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- //
- // UIImage+ImageEffects.m
- // AnimationExamples
- //
- // Created by Timothy Patrick Johnson on 7/3/13.
- // Copyright (c) 2013 Meister. All rights reserved.
- //
- #import "UIImage+ImageEffects.h"
- #import <Accelerate/Accelerate.h>
- #import <float.h>
- @implementation UIImage (ImageEffects)
- - (UIImage *)applyLightEffect
- {
- UIColor *tintColor = [UIColor colorWithWhite:1.0 alpha:0.3];
- return [self applyBlurWithRadius:7 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
- }
- - (UIImage *)applyExtraLightEffect
- {
- UIColor *tintColor = [UIColor colorWithWhite:0.97 alpha:0.82];
- return [self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
- }
- - (UIImage *)applyDarkEffect
- {
- UIColor *tintColor = [UIColor colorWithWhite:0.11 alpha:0.73];
- return [self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
- }
- - (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor
- {
- const CGFloat EffectColorAlpha = 0.6;
- UIColor *effectColor = tintColor;
- int componentCount = CGColorGetNumberOfComponents(tintColor.CGColor);
- if (componentCount == 2) {
- CGFloat b;
- if ([tintColor getWhite:&b alpha:NULL]) {
- effectColor = [UIColor colorWithWhite:b alpha:EffectColorAlpha];
- }
- }
- else {
- CGFloat r, g, b;
- if ([tintColor getRed:&r green:&g blue:&b alpha:NULL]) {
- effectColor = [UIColor colorWithRed:r green:g blue:b alpha:EffectColorAlpha];
- }
- }
- return [self applyBlurWithRadius:10 tintColor:effectColor saturationDeltaFactor:-1.0 maskImage:nil];
- }
- - (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;
- }
- @end
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