ios - 如何绘制高斯模糊效果？

Question

我需要使用 Objective C 在 UIView 上绘制模糊效果。

这是我的设计

    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle: UIBlurEffectStyleExtraLight];

    UIVisualEffectView *contentView = [[UIVisualEffectView alloc] initWithEffect: blurEffect];

    contentView.layer.cornerRadius = 18.0;

    contentView.layer.masksToBounds = YES;

    contentView.backgroundColor = [UIColor whiteColor];

    contentView.userInteractionEnabled = NO;

    contentView.layer.shadowRadius = 10;

    contentView.layer.shadowOpacity = 0.2f;

    contentView.layer.shadowColor = [UIColor whiteColor].CGColor;

    contentView.layer.shadowOffset =  CGSizeZero;

    [contentView setFrame: annotationFrame];

    [contentView setTranslatesAutoresizingMaskIntoConstraints: YES];

    self.contentView = contentView;

下面的截图是使用上面代码的当前输出

我试过上面的代码。 , 但我没有得到确切的模糊效果请建议我画这个设计。

我更新了下面的代码

- (void)drawRect:(CGRect)rect {

    [super drawRect: rect]; //i doubt we need a super drarRect here…

    [self drawMarker: self.markerView fillColor: [UIColor whiteColor]];

    CGContextRef ctx = UIGraphicsGetCurrentContext();


    CGPathRef path = CGPathCreateWithRoundedRect(CGRectInset(rect,  self.frame.size.width/4,  self.frame.size.height/4), self.frame.size.width/8, self.frame.size.height/8, nil);

    CGContextSetFillColorWithColor(ctx,[UIColor slateColor].CGColor);

    CGContextSetShadowWithColor(ctx, CGSizeZero, self.frame.size.height/4,  [UIColor slateColor].CGColor);


    for ( int i = 0; i<=6; i++) {
        CGContextAddPath(ctx, path);
        CGContextFillPath(ctx);
    }

}

我需要我的观点背后的模糊效果，请就此向我提出建议。

谢谢。

Answer 1

将我之前的回答从 swift 翻译成 Objective-C，我们得到了这个

@implementation UICustomBackgroundButton


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
    [super drawRect:rect];

    CGContextRef ctx = UIGraphicsGetCurrentContext();

    CGPathRef path = CGPathCreateWithRoundedRect(CGRectInset(rect,  self.frame.size.width/4,  self.frame.size.height/4), self.frame.size.width/8, self.frame.size.height/8, nil);

    CGContextSetFillColorWithColor(ctx,[UIColor blueColor].CGColor);
    CGContextSetShadowWithColor(ctx, CGSizeZero, self.frame.size.height/4,  [UIColor blueColor].CGColor);


    for ( int i = 0; i<=6; i++) {
        CGContextAddPath(ctx, path);
        CGContextFillPath(ctx);
    }
}


@end

结果