我正在使用Core Image,并希望对所选图像产生黑白效果。
理想情况下,我希望能够使用类似于Photoshop中可用的选项,例如:红色、青色、绿色、蓝色和品红。目标是创建不同类型的黑白效果。
有人知道最好的滤镜是哪个来操纵这些选项吗?如果没有,有人知道使用其他滤镜创建黑白效果的好方法吗?
谢谢
Oliver
我正在使用Core Image,并希望对所选图像产生黑白效果。
理想情况下,我希望能够使用类似于Photoshop中可用的选项,例如:红色、青色、绿色、蓝色和品红。目标是创建不同类型的黑白效果。
有人知道最好的滤镜是哪个来操纵这些选项吗?如果没有,有人知道使用其他滤镜创建黑白效果的好方法吗?
谢谢
Oliver
- (UIImage *)imageBlackAndWhite
{
CIImage *beginImage = [CIImage imageWithCGImage:self.CGImage];
CIImage *blackAndWhite = [CIFilter filterWithName:@"CIColorControls" keysAndValues:kCIInputImageKey, beginImage, @"inputBrightness", [NSNumber numberWithFloat:0.0], @"inputContrast", [NSNumber numberWithFloat:1.1], @"inputSaturation", [NSNumber numberWithFloat:0.0], nil].outputImage;
CIImage *output = [CIFilter filterWithName:@"CIExposureAdjust" keysAndValues:kCIInputImageKey, blackAndWhite, @"inputEV", [NSNumber numberWithFloat:0.7], nil].outputImage;
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef cgiimage = [context createCGImage:output fromRect:output.extent];
//UIImage *newImage = [UIImage imageWithCGImage:cgiimage];
UIImage *newImage = [UIImage imageWithCGImage:cgiimage scale:image.scale orientation:image.imageOrientation];
CGImageRelease(cgiimage);
return newImage;
}
更新: 对于 iOS6
,有一个 CIColorMonochrome
滤镜,但我试用后发现它不如我的效果好。
这里有一个使用CIColorMonochrome的例子。
- (UIImage *)imageBlackAndWhite
{
CIImage *beginImage = [CIImage imageWithCGImage:self.CGImage];
CIImage *output = [CIFilter filterWithName:@"CIColorMonochrome" keysAndValues:kCIInputImageKey, beginImage, @"inputIntensity", [NSNumber numberWithFloat:1.0], @"inputColor", [[CIColor alloc] initWithColor:[UIColor whiteColor]], nil].outputImage;
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef cgiimage = [context createCGImage:output fromRect:output.extent];
UIImage *newImage = [UIImage imageWithCGImage:cgiimage scale:self.scale orientation:self.imageOrientation];
CGImageRelease(cgiimage);
return newImage;
}
inputIntensity
默认为 1
,无需手动设置。 - Rudolf Adamkovič下面是将排名前的解决方案转换成Swift(适用于iOS 7及以上版本):
func blackAndWhiteImage(image: UIImage) -> UIImage {
let context = CIContext(options: nil)
let ciImage = CoreImage.CIImage(image: image)!
// Set image color to b/w
let bwFilter = CIFilter(name: "CIColorControls")!
bwFilter.setValuesForKeysWithDictionary([kCIInputImageKey:ciImage, kCIInputBrightnessKey:NSNumber(float: 0.0), kCIInputContrastKey:NSNumber(float: 1.1), kCIInputSaturationKey:NSNumber(float: 0.0)])
let bwFilterOutput = (bwFilter.outputImage)!
// Adjust exposure
let exposureFilter = CIFilter(name: "CIExposureAdjust")!
exposureFilter.setValuesForKeysWithDictionary([kCIInputImageKey:bwFilterOutput, kCIInputEVKey:NSNumber(float: 0.7)])
let exposureFilterOutput = (exposureFilter.outputImage)!
