1.  Field of the Invention
The present invention relates to an image editing technique, and in particular to a technique with which when a still image or a moving image photographed with a digital still camera, a digital video camera, or the like is to be displayed and/or printed, composition of the image may be adjusted while displaying the image. 
2.  Related Background Art
Commonly used is a function with which image data photographed with a digital camera is fetched and is displayed on a display device, an arbitrary area of the image is designated as a trimming area using a pointing device such as a mouse or a remote controller, and the designated trimming area is printed.  FIG.  6 shows an example of a very commonly performed trimming process.  In this drawing, a trimming frame 602 is displayed so that it is superimposed on a pre-trimming image 601, and a user designates his/her desired part of the image 601 by reducing/magnifying, rotating, and moving the trimming frame 602.  In this manner, a post-trimming image 603 having composition desired by the user is finally obtained. 
As another conventional technique of obtaining such a post-trimming image in a different manner, for instance, a technique disclosed in Japanese Patent Application Laid-Open No.  2000-83222 is known in which a television set is connected to a digital image editing apparatus which stores certain image editing software, and image data is displayed so as to be fitted in the display area of a screen of the television set.  Then, the image data is magnified to a size exceeding the display area of the television set and the magnified image data is moved in a direction corresponding to an instruction from the outside and is changed so as to be displayed in the display area.  Japanese Patent Application Laid-Open No.  2000-217024 discloses a technique in which the same method is applied to a digital camera and which is characterized in that the digital camera is equipped with a cross key for performing a magnification operation and a cross key for designating a position. 
As still another conventional technique, a technique disclosed in Japanese Patent Application Laid-Open No.  11-341272 is known with which image data obtained by photographing a face of a person is displayed, predetermined two points of the image data are designated with a designation means, an image magnification/reduction ratio giving a face size and position best-suited to the size of output paper is obtained based on the designated two points, and a resultant image is printed at a given position. 
When a trimming operation is performed in the manner shown in FIG.  6, the user reduces and moves the trimming frame while viewing the whole image, so that it is easy for the user to understand which part of the original image is intended to be clipped.  However, there is a shortcoming that it is difficult for the user to grasp an impression that would be given by post-trimming image composition when the image is actually printed in a print area. 
In contrast to this, with the techniques disclosed in Japanese Patent Application Laid-Open No.  2000-83222 and Japanese Patent Application Laid-Open No.  2000-217024, it is easy to grasp composition of an image to be actually printed.  However, trimming is performed by first magnifying an image and then moving the magnified image to change the position thereof, so that it is required to perform two steps, i.e., a magnification operation and a moving operation. 
Also, the technique disclosed in Japanese Patent Application Laid-Open No.  11-341272 relates to creation of a certificate photograph and is aimed at obtaining the size and position of a face best-suited to the size of paper on which the face is to be printed.  Therefore, the points to be designated by the user are preset at the top of a head and the tip of a jaw, for instance, and therefore the application purpose of this technique differs from general view angle correction of snapshots. 
Further, with each of the conventional techniques described above, a user determines a trimming position and size while viewing the overall composition, so that the appearance of a post-trimming image composition greatly depends on the experience and ability of the user.  Also, such the determination of composition itself is burdensome for some users, so that even if it is possible to obtain photographs beyond recognition through trimming of images, they often print the images without using the trimming function. 
When a main object (a person, in many cases) exists in the center area of an image like in the example shown in FIG.  6, for instance, it is possible to obtain composition with a sense of spreading by increasing a front space in a sight direction of the person.  On the other hand, in the case of an example shown in FIG.  13 in which a trimming frame 1802 is set on a pre-trimming image 1801 and a post-trimming image 1803 is generated, a front space in a sight direction of the person is narrowed and this results in composition giving a restless feeling. 
In a like manner, when a moving subject is photographed like in an example shown in FIG.  15A, it is difficult to take a photograph having desired composition.  In the illustrated example, a go-cart is photographed in the center area of the photograph.  However, by increasing a front space in a traveling direction, it is possible to obtain composition with a sense of motion.  Such an image is a good example of an image with which it is possible to obtain a photograph beyond recognition through trimming.  Even in this case, however, it is difficult for a user, in particular for a beginner, to determine a position where the go-cart (main object in this case) should be positioned through trimming in order to obtain a generally favorable composition.