如何在所有视图Storyboard iOS上添加视觉效果视图模糊？

Question

我需要使用objective C为所有设备fullscreen添加带有中心activityindicator指示器的visual effect视图，并带有loading标签。 我正在使用下面发布的图片的storyboard ，无法在所有顶部添加视觉效果模糊视图。

Answer 1

最简单，最干净的方法是将其拖动到您的UIView 中或上方 。 您需要在视觉效果视图中设置自动布局约束。

选择的是视觉效果视图

Answer 2

您可以尝试以下代码来添加模糊效果：

// Usage
[loginView blurBackgroundWithScreenshotView:backgroundImageView
                                   withType:BlurSubView
                                  withColor:BlurBlackView
                                  withPoint:CGPointZero];

//
//  UIImage+Blur.h
//
//  Created by Ankit Thakur on 07/03/14.
//
#import <UIKit/UIKit.h>

@interface UIImage (Blur)
- (UIImage*) blurredSnapshot;
@end

//
//  UIImage+Blur.m
//
//  Created by Ankit Thakur on 07/03/14.
//

#import "UIImage+Blur.h"
#import <Accelerate/Accelerate.h>
@implementation UIImage (Blur)

- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage
{
    // Check pre-conditions.
    if (self.size.width < 1 || self.size.height < 1) {
        NSLog (@"*** error: invalid size: (%.2f x %.2f). Both dimensions must be >= 1: %@", self.size.width, self.size.height, self);
        return nil;
    }
    if (!self.CGImage) {
        NSLog (@"*** error: image must be backed by a CGImage: %@", self);
        return nil;
    }
    if (maskImage && !maskImage.CGImage) {
        NSLog (@"*** error: maskImage must be backed by a CGImage: %@", maskImage);
        return nil;
    }

    CGRect imageRect = { CGPointZero, self.size };
    UIImage *effectImage = self;

    BOOL hasBlur = blurRadius > __FLT_EPSILON__;
    BOOL hasSaturationChange = fabs(saturationDeltaFactor - 1.) > __FLT_EPSILON__;
    if (hasBlur || hasSaturationChange) {
        UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
        CGContextRef effectInContext = UIGraphicsGetCurrentContext();
        CGContextScaleCTM(effectInContext, 1.0, -1.0);
        CGContextTranslateCTM(effectInContext, 0, -self.size.height);
        CGContextDrawImage(effectInContext, imageRect, self.CGImage);

        vImage_Buffer effectInBuffer;
        effectInBuffer.data     = CGBitmapContextGetData(effectInContext);
        effectInBuffer.width    = CGBitmapContextGetWidth(effectInContext);
        effectInBuffer.height   = CGBitmapContextGetHeight(effectInContext);
        effectInBuffer.rowBytes = CGBitmapContextGetBytesPerRow(effectInContext);

        UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
        CGContextRef effectOutContext = UIGraphicsGetCurrentContext();
        vImage_Buffer effectOutBuffer;
        effectOutBuffer.data     = CGBitmapContextGetData(effectOutContext);
        effectOutBuffer.width    = CGBitmapContextGetWidth(effectOutContext);
        effectOutBuffer.height   = CGBitmapContextGetHeight(effectOutContext);
        effectOutBuffer.rowBytes = CGBitmapContextGetBytesPerRow(effectOutContext);

        if (hasBlur) {
            // A description of how to compute the box kernel width from the Gaussian
            // radius (aka standard deviation) appears in the SVG spec:
            // http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
            //
            // For larger values of 's' (s >= 2.0), an approximation can be used: Three
            // successive box-blurs build a piece-wise quadratic convolution kernel, which
            // approximates the Gaussian kernel to within roughly 3%.
            //
            // let d = floor(s * 3*sqrt(2*pi)/4 + 0.5)
            //
            // ... if d is odd, use three box-blurs of size 'd', centered on the output pixel.
            //
            CGFloat inputRadius = blurRadius * [[UIScreen mainScreen] scale];
            NSUInteger radius = floor(inputRadius * 3. * sqrt(2 * M_PI) / 4 + 0.5);
            if (radius % 2 != 1) {
                radius += 1; // force radius to be odd so that the three box-blur methodology works.
            }
            vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);
            vImageBoxConvolve_ARGB8888(&effectOutBuffer, &effectInBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);
            vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);
        }
        BOOL effectImageBuffersAreSwapped = NO;
        if (hasSaturationChange) {
            CGFloat s = saturationDeltaFactor;
            CGFloat floatingPointSaturationMatrix[] = {
                0.0722 + 0.9278 * s,  0.0722 - 0.0722 * s,  0.0722 - 0.0722 * s,  0,
                0.7152 - 0.7152 * s,  0.7152 + 0.2848 * s,  0.7152 - 0.7152 * s,  0,
                0.2126 - 0.2126 * s,  0.2126 - 0.2126 * s,  0.2126 + 0.7873 * s,  0,
                0,                    0,                    0,  1,
            };
            const int32_t divisor = 256;
            NSUInteger matrixSize = sizeof(floatingPointSaturationMatrix)/sizeof(floatingPointSaturationMatrix[0]);
            int16_t saturationMatrix[matrixSize];
            for (NSUInteger i = 0; i < matrixSize; ++i) {
                saturationMatrix[i] = (int16_t)roundf(floatingPointSaturationMatrix[i] * divisor);
            }
            if (hasBlur) {
                vImageMatrixMultiply_ARGB8888(&effectOutBuffer, &effectInBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
                effectImageBuffersAreSwapped = YES;
            }
            else {
                vImageMatrixMultiply_ARGB8888(&effectInBuffer, &effectOutBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
            }
        }
        if (!effectImageBuffersAreSwapped)
            effectImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        if (effectImageBuffersAreSwapped)
            effectImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    }