// Create UIImage from context
let bwCGIImage = context.createCGImage(exposureFilterOutput, fromRect: ciImage.extent)
let resultImage = UIImage(CGImage: bwCGIImage, scale: 1.0, orientation: image.imageOrientation)
return resultImage
}
CIColorMatrix
,其中R、G和B向量参数都设置为(0.2125, 0.7154, 0.0721, 0),而alpha和bias向量则保留其默认值。CIColorMatrix
:https://dev59.com/e2DVa4cB1Zd3GeqPh-6Z - guozqzzuCIColorMonochrome
的建议,现在 iOS7(和 OS X 10.9)有几个专门的灰度滤镜可用:
模拟黑白摄影胶片,而不会显著改变对比度。
模拟黑白摄影胶片,具有夸张的对比度。
以下是@Shmidt的UIImage扩展,使用Swift编写并进行了性能更新,这是最受欢迎的答案:
import CoreImage
extension UIImage
{
func imageBlackAndWhite() -> UIImage?
{
if let beginImage = CoreImage.CIImage(image: self)
{
let paramsColor: [String : AnyObject] = [kCIInputBrightnessKey: NSNumber(double: 0.0),
kCIInputContrastKey: NSNumber(double: 1.1),
kCIInputSaturationKey: NSNumber(double: 0.0)]
let blackAndWhite = beginImage.imageByApplyingFilter("CIColorControls", withInputParameters: paramsColor)
let paramsExposure: [String : AnyObject] = [kCIInputEVKey: NSNumber(double: 0.7)]
let output = blackAndWhite.imageByApplyingFilter("CIExposureAdjust", withInputParameters: paramsExposure)
let processedCGImage = CIContext().createCGImage(output, fromRect: output.extent)
return UIImage(CGImage: processedCGImage, scale: self.scale, orientation: self.imageOrientation)
}
return nil
}
}
这是@FBente将@Shmidt的答案转换成Swift 3版本的macOS(NSImage):
extension NSImage
{
func imageBlackAndWhite() -> NSImage?
{
if let cgImage = self.cgImage(forProposedRect: nil, context: nil, hints: nil)
{
let beginImage = CIImage.init(cgImage: cgImage)
let paramsColor: [String : AnyObject] = [kCIInputBrightnessKey: NSNumber(value: 0.0),
kCIInputContrastKey: NSNumber(value: 1.1),
kCIInputSaturationKey: NSNumber(value: 0.0)]
let blackAndWhite = beginImage.applyingFilter("CIColorControls", withInputParameters: paramsColor)
let paramsExposure: [String : AnyObject] = [kCIInputEVKey: NSNumber(value: 0.7)]
let output = blackAndWhite.applyingFilter("CIExposureAdjust", withInputParameters: paramsExposure)
if let processedCGImage = CIContext().createCGImage(output, from: output.extent) {
return NSImage(cgImage: processedCGImage, size: self.size)
}
}
return nil
}
}
我尝试了Shmidt的解决方案,但在iPad Pro上对我来说似乎过度曝光。我只使用他解决方案的第一部分,没有曝光滤镜:
- (UIImage *)imageBlackAndWhite
{
CIImage *beginImage = [CIImage imageWithCGImage:self.CGImage];
CIImage *blackAndWhite = [CIFilter filterWithName:@"CIColorControls" keysAndValues:kCIInputImageKey, beginImage, @"inputBrightness", [NSNumber numberWithFloat:0.0], @"inputContrast", [NSNumber numberWithFloat:1.1], @"inputSaturation", [NSNumber numberWithFloat:0.0], nil].outputImage;
CIImage *output = [blackAndWhite valueForKey:@"outputImate"];
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef cgiimage = [context createCGImage:output fromRect:output.extent];
//UIImage *newImage = [UIImage imageWithCGImage:cgiimage];
UIImage *newImage = [UIImage imageWithCGImage:cgiimage scale:image.scale orientation:image.imageOrientation];
CGImageRelease(cgiimage);
return newImage;
}