JP3242435B2 - Image drawing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image drawing apparatus capable of drawing linear vector data and image data.
In particular, the present invention relates to an image drawing device that performs a task of drawing a rectangular area.

[0002]

2. Description of the Related Art As an image drawing apparatus using a linear vector, for example, there is one as disclosed in Japanese Patent Laid-Open No. 2-181886. The operation of an information processing system having such an image drawing apparatus will be described with reference to FIG. explain. This information processing system draws image data created in a page description language typified by PostScript in a host computer 1 in an image memory 2.

All the vector data are represented by vectors, and the CPU 3 re-develops all the described vectors into linear vectors in the main scanning direction, and stores the coordinates of the start and end points of the linear vectors and the density values in a first-in first-out memory. (Hereinafter referred to as "FIFO") 4. FIF
Each data stored in O4 is a main scanning direction start address register (hereinafter referred to as “XS register”) 5, a main scanning direction end address register (hereinafter referred to as “XE register”).
6, a sub-scanning direction address register (hereinafter referred to as "YS register") 7, and a density register (hereinafter referred to as "RGB register") 8, respectively.

When a drawing command is issued from the CPU 3, the memory controller 9 generates a write signal, and writes the density specified by the RGB register 8 at the address specified by the XS register 5 and the YS register 7 on the image memory 2. To write. At the same time as the start of the writing operation, the main scanning direction address counter (hereinafter referred to as "X counter") 10 starts a counting operation and the address (X
(Load value from the S register 5).

After that, when the address becomes equal to the value of the XE register 6, the X comparator 11, which is the main scanning direction comparator, informs the memory controller 9 that it has reached the drawing end dot. As a result, a straight line vector can be drawn. By repeating the above operation, one page of image data created by the host computer 1 can be drawn in the image memory 2.

[0006]

However, in the conventional image drawing apparatus as described above, image data to be drawn many times, such as text data, must be developed into a linear vector in the main scanning direction each time. Was. In addition, when rendering image data, it is necessary to perform rendering by dividing into a large number of linear vectors, which not only increases the load on the CPU but also increases the time required for developing the linear vectors.

The present invention has been made in view of the above points, and aims to reduce the load on the CPU when rendering image data such as characters and image data, and to increase the speed of developing linear vectors. With the goal.

[0008]

Means for Solving the Problems] The present invention, input from the outside
Expand the input image data into a linear vector,
Image drawing by writing vector drawing data to
In order to achieve the above object , in an image drawing apparatus for drawing an image , as shown in a functional block diagram in FIG.
Image data input from outside
Expand to a vector and enter the start and end addresses of the line
Linear vector expansion means A for generating density value data;
Configured with dedicated hardware different from the above processor
And based on the data from the linear vector developing means A
Image drawing to write vector drawing data to image memory B
A control means C, an image developing means D for developing data developed by the linear vector developing means A for each predetermined rectangular area, a cache memory E for storing the image data developed by the means D, When image data is input, it is determined whether or not image data to be drawn based on the image data is stored in the cache memory E for each of the rectangular areas. A memory / image data sending means F for sending in place of the data by the developing means A ;
Sent by the memory image data sending means F
Means for writing image data to the image memory B.

Further, the image drawing control means C is
A memory for temporarily storing data from the
Main scanning method that stores the drawing start address in the main scanning direction
Direction start address register and drawing end address in the main scanning direction.
Main scan direction end address register for storing address
And a sub-scan to store a drawing start address in the sub-scanning direction.
Scan direction start address register and drawing end in sub-scan direction
Sub-scan direction end address register that stores the address
And RGB data indicating the color density value are stored in advance.
RGB register and drawing in the main scanning direction of the image memory
A main scanning address counter for specifying an address;
A main scanning controller that notifies the end of drawing in the main scanning direction of the image memory
And a parator. Further, the length of the rectangular area in the main scanning direction may be set to an integral multiple of the size of the data bus of the linear vector developing means A. Further , when image data is input from outside, it is preferable to provide input image data transmitting means G for determining whether or not the image data is image data, and transmitting the image data as it is to the image drawing control means C. .

[0010]

According to the image drawing apparatus of the present invention, when image data is input from the outside, the memory / image data sending means F stores image data to be drawn by the image data for each rectangular area in the cache memory E. It is determined whether or not the image data is stored. If the image data is stored, the image data is read out and transmitted, and the transmitted image data is written into the image memory B by the image drawing control means G. In other words, by storing image data such as characters once expanded as image data in the cache memory E, there is no need for the linear vector developing means A (CPU) to perform the work of expanding the same image data into linear vectors many times. The load on the CPU can be reduced and the speed can be significantly increased.

