JPH09150558A - Plotting device for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the developing processing of a horizontal straight line and a rectangle high in use frequency without performing operation at every one dot by forming bit map data on the basis of stored coordinates data and the word length of a memory access and plotting the formed bit map data in an external memory. SOLUTION: The start coordinates and completion coordinates of inputted data are stored in a coordinates memory means 1 and bit map data is formed on the basis of the stored coordinates data and the word length of a memory access by a bit map forming means 3 equipped with a left end edge forming part 6, an intermediate forming part 7 and a right end edge forming part 8. The bit map data formed by the bit map forming means 3 is plotted in on an external memory by a bit map drawing means 4 equipped with a DMA circuit operation part 9 and a bit map selection part 11. By this constitution, a horizontal straight line and a rectangle high in use frequency can be subjected to developing processing without performing operation at every one dot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing device for a printer, and more particularly to a drawing device for a printer that develops a real straight line in a horizontal direction and a vertical direction to a scanning line and a rectangle in a horizontal direction from given parameters. .

[0002]

2. Description of the Related Art Conventionally, in order to draw and develop a straight line,
The minute displacement of the straight line is obtained, the calculation is performed for each dot from the start dot, and the dot position is determined (for example, JP-A-1-222385). Therefore, a dot clock for performing the calculation for each dot is required. In addition, when rendering and developing a horizontal straight line, a dot clock for one word was required.

[0003]

SUMMARY OF THE INVENTION In a conventional printer,
Since the straight line image developing process is performed for each dot while judging the inclination or the like, a considerable amount of time is required for a straight line image developing process for a simple and frequently used horizontal straight line or a vertical straight line.

[0004]

It is an object of the present invention to improve the disadvantages of the conventional example, and particularly to reduce the number of frequently used horizontal straight lines and rectangles.
It is an object of the present invention to provide a drawing device for a printer that can perform expansion processing without performing calculation for each dot.

[0005]

Therefore, according to the present invention, as first means, coordinate storage means for storing start coordinates and end coordinates of input data, and coordinate information stored in the coordinate storage means. There is provided a bitmap generating means for generating bitmap data based on the word length of the memory access, and a bitmap drawing means for drawing the bitmap data generated by the bitmap generating means in an external memory. In addition, the bitmap generation means is configured to generate bitmap data of the rightmost word specified by the coordinate information stored in the coordinate storage means, and is specified by the coordinate information stored in the coordinate storage means. A left edge generating unit for generating bitmap data of the leftmost word, and an intermediate generating unit for generating bitmap data of a word between the leftmost word and the rightmost word are provided. Further, the bit map drawing means calculates the number of memory accesses based on the length of the bit map data determined by the coordinate information stored in the coordinate storage means and the predetermined word length of the word, A bitmap selection unit that selects an output from each generation unit of the bitmap generation unit based on a calculation result output from the DMA count calculation unit. Further, the bitmap selecting unit has a composite output function for generating a logical product of the output from the right edge generating unit and the output from the left edge generating unit when the memory access count is "1". Is taking.

The first means draws a horizontal straight line based on the coordinates stored in the coordinate storage means.
Since the bitmap drawing means draws the bitmap data on the memory in word units, the bitmap generation means generates the bitmap data in word units.

If there is a start point and an end point in one word, the bitmap generator generates a logical product of the output from the right edge generator and the output from the left edge generator by the composite output function. . Then, bitmap data in word units is generated without performing operations in dot units.

In the second means, in addition to the items specifying the first means, a DMA counter for counting the number of times of outputting bitmap data in word units by the bitmap selector is provided in the bitmap selector. I have. In addition, the bitmap selection unit outputs the bitmap data generated by the left edge generation unit when the memory access count exceeds "1", and a left edge output function,
After the left end bit map data is output by the left end output function, an intermediate output function that outputs one word of bit map data until the output value of the DMA counter reaches the operation result of the DMA count operation unit, and the output of the DMA counter When the value reaches the calculation result of the DMA number calculation unit, a right end output function for outputting the bit map data generated by the right end edge generation unit is provided.

