User interface device and image displaying method

A user interface device comprising:

• a preview generating unit that generates a preview image of input information and rotation-process check information for checking whether to perform a rotation process on the preview image;
• an operation displaying unit that displays thereon (a) the preview image, (b) the rotation-process check information, and (c) setting information for setting details of the rotation process;
• a receiving unit that receives a request for rotating displayed preview image based on the rotation-process check information and the setting information;
• a post-processing unit that receives a setting of post-processing to be processed on an image;
• an orientation determining unit that determines an image type of the preview image as any one of a character image type, a photographic image type and a chart image type, and determines a vertical orientation of the preview image based on the determined image type of the preview image;
• and
• a processing unit that rotates the displayed preview image in response to (i) the determined vertical orientation of the preview image and (ii) the received request for rotating the displayed preview image and received setting regarding post-processing, and displays the rotated preview image on the operation displaying unit,
• wherein in a case that duplex printing is specified for the input information including a front page and a back page, the processing unit causes the back page to be processed via a horizontally-reversed mirror-image conversion process to generate a preview back page image, and causes a preview front page image and the preview back page image to be superposed, and causes the superposed preview images to be displayed by the operation displaying unit.