Image display processing apparatus, image display processing method, and recording medium

1. An image display processing apparatus that allows changing an enlargement ratio of an image displayed on a monitor screen, the image display processing apparatus comprising:

an input-shape detector running on a processor detecting a shape of a trajectory of a line drawn in the monitor screen;

a center-point determiner determining, in a case where the shape of the trajectory of the line is formed of a circular line and an offshoot line extending from the circular line, a center point of a graphic object formed of the circular line;

a ratio calculator calculating a distance ratio between a distance from the center point of the graphic object to the circular line in the monitor screen and a distance from the center point of the graphic object to an end point of the offshoot line in the monitor screen; and

an enlargement-ratio changer changing the enlargement ratio of the image on the basis of the distance ratio.

2. The image display processing apparatus according to claim 1 , wherein the circular line and the offshoot line are drawn unicursally.

3. The image display processing apparatus according to claim 1 , wherein the enlargement-ratio changer defines the center point so that the center point coincides with a center point of the monitor screen.

4. The image display processing apparatus according to claim 1 , wherein, in a case where the circular line is closed, the center-point determiner defines the center point of the graphic object formed of the circular line at an intersection of a line connecting two points of the graphic object that are most separated in a vertical direction of the monitor screen and a line connecting two points of the graphic object that are most separated in a horizontal direction of the monitor screen.

5. The image display processing apparatus according to claim 1 , wherein, in a case where the circular line is not closed, the center-point determiner defines the center point of the graphic object on the basis of a start point of drawing of the circular line and an end point of drawing of the offshoot line.

6. An image display processing method for changing an enlargement ratio of an image displayed on a monitor screen, the image display processing method comprising:

detecting a shape of a trajectory of a line drawn on the monitor screen;

determining a center point of a graphic object formed of a circular line in a case where the shape of the trajectory of the line is formed of the circular line and an offshoot line extending from the circular line;

calculating a distance ratio between a distance from the center point of the graphic object to the circular line on the monitor screen and a distance from the center point of the graphic object to an end point of the offshoot line on the monitor screen; and

changing the enlargement ratio of the image on the basis of the distance ratio.

7. A non-transitory computer-readable recording medium having recorded thereon a program for causing a computer to function so that an enlargement ratio of an image displayed on a monitor screen is changed, the program comprising:

an input-shape detector detecting a shape of a trajectory of a line drawn in the monitor screen;

a center-point determiner determining, in a case where the shape of the trajectory of the line is formed of a circular line and an offshoot line extending from the circular line, a center point of a graphic object formed of the circular line;

a ratio calculator calculating a distance ratio between a distance from the center point of the graphic object to the circular line in the monitor screen and a distance from the center point of the graphic object to an end point of the offshoot line in the monitor screen; and

an enlargement-ratio changer changing the enlargement ratio of the image on the basis of the distance ratio.

8. The image display processing apparatus according to claim 1 , wherein the monitor screen is a touch panel.

9. The image display processing apparatus according to claim 1 , wherein, when the circular line is closed, the distance from the center point of the graphic object to the circular line is calculated from the center point to a closed point and, when the circular line is not closed, the distance from the center point of the graphic object to the circular line is calculated from the center point to an start point of the offshoot line.

10. The image display processing apparatus according to claim 1 , wherein, when the end point of the offshoot line is located within the circular line, the image is set to be reduced and, when the end point of the offshoot line is not located within the circular line, the image is set to be enlarged.

11. The image display processing method according to claim 6 , wherein the monitor screen is a touch panel.

12. The image display processing method according to claim 6 , further comprising:

calculating the distance from the center point of the graphic object to the circular line from the center point to a closed point when the circular line is closed; and

calculating the distance from the center point of the graphic object to the circular line from the center point to a start point of the offshoot line when the circular line is not closed.

13. The image display processing method according to claim 6 , further comprising:

setting a reduction of the image when the end point of the offshoot line is located within the circular line; and

setting an enlargement of the image when the end point of the offshoot line is not located within the circular line.

14. The non-transitory computer-readable recording medium according to claim 7 , wherein the monitor screen is a touch panel.

15. The non-transitory computer-readable recording medium according to claim 7 , wherein, when the circular line is closed, the distance from the center point of the graphic object to the circular line is calculated from the center point to a closed point and, when the circular line is not closed, the distance from the center point of the graphic object to the circular line is calculated from the center point to an start point of the offshoot line.

16. The non-transitory computer-readable recording medium according to claim 7 , wherein, when the end point of the offshoot line is located within the circular line, the image is set to be reduced and, when the end point of the offshoot line is not located within the circular line, the image is set to be enlarged.