According to the second means, in addition to the items specifying the first means, when the data stored in the coordinate storage means extends for several words, the right edge generation unit, the left edge generation unit, and the intermediate generation unit The bitmap selection unit appropriately selects each bitmap data generated in accordance with the calculation result of the memory access count and the DMA count calculation unit.

A bit map at both ends of a straight line and a bit map when one word is entirely on the line (all words are black) and a bit map when both ends of a straight line are present within one word are:
Switches the bitmap to be expanded in the memory.

According to the third means, in addition to the items specifying the second means, an address generation section for generating output coordinates of the next word based on the output value of the DMA counter is provided in the DMA counter. It has a configuration.

In the third means, the address generator generates the address (output coordinate) of the bitmap data in word units in accordance with the timing at which each function of the bitmap selector sequentially outputs the bitmap data. . This is not word-based drawing but word-based access based on the value of the DMA counter.

In the fourth means, in addition to the items specifying the third means, the address generator outputs bitmap data by the right end output function based on the vertical coordinates stored in the coordinate storage means. A configuration is provided in which a rectangular output control function for specifying the coordinates of the next line is provided later.

The fourth means draws a rectangle by repeatedly performing the horizontal straight line drawn by the third means.

In the fifth means, in addition to the items specifying the first means, the bitmap generation means compares a start coordinate with an end coordinate based on an output of the start point end point comparison circuit and an output of the start point end point comparison circuit. And a coordinate selection unit for selecting the left end coordinates and the right end coordinates and outputting the left end coordinates and the right end coordinates to the coordinate storage means as coordinate information.

In the fifth means, even when the starting coordinates and the ending coordinates are different from the drawing direction, the coordinate selecting section adjusts them.

The present invention aims to achieve the above-mentioned object by each of these means.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the drawing apparatus for a printer according to the present embodiment.

The drawing apparatus for a printer includes a coordinate storage means 1 for storing start coordinates and end coordinates of input data.
A bitmap generating means 3 for generating bitmap data based on the coordinate information stored in the coordinate storage means 1 and a word length of the memory access; and a bitmap data generated by the bitmap generating means 3 Bitmap drawing means 4 for drawing in an external memory. In addition, the bitmap generation unit 3 generates the bitmap data of the rightmost word specified by the coordinate information stored in the coordinate storage unit 1 and the right edge generation unit 8 using the coordinate information stored in the coordinate storage unit. A left edge generator 6 generates bitmap data of a specified leftmost word, and an intermediate generator 7 generates bitmap data of a word between the leftmost word and the rightmost word. Here, the left end of the word is shown in FIG.
As shown in, refers to the left end of the external memory,
The rightmost word is the rightmost word in the external memory.

Further, the bit map drawing means 4 calculates the number of memory accesses based on the length of the bit map data determined by the coordinate information stored in the coordinate storage means 1 and the predetermined word length of the word. An arithmetic unit 9 and a bitmap selection unit 11 for selecting an output from each generation unit of the bitmap generation unit based on the operation result output from the DMA number operation unit 9 are provided.

When the number of memory accesses is "1", the bitmap selecting unit 11
And a composite output function for generating a logical product of the output from the left edge generation unit 6 and the output from the left edge generation unit 6.

Further, the bit map generating means includes a start point / end point comparison circuit 2A for comparing the start coordinates and the end coordinates, and selects the left end coordinates and the right end coordinates based on the output of the start point / end point comparison circuit 2A. And a coordinate selection section 2 for outputting the right end coordinates as coordinate information to the coordinate storage means
B, 2C.

This will be described in detail.

FIG. 2 is an explanatory diagram showing a detailed configuration of the drawing apparatus for a printer. In the example shown in FIG. 2, the coordinate storage unit 1 includes a horizontal coordinate storage unit 1A that stores horizontal start point coordinates and an end point coordinate, and a vertical coordinate storage unit 1B that stores vertical start and end point coordinates. And

The coordinate selection unit 2 also distributes the horizontal start point and end point to the left end and right end of the linear bit map based on the result of comparison by the start point end point comparison circuit 2A, similarly to the left end / right end coordinate selection unit 2B. A left / bottom coordinate selection unit 2C for allocating the vertical start point to the upper and lower ends of the linear bit map based on the comparison result of the start / end point comparison circuit 2A is provided.

