Apparatus and methods for stenciling an image
View Patent ↗The invention provides methods of protecting selected regions of an image from subsequent modification during the operation of a graphics application. The methods allow a user to select a region of an image to protect, and to assign a level of protection to the selected region. Subsequent brush strokes in the region are then attenuated according to the assigned level of protection and blended into the image without artifacts caused by overlapping strokes. The invention also provides a method of blending individual strokes into a texture without segmentation artifacts.
1. A method of blending erase strokes into an image while at least partially protecting a selected region of an image from subsequent editing, the method comprising the steps of:
(a) creating a first texture comprising a plurality of pixels each with an assigned scalar value indicating a level of protection for a corresponding pixel of a protected image;
(b) following a first user signal, directing graphical input representing at least one erase stroke performed by the user into a second texture, wherein the protected image is at least initially unedited by the graphical input;
(c) modifying a value of the at least one erase stroke using the first texture;
(d) modifying a value of at least one pixel of the protected image using the modified erase stroke;
(e) following a second user signal subsequent to the first user signal, blending at least one pixel of the second texture into the protected image; and
(f) displaying an image based on the result of step (e).
2. The method of claim 1 , further comprising the step of:
(i) modifying a value of at least one pixel of the second texture using the first texture.
3. The method of claim 1 , further comprising the steps of:
(i) copying at least one pixel of the protected image into a display image; and
(ii) blending at least one pixel of the second texture into the display image.
4. The method of claim 1 , wherein the graphical input represents a plurality of erase strokes performed by the user.
5. The method of claim 4 , wherein the plurality of erase strokes comprises at least one overlapping portion.
6. The method of claim 5 , wherein the at least one overlapping portion corresponds to an area overlapped by a plurality of brush strokes.
7. The method of claim 1 , further comprising the step of generating the graphical input of step (b), wherein the graphical input corresponds to a movement of a user.
8. The method of claim 1 , wherein the first user signal is a button click.
9. The method of claim 1 , wherein the first texture represents at least one user-selected region of the image.
10. The method of claim 1 , wherein the erase stroke is represented by a scratch texture.
11. The method of claim 10 , wherein step (c) comprises attenuating a value of a pixel n the protected image subject to a minimum RGBα alpha value, where the minimum alpha value is determined using the first texture.