Unitary shadows

Patent metadata

Field	Value
Publication number	US-10013776-B2
Application number	US-201715587869-A
Country	US
Kind code	B2
Filing date	May 5, 2017
Priority date	May 30, 2014
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

Methods, devices, systems, and computer readable media to improve the operation of window-based operating systems are disclosed. In general, techniques are disclosed for rendering areas on a display in which two or more shadows overlap. More particularly, two or more shadow regions (based on the arrangement of overlapping windows/shadows) are identified and merged in a top-down process so that no region's shadow is painted or rendered more than once. A shadowbuffer (analogous to a system's framebuffer) may be used to retain windows' alpha information separately from the corresponding windows' shadow intensity information.

First claim

What is claimed is:

1. A method for rendering shadows for display, comprising:
identifying a plurality of overlapping windows arranged in an above to below order, each window below a top window having a shadow-above region, a window's shadow-above region comprising that region of the window onto which an overlapping immediately above window would cast a shadow, each shadow-above region having one or more shadow intensity values;
determining a single perimeter of the plurality of overlapping windows, the single perimeter comprising one or more edges of the plurality of overlapping windows;
generating a set union of the plurality of overlapping windows whose one or more edges are part of the single perimeter, the set union corresponding to a surface having edges that comprise the single perimeter;
generating a unitary shadow region corresponding to the set union;
determining a shadow intensity value for the unitary shadow region; and
rendering the unitary shadow region's shadow intensity value into a first memory.

2. The method of claim 1 , wherein the unitary shadow region's shadow intensity value is rendered no more than once.

3. The method of claim 1 , wherein the unitary shadow region comprises a region of a surface onto which the set union would cast a shadow.

4. The method of claim 1 , wherein generating the set union comprises rendering each of the plurality of windows whose one or more edges form the single perimeter into a second memory to form the set union.

5. The method of claim 1 , wherein determining a shadow intensity value for the unitary shadow region comprises:
identifying alpha values for each of the windows used for forming the set union; and
blurring the alpha values of the windows used for forming the set union into the unitary shadow region in accordance with a blur parameter.

6. The method of claim 1 , wherein the first memory comprises one or more of a shadowbuffer memory and a framebuffer memory.

7. The method of claim 6 , further comprising rendering the first memory into one or more of the shadowbuffer memory and the framebuffer memory.

8. A non-transitory computer-readable storage medium storing instructions, the instructions comprising instructions for rendering shadows for display that are executable by one or more processors to:
identify a plurality of overlapping windows arranged in an above to below order, each window below a top window having a shadow-above region, a window's shadow-above region comprising that region of the window onto which an overlapping immediately above window would cast a shadow, each shadow-above region having one or more shadow intensity values;
determine a single perimeter of the plurality of overlapping windows, the single perimeter comprising one or more edges of the plurality of overlapping windows;
generate a set union of the plurality of overlapping windows whose one or more edges are part of the single perimeter, the set union corresponding to a surface having edges that comprise the single perimeter;
generate a unitary shadow region corresponding to the set union;
determine a shadow intensity value for the unitary shadow region; and
render the unitary shadow region's shadow intensity value into a first memory.

9. The non-transitory computer-readable storage medium of claim 8 , wherein the unitary shadow region's shadow intensity value is rendered no more than once.

10. The non-transitory computer-readable storage medium of claim 8 , wherein the unitary shadow region comprises a region of a surface onto which the set union would cast a shadow.

11. The non-transitory computer-readable storage medium of claim 8 , wherein the instructions executable by the one or more processors to generate the set union comprise instructions executable by the one or more processors to render each of the plurality of windows whose one or more edges form the single perimeter into a second memory to form the set union.

12. The non-transitory computer-readable storage medium of claim 8 , wherein the instructions executable by the one or more processors to determine a shadow intensity value for the unitary shadow region comprise instructions executable by the one or more processors to:
identify alpha values for each of the windows used for forming the set union; and
blur the alpha values of the windows used for forming the set union into the unitary shadow region in accordance with a blur parameter.

13. The non-transitory computer-readable storage medium of claim 8 , wherein the first memory comprises one or more of a shadowbuffer memory and a framebuffer memory.

14. The non-transitory computer-readable storage medium of claim 13 , wherein the instructions comprise additional instructions executable by the one or more processors to render the first memory into one or more of the shadowbuffer memory and the framebuffer memory.

15. A system configured for rendering shadows for display, the system comprising:
one or more processors; and
a memory coupled to the one or more processors, on which are stored instructions, comprising instructions that when executed by the one or more processors cause at least some of the one or more processors to:
identify a plurality of overlapping windows arranged in an above to below order, each window below a top window having a shadow-above region, a window's shadow-above region comprising that region of the window onto which an overlapping immediately above window would cast a shadow, each shadow-above region having one or more shadow intensity values;
determine a single perimeter of the plurality of overlapping windows, the single perimeter comprising one or more edges of the plurality of overlapping windows;
generate a set union of the plurality of overlapping windows whose one or more edges are part of the single perimeter, the set union corresponding to a surface having edges that comprise the single perimeter;
generate a unitary shadow region corresponding to the set union;
determine a shadow intensity value for the unitary shadow region; and
render the unitary shadow region's shadow intensity value into a first memory.

16. The system of claim 15 , wherein the unitary shadow region's shadow intensity value is rendered no more than once.

17. The system of claim 15 , wherein the unitary shadow region comprises a region of a surface onto which the set union would cast a shadow.

18. The system of claim 15 , wherein the instructions that, when executed by the one or more processors, cause at least some of the one or more processors to generate the set union comprise instructions that, when executed by the one or more processors, cause at least some of the one or more processors to render each of the plurality of windows whose one or more edges form the single perimeter into a second memory to form the set union.

19. The system of claim 15 , wherein the instructions that, when executed by the one or more processor, cause at least some of the one or more processors to determine a shadow intensity value for the unitary shadow region comprise instructions that, when executed by the one or more processors, cause the at least some of the one or more processors to:
identify alpha values for each of the windows used for forming the set union; and
blur the alpha values of the windows used for forming the set union into the unitary shadow region in accordance with a blur parameter.

20. The system of claim 15 , wherein the first memory comprises one or more of a shadowbuffer memory and a framebuffer memory.

Assignees

• Apple Inc

Inventors

• Shearer James J
• Wright Christopher P
• Armstrong Ryan N
• Jones Chad E

Classifications

• G06T11/10 Primary

  Texturing; Colouring; Generation of textures or colours (retouching, inpainting or scratch removal G06T5/77) · CPC title

• G09G5/397

  Arrangements specially adapted for transferring the contents of two or more bit-mapped memories to the screen simultaneously, e.g. for mixing or overlay (G09G5/02 takes precedence) · CPC title

• G09G5/14

  Display of multiple viewports · CPC title

• G06T11/00 Primary

  Two-dimensional [2D] image generation · CPC title

• G06F3/14

  Digital output to display device {; Cooperation and interconnection of the display device with other functional units} · CPC title