Changed blur to the blur provided by UIImageEffects

cezarywojcik · Sep 22, 2013 · 8f13381 · 8f13381
1 parent 06f71ad
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Showing 4 changed files with 131 additions and 24 deletions.
diff --git a/CWPopup.podspec b/CWPopup.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "CWPopup"
-  s.version      = "1.1.2"
+  s.version      = "1.2.0"
   s.summary      = "A category on UIViewController to present a popup view controller."
   s.description  = "CWPopup adds a category on UIViewController to present a popup view controller. It offers an animated and non-animated presentation of the popup, similarly to presenting a modal controller or pushing a view controller."
   s.homepage     = "http://github.com/cezarywojcik/CWPopup"

diff --git a/CWPopup/UIViewController+CWPopup.m b/CWPopup/UIViewController+CWPopup.m
@@ -9,36 +9,143 @@
 #import "UIViewController+CWPopup.h"
 #import <objc/runtime.h>
 #import <QuartzCore/QuartzCore.h>
-
-// image blurring from http://stackoverflow.com/a/8916196
+@import Accelerate;
+#import <float.h>
 
 @interface UIImage (ImageBlur)
-- (UIImage *)getImageWithBlur;
+- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage;
 @end
 
 @implementation UIImage (ImageBlur)
-- (UIImage *)getImageWithBlur {
-    float weight[5] = {0.2270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162};
-    // Blur horizontally
-    UIGraphicsBeginImageContext(self.size);
-    [self drawInRect:CGRectMake(0, 0, self.size.width, self.size.height) blendMode:kCGBlendModePlusLighter alpha:weight[0]];
-    for (int x = 1; x < 5; ++x) {
-        [self drawInRect:CGRectMake(x, 0, self.size.width, self.size.height) blendMode:kCGBlendModePlusLighter alpha:weight[x]];
-        [self drawInRect:CGRectMake(-x, 0, self.size.width, self.size.height) blendMode:kCGBlendModePlusLighter alpha:weight[x]];
+// This method is taken from Apple's UIImageEffects category provided in WWDC 2013 sample code
+- (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;
     }
-    UIImage *horizontallyBlurredImage = UIGraphicsGetImageFromCurrentImageContext();
-    UIGraphicsEndImageContext();
-    // Blur vertically
-    UIGraphicsBeginImageContext(self.size);
-    [horizontallyBlurredImage drawInRect:CGRectMake(0, 0, self.size.width, self.size.height) blendMode:kCGBlendModePlusLighter alpha:weight[0]];
-    for (int y = 1; y < 5; ++y) {
-        [horizontallyBlurredImage drawInRect:CGRectMake(0, y, self.size.width, self.size.height) blendMode:kCGBlendModePlusLighter alpha:weight[y]];
-        [horizontallyBlurredImage drawInRect:CGRectMake(0, -y, self.size.width, self.size.height) blendMode:kCGBlendModePlusLighter alpha:weight[y]];
+    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);
     }
-    UIImage *blurredImage = UIGraphicsGetImageFromCurrentImageContext();
+
+    // 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 blurredImage;
+
+    return outputImage;
 }
 @end
 
@@ -79,7 +186,7 @@ - (UIImage *)getScreenImage {
 }
 
 - (UIImage *)getBlurredImage:(UIImage *)imageToBlur {
-    return [[imageToBlur getImageWithBlur] getImageWithBlur];
+    return [imageToBlur applyBlurWithRadius:10.0f tintColor:[UIColor clearColor] saturationDeltaFactor:1.0 maskImage:nil];
 }
 
 - (void)addBlurView {

diff --git a/popupblur.gif b/popupblur.gif
diff --git a/screenshot.png b/screenshot.png