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| /*
File: UIImageEffects.m
Abstract: This class contains methods to apply blur and tint effects to an image.
This is the code you’ll want to look out to find out how to use vImage to
efficiently calculate a blur.
Version: 1.1
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
Inc. ("Apple") in consideration of your agreement to the following
terms, and your use, installation, modification or redistribution of
this Apple software constitutes acceptance of these terms. If you do
not agree with these terms, please do not use, install, modify or
redistribute this Apple software.
In consideration of your agreement to abide by the following terms, and
subject to these terms, Apple grants you a personal, non-exclusive
license, under Apple's copyrights in this original Apple software (the
"Apple Software"), to use, reproduce, modify and redistribute the Apple
Software, with or without modifications, in source and/or binary forms;
provided that if you redistribute the Apple Software in its entirety and
without modifications, you must retain this notice and the following
text and disclaimers in all such redistributions of the Apple Software.
Neither the name, trademarks, service marks or logos of Apple Inc. may
be used to endorse or promote products derived from the Apple Software
without specific prior written permission from Apple. Except as
expressly stated in this notice, no other rights or licenses, express or
implied, are granted by Apple herein, including but not limited to any
patent rights that may be infringed by your derivative works or by other
works in which the Apple Software may be incorporated.
The Apple Software is provided by Apple on an "AS IS" basis. APPLE
MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
Copyright (C) 2014 Apple Inc. All Rights Reserved.
*/
#import "UIImageEffects.h"
@import Accelerate;
@implementation UIImageEffects
#pragma mark -
#pragma mark - Effects
//| ----------------------------------------------------------------------------
+ (UIImage *)imageByApplyingLightEffectToImage:(UIImage*)inputImage
{
UIColor *tintColor = [UIColor colorWithWhite:1.0 alpha:0.3];
return [self imageByApplyingBlurToImage:inputImage withRadius:60 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
}
//| ----------------------------------------------------------------------------
+ (UIImage *)imageByApplyingExtraLightEffectToImage:(UIImage*)inputImage
{
UIColor *tintColor = [UIColor colorWithWhite:0.97 alpha:0.82];
return [self imageByApplyingBlurToImage:inputImage withRadius:40 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
}
//| ----------------------------------------------------------------------------
+ (UIImage *)imageByApplyingDarkEffectToImage:(UIImage*)inputImage
{
UIColor *tintColor = [UIColor colorWithWhite:0.11 alpha:0.73];
return [self imageByApplyingBlurToImage:inputImage withRadius:40 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
}
//| ----------------------------------------------------------------------------
+ (UIImage *)imageByApplyingTintEffectWithColor:(UIColor *)tintColor toImage:(UIImage*)inputImage
{
const CGFloat EffectColorAlpha = 0.6;
UIColor *effectColor = tintColor;
size_t 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 imageByApplyingBlurToImage:inputImage withRadius:20 tintColor:effectColor saturationDeltaFactor:-1.0 maskImage:nil];
}
#pragma mark -
#pragma mark - Implementation
//| ----------------------------------------------------------------------------
+ (UIImage*)imageByApplyingBlurToImage:(UIImage*)inputImage withRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage
{
#define ENABLE_BLUR 1
#define ENABLE_SATURATION_ADJUSTMENT 1
#define ENABLE_TINT 1
// Check pre-conditions.
if (inputImage.size.width < 1 || inputImage.size.height < 1)
{
NSLog(@"*** error: invalid size: (%.2f x %.2f). Both dimensions must be >= 1: %@", inputImage.size.width, inputImage.size.height, inputImage);
return nil;
}
if (!inputImage.CGImage)
{
NSLog(@"*** error: inputImage must be backed by a CGImage: %@", inputImage);
return nil;
}
if (maskImage && !maskImage.CGImage)
{
NSLog(@"*** error: effectMaskImage must be backed by a CGImage: %@", maskImage);
return nil;
}
BOOL hasBlur = blurRadius > __FLT_EPSILON__;
BOOL hasSaturationChange = fabs(saturationDeltaFactor - 1.) > __FLT_EPSILON__;
CGImageRef inputCGImage = inputImage.CGImage;
CGFloat inputImageScale = inputImage.scale;
CGBitmapInfo inputImageBitmapInfo = CGImageGetBitmapInfo(inputCGImage);
CGImageAlphaInfo inputImageAlphaInfo = (inputImageBitmapInfo & kCGBitmapAlphaInfoMask);
CGSize outputImageSizeInPoints = inputImage.size;
CGRect outputImageRectInPoints = { CGPointZero, outputImageSizeInPoints };
// Set up output context.
