CoreImage Namespace

The CoreImage namespace provides hardware-accelerated image processing.

Classes

CIAccordionFoldTransition	Animates a transition by creating an accordion-fold effect on the source image.
CIAdditionCompositing	The CIAdditionCompositing CoreImage filter.
CIAffineClamp	A CIAffineFilter that extends the border pixels to the post-transform boundaries.
CIAffineFilter	An abstract class that defines a CIFilter that performs an affine transform on an image and then performs a filtering operation on the transformed image.
CIAffineTile	A CIAffineFilter that tiles the transformed image.
CIAffineTransform	Performs an affine transform on an image.
CIAreaAverage	Produces a single-pixel image. The pixel is the average color of the input extent.
CIAreaHistogram	Creates histogram data for a given image and rectangle of interest.
CIAreaMaximum	Produces a single-pixel image. The pixel's components are set to the maximum of that component within the input extent.
CIAreaMaximumAlpha	Returns a single-pixel image. The color is that of the pixel in the input extent with the greatest alpha value.
CIAreaMinimum	Returns a single-pixel image. The pixel's components are set to the minimum of that component within the input extent.
CIAreaMinimumAlpha	Returns a single-pixel image. The color is that of the pixel in the input extent with the lowest alpha value.
CIAreaMinMax
CIAreaMinMaxRed
CIAttributedTextImageGenerator	A CIImageGenerator that generates an image from attributed text.
CIAutoAdjustmentFilterOptions	When passed to GetAutoAdjustmentFilters(CIAutoAdjustmentFilterOptions), limits the results.
CIAztecCodeDescriptor	A CIBarcodeDescriptor for the Aztec barcode scheme.
CIAztecCodeGenerator	Generates an Aztec code for the specified P:CoreImage.CIAztecCodeGenerator.Message.
CIBarcodeDescriptor	Base class for barcode descriptions. Subclasses for specific schemes define relevant properties.
CIBarcodeGenerator	A CIFilter that generates barcodes.
CIBarsSwipeTransition	A CITransitionFilter that animates a transition by moving a bar over the source image.
CIBicubicScaleTransform
CIBlendFilter	An abstract CIFilter that combines a background and foreground image.
CIBlendKernel	A CIColorKernel that blends images using the GPU.
CIBlendWithAlphaMask	A CIBlendWithMask that uses a mask image to blend foreground and background images.
CIBlendWithBlueMask
CIBlendWithMask	A CIBlendFilter that uses a grayscale mask to blends its foreground and background images.
CIBlendWithRedMask
CIBloom	A CIFilter that creates an edge-flow effect.
CIBokehBlur	A blur simulating the the unfocused background of a larger-aperture camera with an iris shutter.
CIBoxBlur	Applies a blur created with a box-shaped convolution kernel.
CIBumpDistortion	A CIDistortionFilter that creates a bump at the specified center point.
CIBumpDistortionLinear	A filter that distorts the image around a convex or concave line.
CICameraCalibrationLensCorrection
CICheckerboardGenerator	The CICheckerboardGenerator CoreImage filter
CICircleSplashDistortion	Makes the pixels at the circumference of a circle spread out to the boundaries of the image.
CICircularScreen	A CIScreenFilter that creates a circular bulls-eye-style halftone screen.
CICircularWrap	Distorts the input image so that it appears as if wrapped around a transparent circle.
CIClamp
CICode128BarcodeGenerator	Generates a Code 128 barcode.
CICodeGenerator	Base class for code generators.
CIColor	A Core Image color, including both color values and a reference to a color space.
CIColorBlendMode	The CIColorBlendMode CoreImage filter
CIColorBurnBlendMode	The CIColorBurnBlendMode CoreImage filter
CIColorClamp	A filter that constrains the color values between the range specified.
CIColorControls	The CIColorControls CoreImage filter
CIColorCrossPolynomial	A filter that modifies the source pixels by applying a set of polynomial cross-products.
