US 5,555,358 A · Digital printing system and process using compact trapezoidal representations

Abstract

A system and process for digital printing processes commands to draw a trapezoidal image by initially rendering those commands into an intermediate representation based on pixel rows. Depending on the dimensions of the trapezoid or the regularity of the offset of the end pixels of each pixel row from the end pixels of an adjacent pixel row, data representing the trapezoid are sent to a display list as either individual pixel data, pixel row data, or a compact grouping of data derived from the intermediate representation.

Claims8

Dependent claims

A process of drawing a convex polygon on a computer output device in response to a command generated by a computer, the process comprising the steps of:

creating a pixel-based intermediate representation of said convex polygon;
determining a change in slope over a portion of said intermediate representation;
selectively drawing said polygon on said output device using a first final representation of said convex polygon in response to the results of said step of determining said change in slope indicating said change in slope exceeding a predetermined threshold;
and
selectively drawing said convex polygon on said output device using a second final representation of said polygon in response to the results of said step of determining said change in slope indicating said change in slope not exceeding the predetermined threshold.

2 more elements

A process of drawing a trapezoid on a computer output device in response to a command generated by a computer, the process comprising the steps of:

(a) receiving said command from said computer;
(b) rendering said received command into a number M of rows of pixels representative of said trapezoid;
(c) determining a y coordinate vertically locating a first one of said rows;
(d) determining, for each one of said rows, an x1 coordinate locating the left-most pixel of said row and an x2 coordinate locating the right-most pixel of said row;
(e) determining, for each one of said rows except a last one of said rows, an x1 offset representative of a difference between said x1 coordinate for said one row and a corresponding x1 coordinate for an immediately adjacent row;
(f) determining, for each one of said rows except said last row, an x2 offset representative of a difference between said x2 coordinate for said one row and a corresponding x2 coordinate for said immediately adjacent row;
(g) selecting a representation for the trapezoid as follows:
(1) representing the trapezoid by each of said rows, in response to said x1 and x2 offsets not being within predetermined x1 and x2 ranges over all of said rows exclusive of a subset of said rows;
(2) representing the trapezoid by said subset of said rows, and by a representation of a sub-trapezoid formed by removing said subset of said rows from said rows, in response to said x1 and x2 offsets being within said predetermined x1 and x2 ranges over all of said rows exclusive of said subset of rows, but not being within said predetermined x1 and x2 ranges over all of said rows inclusive of said subset of rows;
(3) representing the trapezoid by the number M, the x1, x2 and y coordinates of said first row, and said x1 and x2 offsets, in response to equality of said x1 offsets over said rows and equality of said x2 offsets over said rows;
(4) representing the trapezoid by the number M, the x1, x2 and y coordinates of said first row, a minimum of each of the x1 and x2 offsets, a set of x1 deltas indicative of a difference between said x1 minimum and said x1 offsets for each of said rows, and a set of x2 deltas indicative of a difference between said x2 minimum and said x2 offsets for each of said rows, in response to said x1 offsets being within said predetermined x1 range over said rows and said x2 offsets being within said predetermined x2 range over said rows;
and
(h) drawing said trapezoid in response to the results of step (g).

10 more elements

A system for displaying a trapezoidal image represented by image data in a computer, comprising:

interpreter means disposed to receive the image data and produce a plurality of graphic primitives therefrom, each representing a specific shape at a specific location;
a display list storage area;
trapezoid processor means, receiving from the interpreter means a graphic primitive corresponding to said trapezoidal image, creating, in response to characteristics of said trapezoidal image, a compact representation of said trapezoidal image, and storing said compact representation in said display list storage area;
a display driver coupled to the display list storage area for receiving therefrom and processing said compact representation;
and
display means coupled to the display driver for producing the trapezoidal image responsive to the processing by the display driver.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application

08/501,518Filed 12 Jul 1995 · continuation

Priority

1 Mar 1993

Granted

10 Sep 1996

Term ends

Not estimatedThe source records don’t support an estimate.

