Information processing apparatus and image forming apparatus capable of display control of their display device

An information processing apparatus comprising:

• an operation device that accepts an input of a user's instruction;
• a display device in a rectangular shape having longer sides and shorter sides;
• a rotation mechanism capable of rotating the display device between a landscape orientation with the longer sides being top and bottom and a portrait orientation with the shorter sides being top and bottom;
• a detection sensor that detects whether the display device is in the landscape orientation or the portrait orientation;
• and
• a control device that includes a processor and functions, through the processor executing a control program, as a controller that allows the display device to display an operation screen including a preview display area where a preview of an image represented by image data is to be displayed and, during detection of the landscape orientation of the display device by the detection sensor, allows the preview to be displayed in the preview display area to make top and bottom edges of the preview parallel to the longer sides of the display device,
• wherein when the operation device accepts an instruction to enlarge the preview while the landscape orientation of the display device is detected by the detection sensor and the operation screen is displayed on the display device, the controller enlarges the preview display area to change the preview display area to a first enlarged size and allows the preview to be displayed in a size enlarged to fit the preview display area enlarged to the first enlarged size, and
• when orientation of the display device being detected by the detection sensor changes from the landscape orientation to the portrait orientation while the preview is displayed on the preview display area enlarged to the first enlarged size, the controller further enlarges the preview display area to change the preview display area to a second enlarged size and allows the preview to be displayed in a size enlarged to fit the preview display area enlarged to the second enlarged size and displayed to make the top and bottom edges of the preview parallel to the shorter sides of the display device.