CIColorCube	The CIColorCube CoreImage filter
CIColorCubesMixedWithMask
CIColorCubeWithColorSpace	A filter that modifies the source pixels using a 3D color-table and then maps the result to a color space.
CIColorCurves
CIColorDodgeBlendMode	The CIColorDodgeBlendMode CoreImage filter
CIColorInvert	The CIColorInvert CoreImage filter
CIColorKernel	Kernel for a GPU process that only operates on color data.
CIColorMap	Changes colors based on an input gradient image's mapping.
CIColorMatrix	The CIColorMatrix CoreImage filter.
CIColorMonochrome	The CIColorMonochrome CoreImage filter
CIColorPolynomial	A filter that modifies the source pixels by applying a set of cubic polynomials.
CIColorPosterize	Reduces the number of levels for each color component.
CIColumnAverage	Returns a 1-pixel high image with the same width as the input image. Every pixel is the average color of the corresponding column in the input image.
CIComicEffect	Produces an image with outlined edges and a color halftone effect.
CICompositingFilter	An abstract CIFilter that composites two images.
CIConstantColorGenerator	Generates a solid color.
CIContext	Orchestrates the rendering of a CIFilter pipeline.
CIContext_CIDepthBlurEffect
CIContext_CIRenderDestination
CIContext_ImageRepresentation	Extension methods for CIContext that can generate common image formats.
CIContextOptions	Use to configure the CIContext rendering pipeline.
CIConvolution3X3	A filter that performs a custom 3x3 matrix convolution.
CIConvolution5X5	A filter that performs a custom 5x5 matrix convolution.
CIConvolution7X7	A filter that performs a custom 7x7 matrix convolution.
CIConvolution9Horizontal	A filter that performs a horizontal convolution of 9 elements.
CIConvolution9Vertical	A filter that performs a vertical convolution of 9 elements.
CIConvolutionCore	An abstract class that is the base for convolution filters.
CICopyMachineTransition	A CITransitionFilter that mimics the effect of a photocopier.
CICoreMLModelFilter
CICrop	The CICrop CoreImage filter
CICrystallize	Creates irregular blocks of average color from the source image.
CIDarkenBlendMode	The CIDarkenBlendMode CoreImage filter
CIDataMatrixCodeDescriptor	A CIBarcodeDescriptor for the Data Matrix barcode scheme.
CIDepthBlurEffect
CIDepthDisparityConverter
CIDepthOfField	Simulates a blurred depth of field and applies a saturation effect to the 'in-focus' region.
CIDepthToDisparity
CIDetector	Image analysis class for face detection.
CIDetectorOptions	Options for use with face detection. Used with CreateFaceDetector(CIContext, Nullable<FaceDetectorAccuracy>, Nullable<Single>, Nullable<Boolean>).
CIDifferenceBlendMode	The CIDifferenceBlendMode CoreImage filter
CIDiscBlur	Applies a blur created with a disc-shaped convolution kernel.
CIDisintegrateWithMaskTransition	A CITransitionFilter that uses a mask to define the transition.
CIDisparityToDepth
CIDisplacementDistortion	Textures the input image by the grayscale value of the corresponding pixels in the displacement image.
CIDissolveTransition	A CITransitionFilter that performs a cross-dissolve.
CIDistortionFilter	An abstract CIFilter for distortions.
CIDither
CIDivideBlendMode	A CIBlendFilter that divides the color values of its P:CIBlendFilter.Image and BackgroundImage.
CIDotScreen	A CIScreenFilter that screens with a halftone dot pattern.
CIDroste	Creates a series of increasingly smaller boxes repeating a portion of the image.
CIEdgePreserveUpsampleFilter
CIEdges	Creates a colorized edge-detection effect.
CIEdgeWork	Creates a black and white woodblock effect.
CIEightfoldReflectedTile	A CITileFilter that applies 8-way reflected symmetry.
CIExclusionBlendMode	The CIExclusionBlendMode CoreImage filter
CIExposureAdjust	The CIExposureAdjust CoreImage filter
CIFaceBalance	The CIFaceBalance CoreImage filter
CIFaceFeature	Locations of the eyes and mouths in a detected face. In video sequences, attempts to maintain a consistent P:CoreImage.CIFaceFeature.TrackingID.
