78 lines
3.2 KiB
Mathematica
78 lines
3.2 KiB
Mathematica
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/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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#import "RCTImageBlurUtils.h"
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UIImage *RCTBlurredImageWithRadius(UIImage *inputImage, CGFloat radius)
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{
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CGImageRef imageRef = inputImage.CGImage;
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CGFloat imageScale = inputImage.scale;
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UIImageOrientation imageOrientation = inputImage.imageOrientation;
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// Image must be nonzero size
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if (CGImageGetWidth(imageRef) * CGImageGetHeight(imageRef) == 0) {
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return inputImage;
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}
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//convert to ARGB if it isn't
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if (CGImageGetBitsPerPixel(imageRef) != 32 ||
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CGImageGetBitsPerComponent(imageRef) != 8 ||
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!((CGImageGetBitmapInfo(imageRef) & kCGBitmapAlphaInfoMask))) {
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UIGraphicsBeginImageContextWithOptions(inputImage.size, NO, inputImage.scale);
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[inputImage drawAtPoint:CGPointZero];
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imageRef = UIGraphicsGetImageFromCurrentImageContext().CGImage;
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UIGraphicsEndImageContext();
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}
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vImage_Buffer buffer1, buffer2;
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buffer1.width = buffer2.width = CGImageGetWidth(imageRef);
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buffer1.height = buffer2.height = CGImageGetHeight(imageRef);
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buffer1.rowBytes = buffer2.rowBytes = CGImageGetBytesPerRow(imageRef);
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size_t bytes = buffer1.rowBytes * buffer1.height;
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buffer1.data = malloc(bytes);
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buffer2.data = malloc(bytes);
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// A description of how to compute the box kernel width from the Gaussian
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// radius (aka standard deviation) appears in the SVG spec:
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// http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
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uint32_t boxSize = floor((radius * imageScale * 3 * sqrt(2 * M_PI) / 4 + 0.5) / 2);
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boxSize |= 1; // Ensure boxSize is odd
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//create temp buffer
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void *tempBuffer = malloc((size_t)vImageBoxConvolve_ARGB8888(&buffer1, &buffer2, NULL, 0, 0, boxSize, boxSize,
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NULL, kvImageEdgeExtend + kvImageGetTempBufferSize));
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//copy image data
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CFDataRef dataSource = CGDataProviderCopyData(CGImageGetDataProvider(imageRef));
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memcpy(buffer1.data, CFDataGetBytePtr(dataSource), bytes);
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CFRelease(dataSource);
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//perform blur
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vImageBoxConvolve_ARGB8888(&buffer1, &buffer2, tempBuffer, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
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vImageBoxConvolve_ARGB8888(&buffer2, &buffer1, tempBuffer, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
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vImageBoxConvolve_ARGB8888(&buffer1, &buffer2, tempBuffer, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
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//free buffers
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free(buffer2.data);
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free(tempBuffer);
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//create image context from buffer
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CGContextRef ctx = CGBitmapContextCreate(buffer1.data, buffer1.width, buffer1.height,
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8, buffer1.rowBytes, CGImageGetColorSpace(imageRef),
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CGImageGetBitmapInfo(imageRef));
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//create image from context
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imageRef = CGBitmapContextCreateImage(ctx);
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UIImage *outputImage = [UIImage imageWithCGImage:imageRef scale:imageScale orientation:imageOrientation];
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CGImageRelease(imageRef);
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CGContextRelease(ctx);
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free(buffer1.data);
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return outputImage;
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}
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