The number-of-DMA operations unit 9 calculates a required number of times of DMA (direct memory access) in the horizontal direction from the result of the left / right coordinate selection unit 2B, and a left / bottom coordinate selection unit 9A. A vertical DMA line number calculation unit 9B for calculating the required number of DMA lines in the vertical direction from the upper and lower coordinates from the result of 2C, and a DMA counter 10 are provided.

As shown in FIG. 2, the left edge generating unit 6 generates the left end bitmap by converting the lower bit (left side) to black data from the bit position in the word where the coordinates are located based on the left end coordinate value. I do. Similarly, the right end edge generation unit 7 generates a right end bitmap by setting upper bits (right side) from the bit position in the word where the coordinates are located to the black data in the right end coordinate value. In the example illustrated in FIG. 2, the intermediate generation unit 7 is realized as one function of the bitmap selection unit 11.

The bitmap selection section 11 selects and combines bitmaps generated by the left edge generation section 6 and the right edge generation section 7, and outputs necessary data. The address generator 12 generates an address required for the DMA.

Next, the operation will be described.

[Drawing of Horizontal Straight Line] FIG. 3 is a flowchart showing an example of a drawing process of a horizontal straight line. First, when the horizontal straight line (X direction) is drawn and expanded, the comparison unit 3 compares the start point and end point (X start, X end) of the storage unit 1A to check whether X end> X start (step). S1).

If X end> X start is not satisfied, the left end / right end coordinate selection unit 2B sets (X left, X right) = (X start, X end) (step S2). On the other hand, if X end> X start,
(X left, X right) = (X end, X start) (Step S
3).

Further, based on the X left value and the X right value, bitmaps at both ends of the straight line are generated by the edge generators 6 and 7 (step S4).

Next, the necessary number of DMAs in the horizontal direction is calculated based on the difference between the X-end value and the X-start value (step S5). The number of DMAs is a value indicating how many words the difference between the X end and the X start corresponds to.

Next, if the required number of horizontal DMAs is one (that is, both ends of a straight line are included in one word), the bitmap selection unit 11 outputs the logical product of the leftmost and rightmost bitmaps. (Step S7, composite output function).
Next, the value of the DMA counter is incremented. The address generation unit calculates an address to write the next word based on the value of the DMA counter.

On the other hand, if the required number of horizontal DMAs is one or more in step S6, the result of the left edge generator 6 is output when the first DMA occurs (step S9, left end output function). Further, the DMA counter is incremented. Then, the address generator 12 calculates the address of the next word.

Here, the bitmap selection unit 11 checks whether or not the next word to be generated is the last word from the operation result of the horizontal DMA number operation unit 9A and the value of the DMA counter 10 (step). S11). When the last DMA is generated, the result of the right end edge generation unit 7 is output (step S12, right end output function).
H "(step S13, intermediate output function). In either case, the DMA counter is incremented (steps S10, S8).

[Rectangle Drawing] When drawing a rectangle, the comparison unit 3 compares the horizontal start point and end point (X start, X end) of the storage unit 1. If X end> X start, left end / right end Coordinate selection unit 2
In B, (X left, X right) = (X end, X start). Similarly,
From the vertical start point end point (Y start, Y end) of the storage unit 2 to (Y
Select up, Y down).

Based on the values of (X left, X right), straight line drawing development in the horizontal direction is performed.
When the DMA is performed for A times), the address generation unit moves the address from the preset number of words of one line and the initial address calculated before the start of DMA to the leftmost position of the straight line after one line, and the same as for all lines. The process is performed. The number of lines to be processed is calculated from the (Y upper, Y lower) coordinates
It is obtained by the vertical DMA line number calculation unit 9B.

The drawing development of the vertical straight line is performed in the same manner as the rectangle drawing development.

