ImageMagick: MagickCore, C API for ImageMagick: Add an Effect
Author: ImageMagick Studio LLC
Description: ImageMagick (TM) is a free software suite to create, edit and compose bitmap images. It can read, convert and write images in a large variety of formats. Images can be cropped, colors can be changed, various effects can be applied, images can be rotated and combined, and text, lines, polygons, ellipses and Bézier curves can be added to images and stretched and rotated. ImageMagick is free software: it is delivered with full source code and can be freely used, copied, modified and distributed. Its license is compatible with the GPL. It runs on all major operating systems. Most of the functionality of ImageMagick can be used interactively from the command line; more often, however, the features are used from programs written in the programming languages Perl, C, C++, Python, PHP, Ruby or Java, for which ready-made ImageMagick interfaces (PerlMagick, Magick++, PythonMagick, MagickWand for PHP, RubyMagick, and JMagick) are available. This makes it possible to modify or create images automa [cell cut: 1159 characters, first 1000 kept]
Keywords: magickcore, c, api, for, imagemagick:, add, an, effect, ImageMagick, PerlMagick, Magick++, Image, Magick

## AdaptiveThresholdImage AdaptiveThresholdImage() selects an individual threshold for each pixel based on the range of intensity values in its local neighborhood. This allows for thresholding of an image whose global intensity histogram doesn't contain distinctive peaks. The format of the AdaptiveThresholdImage method is:
      Image *AdaptiveThresholdImage(const Image *image,
        const unsigned long width,const unsigned long height,
        const long offset,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### width The width of the local neighborhood. #### height The height of the local neighborhood. #### offset The mean offset. #### exception Return any errors or warnings in this structure. ## AddNoiseImage AddNoiseImage() adds random noise to the image. The format of the AddNoiseImage method is:
      Image *AddNoiseImage(const Image *image,const NoiseType noise_type,
        ExceptionInfo *exception)
      Image *AddNoiseImageChannel(const Image *image,const ChannelType channel,
        const NoiseType noise_type,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### channel The channel type. #### noise_type The type of noise: Uniform, Gaussian, Multiplicative, Impulse, Laplacian, or Poisson. #### exception Return any errors or warnings in this structure. ## BilevelImage BilevelImage() changes the value of individual pixels based on the intensity of each pixel channel. The result is a high-contrast image. The format of the BilevelImageChannel method is:
      MagickBooleanType BilevelImage(Image *image,const double threshold)
      MagickBooleanType BilevelImageChannel(Image *image,
        const ChannelType channel,const double threshold)
A description of each parameter follows: #### image The image. #### channel The channel type. #### threshold define the threshold values. ## BlackThresholdImage BlackThresholdImage() is like ThresholdImage() but forces all pixels below the threshold into black while leaving all pixels above the threshold unchanged. The format of the BlackThresholdImage method is:
      MagickBooleanType BlackThresholdImage(Image *image,const char *threshold)
A description of each parameter follows: #### image The image. #### threshold Define the threshold value ## BlurImage BlurImage() blurs an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, the radius should be larger than sigma. Use a radius of 0 and BlurImage() selects a suitable radius for you. BlurImage() differs from GaussianBlurImage() in that it uses a separable kernel which is faster but mathematically equivalent to the non-separable kernel. The format of the BlurImage method is:
      Image *BlurImage(const Image *image,const double radius,
        const double sigma,ExceptionInfo *exception)
      Image *BlurImageChannel(const Image *image,const ChannelType channel,
        const double radius,const double sigma,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### channel The channel type. #### radius The radius of the Gaussian, in pixels, not counting the center pixel. #### sigma The standard deviation of the Gaussian, in pixels. #### exception Return any errors or warnings in this structure. ## DespeckleImage DespeckleImage() reduces the speckle noise in an image while perserving the edges of the original image. The format of the DespeckleImage method is:
      Image *DespeckleImage(const Image *image,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### exception Return any errors or warnings in this structure. ## EdgeImage EdgeImage() finds edges in an image. Radius defines the radius of the convolution filter. Use a radius of 0 and EdgeImage() selects a suitable radius for you. The format of the EdgeImage method is:
      Image *EdgeImage(const Image *image,const double radius,
        ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### radius the radius of the pixel neighborhood. #### exception Return any errors or warnings in this structure. ## EmbossImage EmbossImage() returns a grayscale image with a three-dimensional effect. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and Emboss() selects a suitable radius for you. The format of the EmbossImage method is:
      Image *EmbossImage(const Image *image,const double radius,
        const double sigma,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### radius the radius of the pixel neighborhood. #### sigma The standard deviation of the Gaussian, in pixels. #### exception Return any errors or warnings in this structure. ## GaussianBlurImage GaussianBlurImage() blurs an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, the radius should be larger than sigma. Use a radius of 0 and GaussianBlurImage() selects a suitable radius for you The format of the GaussianBlurImage method is:
      Image *GaussianBlurImage(const Image *image,onst double radius,
        const double sigma,ExceptionInfo *exception)
      Image *GaussianBlurImageChannel(const Image *image,
        const ChannelType channel,const double radius,const double sigma,
        ExceptionInfo *exception)
A description of each parameter follows: #### radius the radius of the Gaussian, in pixels, not counting the center pixel. #### channel The channel type. #### sigma the standard deviation of the Gaussian, in pixels. #### exception Return any errors or warnings in this structure. ## MedianFilterImage MedianFilterImage() applies a digital filter that improves the quality of a noisy image. Each pixel is replaced by the median in a set of neighboring pixels as defined by radius. The algorithm was contributed by Mike Edmonds and implements an insertion sort for selecting median color-channel values. For more on this algorithm see "Skip Lists: A probabilistic Alternative to Balanced Trees" by William Pugh in the June 1990 of Communications of the ACM. The format of the MedianFilterImage method is:
      Image *MedianFilterImage(const Image *image,const double radius,
        ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### radius The radius of the pixel neighborhood. #### exception Return any errors or warnings in this structure. ## MotionBlurImage MotionBlurImage() simulates motion blur. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and MotionBlurImage() selects a suitable radius for you. Angle gives the angle of the blurring motion. Andrew Protano contributed this effect. The format of the MotionBlurImage method is:
          Image *MotionBlurImage(const Image *image,const double radius,
      const double sigma,const double angle,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### radius The radius of the Gaussian, in pixels, not counting the center pixel. #### sigma The standard deviation of the Gaussian, in pixels. #### angle Apply the effect along this angle. #### exception Return any errors or warnings in this structure. ## PreviewImage PreviewImage() tiles 9 thumbnails of the specified image with an image processing operation applied with varying parameters. This may be helpful pin-pointing an appropriate parameter for a particular image processing operation. The format of the PreviewImages method is:
      Image *PreviewImages(const Image *image,const PreviewType preview,
        ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### preview The image processing operation. #### exception Return any errors or warnings in this structure. ## RadialBlurImage RadialBlurImage() applies a radial blur to the image. Andrew Protano contributed this effect. The format of the RadialBlurImage method is:
          Image *RadialBlurImage(const Image *image,const double angle,
      ExceptionInfo *exception)
          Image *RadialBlurImageChannel(const Image *image,const ChannelType channel,
      const double angle,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### channel The channel type. #### angle The angle of the radial blur. #### exception Return any errors or warnings in this structure. ## RandomThresholdImage RandomThresholdImage() changes the value of individual pixels based on the intensity of each pixel compared to a random threshold. The result is a low-contrast, two color image. The format of the RandomThresholdImage method is:
      MagickBooleanType RandomThresholdImageChannel(Image *image,
        const char *thresholds,ExceptionInfo *exception)
      MagickBooleanType RandomThresholdImageChannel(Image *image,
        const ChannelType channel,const char *thresholds,
        ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### channel The channel or channels to be thresholded. #### thresholds a geometry string containing low,high thresholds. If the string contains 2x2, 3x3, or 4x4, an ordered dither of order 2, 3, or 4 is performed instead. #### exception Return any errors or warnings in this structure. ## ReduceNoiseImage ReduceNoiseImage() smooths the contours of an image while still preserving edge information. The algorithm works by replacing each pixel with its neighbor closest in value. A neighbor is defined by radius. Use a radius of 0 and ReduceNoise() selects a suitable radius for you. The format of the ReduceNoiseImage method is:
      Image *ReduceNoiseImage(const Image *image,const double radius,
        ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### radius The radius of the pixel neighborhood. #### exception Return any errors or warnings in this structure. ## ShadeImage ShadeImage() shines a distant light on an image to create a three-dimensional effect. You control the positioning of the light with azimuth and elevation; azimuth is measured in degrees off the x axis and elevation is measured in pixels above the Z axis. The format of the ShadeImage method is:
      Image *ShadeImage(const Image *image,const MagickBooleanType gray,
        const double azimuth,const double elevation,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### gray A value other than zero shades the intensity of each pixel. #### azimuth, elevation Define the light source direction. #### exception Return any errors or warnings in this structure. ## SharpenImage SharpenImage() sharpens the image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and SharpenImage() selects a suitable radius for you. Using a separable kernel would be faster, but the negative weights cancel out on the corners of the kernel producing often undesirable ringing inthe filtered result; this can be avoided by using a 2D gaussian shaped image sharpening kernel instead. The format of the SharpenImage method is:
          Image *SharpenImage(const Image *image,const double radius,
      const double sigma,ExceptionInfo *exception)
          Image *SharpenImageChannel(const Image *image,const ChannelType channel,
      const double radius,const double sigma,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### channel The channel type. #### radius The radius of the Gaussian, in pixels, not counting the center pixel. #### sigma The standard deviation of the Laplacian, in pixels. #### exception Return any errors or warnings in this structure. ## SpreadImage SpreadImage() is a special effects method that randomly displaces each pixel in a block defined by the radius parameter. The format of the SpreadImage method is:
      Image *SpreadImage(const Image *image,const double radius,
        ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### radius Choose a random pixel in a neighborhood of this extent. #### exception Return any errors or warnings in this structure. ## UnsharpMaskImage UnsharpMaskImage() sharpens one or more image channels. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and UnsharpMaskImage() selects a suitable radius for you. The format of the UnsharpMaskImage method is:
          Image *UnsharpMaskImage(const Image *image,const double radius,
      const double sigma,const double amount,const double threshold,
      ExceptionInfo *exception)
          Image *UnsharpMaskImageChannel(const Image *image,
      const ChannelType channel,const double radius,const double sigma,
      const double amount,const double threshold,ExceptionInfo *exception)
A description of each parameter follows: #### image The image. #### channel The channel type. #### radius The radius of the Gaussian, in pixels, not counting the center pixel. #### sigma The standard deviation of the Gaussian, in pixels. #### amount The percentage of the difference between the original and the blur image that is added back into the original. #### threshold The threshold in pixels needed to apply the diffence amount. #### exception Return any errors or warnings in this structure. ## WhiteThresholdImage WhiteThresholdImage() is like ThresholdImage() but forces all pixels above the threshold into white while leaving all pixels below the threshold unchanged. The format of the WhiteThresholdImage method is:
      MagickBooleanType WhiteThresholdImage(Image *image,const char *threshold)
A description of each parameter follows: #### image The image. #### threshold Define the threshold value |

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