CIFalseColor	The CIFalseColor CoreImage filter
CIFeature	An area of an image in which a CIDetector has detected a match.
CIFilter	CoreImage image filter.
CIFilterAttributes	Constants used for CIFilter's attributes
CIFilterCategory	Constants used for CIFilter filtering facilities to find filters by category.
CIFilterInputKey	Keys that can be used to configure the CIFilter input values.
CIFilterOutputKey	Keys that can be used to get output results out of a CIFilter.
CIFilterShape	Masks filter operations to areas composed of the intersections, unions, and affine transformations of rectangles and other similarly constructed filter shapes.
CIFlashTransition	A CITransitionFilter that presents a starburst-like flash.
CIFourfoldReflectedTile	A CITileFilter that applies 4-way reflected symmetry.
CIFourfoldRotatedTile	A CITileFilter that rotates the source image in 90-degree increments.
CIFourfoldTranslatedTile	A CITileFilter that applies four translations to the source image.
CIGammaAdjust	The CIGammaAdjust CoreImage filter
CIGaussianBlur	Applies a Gaussian blur.
CIGaussianGradient	Generates a gradient that fades via a 2D Gaussian distribution
CIGlassDistortion	Distorts the input image so that it appears viewed through glass blocks whose geometry corresponds to the Texture image.
CIGlassLozenge	Creates an effect as if a lozenge-shaped lens were placed on the input image.
CIGlideReflectedTile	A CITileFilter that translates and smears the source image.
CIGloom	A CIFilter that dulls the highlights of the source image.
CIGuidedFilter
CIHardLightBlendMode	The CIHardLightBlendMode CoreImage filter
CIHatchedScreen	A CIScreenFilter that filters via a hatched halftone pattern.
CIHeightFieldFromMask	Creates a continuous height field from a grayscale mask. Use with CIShadedMaterial to create realistic dropshadows.
CIHexagonalPixellate	Pixellates the image with hexagonals based on the average color of pixels within the hexagon.
CIHighlightShadowAdjust	The CIHighlightShadowAdjust CoreImage filter
CIHistogramDisplayFilter	Renders a one-dimensional Image histogram as a typical two-dimensional histogram.
CIHoleDistortion	A CIDistortionFilter that distorts pixels around a circular area.
CIHueAdjust	The CIHueAdjust CoreImage filter
CIHueBlendMode	The CIHueBlendMode CoreImage filter
CIHueSaturationValueGradient	Creates a gradient specified using HSV.
CIImage	Represents a set of instructions to create an image for use by CoreImage.
CIImageAccumulator	A feedback image processor.
CIImageGenerator	A CIFilter that generates images.
CIImageInitializationOptions	Options that can be used when initializing a new CIImage.
CIImageInitializationOptionsWithMetadata	A type of CIImageInitializationOptions that has additional metadata properties.
CIImageProcessorInput_Extensions	Contains an extension method for getting the surface from a ICIImageProcessorInput.
CIImageProcessorKernel	Base class for image-processing classes whose processing can be inserted into the CoreImage processing pipeline.
CIImageProcessorOutput_Extensions	Contains an extension method for getting the surface from a ICIImageProcessorOutput.
CIImageProviderOptions	Options used in various calls to CIImage involving ICIImageProvider objects.
CIImageRepresentationOptions
CIKaleidoscope	Produces a kaleidoscopic, 12-way-symmetrical, image.
CIKernel	A kernel for filters that use custom GPU steps.
CILabDeltaE
CILanczosScaleTransform	A scaling transform that uses Lanczos resampling.
CILenticularHaloGenerator	Creates an artificial lens-flare.
CILightenBlendMode	The CILightenBlendMode CoreImage filter
CILightTunnel	A CIFilter that creates a spiraling effect.
CILinearBlur
CILinearBurnBlendMode	Darkens the image based on the colors of the background image.
CILinearDodgeBlendMode	Darkens the image based on the colors of the background image.
CILinearGradient	A gradient that fades one color linearly into another.
