ImageMagick has a number of functions that allow you to read, manipulate, write, or display an image. These functions are accessible through the various tools or the object-oriented Perl interface, PerlMagick. However, you can also access the functions directly from your program through the Magick Application Programmer Interface. To invoke the functions, write your program in your favorite language while making calls to the Magick image functions and link with libMagick.a, libMagick.so, or Magick.dll depending on your system.
The API is divided into a number of categories:
ImageMagick
Methods to Constitute an Image ImageMagick
Image Methods Methods
to Count the Colors in an Image Methods
to Reduce the Number of Unique Colors in an Image Methods
to Segment an Image with Thresholding Fuzzy c-Means Methods
to Resize an Image Methods
to Transform an Image Methods
to Shear or Rotate an Image by an Arbitrary Angle Methods
to Enhance an Image ImageMagick
Image Effects Methods ImageMagick
Image Decoration Methods Image
Text Attributes Methods Methods
to Annotate an Image Methods
to Draw on an Image ImageMagick
Methods to Create Image Thumbnails Methods
to Interactively Display and Edit an Image Methods
to Interactively Animate an Image Sequence Methods
to Get or Set Image Pixels Working
with Image Lists ImageMagick
Cache Views Methods Image
Pixel FIFO Methods
to Read or Write Binary Large OBjects Methods
to Read or List ImageMagick Image formats Methods
to Compute a Message Digest for an Image ImageMagick
Registry Methods ImageMagick
Error Methods ImageMagick
Memory Allocation Methods ImageMagick
Progress Monitor MethodsHere is a sample program to get you started. To find out about all the functions that are available, read the source code. Each function is delineated with a full rows of percent signs with comments describing the parameters required for the function and what it does. For ease in finding a function, they are sorted in alphabetical order. Most of the image functions are found in image.c and effects.c.
Here is a full example of a program, demo.c, that reads a JPEG image, creates a thumbnail, and writes it to disk in the PNG image format.
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/types.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=ShiftImageList(&images)) != (Image *) NULL)
{
resize_image=ResizeImage(image,106,80,MitchellFilter,1.0,&exception);
if (resize_image == (Image *) NULL)
MagickError(exception.severity,exception.reason,exception.description);
(void) PushImageList(&thumbnails,resize_image,&exception);
DestroyImage(image);
DestroyImage(resize_image);
}
/*
Write the image as MIFF and destroy it.
*/
(void) strcpy(thumbnails->filename,"image.miff");
WriteImage(image_info,thumbnails);
DestroyImageList(thumbnails);
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`Another example is smile.c. Compile and excute it to display a smiley face on your X server.
For C++, use:
g++ `Magick++-config --cxxflags --cppflags` demo.cpp `Magick++-config --ldflags --libs`
Image manipulation software that works like magic.