        CGContextFillRect(context, rect);
        CGContextRestoreGState(context);
    }
    //绘制自定义图标
    else {
        [self drawIcons];//绘制
    }
}

*绘制蒙版图像，即剪切路径

- (CGImageRef)clipPathImage
{
    //在内存中创建image绘制画布
    CGFloat scale = [UIScreen mainScreen].scale;//必须设置画布分辨率，否则会模糊
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, scale);
    CGContextRef imageContext = UIGraphicsGetCurrentContext();
    //翻转画布坐标系Y轴再平移坐标系原点到(0,0)位置，此处使用矩阵变换
    CGFloat transY = CGContextGetClipBoundingBox(imageContext).size.height;
    CGContextConcatCTM(imageContext, CGAffineTransformMake(1, 0, 0, -1, 0, transY));
    //绘制
    [self drawIcons];
    //提取UIImage
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    //释放该画布
    CGContextRelease(imageContext);
    UIGraphicsEndImageContext();//关闭image绘制
    return image.CGImage;
}