Patent ID: 8054513

Claim:
An image displaying method for displaying image data stored in an image memory to a rectangular display screen provided on a display unit, comprising: a first obtaining step of obtaining a minimum or maximum black dot position in a first scanning direction in said image data stored in said image memory; a second obtaining step of obtaining a minimum or maximum black dot position in a second scanning direction in said image data stored in said image memory; a step of deciding a position of one corner portion of a rectangular effective image data area in said image data stored in said image memory from the minimum or maximum black dot positions in the first scanning direction and the second scanning direction; and a step of controlling said display unit to display said rectangular effective image data area based on the position of said decided one corner portion in said image data stored in said image memory on said display screen of said display unit starting from said one corner portion, wherein the first obtaining step includes a step of, for respective lines extending in the first scanning direction, judging whether a black dot exists in each line and a step of judging whether a position of the existing black dot is one of a minimum and maximum black dot position in the first scanning direction, and obtains the minimum or maximum black dot position in the first scanning direction based on a result of the judgment, and the second obtaining step includes a step of judging whether the position of the existing black dot is one of a minimum and maximum black dot position in the second scanning direction, and obtains the minimum or maximum black dot position in the second scanning direction based on a result of the judgment.