    // Set up output context.
    UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
    CGContextRef outputContext = UIGraphicsGetCurrentContext();
    CGContextScaleCTM(outputContext, 1.0, -1.0);
    CGContextTranslateCTM(outputContext, 0, -self.size.height);

    // Draw base image.
    CGContextDrawImage(outputContext, imageRect, self.CGImage);

    // Draw effect image.
    if (hasBlur) {
        CGContextSaveGState(outputContext);
        if (maskImage) {
            CGContextClipToMask(outputContext, imageRect, maskImage.CGImage);
        }
        CGContextDrawImage(outputContext, imageRect, effectImage.CGImage);
        CGContextRestoreGState(outputContext);
    }

    // Add in color tint.
    if (tintColor) {
        CGContextSaveGState(outputContext);
        CGContextSetFillColorWithColor(outputContext, tintColor.CGColor);
        CGContextFillRect(outputContext, imageRect);
        CGContextRestoreGState(outputContext);
    }

    // Output image is ready.
    UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return outputImage;
}

- (UIImage*) blurredSnapshot{

    UIColor *tintColor = [UIColor colorWithWhite:0.8 alpha:0.7];
    //     UIColor *tintColor = [UIColor colorWithRed:255.0/255.0 green:255.0/255.0 blue:255.0/255.0 alpha:0.5];
    UIImage *image = [self applyBlurWithRadius:5 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
    return image;
}
@end

//
//  BlurView.h
//
//  Created by Ankit Thakur on 07/03/14.
//
#import <UIKit/UIKit.h>

typedef NS_ENUM(NSUInteger, BlurViewType) {
    BlurSubView,
    BlurPopView
};
typedef NS_ENUM(NSUInteger, BlurViewColorType) {
    BlurWhiteView,
    BlurBlackView
};

@interface BlurView : UIView

- (void) blurBackgroundWithScreenshotView:(UIView*)screenshotView withType:(BlurViewType)type withColor:(BlurViewColorType)colorType withPoint:(CGPoint)point;


@end


//
//  BlurView.m
//
//  Created by Ankit Thakur on 07/03/14.
//

#import "BlurView.h"
#import "UIImage+Blur.h"

@interface BlurView (){
}

@end

@implementation BlurView

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self) {
        // Initialization code
    }
    return self;
}

- (void) blurBackgroundWithScreenshotView:(UIView*)screenshotView withType:(BlurViewType)type withColor:(BlurViewColorType)colorType withPoint:(CGPoint)point{

    NSLog(@"%ld",(long)screenshotView.tag);

    if ([self viewWithTag:111]) {
        [[self viewWithTag:111] removeFromSuperview];
    }
    @autoreleasepool {

        UIGraphicsBeginImageContext(screenshotView.frame.size);
        if([self respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)]){
            [screenshotView drawViewHierarchyInRect:self.frame afterScreenUpdates:NO];
        }
        else{
            [screenshotView.layer renderInContext:UIGraphicsGetCurrentContext()];
        }
        UIGraphicsEndImageContext();

        CGPoint origin = self.frame.origin;
        switch (type) {
            case BlurSubView:
                origin.x = - origin.x;
                origin.y = -origin.y;
                break;

            case BlurPopView:
                origin.x = -point.x;
                origin.y = -point.y;
                break;

            default:
                break;
        }

        UIImage *blurImage =  nil;
        UIGraphicsBeginImageContext(self.bounds.size);
        CGContextTranslateCTM(UIGraphicsGetCurrentContext(), origin.x, origin.y);
        [screenshotView.layer renderInContext:UIGraphicsGetCurrentContext()];
        blurImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        NSData *imageData = UIImageJPEGRepresentation(blurImage, 1.0);
        blurImage = [UIImage imageWithData:imageData];
        switch (colorType) {
            case BlurWhiteView:
                blurImage = [blurImage blurredWhiteSnapshot];
                break;
            case BlurBlackView:
                blurImage = [blurImage blurredBlackSnapshot];
                break;
            default:
                break;
        }

        UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.bounds];
        imageView.tag = 111;
        imageView.image = blurImage;
        [self addSubview:imageView];
        [self sendSubviewToBack:imageView];

        blurImage = nil;

    }
}
@end