As described above, according to the present embodiment, for the frequently used horizontal straight line, vertical straight line, and horizontal rectangle, the processing by the CPU is not performed and the calculation for each dot is not performed. Since the expansion processing can be performed, the processing can be completed in a shorter time than the time required for the conventional expansion processing. In other words, the CPU that performs the processing for developing the print data develops a straight line or a rectangle in the drawing memory only by outputting the start / end coordinates to the drawing apparatus for a printer according to the present embodiment. It is released from the expansion processing, and therefore, the entire expansion time of the print data is shortened, and therefore, the print output of the print data can be performed at a high speed.

[0041]

According to the present invention, the bitmap drawing means draws the bitmap data in the memory in word units. Bitmap data can be generated in units, so that drawing can be performed at a higher speed than in dot-based drawing processing. Further, when there is a start point and an end point in one word, The generation unit generates logical product of the output from the right edge generation unit and the output from the left edge generation unit using the composite output function, so that bitmap data is generated in word units without performing dot-by-dot operations Therefore, even a short straight line less than one word can be drawn at high speed. As described above, it is possible to provide an unprecedented excellent drawing device for a printer, which can perform a developing process on a frequently used horizontal straight line and a rectangle without performing an operation for each dot.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a detailed configuration of the printer drawing apparatus shown in FIG.

3 is a flowchart showing an example of a horizontal straight line drawing process in the configuration shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coordinate storage means 2 Coordinate selection part 3 Bitmap generation means 4 Bitmap drawing means 6 Left edge generation part 7 Intermediate generation part 8 Right end edge generation part 9 DMA line operation part 10 DMA counter 11 Bitmap selection part 12 Address generation part

Claims (5)

[Claims] 1. A bit for generating bitmap data on the basis of coordinate storage means for storing a start coordinate and an end coordinate of input data, and coordinate information stored in the coordinate storage means and a word length of memory access. The map generation means and the bitmap drawing means for drawing the bitmap data generated by the bitmap generation means in an external memory are provided, and the bitmap generation means is designated by the coordinate information stored in the coordinate storage means. A right edge generating unit for generating bitmap data for the rightmost word, a left edge generating unit for generating bitmap data for the leftmost word specified by the coordinate information stored in the coordinate storage unit, and the left edge Intermediate generator that generates bitmap data for words between the word and the rightmost word DMA count calculation, wherein the bitmap drawing means calculates the memory access count based on the length of the bitmap data determined by the coordinate information stored in the coordinate storage means and a predetermined word length of the word. And a bit map selecting section that selects an output from each of the generating sections of the bit map generating means based on a calculation result output from the DMA number calculating section, the bit map selecting section including the memory access section. When the number of times is "1", the drawing device for a printer is provided with a composite output function for generating a logical product of the output from the right edge generation unit and the output from the left edge generation unit. 2. The bit map selecting section is provided with a DMA counter for counting the number of output of the bit map data of the word unit by the bit map selecting section, and the bit map selecting section sets the memory access number to " When it exceeds 1 ”, the left end output function of outputting the bit map data generated by the left end edge generation unit, and the output value of the DMA counter after the left end bit map data is output by the left end output function An intermediate output function for outputting the bit map data for one word up to the calculation result of the calculation section, and the right end edge generation section when the output value of the DMA counter reaches the calculation result of the DMA number calculation section It has a right end output function to output the bitmap data Printer drawing device according to claim 1,. 3. The DMA counter according to claim 2, further comprising an address generator for generating output coordinates of a next word based on an output value of the DMA counter.
The drawing device for a printer according to the above. 4. The rectangular output control, wherein the address generation unit specifies the coordinates of the next row after the bitmap data is output by the right end output function based on the vertical coordinates stored in the coordinate storage means. The drawing device for a printer according to claim 3, further comprising a function. 5. A starting point / ending point comparing circuit for comparing the starting coordinates and the ending coordinates, wherein the bitmap generating means selects a left end coordinate and a right end coordinate based on an output of the starting point / ending point comparing circuit. 2. A drawing device for a printer according to claim 1, further comprising: a coordinate selection unit that outputs right end coordinates to the coordinate storage unit as coordinate information.