A method of zooming in a graphical user interface of an electronic device ( 1 ) having a touch screen ( 2 ) for receiving input from a user via touch interactions is disclosed. The method comprises detecting a first touch event, which is the result of a first touch interaction at a first coordinate (c 1 ) of said touch screen ( 2 ). The method further comprises detecting a second touch event, which is the result of a second touch interaction, subsequent to the first touch interaction, at a second coordinate (c 2 ) of said touch screen ( 2 ). Furthermore, the method comprises detecting a third touch event, which is the result of a third touch interaction, subsequent to the second touch interaction, at a third coordinate (c 3 a , c 3 b ) of said touch screen ( 2 ). Moreover, the method comprises controlling the touch screen to perform a zoom operation on an image displayed on the graphical user interface. The zoom operation is representative of a first distance L 1 between the first coordinate (c 1 ) and the second coordinate (c 2 ) and a second distance L 2 between the first coordinate (c 1 ) and the third coordinate (c 3 a , c 3 b ). A corresponding electronic device, a corresponding computer program product, and a corresponding computer readable medium are also disclosed.
1. A method of zooming in a graphical user interface of an electronic device having a touch screen for receiving input from a user via touch interactions, wherein the method comprises:
detecting a first touch event, which is the result of a first touch interaction at a first coordinate of said touch screen, wherein the first touch interaction is a first press-down operation at said first coordinate;
detecting a second touch event, which is the result of a second touch interaction, subsequent to the first touch interaction, at a second coordinate of said touch screen, wherein the second touch interaction is a second press-down operation at said second coordinate and the first press-down operation is terminated before the second press-down operation is performed;
detecting a third touch event, which is the result of a third touch interaction, subsequent to the second touch interaction, at a third coordinate of said touch screen, wherein the third touch interaction is a third press-down operation at said third coordinate, and the second press-down operation is terminated before the third press-down operation is performed; and
controlling the touch screen to perform a zoom operation on an image displayed on the graphical user interface, wherein the zoom operation is representative of a first distance L 1 between the first coordinate and the second coordinate and a second distance L 2 between the first coordinate and the third coordinate.
2. The method according to claim 1 , wherein the zoom operation is:
a zoom-in operation if L 1 <L 2 ; or
a zoom-out operation if L 2 <L 1 .
3. The method according to claim 1 , wherein performing the zoom operation comprises zooming with a scaling factor proportional to L 2 /L 1 .
4. The method according to claim 1 , wherein the zoom operation is such that image content displayed at the second coordinate before the zoom operation is displayed at a fourth coordinate after the zoom operation, wherein the fourth coordinate has at least one of an x component and a y component in an orthogonal coordinate system of said touch screen in common with the third coordinate.
5. The method according to claim 1 , wherein the zoom operation is such that image content displayed at the first coordinate before the zoom-operation is displayed at the first coordinate also after the zoom operation.
6. The method according to claim 1 , wherein the zoom operation is such that image content displayed at a center coordinate, located in the middle between the first coordinate and the second coordinate, before the zoom operation is displayed at said center coordinate also after the zoom operation.
7. The method according to claim 1 , wherein the zoom operation is such that an aspect ratio is preserved.
8. The method according to claim 1 , wherein the touch screen is a resistive touch screen.
9. The method according to claim 1 , wherein the zoom operation is:
a zoom-out operation if L 1 <L 2 ; or
a zoom-in operation if L 2 <L 1 .
10. The method according to claim 1 , comprising inhibiting the zoom operation if:
the second touch interaction has not occurred within a first predefined time period starting from the detection of the first touch event; or
the third touch interaction has not occurred within a second predefined time period starting from the detection of the first touch event or from the detection of the second touch event.
11. An electronic device comprising:
a touch screen having a graphical user interface and configured to receive input from a user via touch interactions; and
a control unit connected to the touch screen and configured to:
detect a first touch event, which is the result of a first touch interaction at a first coordinate of said touch screen, wherein the first touch interaction is a first press-down operation at said first coordinate;
detect a second touch event, which is the result of a second touch interaction, subsequent to the first touch interaction, at a second coordinate of said touch screen, wherein the second touch interaction is a second press-down operation at said second coordinate and the first press-down operation is terminated before the second press-down operation is performed;
detect a third touch event, which is the result of a third touch interaction, subsequent to the second touch interaction, at a third coordinate of said touch screen, wherein the third touch interaction is a third press-down operation at said third coordinate, and the second press-down operation is terminated before the third press-down operation is performed; and
control the touch screen to perform a zoom operation on an image displayed on the graphical user interface, wherein the zoom operation is representative of a first distance L 1 between the first coordinate and the second coordinate and a second distance L 2 between the first coordinate and the third coordinate.
12. The electronic device according to claim 11 , wherein the touch screen is a resistive touch screen.
13. The electronic device according to claim 11 , wherein the control unit is configured to inhibit the zoom operation if the second touch interaction has not occurred within a first predefined time period starting from the detection of the first touch event.
14. The electronic device according to claim 11 , wherein the control unit is configured to inhibit the zoom operation if the third touch interaction has not occurred within a second predefined time period starting from the detection of the first touch event or from the detection of the second touch event.
15. A non-transitory computer readable medium having stored thereon a computer program product comprising computer program code, which when executed by a programmable control unit connected to a touch screen of an electronic device causes the programmable control unit to:
detect a first touch event, which is the result of a first touch interaction at a first coordinate of said touch screen, wherein the first touch interaction is a first press-down operation at said first coordinate;
detect a second touch event, which is the result of a second touch interaction, subsequent to the first touch interaction, at a second coordinate of said touch screen, wherein the second touch interaction is a second-press down operation at said second coordinate and the first press-down operation is terminated before the second press-down operation is performed;
detect a third touch event, which is the result of a third touch interaction, subsequent to the second touch interaction, at a third coordinate of said touch screen, wherein the third touch interaction is a third press-down operation at said third coordinate, and the second press-down operation is terminated before the third press-down operation is performed; and
control the touch screen to perform a zoom operation on an image displayed on the graphical user interface, wherein the zoom operation is representative of a first distance L 1 between the first coordinate and the second coordinate and a second distance L 2 between the first coordinate and the third coordinate.
16. The non-transitory computer readable medium according to claim 15 , wherein the zoom operation is:
a zoom-in operation if L 1 <L 2 ; or
a zoom-out operation if L 2 <L 1 .
17. The non-transitory computer readable medium according to claim 15 , wherein performing the zoom operation comprises zooming with a scaling factor proportional to L 2 /L 1 .
18. The non-transitory computer readable medium according to claim 15 , wherein the zoom operation is such that image content displayed at the second coordinate before the zoom operation is displayed at a fourth coordinate after the zoom operation, wherein the fourth coordinate has at least one of an x component and a y component in an orthogonal coordinate system of said touch screen in common with the third coordinate.
19. The non-transitory computer readable medium according to claim 15 , wherein the touch screen is a resistive touch screen.