The rectangular area (the cache memory E
The length of the data stored in the main scanning direction in the main scanning direction is set to an integral multiple of the size of the data bus of the linear vector developing means A, so that the time for reloading the addresses by counting up the addresses in the sub-scanning direction is reduced. Therefore, the image memory B
It is possible to perform high-speed drawing without stopping the high-speed page mode when a dynamic RAM is used.
When image data is input from the outside, the input image data sending means G determines whether or not the image data is image data. If the image data is image data, the image data is sent directly to the image drawing control means C for drawing. Accordingly, the speed of drawing the image data can be increased.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a block diagram showing an information processing system embodying the present invention, and FIG. 3 is a block diagram showing a configuration example of a printer controller (image drawing apparatus). Is attached.

This information processing system comprises a host computer 1 and a printer controller 3 as an image drawing device.
0 and a printer device including a printer engine 31. The printer controller 30
The microcomputer comprises a CPU 3, a ROM 32, and a RAM 33, an image memory (frame memory) 2, a cache memory 12, an image drawing control device 34, a receiving device 35, and a transmitting device 36.

The CPU 3 is a central processing unit that controls the entire printer controller 30 according to a program in the ROM 32 and a command from the host computer 1. The ROM 32 is a read-only memory that stores a control program for operating the CPU 3 and fixed data such as fonts. The RAM 33 is a work memory for the CPU 3, an input buffer for storing input data, a page buffer for storing page data, a random access memory used for a font file for storing download fonts, and the like, and the image memory 2. Is image image data (bitmap data)
Is a random access memory for temporarily storing image data for each predetermined rectangular area, which will be described later.

The image drawing control device 34 controls drawing on the image memory 2, and will be described later in detail.
The receiving device 35 manages reception of data transmitted from the host computer 1, and the transmitting device 36 manages transmission of image data to the printer engine 31 that actually performs printing.

FIG. 4 is a block diagram showing details of the image drawing control device 34 shown in FIG. 3. As shown in FIG.
A FIFO 4 for temporarily storing each data from the PU 3; an XS register 5 for storing a drawing start address in the main scanning direction; an XE register 6 for storing a drawing end address in the main scanning direction; A YS register 7 indicating coordinates, an RGB register 8 for storing RGB data indicating a color density value, an X address counter 10 for specifying a drawing address of the image memory 2 in the main scanning direction, An X comparator 11 is provided to notify the end of drawing in the scanning direction.

An acquisition controller (hereinafter referred to as an "operation controller") 13 for fetching data from the FIFO 4 and determining its type; a parallel / serial converter 14 for converting parallel data fetched from the FIFO 4 into serial data; A sub-scanning direction end address register (hereinafter referred to as “YE counter”) 15 for storing a drawing end address in the sub-scanning direction, and a sub-scanning direction address counter (hereinafter “Y address”) for counting the number of lines drawn in the sub-scanning direction. A counter 16), a sub-scanning direction comparator (hereinafter referred to as a "Y comparator") 17 for notifying the end of a line to be drawn, an image memory 2 capable of read-modify-write, and a read-modify-write function of the image memory 2. OR gate 18, latch circuits 19 and 20 And a memory data controller comprised of the inverters 21.

In the printer controller 30 configured as described above, the data obtained from the host computer 1 is converted into a linear vector by the CPU 3 in the same manner as described above when performing the first drawing before registration in the cache memory 12. You. For example, in the case of drawing the characters shown in FIGS. 5A and 5B, first, the coordinates on the paper on which the characters are drawn are set as offset addresses (Xa, Ya).

Next, the density value (RGB data) corresponding to the color of the character to be drawn is stored in the FIFO 4, and the starting coordinate of the character to be drawn in the sub-scanning direction is set to YS = Ya.
Then, the X coordinate of the starting point of the dot row to be drawn in the first row is added to the offset address, and the XS
= Xa + X1 and stored in FIFO4. Next, the X coordinate of the end point of the dot row to be drawn on the same line is added to the X coordinate of the offset address, and XE = Xa + X2, and F
The data is stored in the FIFO 4 and the line is updated, and data indicating that the next drawing is the YS = Ya + 1-th line is stored in the FIFO 4.
Store in O4. Thereafter, in the same manner, XS,
Calculate XE and YS and store them in FIFO4.

Next, the operation of storing image data developed into a linear vector in the cache memory 12 will be described.
In addition to the coordinate data calculated as described above, the CPU 3
At the same time, data such as characters to be drawn (image data expanded into linear vectors) is image-expanded for each predetermined rectangular area and stored in the cache memory 12. When rendering the image data stored therein again, which image data is written to which address in the cache memory 12 has a separate look-up table, and refer to the look-up table. The image data is read from the address and stored in the FIFO 4.

