[英]How do I use the Accelerate Framework With Core Graphics?
I have a project. 我有一个项目。 It basically takes photo from iPhone camera and applies some effects on photo.
它基本上是从iPhone相机拍照并对照片应用了一些效果。 Before I apply effect I use core graphics to scale image to appropriate size.
在我应用效果之前,我使用核心图形将图像缩放到合适的大小。 After scaling and rotating image I use Accelerate framework(vImage) in order to create effect.
缩放和旋转图像后,我使用Accelerate框架(vImage)来创建效果。 My problem is after applying effect it is ended up some bluish image.
我的问题是在应用效果之后它最终变成了一些蓝色的图像。 However If I don't scale image with core graphics this bluish looks doesn't happen.
但是,如果我不使用核心图形缩放图像,则这种偏蓝的外观不会发生。
Scaling code that I use is from this post. 我使用的缩放代码来自这篇文章。
And here is my code that applies effect: 这是我的代码应用效果:
- (UIImage *)applyFiltertoImage:(UIImage *)img
{
CGImageRef image = img.CGImage;
vImage_Buffer inBuffer, outBuffer;
void *pixelBuffer;
CGDataProviderRef inProvider = CGImageGetDataProvider(image);
CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);
inBuffer.width = CGImageGetWidth(image);
inBuffer.height = CGImageGetHeight(image);
inBuffer.rowBytes = CGImageGetBytesPerRow(image);
inBuffer.data = (void *)CFDataGetBytePtr(inBitmapData);
pixelBuffer = malloc(CGImageGetBytesPerRow(image) * CGImageGetHeight(image));
if (pixelBuffer == NULL) {
NSLog(@"No buffer");
}
outBuffer.data = pixelBuffer;
outBuffer.width = CGImageGetWidth(image);
outBuffer.height = CGImageGetHeight(image);
outBuffer.rowBytes = CGImageGetBytesPerRow(image);
vImageConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, self.kernel, self.size, self.size, self.divisor, NULL, kvImageEdgeExtend);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef ctx = CGBitmapContextCreate(outBuffer.data,
outBuffer.width,
outBuffer.height,
8,
outBuffer.rowBytes,
colorSpace,
kCGImageAlphaNoneSkipLast);
CGImageRef imageRef = CGBitmapContextCreateImage(ctx);
UIImage *blurredImage = [UIImage imageWithCGImage:imageRef];
CGContextRelease(ctx);
CGColorSpaceRelease(colorSpace);
free(pixelBuffer);
CFRelease(inBitmapData);
CGImageRelease(imageRef);
return blurredImage;
}
Try letting vImage initialize the values for you. 尝试让vImage为您初始化值。
vImageBuffer_InitWithCGImage
can help you avoid some pain. vImageBuffer_InitWithCGImage
可以帮助您避免一些痛苦。
- (UIImage *)applyFiltertoImage:(UIImage *)image
CGImageRef originalImageRef = image.CGImage;
CGColorSpaceRef originalColorSpace = CGColorSpaceRetain(CGImageGetColorSpace(originalImageRef));
if (_pixelBuffer == NULL) {
_pixelBuffer = malloc(CGImageGetBytesPerRow(originalImageRef) * CGImageGetHeight(originalImageRef));
}
vImage_CGImageFormat inputImageFormat =
{
.bitsPerComponent = (uint32_t) CGImageGetBitsPerComponent(originalImageRef),
.bitsPerPixel = (uint32_t) CGImageGetBitsPerComponent(originalImageRef) * (uint32_t)(CGColorSpaceGetNumberOfComponents(originalColorSpace) + (kCGImageAlphaNone != CGImageGetAlphaInfo(originalImageRef))),
.colorSpace = originalColorSpace,
.bitmapInfo = CGImageGetBitmapInfo(originalImageRef),
.version = 0,
.decode = NULL,
.renderingIntent = kCGRenderingIntentDefault
};
vImage_Buffer inputImageBuffer;
vImageBuffer_InitWithCGImage(&inputImageBuffer, &inputImageFormat, NULL, originalImageRef, kvImageNoFlags);
vImage_Buffer outputImageBuffer = {
.data = _pixelBuffer,
.width = CGImageGetWidth(originalImageRef),
.height = CGImageGetHeight(originalImageRef),
.rowBytes = CGImageGetBytesPerRow(originalImageRef)
};
vImage_Error error;
error = vImageConvolve_ARGB8888(&inputImageBuffer,
&outputImageBuffer,
NULL,
0,
0,
self.kernel,
self.size,
self.divisor,
NULL,
kvImageEdgeExtend);
if (error) {
NSLog(@"vImage error %zd", error);
}
free(inputImageBuffer.data);
vImage_CGImageFormat outFormat =
{
.bitsPerComponent = (uint32_t) CGImageGetBitsPerComponent(originalImageRef),
.bitsPerPixel = (uint32_t) CGImageGetBitsPerComponent(originalImageRef) * (uint32_t)(CGColorSpaceGetNumberOfComponents(originalColorSpace) + (kCGImageAlphaNone != CGImageGetAlphaInfo(originalImageRef))),
.colorSpace = originalColorSpace,
.bitmapInfo = CGImageGetBitmapInfo(originalImageRef),
.version = 0,
.decode = NULL,
.renderingIntent = kCGRenderingIntentDefault
};
CGImageRef modifiedImageRef = vImageCreateCGImageFromBuffer(&outputImageBuffer,
&outFormat,
NULL,
NULL,
kvImageNoFlags,
&error);
CGColorSpaceRelease(originalColorSpace);
UIImage *returnImage = [UIImage imageWithCGImage:modifiedImageRef];
CGImageRelease(modifiedImageRef);
return returnImage;
}
Create the _inputImageBuffer, _outputImageBuffer, and _outputImageFormat one-time per image and then just reapply the filter to the source image. 每个图像一次创建_inputImageBuffer,_outputImageBuffer和_outputImageFormat,然后只需将过滤器重新应用到源图像。 Once vImage warms up it will start shaving off several milliseconds from the call.
一旦vImage变暖,它将从呼叫开始削减几毫秒。
- (UIImage *)applyFilter
vImage_Error error;
error = vImageConvolve_ARGB8888(&_inputImageBuffer,
&_outputImageBuffer,
NULL,
0,
0,
self.kernel,
self.size,
self.divisor,
NULL,
kvImageEdgeExtend);
if (error) {
NSLog(@"vImage error %zd", error);
}
CGImageRef modifiedImageRef = vImageCreateCGImageFromBuffer(&_outputImageBuffer,
&_outputImageFormat,
NULL,
NULL,
kvImageNoFlags,
&error);
UIImage *returnImage = [UIImage imageWithCGImage:modifiedImageRef];
CGImageRelease(modifiedImageRef);
return returnImage;
}
Usually, a strong color tint means that the color channel order was lost in translation somewhere along the way, for example you created a CG image with BGRA data, but it was actually ARGB. 通常,强烈的色调意味着颜色通道顺序在沿途的某处翻译时丢失,例如您创建了带有BGRA数据的CG图像,但它实际上是ARGB。
Have you looked at vImage_Utilities.h? 你看过vImage_Utilities.h吗?
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.