CILinearToSRGBToneCurve	A filter that maps color intensity from a linear gamma curve to the sRGB color space.
CILineOverlay	Produces a black-and-white sketch-like image via edge detection.
CILineScreen	A CIScreenFilter that simulates a halftone made of lines.
CILuminosityBlendMode	The CILuminosityBlendMode CoreImage filter
CIMaskedVariableBlur	A CIFilter that blurs based on a black-and-white mask.
CIMaskToAlpha	A CIFilter that converts a grayscale image to an alpha mask.
CIMaximumComponent	A CIFilter that creates a grayscale image from the maximum value of the RGB color values.
CIMaximumCompositing	The CIMaximumCompositing CoreImage filter
CIMedianFilter	Replaces pixel values with the median of neighboring pixel values, thus reducing noise in the input image.
CIMeshGenerator
CIMinimumComponent	A CIFilter that creates a grayscale image from the minimum component of the RGB values.
CIMinimumCompositing	The CIMinimumCompositing CoreImage filter
CIMix
CIModTransition	A CITransitionFilter that reveals the background image via a series of irregularly shaped holes.
CIMorphology
CIMorphologyGradient
CIMorphologyMaximum
CIMorphologyMinimum
CIMotionBlur	Applies a blur that simulates the motion of a camera during capture.
CIMultiplyBlendMode	The CIMultiplyBlendMode CoreImage filter
CIMultiplyCompositing	The CIMultiplyCompositing CoreImage filter
CINinePartStretched
CINinePartTiled
CINoiseReduction	Reduces noise by detecting luminance variations. Small luminance variations are locally blurred, large variations are locally sharpened.
CIOpTile	Creates an 'op art' effect by tiling, scaling, and rotating regions of the image.
CIOverlayBlendMode	The CIOverlayBlendMode CoreImage filter
CIPageCurlTransition	Animates a page curl transition between images.
CIPageCurlWithShadowTransition	Animates a page curl transition, with a shadow, between images.
CIParallelogramTile	Warps an image into a parallelogram and then tiles the result.
CIPdf417BarcodeGenerator	Generator for 2-dimensional PDF417 bar codes.
CIPdf417CodeDescriptor	A CIBarcodeDescriptor for the CIPDF417 barcode scheme.
CIPerspectiveCorrection	A CIPerspectiveTransform that is cropped according to the perspective control points, but whose pixels are not transformed.
CIPerspectiveTile	A CIFilter that applies a perspective transform and then tiles the result.
CIPerspectiveTransform	A CIFilter that applies a transform the simulates perspective.
CIPerspectiveTransformWithExtent	A filter that alters a portion of the total image based on a perspective transform.
CIPhotoEffect	The base class for photo effect filters.
CIPhotoEffectChrome	A filter that exaggerates color of the image producing a vintage look.
CIPhotoEffectFade	A filter that reduces color of the image producing a vintage look.
CIPhotoEffectInstant	A filter that that distorts colors in a style reminiscent of instant film.
CIPhotoEffectMono	A filter that produces a low-contrast black-and-white image.
CIPhotoEffectNoir	A filter that produces a high-contrast black-and-white image.
CIPhotoEffectProcess	A filter that produces a vintage look with exagerrated cool colors.
CIPhotoEffectTonal	A filter that produces a black-and-white image with minimal contrast changes.
CIPhotoEffectTransfer	A filter that produces a vintage look with exagerrated warm colors.
CIPinchDistortion	A CIDistortionFilter that pinches pixels towards a rectangular area.
CIPinLightBlendMode	Replaces image colors with the bright colors from the background image.
CIPixellate	A CIFilter that pixelates the original image.
CIPointillize	Creates an effect mimicking artistic pointillization.
CIQRCodeDescriptor	A CIBarcodeDescriptor for QR codes.
CIQRCodeFeature	A detected QR code.
CIQRCodeGenerator	Generates a QR code.
CIRadialGradient	Generates a gradient between two colors as if reflected on a sphere.
CIRandomGenerator	A CIFilter whose pixels are randomly colored.
