1. Field of the Invention
The present invention relates to an image forming apparatus which displays a preview upon outputting images of a plurality of pages, a control method thereof, and a storage medium.
2. Description of the Related Art
Some image forming apparatuses such as digital multifunction peripherals (MFPs) include a function of displaying a thumbnail of a generated page image as an image formation target on a liquid crystal panel of an operation unit as a preview so as to prevent a wasteful output due to a setting error. In an image forming apparatus which includes post-processing functions such as stapling, folding, and punch hole functions, a method of processing a page image generated based on input print data, and displaying a finish preview which allows the user to recognize a final output form applied with post-processes has been proposed.
For example, Japanese Patent Laid-Open No. 2003-87560 has proposed an image forming apparatus which displays pages in a two-page spread state except for the first and last pages, when post-processing is stapling processing upon displaying a finish image indicating a state applied with the post-processing by processing image data obtained by converting input image data to reduced-scale data. Also, Japanese Patent Laid-Open No. 2010-35030 has proposed a preview method which prevents user's confusion by displaying finish information outside a print sheet area of a preview image so as to improve visibility, and deciding a direction of the preview image in accordance with the convey direction of a sheet.
However, the above related arts suffer the following problems. For example, in an image forming apparatus which includes a preview function in consideration of post-processing like in the related art, the user can confirm if post-processing settings are as the user intended, but a configuration which allows the user to recognize a relationship between pages before and after a preview target page is not provided. That is, in a preview of the related art, a preview image is displayed by reflecting a finish result for each page image of a sheet, or only the method of displaying sheets in a two-page spread state upon designation of stapling as a case in which pages are displayed to allow easy understanding of an anteroposterior relationship has been proposed. For this reason, in an image forming apparatus including various finishing functions and output instruction forms, a preview method which allows the user to easily recognize a relevance according to output forms between a plurality of pages such as the anteroposterior relationship or positional relationship of a plurality of pages to be output is demanded.