ImageMagick has a number of methods that allow you to read, manipulate, write, or display an image. These methods are accessible through the various tools or the object-oriented Perl interface, PerlMagick. However, you can also access the methods directly from your program through the Magick Application Programmer Interface. To invoke the methods, write your program in your favorite language while making calls to the Magick image methods and link with libMagick.a, libMagick.so, or Magick.dll depending on your system.

MagickWand -- C API for ImageMagick

The Magick Wand API is a new high level interface to ImageMagick. The Wand API is recommended over the ImageMagick Core API below. A description of the methods in the MagickWand API are found here:

Magick Wand

Pixel Iterator

Pixel Wand

Image Vector Drawing

Here is a example of a program that utilizes the MagickWand API, demo.c, that reads a GIF image, creates a thumbnail, and writes it to disk in the MIFF image format.

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <time.h>
    #include <wand/magick_wand.h>
    
    int main(int argc,char **argv)
    {
    #define ThrowWandException(wand) \
    { \
      char \
        *description; \
     \
      ExceptionType \
        severity; \
     \
      description=MagickGetException(wand,&severity); \
      (void) fprintf(stderr,"%s %s %ld %s\n",GetMagickModule(),description); \
      description=(char *) MagickRelinquishMemory(description); \
      exit(-1); \
    }
    
      MagickBooleanType
        status;
    
      MagickWand
        *magick_wand;
    
      /*
        Read an image.
      */
      magick_wand=NewMagickWand();  
      status=MagickReadImage(magick_wand,"image.gif");
      if (status == MagickFalse)
        ThrowWandException(magick_wand);
      /*
        Turn the images into a thumbnail sequence.
      */
      MagickResetIterator(magick_wand);
      while (MagickNextImage(magick_wand) != MagickFalse)
        MagickResizeImage(magick_wand,106,80,LanczosFilter,1.0);
      /*
        Write the image as MIFF and destroy it.
      */
      status=MagickWriteImages(magick_wand,"image.miff",True);
      if (status == MagickFalse)
        ThrowWandException(magick_wand);
      magick_wand=DestroyMagickWand(magick_wand);
      return(0);
    }

To compile, type:

    cc `Wand-config --cflags --cppflags` demo.c `Wand-config --ldflags --libs`

ImageMagick Core API

The recommended MagickWand API is a wrapper around the lower level ImageMagick Core API. This API is only recommended for Wizards. A description of the methods in the ImageMagick Core API are found here:

Constitute an Image

Composite an Image

Image Methods

Count the Colors in an Image

Dealing with Image Colorspaces

Dealing with Image Profiles

Reduce the Number of Unique Colors in an Image

Segment an Image with Thresholding Fuzzy c-Means

Resize an Image

Transform an Image

Shear or Rotate an Image by an Arbitrary Angle

Enhance an Image

Add an Effect

Add a Special Effect

Decorate an Image

Set Text Attributes

Annotate an Image

Paint on an Image

Draw on an Image

Create an Image Thumbnail

Compare an Image to a Reconstructed Image

Interactively Display and Edit an Image

Interactively Animate an Image Sequence

Get or Set Image Pixels

Working with Image Lists

Working with Cache Views

The Pixel FIFO

Read or Write Binary Large OBjects

Read or List Image formats

Compute a Message Digest for an Image

The Registry

Dealing with Exceptions

Memory Allocation

Monitor or Limit Resource Consumption

Monitor the Progress of an Image Operation

Get the Version and Copyrights

Deprecated Methods

Here is a example of a program that utilizes the ImageMagick Core API, demo.c, that reads a GIF image, creates a thumbnail, and writes it to disk in the MIFF image format.

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <time.h>
    #include <magick/api.h>

    int main(int argc,char **argv)
    {
      ExceptionInfo
        exception;

      Image
        *image,
        *images,
        *resize_image,
        *thumbnails;

      ImageInfo
        *image_info;

      /*
        Initialize the image info structure and read an image.
      */
      InitializeMagick(*argv);
      GetExceptionInfo(&exception);
      image_info=CloneImageInfo((ImageInfo *) NULL);
      (void) strcpy(image_info->filename,"image.gif");
      images=ReadImage(image_info,&exception);
      if (exception.severity != UndefinedException)
        CatchException(&exception);
      if (images == (Image *) NULL)
        exit(1);
      /*
        Turn the images into a thumbnail sequence.
      */
      thumbnails=NewImageList();
      while ((image=RemoveFirstImageFromList(&images)) != (Image *) NULL)
      {
        resize_image=ResizeImage(image,106,80,LanczosFilter,1.0,&exception);
        if (resize_image == (Image *) NULL)
          MagickError(exception.severity,exception.reason,exception.description);
        (void) AppendImageToList(&thumbnails,resize_image);
        DestroyImage(image);
      }
      /*
        Write the image as MIFF and destroy it.
      */
      (void) strcpy(thumbnails->filename,"image.miff");
      WriteImage(image_info,thumbnails);
      thumbnails=DestroyImageList(thumbnails);
      image_info=DestroyImageInfo(image_info);
      DestroyExceptionInfo(&exception);
      DestroyMagick();
      return(0);
    }

Now we need to compile. On Unix, the command would look something like this:

    setenv LD_LIBRARY_PATH /usr/local/lib
    gcc `Magick-config --cflags --cppflags` demo.c `Magick-config --ldflags --libs`

Magick++

Magick++ is the C++ API for ImageMagick. To compile a Magick++ program, use:

    c++ `Magick++-config --cxxflags --cppflags` demo.cpp `Magick++-config --ldflags --libs`