Image drawing apparatus, image drawing method, and storage medium
AssigneeCanon Kabushiki Kaisha
InventorHiroyuki Akai
Life of this patent
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Abstract
A division number that defines the number of divided straight lines representing a circular graphic pattern is registered beforehand in a division number table in relation to a radius r of the circular graphic pattern. Further, data usable to calculate X-coordinate and Y-coordinate values of endpoints of respective divided straight lines are registered beforehand in an endpoint table in relation to a straight line division number N. Accordingly, if a graphic pattern to be drawn is a circular graphic pattern, it is unnecessary to approximate an outline (curve) with Bezier curves and each division point (endpoint) of divided straight lines can be directly and quickly obtained using the trigonometric function.
Claims18
An apparatus which divides vector data representing a circle into a plurality of straight lines and rasterizes a part or a whole of the circle based on the divided plurality of straight lines, the apparatus comprising:
- a first calculation unit configured to calculate a division number N of the circle referring to a first storage area in which information relating to the division number is registered in advance with respect to information relating to a size of the circle;
- a second calculation unit configured to calculate endpoint positions of the plurality of straight lines by using the calculated division number referring to a second storage area in which information relating to the endpoint positions is registered in advance with respect to the information relating to the division number;
- and
- a drawing unit configured to rasterize the circle by using a third calculation unit configured to calculate a rasterization pattern representing a drawing content of a finite number of straight lines having endpoints at the calculated positions referring to a third storage area in which information relating to the rasterization pattern representing the straight lines is registered in advance with respect to information relating to a relative positional relationship between both endpoints of the straight lines.
A method for drawing an image in which vector data representing a circle is divided into a plurality of straight lines and a part or a whole of the circle is rasterized based on the divided plurality of straight lines, the method comprising:
- calculating a division number N of the circle referring to a first storage area in which information relating to the division number is registered in advance with respect to information relating to a size of the circle;
- calculating endpoint positions of the plurality of straight lines by using the calculated division number referring to a second storage area in which information relating to the endpoint positions is registered in advance with respect to the information relating to the division number;
- and
- rasterizing the circle by calculating a rasterization pattern representing a drawing content of a finite number of straight lines having endpoints at the calculated positions referring to a third storage area in which information relating to the rasterization pattern representing the straight lines is registered in advance with respect to information relating to a relative positional relationship between both endpoints of the straight lines.
A computer-readable storage medium storing a program causing a computer to divide vector data representing a circle into a plurality of straight lines and rasterize a part or a whole of the circle based on the divided plurality of straight lines, the program comprising:
- a computer-executable instruction for calculating a division number N of the circle referring to a first storage area in which information relating to the division number is registered in advance with respect to information relating to a size of the circle;
- a computer-executable instruction for calculating endpoint positions of the plurality of straight lines by using the calculated division number referring to a second storage area in which information relating to the endpoint positions is registered in advance with respect to the information relating to the division number;
- and
- a computer-executable instruction for rasterizing the circle by calculating a rasterization pattern representing a drawing content of a finite number of straight lines having endpoints at the calculated positions referring to a third storage area in which information relating to the rasterization pattern representing the straight lines is registered in advance with respect to information relating to a relative positional relationship between both endpoints of the straight lines.
Dependencies are inferred from the claim text.