Method and system for generating and selectively outputting two types of ink vector data
A computer-implemented method is provided to selectively output two types of vector data representative of user-input strokes. Type one stroke objects are generated in a device including a position input sensor, on which a user operates a pointer to generate a type one stroke object representative of a stroke. A stroke starts at a pen-down time at which the pointer is placed on the position input sensor and ends at a pen-up time at which the pointer is removed from the position input sensor. Real-time rendering of a type one stroke object is started after the pen-down time of a stroke without waiting for the pen-up time. After completion of a type one stroke object through its pen-up time, the type one stroke object is converted to a type two stroke object, which is a set of curves defining a boundary of the stroke, and can be rendered.
1. A computer-implemented method of selectively outputting two types of vector data representative of user-input strokes, comprising:
generating type one stroke objects in a device including a position input sensor, wherein the type one stroke objects represent strokes formed by a user operating a pointer relative to the position input sensor, and each type one stroke object represents a stroke starting at a pen-down time at which the pointer is detectably placed relative to the position input sensor and ending at a pen-up time at which the pointer is removed from the position input sensor;
starting real-time rendering of a type one stroke object after the pen-down time of a stroke represented by said type one stroke object without waiting for completion of the stroke at the pen-up time;
after completion of a type one stroke object representative of a stroke from its pen-down time to its pen-up time, converting the type one stroke object to a type two stroke object, wherein the type two stroke object is a set of curves defining a boundary of the stroke; and
rendering the type two stroke object, instead of the corresponding type one stroke object, after the pen-up time of the stroke represented by said type one stroke object.
2. The computer-implemented method of claim 1 , wherein the step of generating type one stroke objects includes:
sequentially receiving pen event data detected by the position input sensor;
sequentially generating point objects based on coordinate values included in the received pen event data, wherein the point objects serve as control points for interpolating curve segments according to a defined curve interpolation algorithm to form a type one stroke object and wherein each point object is associated with width information; and
generating a type one stroke object as a collection of the point objects that define a stroke represented by the type one stroke object.
3. The computer-implemented method of claim 2 , wherein the step of generating type one stroke objects further includes:
sequentially obtaining at least one of color values and transparency values for the point objects; and
generating the type one stroke object as a collection of the point objects each associated with a color value and/or a transparency value.
4. The computer-implemented method of claim 2 , wherein the width information is indicative of a radius of a point object for use in defining a width of a stroke represented by the type one stroke object.
5. The computer-implemented method of claim 2 , wherein the defined curve interpolation algorithm is a Catmull-Rom Curve algorithm.
6. The computer-implemented method of claim 2 , wherein the step of starting real-time output of the type one stroke object includes:
segmenting each curve segment of the type one stroke object into multiple division points i;
applying the width information to each of the division points i to determine two outline curves forming the type one stroke object; and
rendering the type one stroke object by rasterizing between the two outline curves.
7. The computer-implemented method of claim 6 , wherein the division points i are in the same sequential order as a sequential order in which the stroke represented by the type one stroke object is user-inputted from the pen-down time to the pen-up time.
8. The computer-implemented method of claim 6 , wherein the step of segmenting the curve segments into multiple division points i includes:
as the division points, in addition to the control points, using filler points added to achieve a desired level of pixel resolution when the type one stroke object is rendered.
9. The computer-implemented method of claim 6 , wherein the step of starting real-time output of the type one stroke object further includes:
after the step of segmenting the curve segments into multiple division points i, applying smoothing to rearrange the division points i.
10. The computer-implemented method of claim 6 , wherein the step of rendering the type one stroke object includes:
defining a plurality of polygons between the two outline curves; and
rasterizing the polygons.
11. The computer-implemented method of claim 1 , wherein the step of converting the type one stroke object to the type two stroke object includes:
using a clipping algorithm, simplifying a shape of the type one stroke object into one or more simplified shapes that do not include self-intersection, wherein each simplified shape is defined by boundary points and the curves formed between the boundary points; and
outputting the one or more simplified shapes as the type two stroke object comprised of the set of curves defining the boundary of the stroke.
