contrib/mul/vil3d/vil3d_property.h

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#ifndef vil3d_property_h_
#define vil3d_property_h_
//:
// \file
//
// There is no class or function called vil3d_property.
//
// The image class vil3d_image_resource has the method :
// \code
//   bool get_property(char const *label, void *property_value = 0) const;
// \endcode
// which allow format extensions to be added without cluttering the
// interface to vil_image_resource. The idea is that properties can be
// identified by a "label" (some name or other textual description)
// through which clients can obtain or manipulate extra properties.
//
// A false return value means that the underlying image does not
// understand the given property or that the given data was invalid.
// A true return value means it does understand the property and has
// used the supplied data according to the relevant protocol.
// Passing a null pointer as the second argument can be useful for
// protocols for manipulating boolean properties (i.e. when there is
// no data to be passed).
//
// To make this work in practice, it is necessary to avoid name clashes
// and to make sure everyone agrees on the meaning of the property data.
// That is the purpose of this file. The set of labels is a namespace in
// the general sense of the word. We only have one namespace, so try
// not to clutter it. All property labels described in this file should
// begin with "vil3d_property_" and that chunk of the namespace is reserved.
//
// An example
// \code
// float vs[3];
// vcl_cout << "Volume of image is ";
// if (image.get_property(vil3d_property_voxel_size, &voxel_size))
//   vcl_cout << vs[0]*vs[1]*vs[2]*im.ni()*im.nj()*im.nk() << vcl_endl;
// else
//   vcl_cout << "unknown\n";
// \endcode
//
// \author Ian Scott - Copied from fsm's design in vil.


//: Indicate whether this is an in-memory image or an on-disk image
//  By default an image is not in-memory, and since this is a boolean property
//  the return value of get_property(), which is "false" by default, will be
//  correct.  Only in-memory images must implement this property, and return
//  "true".
#define vil3d_property_memory "memory"

//: Indicate that you can't call put_view on this image.
//  By default an image is not read-only, and since this is a boolean property
//  the return value of get_property(), which is "false" by default, will be
//  correct.  Only images which do not allow put_view must implement this
//  property, and return "true".
#define vil3d_property_read_only "read-only"


//: voxel size in metres.
// Type is float[3].
// If this property exists you may get and set the values
// through the size_i(), and set_pixel_size() members of vil3d_image_resource.
#define vil3d_property_voxel_size "voxel_size"

//: Original image origin in pixels.
// Measured from vil3d origin in standard direction.
// Type is float[3].
#define vil3d_property_origin_offset "origin_offset"

#endif // vil3d_property_h_