Next, the normal drawing operation (when the image data is not the image data from the cache memory 12) will be described.
When necessary data is stored in the FIFO 4, the operation controller 13 sequentially retrieves each data, and
These are assigned to the T as shown in FIG.
The XS register 5, the XE register 6, the YS register 7, and the RGB register 8 are respectively latched by referring to the state of the flag of the AG bit. For example, if the TAG bit XS flag added to the extracted data is “1”, the data is latched in the XS register 5.

If the data fetched from the FIFO 4 is a drawing command, the XS register of the image memory 2 and the Y
The writing is performed at the address specified by the S register 7 at the density specified by the RGB register 8.
At the same time as the start of the write operation, the value of the XS register 5 is loaded into the X address counter 10 to start incrementing the address (+1). This increment is performed in synchronization with a reference clock from a circuit (not shown). Further, the value of the YS register 7 is loaded into the Y address counter 16.

At this time, the X comparator 11 compares the value of the X address counter 10 with the value of the XE register 6,
When the values match each other, a signal indicating the end of drawing of one line in the image memory 2 is output. At that point, drawing of the first line is finished. Thereafter, the same operation as described above is repeated for each of the second and subsequent lines, and linear vector drawing, that is, vector drawing data is written to the image memory 2. Perform

Next, the operation for drawing the image data expanded in the cache memory 12 will be described. CPU
3 is the cache memory 1 where the image data to be drawn is
It is checked whether the image data is stored in the image data 2 and if it is stored, the drawing start coordinates (XS, YS) and the drawing end coordinates (XE, Y) of the rectangular area for drawing the image data are checked.
E), a drawing command of the rectangular area, and the cache memory 12
And the image data to be drawn are sequentially written into the FIFO 4.

When the necessary data is stored in the FIFO 4, the operation controller 13 extracts the data and performs an operation according to the data. That is, the first data is the drawing start coordinates (XS, YS) and the drawing end coordinates (XE, YE) of the rectangular area for drawing the image data.
Therefore, they are stored in XS register 5, YS register 7, X
The E register 6 and the YE register 15 are respectively latched. Since the next data is a drawing command for a rectangular area, the drawing operation of the rectangular area is started, and the data following the drawing command is image data.
The data is loaded into the serial converter 14.

At this time, the parallel / serial converter 14
The data input first is the drawing start coordinates (XS, Y
Since the data is to be drawn in S), the parallel / serial converter 14 converts the data into serial data and outputs the data one dot at a time. When the output of the parallel / serial converter 14 is the drawing dot “1”, the OR gate 18 inverts “1” by the inverter 21 to “0”.
Is input, the OR gate 18 sets the RGB register 8
Is ORed with the data previously written at the address to be written on the image memory 2 and the data obtained thereby is rewritten to the same address on the image memory 2 via the latch circuit 19.

When the output of the parallel / serial converter 14 is "0" which is not a drawing dot, the OR gate 1
Since “1”, which is obtained by inverting “0” by the inverter 21, is input to 8, the OR gate 18 does not operate, and the data previously written at the address to be written on the image memory 2 is stored in the latch circuit 20. Image memory 2 as it is
Write to the same address above.

Further, simultaneously with the output of the image data from the parallel / serial converter 14, the operation controller 13 controls the X address counter 10 to store the XS counter 5
To start the address increment (+1). At this time, the X comparator 11 compares the value of the X address counter 10 with the value of the XE register 6,
When the values match, a signal notifying the end of drawing of one line in the image memory 2 is output to the Y address counter 16. The Y address counter 16 increments (+1) and updates the next line when receiving a signal indicating the end of drawing of one line from the X comparator 11, and reloads the value of the XS counter 5 to the X address counter 10. Then, the address increment (+1) is started, and thereafter, the same operation as described above is repeated for each of the second and subsequent lines in the specified rectangular area of the image memory 2.

When the drawing on the last line of the rectangular area is completed and a signal indicating the end of drawing of one line is output from the X comparator 11, the value of the Y address counter 16 and the value of the YE register 15 are changed. Because they match, Y
The comparator 11 outputs to the operation controller 13 a signal indicating that the drawing on the last line has been completed, and ends the drawing of the image data on the specified rectangular area of the image memory 2.

As described above, according to this embodiment, by specifying the coordinates of the starting point and the ending point of the rectangular area to be drawn in the image memory 2 in the main scanning direction and the sub-scanning direction, all of the rectangular area can be designated. It is obtained as a linear vector in the main scanning direction, and high-speed drawing can be performed. In addition, by storing the image data once expanded as image data in the cache memory 12, the CPU 3 does not need to perform the process of expanding the same data into a linear vector many times, so that the load on the CPU 3 is reduced and the load is greatly reduced. Higher speed can be achieved. Further, the image data in the cache memory 12 can be collectively drawn in a two-dimensional rectangular area without damaging the background data previously written in the image memory 2.

