Displaying a shadow of a stylus or of content on a display device

1. A computing device comprising:

a display device;

one or more processors, and one or more non-transitory computer storage media to store instructions that are executable by the one or more processors to perform operations comprising:

receiving stylus sensor data from one or more sensors in a stylus;

determining, based on the stylus sensor data, a stylus height of a tip of the stylus from the display device;

determining, based on the stylus sensor data, a stylus angle of the stylus relative to the display device;

displaying, on the display device, a virtual shadow of the stylus at a first location based at least in part on:

the stylus height of the tip of the stylus;

the stylus angle; and

a location of a virtual light source;

determining a location of a shadow tip of the virtual shadow corresponding to the tip of the stylus; and

based at least in part on determining that the location of the shadow tip of the virtual shadow is within a predetermined distance from an element in a user interface, indicating a selection of the element;

wherein a light source interface associated with the virtual light source enables specification of:

the location, in three dimensions, of the virtual light source relative to a center of the display device; and

a size of the virtual light source.

2. The computing device of claim 1 , wherein the operations further comprise:

determining a change to the stylus angle of the stylus; and

moving the virtual shadow based at least in part on the change to the stylus angle of the stylus.

3. The computing device of claim 1 , wherein the operations further comprise:

receiving, from the one or more sensors in the stylus, button press data indicating a confirmation of the selection of the element; and

confirming the selection of the element in the user interface.

4. The computing device of claim 1 , wherein:

the stylus comprises one or more buttons; and

button press data is sent from the stylus to the computing device based at least in part on detecting a button selection of a particular button of the one or more buttons.

5. The computing device of claim 1 , wherein the operations further comprise:

determining that the tip of the stylus is not touching a surface of the display device; and

based at least in part on determining that the shadow tip of the virtual shadow is selecting a first element in the user interface:

indicating that the first element is selected; and

receiving, from the stylus, a confirmation that the first element is selected.

6. The computing device of claim 5 , wherein the operations further comprise:

determining that the tip of the stylus is touching the surface of the display device; and

based at least in part on determining that the tip of the stylus is selecting a second element in the user interface confirming that the second element in the user interface is selected.

7. The computing device of claim 1 , wherein the operations further comprise:

receiving second stylus sensor data from the one or more sensors of a stylus;

determining, based at least in part on the second stylus sensor data, a second stylus height of the tip of the stylus from the display device;

determining, based at least in part on the second stylus sensor data, a second stylus angle of the stylus relative to the display device; and

displaying, on the display device, the virtual shadow of the stylus at a second location based at least in part on:

the second stylus height of the tip of the stylus;

the second stylus angle; and

the virtual light source.

8. A method comprising:

receiving, by a computing device, stylus sensor data from one or more sensors in a stylus;

determining, based on the stylus sensor data, a stylus height of a tip of the stylus from a display device that is associated with the computing device;

determining, based on the stylus sensor data, a stylus angle of the stylus relative to the display device; and

displaying, on the display device, a virtual shadow of the stylus at a first location based at least in part on:

the stylus height of the tip of the stylus;

the stylus angle; and

a location of a virtual light source;

determining, by the computing device, that the tip of the stylus is not touching a surface of the display device; and

based at least in part on determining, by the computing device, that a shadow tip of the virtual shadow is selecting a first element in a user interface:

indicating, by the computing device, that the first element is selected; and

receiving, from the stylus, a confirmation that the first element is selected;

wherein a light source interface associated with the virtual light source enables specification of:

the location, in three dimensions, of the virtual light source relative to a center of the display device; and

a size of the virtual light source.

9. The method of claim 8 , further comprising:

determining a location of the shadow tip of the virtual shadow corresponding to the tip of the stylus;

determining that the location of the shadow tip of the virtual shadow is within a predetermined distance from the first element in the user interface; and

indicating a selection of the first element.

10. The method of claim 9 , further comprising:

receiving, from the one or more sensors in the stylus, button press data indicating a confirmation of the selection of the first element; and

confirming the selection of the first element in the user interface.

11. The method of claim 8 , wherein:

the stylus comprises one or more buttons; and

based at least in part on detecting a button selection of a particular button of the one or more buttons, the stylus sends button press data from the stylus to the computing device.

12. The method of claim 8 , further comprising:

determining that the tip of the stylus is touching the surface of the display device;

determining that the tip of the stylus is selecting a second element in the user interface; and

confirming that the second element in the user interface is selected.

13. The method of claim 8 , further comprising:

receiving second stylus sensor data from the one or more sensors in the stylus;

determining, based at least in part on the second stylus sensor data, a second stylus height of the tip of the stylus from the display device;

determining, based at least in part on the second stylus sensor data, a second stylus angle of the stylus relative to the display device; and

displaying, on the display device, the virtual shadow of the stylus at a second location based at least in part on:

the second stylus height of the tip of the stylus;

the second stylus angle; and

the virtual light source.

14. One or more non-transitory computer storage media to store instructions that are executable by one or more processors to perform operations comprising:

receiving stylus sensor data from one or more sensors in a stylus;

determining, based on the stylus sensor data, a stylus height of a tip of the stylus from a display device that is associated with a computing device;

determining, based on the stylus sensor data, a stylus angle of the stylus relative to the display device; and

displaying, on the display device, a virtual shadow of the stylus at a first location based at least in part on:

the stylus height of the tip of the stylus;

the stylus angle; and

a location of a virtual light source;

determining that the tip of the stylus is not touching a surface of the display device;

and based at least in part on determining that a shadow tip of the virtual shadow is selecting a first element in a user interface:

indicating that the first element is selected; and

receiving, from the stylus, a confirmation that the first element is selected;

wherein a light source interface enables specification of:

the location, in three dimensions, of the virtual light source relative to a center of the display device; and

a size of the virtual light source.

15. The one or more non-transitory computer storage media of claim 14 , wherein the operations further comprise:

determining a location of the shadow tip of the virtual shadow corresponding to the tip of the stylus;

determining that the location of the shadow tip of the virtual shadow is within a predetermined distance from the first element in the user interface; and

indicating a selection of the first element.

16. The one or more non-transitory computer storage media of claim 15 , wherein the operations further comprise:

receiving, from the one or more sensors in the stylus, button press data indicating a confirmation of the selection of the first element; and

confirming the selection of the first element in the user interface.

17. The one or more non-transitory computer storage media of claim 14 , wherein:

the stylus comprises one or more buttons; and

button press data is sent from the stylus to the computing device based at least in part on detecting a button selection of a particular button of the one or more buttons.

18. The one or more non-transitory computer storage media of claim 15 , wherein the light source interface enables specification of the location of the virtual light source per application.

19. The one or more non-transitory computer storage media of claim 18 , wherein the operations further comprise:

determining that the tip of the stylus is touching the surface of the display device; and

based at least in part on determining that the tip of the stylus is selecting a second element in the user interface confirming that the second element in the user interface is selected.

20. The one or more non-transitory computer storage media of claim 14 , wherein the operations further comprise:

receiving second stylus sensor data from the one or more sensors of a stylus;

determining, based at least in part on the second stylus sensor data, a second stylus height of the tip of the stylus from the display device;

determining, based at least in part on the second stylus sensor data, a second stylus angle of the stylus relative to the display device; and

displaying, on the display device, the virtual shadow of the stylus at a second location based at least in part on:

the second stylus height of the tip of the stylus;

the second stylus angle; and

the virtual light source.