Rotation of visual content on a display unit

1. A graphics presentation apparatus, comprising:

a display unit configured to present visual content on a screen;

a data output module comprising computer software code stored on a computer readable medium configured to cause one or more processors to:

receive graphics data and a control signal; and

produce, in response to receiving the graphics data and the control signal, the visual content on the screen of said display unit, wherein that the visual content has a particular orientation relative to the display unit; and

an eye-tracking device configured to:

in parallel with the visual content being displayed on the screen of the display unit, register image data representing at least one eye of a user watching the visual content being displayed in the screen of the display unit;

determine, based on said image data, an orientation of the at least one eye of the user relative to the display unit, which includes a rotation of the display unit relative to the at least one eye of the user; and

generate, in response to determining an orientation, the control signal so that the control signal controls one or more processors operating the data output module to produce at least part of the visual content in a rotated orientation with respect to the display unit, wherein such rotated orientation minimizes a misalignment between the rotated orientation of the visual content and the orientation of the at least one eye of the user; and

a rotation detection module comprising computer software code stored on a computer readable medium configured to cause one or more processors to register a content attitude angle representing an angle between the orientation of the visual content and a frame of reference external to the graphics presentation apparatus;

wherein the data output module is further configured to cause one or more processors to produce the visual content in such a manner that said content is presented with an orientation and a format that depends on the content attitude angle,

wherein the rotation detection module being configured to cause one or more processors to generate a trigger signal if an absolute value of the content attitude angle has exceeded an absolute value of a content threshold angle relative to the frame of reference during a threshold time, and

wherein the eye tracking device is further configured to be activated in response to the trigger signal.

2. The graphics presentation apparatus according to claim 1 , wherein the data output module is configured to cause one or more processors to produce the visual content with an orientation relative to the display unit, wherein the orientation may only be varied in predefined angular increments.

3. The graphics presentation apparatus according to claim 1 , wherein the trigger signal is generated exclusively during a predetermined period after that the content threshold angle has been exceeded.

4. The graphics presentation apparatus according to claim 1 , wherein the data output module is further configured to cause one or more processors to:

maintain a selected orientation in agreement with an orientation in which the visual content was presented on the display unit during a preceding period if one or more processors operating the rotation detection module registers a content attitude angle having an absolute value less than or equal to the absolute value of the content threshold angle; and

send the trigger signal to the eye tracking device.

5. The graphics presentation apparatus according to claim 4 , wherein, in response to the trigger signal, the eye tracking device is further configured to generate the control signal so that one or more processors operating the data output module produces at least part of the visual content in a rotated orientation with respect to the display unit so that a misalignment between the rotated orientation and the orientation of the at least one eye of the user is minimized.

6. The graphics presentation apparatus according to claim 1 , wherein the graphics presentation apparatus is included in a portable electronic device and the portable device comprises a main body relative to which the display unit has a permanently fixed orientation.

7. The graphics presentation apparatus according to claim 1 , wherein the eye-tracking device comprises at least one illuminator configured to emit light towards the user of the graphics presentation apparatus.

8. A method of presenting visual content on a display unit of a graphics presentation apparatus, the method comprising:

presenting the visual content with a particular orientation relative to the display unit; and

producing the visual content on the screen of said display unit in response to graphics data and a control signal, wherein producing the visual content further comprises:

in parallel with the visual content being displayed on the screen of the display unit, registering image data representing at least one eye of a user watching the visual content being displayed in the screen of the display unit;

determining, based on said image data, an orientation of the at least one eye of the user relative to the display unit, which includes a rotation of the display unit relative to the at least one eye of the user;

generating, in response to determining an orientation of the at least one eye of the user relative to the display unit, the control signal so that the control signal produces at least part of the visual content in a rotated orientation with respect to the display unit, wherein such rotated orientation minimizes a misalignment between the rotated orientation of the visual content and the orientation of the at least one eye of the user;

registering, via an eye-tracking device in the graphics presentation apparatus, a content attitude angle representing an angle between the orientation of the visual content and a frame of reference external to the graphics presentation apparatus;

producing the visual content in such a manner that said content is presented with an orientation and a format that depends on the content attitude angle;

generating a trigger signal if an absolute value of the content attitude angle has exceeded an absolute value of a content threshold angle relative to the frame of reference during a threshold time; and

activating the eye tracking device in response to the trigger signal.

9. The method according to claim 8 , wherein the visual content is produced with an orientation relative to the display unit, which orientation may only be varied in predefined angular increments.

10. The method according to claim 8 , further comprising generating the trigger signal exclusively during a predetermined period after that the content threshold angle has been exceeded.

11. The method according to claim 8 , further comprising:

maintaining a selected orientation in agreement with an orientation in which the visual content was presented on the display unit during a preceding period if the absolute value of a content attitude angle is less than or equal to an absolute value of the content threshold angle; and

sending a trigger signal to the eye tracking device.

12. The method according to claim 11 , further comprising generating, in response to the trigger signal, the control signal so that at least part of the visual content is produced in a rotated orientation with respect to the display unit so that a misalignment between the rotated orientation and the orientation of the at least one eye of the user is minimized.

13. A computer program product comprising at least one non-transitory computer-readable medium having computer-readable program code portions embodied therein, the computer-readable program code portions executable to control the steps of:

presenting a visual content with a particular orientation relative to the display unit; and

producing the visual content on the screen of said display unit in response to graphics data and a control signal, wherein producing the visual content further comprises:

in parallel with the visual content being displayed on the screen of the display unit, registering image data representing at least one eye of a user watching the visual content being displayed in the screen of the display unit;

determining, based on said image data, an orientation of the at least one eye of the user relative to the display unit, which includes a rotation of the display unit relative to the at least one eye of the user;

generating, in response to determining an orientation of the at least one eye of the user relative to the display unit, the control signal so that the control signal produces at least one part of the visual content in a rotated orientation with respect to the display unit, wherein such rotated orientation minimizes a misalignment between the rotated orientation of the visual content and the orientation of the at least one eye of the user;

registering, via an eye-tracking device in the graphics presentation apparatus, a content attitude angle representing an angle between the orientation of the visual content and a frame of reference external to the graphics presentation apparatus;

producing the visual content in such a manner that said content is presented with an orientation and a format that depends on the content attitude angle;

generating a trigger signal if an absolute value of the content attitude angle has exceeded an absolute value of a content threshold angle relative to the frame of reference during a threshold time; and

activating the eye tracking device in response to the trigger signal.