12. The computer-implemented method of claim 11 , wherein the clipping algorithm is a Vatti clipping algorithm or a Greiner-Hormann algorithm.
13. The computer-implemented method of claim 11 , wherein the boundary points are not in the same sequential order as a sequential order in which the stroke represented by the type two stroke object is user-inputted from the pen-down time to the pen-up time.
14. The computer-implemented method of claim 11 , wherein the step of simplifying the shape of the type one stroke object includes:
placing the boundary points at corners of the one or more simplified shapes.
15. The computer-implemented method of claim 11 , wherein the step of simplifying the shape of the type one stroke object includes:
applying smoothing to rearrange the boundary points.
16. The computer-implemented method of claim 11 , wherein the step of converting the type one stroke object to the type two stroke object further includes:
applying curve fitting to the type two stroke object.
17. The computer-implemented method of claim 11 , wherein the step of outputting the one or more simplified shapes as the type two stroke object includes:
rendering the type two stroke object on a display.
18. The computer-implemented method of claim 11 , wherein the curves formed between the boundary points are Bezier curves.
19. The computer-implemented method of claim 1 , further comprising:
storing the type one stroke objects;
storing the type two stroke objects; and
selectively outputting the type one stroke objects or the type two stroke objects depending on an output request.
20. The computer-implemented method of claim 19 , further comprising:
outputting the type one stroke objects in response to an output request from applications including a real-time drawing application and a text recognition application; and
outputting the type two stroke objects in response to an output request from applications including a bulk drawing application and a portable document format (PDF) application.
21. The computer-implemented method of claim 11 , further comprising:
adjusting a color value of each boundary point based on the color value and a transparency value of the boundary point; and
outputting the boundary points associated with adjusted color values in response to an output request from a portable document format (PDF) application.
22. A system of selectively outputting two types of vector data representative of user-input strokes, comprising:
a memory device;
a processor coupled to the memory device, wherein the processor is configured to perform:
receiving pen event data from a position input sensor, the pen event data being representative of strokes formed by a user operating a pointer relative to the position input sensor, each stroke starting at a pen-down time at which the pointer is detectably placed relative to the position input sensor and ending at a pen-up time at which the pointer is removed from the position input sensor;
generating type one stroke objects based on the received pen event data, wherein the type one stroke objects represent the strokes, respectively;
starting real-time rendering of a type one stroke object after the pen-down time of a stroke represented by said type one stroke object without waiting for completion of the stroke at the pen-up time;
after completion of a type one stroke object representative of a stroke from its pen-down time to its pen-up time, converting the type one stroke object to a type two stroke object, wherein the type two stroke object includes a set of curves defining a boundary of the stroke; and
rendering the type two stroke object, instead of the corresponding type one stroke object, after the pen-up time of the stroke represented by said type one stroke object.
23. The system of claim 22 , wherein the processor further performs:
storing the type one stroke objects in the memory device;
storing the type two stroke objects in the memory device; and
selectively outputting the type one stroke objects or the type two stroke objects depending on an output request.
24. A computer-implemented method of selectively outputting two types of vector data representative of user-input strokes, comprising:
generating type one stroke objects in a device including a position input sensor, wherein the type one stroke objects represent strokes formed by a user operating a pointer relative to the position input sensor, and each type one stroke object represents a stroke starting at a pen-down time at which the pointer is detectably placed relative to the position input sensor and ending at a pen-up time at which the pointer is removed from the position input sensor;
starting real-time rendering of a type one stroke object after the pen-down time of a stroke represented by said type one stroke object without waiting for completion of the stroke at the pen-up time;
after completion of a type one stroke object representative of a stroke from its pen-down time to its pen-up time, converting the type one stroke object to a type two stroke object, wherein the type two stroke object is a set of boundary points that represent a boundary of the entire stroke; and
rendering the type two stroke object, instead of the corresponding type one stroke object, after the pen-up time of the stroke represented by said type one stroke object.
25. The computer-implemented method of claim 24 , further comprising:
storing the type one stroke objects;
storing the type two stroke objects; and
selectively outputting the type one stroke objects or the type two stroke objects depending on an output request.