Classification10 codes

G06K 15/02
Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printers: using printers
G06K 15/1838
Rasterization: from outline-coded data
G06K 15/1848
Conditioning data for presenting it to the physical printing elements: generation of the printable image
G06K 15/1849
Generation of the printable image: using an intermediate representation, e.g. a list of graphical primitives

Abstract

Claims8

Dependent claims

A process of drawing a convex polygon on a computer output device in response to a command generated by a computer, the process comprising the steps of:

creating a pixel-based intermediate representation of said convex polygon;
determining a change in slope over a portion of said intermediate representation;
selectively drawing said polygon on said output device using a first final representation of said convex polygon in response to the results of said step of determining said change in slope indicating said change in slope exceeding a predetermined threshold;
and
selectively drawing said convex polygon on said output device using a second final representation of said polygon in response to the results of said step of determining said change in slope indicating said change in slope not exceeding the predetermined threshold.

2 more elements

A process of drawing a trapezoid on a computer output device in response to a command generated by a computer, the process comprising the steps of:

(a) receiving said command from said computer;
(b) rendering said received command into a number M of rows of pixels representative of said trapezoid;
(c) determining a y coordinate vertically locating a first one of said rows;
(d) determining, for each one of said rows, an x1 coordinate locating the left-most pixel of said row and an x2 coordinate locating the right-most pixel of said row;
(e) determining, for each one of said rows except a last one of said rows, an x1 offset representative of a difference between said x1 coordinate for said one row and a corresponding x1 coordinate for an immediately adjacent row;
(f) determining, for each one of said rows except said last row, an x2 offset representative of a difference between said x2 coordinate for said one row and a corresponding x2 coordinate for said immediately adjacent row;
(g) selecting a representation for the trapezoid as follows:
(1) representing the trapezoid by each of said rows, in response to said x1 and x2 offsets not being within predetermined x1 and x2 ranges over all of said rows exclusive of a subset of said rows;
(2) representing the trapezoid by said subset of said rows, and by a representation of a sub-trapezoid formed by removing said subset of said rows from said rows, in response to said x1 and x2 offsets being within said predetermined x1 and x2 ranges over all of said rows exclusive of said subset of rows, but not being within said predetermined x1 and x2 ranges over all of said rows inclusive of said subset of rows;
(3) representing the trapezoid by the number M, the x1, x2 and y coordinates of said first row, and said x1 and x2 offsets, in response to equality of said x1 offsets over said rows and equality of said x2 offsets over said rows;
(4) representing the trapezoid by the number M, the x1, x2 and y coordinates of said first row, a minimum of each of the x1 and x2 offsets, a set of x1 deltas indicative of a difference between said x1 minimum and said x1 offsets for each of said rows, and a set of x2 deltas indicative of a difference between said x2 minimum and said x2 offsets for each of said rows, in response to said x1 offsets being within said predetermined x1 range over said rows and said x2 offsets being within said predetermined x2 range over said rows;
and
(h) drawing said trapezoid in response to the results of step (g).

10 more elements

A system for displaying a trapezoidal image represented by image data in a computer, comprising:

interpreter means disposed to receive the image data and produce a plurality of graphic primitives therefrom, each representing a specific shape at a specific location;
a display list storage area;
trapezoid processor means, receiving from the interpreter means a graphic primitive corresponding to said trapezoidal image, creating, in response to characteristics of said trapezoidal image, a compact representation of said trapezoidal image, and storing said compact representation in said display list storage area;
a display driver coupled to the display list storage area for receiving therefrom and processing said compact representation;
and
display means coupled to the display driver for producing the trapezoidal image responsive to the processing by the display driver.

3 more elements

Dependencies are inferred from the claim text.

Digital printing system and process using compact trapezoidal representations

Life of this patent

Abstract

Claims8

Digital printing system and process using compact trapezoidal representations

Life of this patent

Abstract

Claims8