When a dynamic RAM is used as the image memory 2, for example, by assigning continuous coordinates of each image in the main scanning direction to continuous addresses of the dynamic RAM, the high-speed page mode can be used. . However, if the length of the rectangular area of the image memory 2 in the main scanning direction is not an integral multiple of the size of the data bus of the CPU 3,
Since image data over a plurality of lines is input to the FIFO 3 and the address value is skipped when updating the line when rendering each data, the high-speed page mode is temporarily terminated and the address value is reloaded. And it takes time as a whole.

Therefore, the length of the rectangular area of the image memory 2 in the main scanning direction is set to an integral multiple of the size of the data bus of the CPU 3. As a result, the image data input to the FIFO 4 are all on the same line in the main scanning direction, so that the speed can be further increased.

When image data is input from the outside, the CPU 3 transmits the image data to the host computer 1.
Alternatively, it is determined whether the image data is image data transmitted from an image reading device such as a scanner (not shown). If the image data is image data, the starting point and the ending point in the main scanning direction and the sub-scanning direction of the rectangular area to be drawn on the image memory 2 are determined. , Coordinates of a rectangular area, and external image data
By writing the data to the FO 4 and then sequentially extracting the data by the operation controller 13, the same drawing operation as described above can be performed, and such image data can be written to an arbitrary rectangular area.

[0034]

As described above, according to the present invention, the load on the CPU when drawing image data such as characters and image data is reduced, and the speed of developing linear vectors is improved.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram showing an information processing system embodying the present invention;

FIG. 3 is a block diagram illustrating an example of the printer controller of FIG. 2;

FIG. 4 is a block diagram showing details of the image drawing control device of FIG. 3;

FIG. 5 is an explanatory diagram for explaining a drawing operation on the image memory 2 of FIG. 4;

FIG. 6 is an explanatory diagram showing a configuration example of each data taken into the operation controller 13 from the FIFO 4 in FIG. 4;

FIG. 7 is a block diagram showing an information processing system having a conventional image drawing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Host computer 2 Image memory 3 CPU 4 First-in first-out memory (FIFO) 5 Main scanning direction start address register (XS register) 6 Main scanning direction end address register (XE register) 7 Sub-scanning direction start address register (YS register) 8 Density register (RGB register) 10 Main scanning direction address counter (X address counter) 11 Main scanning direction comparator (X comparator) 12
Cache memory 13 Capture controller (operation controller) 14 Parallel / serial converter 15 Sub-scanning direction end address register (YE register) 16 Sub-scanning direction address counter (Y address counter) 17 Sub-scanning direction comparator (Y comparator) 18
OR gate 19, 20 Latch circuit 30 Printer controller 31 Printer engine 32 ROM 33 RAM 34 Image drawing control device

Claims (4)

(57) [Claims] 1. An image data input from the outside is developed into a linear vector, and vector drawing data is written to an image memory.
An image drawing apparatus that performs image drawing by burn them, is constituted by a processor, image de externally inputted
Data into a straight line vector to determine the start and end points of the straight line.
Linear vector expansion to generate address and density data
Means and dedicated hardware different from the processor
Data from the linear vector expansion means.
Write vector drawing data to the image memory based on
Image drawing control means, image developing means for developing the data developed by the linear vector developing means for each predetermined rectangular area, a cache memory for storing the image data developed by the means, and an external image. When data is input, it is determined whether or not image data to be drawn by the image data is stored in the cache memory for each of the rectangular areas. If so, the image data is read out and the straight line vector is read. Memo to send instead of data by expansion means
Re-image data sending means, wherein the image drawing control means comprises the memory image data
The image data sent by the sending means
An image drawing apparatus comprising means for writing to a memory . 2. The image drawing apparatus according to claim 1, wherein The image drawing control means is the straight line vector development means;
Memory for temporarily storing these data and drawing in the main scanning direction
Main scan direction start address register that stores the start address
Register and the drawing end address in the main scanning direction.
The main scan direction end address register and the sub-scan direction
Sub-scanning direction start address for storing the image start address
Register and store the drawing end address in the sub-scanning direction
Sub-scan direction end address register and color density value
An RGB register for storing RGB data indicating
Designates a drawing address in the main scanning direction of the image memory
Main scanning address counter and main scanning method of the image memory
And a main scanning comparator to notify the end of the drawing
An image drawing apparatus characterized by the above-mentioned. 3. An image drawing apparatus according to claim 1 or 2, wherein the image, characterized in that the main scanning direction of the length of the rectangular area to an integral multiple size of the data bus of the linear vector expansion means Drawing device. 4. An image drawing apparatus according to claim 1, wherein when image data is inputted from the outside, it is determined whether or not the image data is image data. An image drawing device provided with a means for directly sending the image drawing control means to the image drawing control means.