CIRawFilterOptions	Settings for use with CreateRawFilter(CVPixelBuffer, NSDictionary, NSDictionary).
CIRectangleFeature	A CIFeature an image space rectange that contains a detected physical rectangle.
CIReductionFilter
CIRenderDestination
CIRenderInfo	Holds information about a render pass, including timing information and number of pixels processed.
CIRenderTask
CIRippleTransition	Animates a ripple transition between images.
CIRowAverage	Returns a 1-pixel-high image, the pixels of which are the average color for the corresponding row in the input image.
CISaliencyMapFilter
CISampleNearest
CISampler	Samples images for processing by a CISampler.
CISamplerOptions	Options to conrol sampler operations for CISampler objects.
CISaturationBlendMode	The CISaturationBlendMode CoreImage filter
CIScreenBlendMode	The CIScreenBlendMode CoreImage filter
CIScreenFilter	A CIFilter that mimics halftone screens.
CISepiaTone	The CISepiaTone CoreImage filter
CIShadedMaterial	Produces a shaded image from a height field, such as that produced by CIHeightFieldFromMask.
CISharpenLuminance	A CIFilter that sharpens the image.
CISixfoldReflectedTile	A CITileFilter that applies 6-way reflected symmetry.
CISixfoldRotatedTile	A CITileFilter that rotates the image in 60-degree increments.
CISmoothLinearGradient	A filter that produces a gradient along a linear axis between two endpoints.
CISoftLightBlendMode	The CISoftLightBlendMode CoreImage filter
CISourceAtopCompositing	The CISourceAtopCompositing CoreImage filter
CISourceInCompositing	The CISourceInCompositing CoreImage filter
CISourceOutCompositing	The CISourceOutCompositing CoreImage filter
CISourceOverCompositing	The CISourceOverCompositing CoreImage filter
CISpotColor	Replaces color ranges with specified replacement colors.
CISpotLight	Produces an effect mimicking that of a directional spotlight.
CISRGBToneCurveToLinear	A filter that adjusts tone response in sRGB color space and then maps it to a linear gamma curve.
CIStarShineGenerator	A CIFilter that simulates lens flare.
CIStraightenFilter	The CIStraightenFilter CoreImage filter
CIStretchCrop	Stretches and crops an image.
CIStripesGenerator	Generates hard-edged strips of alternating colors.
CISubtractBlendMode	Subtracts the background image pixels from those in the Image.
CISunbeamsGenerator	Creates an artificial sun and light-ray effect.
CISwipeTransition	A CITransitionFilter that swipes from one image to the other.
CITemperatureAndTint	The CITemperatureAndTint CoreImage filter
CITextFeature	A detected text feature.
CITextImageGenerator	A CIImageGenerator that generates an image from text.
CIThermal
CITileFilter	A CIFilter that applies a filter and then tiles the results.
CIToneCurve	The CIToneCurve CoreImage filter
CITorusLensDistortion	Produces an effect as if a toroidal lens were placed on the input image.
CITransitionFilter	A CITransitionFilter that animates a transition between two images.
CITriangleKaleidoscope	A CIFilter that creates a kaleidoscopic effect.
CITriangleTile	Tiles the image with a triangular region of the input image.
CITwelvefoldReflectedTile	A CITileFilter that applies 12-way reflected symmetry.
CITwirlDistortion	A CIDistortionFilter that rotates pixels around a point.
CIUIParameterSet	Contains options for core image filter user interfaces.
CIUnsharpMask	A CIFilter that increases the contrast of edges in the image.
CIVector	A vector for use with Core Image objects such as CIFilter.
CIVibrance	The CIVibrance CoreImage filter
CIVignette	The CIVignette CoreImage filter
CIVignetteEffect	A filter that modifies the brightness of the outside of an image.
CIVortexDistortion	A CIDistortionFilter that creates a tight spiraling distortion suggestive of a vortex.
CIWarpKernel	A kernel for GPU transforms that operate only on geometry.
CIWhitePointAdjust	The CIWhitePointAdjust CoreImage filter
CIXRay
CIZoomBlur	Applies a blur that simulates a camera zoom during capture.

