Method and apparatus for rendering characters

Claim 2

A method for rendering a character as recited in claim 1 wherein the rendering step includes retrieving a character program, font values and font family values corresponding to the character to be rendered; and wherein the character program is executed to determine the locations of stem edges of the character with respect to the coarse grid.

Claim 3

A method for rendering characters as recited in claim 1 wherein the step of aligning the stem is further dependent upon either the proximity of the stem to the coarse grid, ghost stem information, or both, where a ghost stem is a stem with only one edge to control.

Claim 4

A method for rendering characters as recited in claim 3 wherein if a stem is a ghost stem, the step of aligning the stem with the coarse grid comprises the steps of: for a left/bottom ghost stem, aligning the left/bottom of such stem to the left/bottom coarse grid edge; and for a right/top ghost stem, aligning the right/top of such stem to a right/bottom coarse grid edge.

Claim 5

A method for rendering a character as recited in claim 3 wherein, if a stem is not a ghost stem, the step of aligning a stem with the coarse grid comprises the steps of: determining a proximity of the stem to the coarse grid to be either a proximity to the left/bottom, or a proximity to the right/top of the coarse grid; for a left/bottom proximity, aligning the left/bottom of such stem to a left/bottom coarse grid edge; and for a right/top proximity, aligning the right/top of such stem to a right/bottom coarse grid edge.

Claim 6

A character renderer for rendering a character on an output device having a target resolution, the character being rendered at a resolution of a grid having a higher resolution than the target resolution, the renderer displaying a predetermined number of greyscales and the character having a stem with a predetermined width, the renderer comprising: a coarse grid generator for generating a coarse grid having a matrix of cells, the coarse grid having about the same resolution as the target resolution, each cell of the coarse grid corresponding to a device pixel of the output device, the high-resolution grid being contained within respective cells of the coarse grid and being aligned with the coarse grid such that a cell of the coarse grid includes an integral number of cells of the high-resolution grid; a character aligner that aligns the character stem from an initial bitmap of the character with the coarse grid to create a high-resolution bitmap, the method of alignment depending upon whether the character is to be rendered with a hard edge or soft edge; where the character is to be rendered with a hard edge, the aligner rounds the stem width to the closest multiple of the coarse grid and centers the stem on the coarse grid; and where the character is to be rendered with a soft edge, the aligner adjusts the stem width by rounding it to the closest integral multiple of the high-resolution grid and aligns the stem with the coarse grid; characterized in that the number of high-resolution pixels in each cell of the coarse grid is a function of the number of greyscales to be displayed by the output device.

Claim 7

A character renderer as recited in claim 6 further comprising a character program for retrieving a character program, font values and font family values corresponding to the character to be rendered, the character program determining the locations of stem edges of the character with respect to the coarse grid.

Claim 8

A character renderer as recited in claim 6 wherein the character aligner further operates in a manner which depends upon either the proximity of the stem to the coarse grid, ghost stem information, or both, where a ghost stem is a stem with only one edge to control.

Claim 9

A character renderer as recited in claim 8 wherein if a stem is a ghost stem, the stem aligner aligns the left/bottom of such stem to a left/bottom coarse grid edge for a left/bottom ghost stem, and aligns the right/top of such stem to a right/bottom coarse grid edge for a right/top ghost stem.

Claim 10

A character renderer as recited in claim 8 wherein if a stem is not a ghost stem, the stem aligner determines the proximity of the stem to be proximate to either a left/bottom of the coarse grid or a right/top of the coarse grid, and aligns the left/bottom of such stem to a left/bottom coarse grid edge for a left/bottom proximity, and aligns the right/top of such stem to a right/bottom coarse grid edge for a right/top proximity.