BOOL useOpaqueContext;
if (inputImageAlphaInfo == kCGImageAlphaNone || inputImageAlphaInfo == kCGImageAlphaNoneSkipLast || inputImageAlphaInfo == kCGImageAlphaNoneSkipFirst)
useOpaqueContext = YES;
else
useOpaqueContext = NO;
UIGraphicsBeginImageContextWithOptions(outputImageRectInPoints.size, useOpaqueContext, inputImageScale);
CGContextRef outputContext = UIGraphicsGetCurrentContext();
CGContextScaleCTM(outputContext, 1.0, -1.0);
CGContextTranslateCTM(outputContext, 0, -outputImageRectInPoints.size.height);
if (hasBlur || hasSaturationChange)
{
vImage_Buffer effectInBuffer;
vImage_Buffer scratchBuffer1;
vImage_Buffer *inputBuffer;
vImage_Buffer *outputBuffer;
vImage_CGImageFormat format = {
.bitsPerComponent = 8,
.bitsPerPixel = 32,
.colorSpace = NULL,
// (kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little)
// requests a BGRA buffer.
.bitmapInfo = kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Little,
.version = 0,
.decode = NULL,
.renderingIntent = kCGRenderingIntentDefault
};
vImage_Error e = vImageBuffer_InitWithCGImage(&effectInBuffer, &format, NULL, inputImage.CGImage, kvImagePrintDiagnosticsToConsole);
if (e != kvImageNoError)
{
NSLog(@"*** error: vImageBuffer_InitWithCGImage returned error code %zi for inputImage: %@", e, inputImage);
UIGraphicsEndImageContext();
return nil;
}
vImageBuffer_Init(&scratchBuffer1, effectInBuffer.height, effectInBuffer.width, format.bitsPerPixel, kvImageNoFlags);
inputBuffer = &effectInBuffer;
outputBuffer = &scratchBuffer1;
#if ENABLE_BLUR
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 * inputImageScale;
if (inputRadius - 2. < __FLT_EPSILON__)
inputRadius = 2.;
uint32_t radius = floor((inputRadius * 3. * sqrt(2 * M_PI) / 4 + 0.5) / 2);
radius |= 1; // force radius to be odd so that the three box-blur methodology works.
NSInteger tempBufferSize = vImageBoxConvolve_ARGB8888(inputBuffer, outputBuffer, NULL, 0, 0, radius, radius, NULL, kvImageGetTempBufferSize | kvImageEdgeExtend);
void *tempBuffer = malloc(tempBufferSize);
vImageBoxConvolve_ARGB8888(inputBuffer, outputBuffer, tempBuffer, 0, 0, radius, radius, NULL, kvImageEdgeExtend);
vImageBoxConvolve_ARGB8888(outputBuffer, inputBuffer, tempBuffer, 0, 0, radius, radius, NULL, kvImageEdgeExtend);
vImageBoxConvolve_ARGB8888(inputBuffer, outputBuffer, tempBuffer, 0, 0, radius, radius, NULL, kvImageEdgeExtend);
free(tempBuffer);
vImage_Buffer *temp = inputBuffer;
inputBuffer = outputBuffer;
outputBuffer = temp;
}
#endif
#if ENABLE_SATURATION_ADJUSTMENT
if (hasSaturationChange)
{
CGFloat s = saturationDeltaFactor;
// These values appear in the W3C Filter Effects spec:
// https://dvcs.w3.org/hg/FXTF/raw-file/default/filters/index.html#grayscaleEquivalent
//
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);
}
vImageMatrixMultiply_ARGB8888(inputBuffer, outputBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
vImage_Buffer *temp = inputBuffer;
inputBuffer = outputBuffer;
outputBuffer = temp;
}
#endif
CGImageRef effectCGImage;
if ( (effectCGImage = vImageCreateCGImageFromBuffer(inputBuffer, &format, &cleanupBuffer, NULL, kvImageNoAllocate, NULL)) == NULL ) {
effectCGImage = vImageCreateCGImageFromBuffer(inputBuffer, &format, NULL, NULL, kvImageNoFlags, NULL);
free(inputBuffer->data);
}
if (maskImage) {
// Only need to draw the base image if the effect image will be masked.
CGContextDrawImage(outputContext, outputImageRectInPoints, inputCGImage);
}
// draw effect image
CGContextSaveGState(outputContext);
if (maskImage)
CGContextClipToMask(outputContext, outputImageRectInPoints, maskImage.CGImage);
CGContextDrawImage(outputContext, outputImageRectInPoints, effectCGImage);
CGContextRestoreGState(outputContext);
// Cleanup
CGImageRelease(effectCGImage);
free(outputBuffer->data);
}
else
{
// draw base image
CGContextDrawImage(outputContext, outputImageRectInPoints, inputCGImage);
}
#if ENABLE_TINT
// Add in color tint.
if (tintColor)
{
CGContextSaveGState(outputContext);
CGContextSetFillColorWithColor(outputContext, tintColor.CGColor);
CGContextFillRect(outputContext, outputImageRectInPoints);
CGContextRestoreGState(outputContext);
}
#endif
// Output image is ready.
UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return outputImage;
#undef ENABLE_BLUR
#undef ENABLE_SATURATION_ADJUSTMENT
#undef ENABLE_TINT
}
//| ----------------------------------------------------------------------------
// Helper function to handle deferred cleanup of a buffer.
//
void cleanupBuffer(void *userData, void *buf_data)
{ free(buf_data); }
@end
|