Interfaces

ICIFilterConstructor	Interface for classes that create named filters.
ICIImageProcessorInput	The input to a CIImageProcessorKernel.
ICIImageProcessorOutput	The output of a CIImageProcessorKernel.
ICIImageProvider	Interface defining an image provider.

Enums

CIDataMatrixCodeEccVersion	Enumerates the ECC versions for the Data Matrix barcode scheme.
CIFilterMode	Enumerates filter modes.
CIFormat	An enumeration whose values specify pixel formats.
CIImageOrientation	An enumeration whose values specify the origin of the CIImage.
CIQRCodeErrorCorrectionLevel	Enumerates the error correction levels for QR codes.
CIRenderDestinationAlphaMode
CIWrapMode	Enumerates values that control how samples from outside the source image are treated.
FaceDetectorAccuracy	An enumeration whose values specify the accuracy of face detection.

Delegates

CIKernelRoiCallback

Completion handler for deterimining a region of interest in the source image.

Remarks

CoreImage provides a framework for processing still images and applying a set of operations on them to either produce new images or perform image analysis (like performing face detection and photography auto-enhance). The operations are hardware accelerated and provide better performance than most hand written implementations.

CoreImage can apply either one filter to an image or you can use the built-in chaining support to apply a series of filters at once to an image. For example, you could apply a Sepia Filter, followed by a Hue adjustment filter, followed by a contrast filter. The idea behind the chaining support is to avoid intermediate copies and intermediate buffers during image processing. Additionally, some of these filtering operations can be performed entirely on the GPU in a single pass, without having to copy data back and forth from the GPU to the main memory.

The CoreImage runtime sits below the N:CoreGraphics, CoreVideo and N:ImageIO stacks and provides services to all of them. Depending on the filter operations and the hardware platform, CoreImage will execute the filters in the CPU or the GPU.

To use CoreImage on iOS, you follow these steps:

• Create a CIImage object. You can create these from multiple sources: CoreGraphics images, bitmap data, images on disk or CoreVideo image buffers. CIImage objects are immutable and represent recipes, that is, they will be computed on demand.

  :

• Create and configure a CIFilter object. This object combines image inputs or numeric input parameters to configure the effects of the filter. The configuration is done by setting various properties using the object indexer to any of the values documented in the

  :

• Create a CIContext object to track the processing pipeline. This is the object trough which CoreImage draws and it can be CPU or GPU bound.

  :

• Render the filter output into a target image using one of the CIContext methods. :

// This sample turns the image into a sepia image

// Load the image using UIImage, it is convenient
var uiimage = UIImage.FromFile ("sample.jpg");

// Create the CIImage, using the UIImage's CGImage as a reference
var image = new CIImage (uiimage.CGImage);

// Create the filter
var sepia = new CISepiaTone () {
	Image = image,
	Intensity = .8f
};

// Generate the recipe.   It is important to note that at this point
// the resulting CIImage merely contains the recipe on how to create
// the image, this is important, because you can use this result as
// the input to another filter to chain filters together and only 
// at the last minute, when the CIContext rendering APIs are used,
// does the actual pipeline execute.   This allows for a series of
// operations to all be performed in one step without intermediate
// buffer copies.
CIImage output = sepia.OutputImage;

// To render the results, we need to create a context, and then
// use one of the context rendering APIs, in this case, we render the
// result into a CoreGraphics image, which is merely a useful representation
//
var context = CIContext.FromOptions (null);

var cgimage = context.CreateCGImage (output, output.Extent);

// The above cgimage can be added to a screen view, for example, this
// would add it to a UIImageView on the screen:
myImageView.Image = UIImage.FromImage (cgimage);

Face detection is done with the CIDetector class by calling the M:CoreImage.CIDetector.CreateFaceDetector(CoreImage.CIContext,bool) method which returns an array of CIFeature objects with any detected face features found.

Auto-adjustments are implemented by calling the GetAutoAdjustmentFilters() method. This method returns a list of suggested CIFilter which you in turn would apply to your image and render to a context.

To chain filters, all you have to do is connect the OutputImage property from a filter to the Image property of another filter. This is a modified version of the previous example showing how to chain two filters together:

var uiimage = UIImage.FromFile ("sample.jpg");
var image = new CIImage (uiimage.CGImage);

var sepia = new CISepiaTone () {
	Image = image,
	Intensity = .8f
};

// Chain the Sepia filter to a Color inversion filter, this is done
// by assigning the CIColorInvert.Input to the sepia.OutputImage
var invert = new CIColorInvert () {
	Image = sepia.OutputImage;
}

CIImage output = invert.OutputImage;
var context = CIContext.FromOptions (null);
var cgimage = context.CreateCGImage (output, output.Extent);

myImageView.Image = UIImage.FromImage (cgimage);