JPH11202852A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a bit map image at a high speed by erasing a drawing buffer in a short time. SOLUTION: An erasure code generation part 8 selects only color components which are being drawn among drawing codes and converts color information to zero data according to the drawing data to generate erasure data. Further, cells which are mutually successive among cells of the drawing codes are connected to decrease the number of cells. Erasure codes are generated according to the drawing codes reduced in data amount and held in a hold part 9. The drawing buffer 7 is erased by drawing image data (zero data) based upon erasure codes small in data amount, so the erasure time becomes very short.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly, to an image processing apparatus for performing processing for expanding data to be output to an image output device into a drawing buffer.

[0002]

2. Description of the Related Art In an image processing apparatus for supplying data to an image output device such as a CRT display device or a page printer,
Develop the generated image as a bitmap image in the drawing buffer. When a new image is to be drawn in the drawing buffer, the previously stored contents are erased for the entire writing target area of the drawing buffer. This is because the newly drawn image cannot be distinguished from the old image unless the storage contents of the entire area are erased. By the way, the bitmap image information has no structural information itself, unlike code information of a program or the like.
Therefore, in order to erase the contents stored in the drawing memory, a procedure of erasing old data by writing data for erasure in the storage area dot by dot is taken.

[0003] However, it takes a lot of time to erase the entire writing area of the drawing buffer. For example, 30
For a monochrome image with a resolution of 0 dpi (300 dots per inch), a memory capacity of 1 MB is required to store one A4 size image data, and 40
Approximately 59 for a 16 million color image with 0 dpi resolution
Requires MB memory capacity. Such a large-capacity drawing buffer is generally composed of a DRAM, and a process of writing zero data for each address is required for erasing its contents. The erasing process can be performed by one command like a flash memory. It cannot be finished.
For example, for a monochrome image of 300 dpi, several tens of milliseconds, 40
It took several seconds for a 16 million color image at 0 dpi. As described above, since it took a long time to erase the drawing buffer, it is not enough as an image processing device for an image output device such as a CRT or a page printer that requires high-speed generation of a bitmap image. Can not meet the demand.

Therefore, an apparatus for erasing the contents stored in the drawing buffer at high speed has been proposed (Japanese Patent Laid-Open No. 9-16).
138 publication). In this apparatus, coordinate values required for drawing an image, that is, a drawing code, are generated based on the code information, data “1” is written based on the drawing code at the time of writing, and data “0” is written based on the same drawing code at the time of erasing. Is written. This eliminates the need to first erase the entire area of the drawing buffer, so that the previously written data can be erased in a short time.

[0005]

The above-mentioned conventional apparatus has the following problems. The above-described conventional apparatus is configured to always use a drawing code when erasing a bitmap image in a drawing buffer. However, when the drawing code is complicated, it may take longer than writing data “0” in the entire writing area and erasing the previous stored content.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing apparatus which solves the above-mentioned problems and enables the storage contents of a drawing buffer to be erased at a high speed so that a bitmap image can be generated at a higher speed. And

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, the present invention provides an image processing apparatus for generating and outputting image data for each color component of a color image. A drawing buffer for holding, drawing code generating means for generating a drawing code based on document data, drawing means for drawing a bitmap image in the drawing buffer according to the drawing code, and only a color component of a drawing color from the drawing code Color cell extracting means for extracting the extracted color component, cell combining means for combining one of the cells of the drawing code of the extracted color component which are continuous with each other to generate one cell, and drawing including the combined cells. Color information replacing means for converting the value of the color information of the code into zero data and outputting an erasure code, wherein the drawing means Using said erase code after the bitmap image drawing that is characterized in that is configured to erase the rendering buffer.

According to this feature, the drawing code of only the color component being drawn is extracted, and at the same time, a plurality of continuous cells are combined into one to reduce the number of cells of the drawing code.
Then, an erasure code is created based on the drawing code in a state where the data amount is reduced in this way.

[0009]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a block diagram of an image forming system including the image processing device of the present invention. In FIG. 1, a document creation device 1 such as a personal computer
In this example, document data expressed in, for example, a page description language is created using a document creation application.
The created document data is transferred to the laser printer 2 via the network. The document data interpreting section 20 of the laser printer 2 interprets the document data using an interpreting means corresponding to the type of the page description language, and creates a drawing code.

The drawing code processing section 21 develops the image data into a bitmap on a drawing buffer (not shown) according to the drawing code. The bitmap-deployed image data is supplied to the image output device 22, and the image output device 22 outputs the print image 3 based on the supplied image data. Here, a laser printer is assumed as the image forming apparatus, but a display device that outputs an image to a CRT display device has the same configuration.

Next, the main functions of the laser printer 2 will be described. FIG. 1 is a block diagram showing the main functions of the laser printer 2. The document data interpreting unit 20 includes a drawing code generation unit 4 and a drawing code holding unit 5 that holds the generated drawing code. The drawing code generation unit 4 generates a drawing code, which will be described later in detail with reference to FIG. 3, based on the document data. The drawing code is a coordinate value necessary for developing the image in the drawing buffer.

The drawing unit 6 reads out the drawing code from the drawing code holding unit 5 in response to the write command, generates image data, and outputs it to the drawing buffer 7. The write command is input from the image output device 22. The drawing buffer 7 is configured as, for example, a band buffer that holds data of an area (band) obtained by dividing one page into a plurality of parts in order to be able to simultaneously process the development of the image data and the output of the developed data. Can be.

The erasure code generation unit 8 generates an erasure code based on the drawing code, and inputs the erasure code to the erasure code holding unit 9. Since the color image is drawn for each color of black (K), yellow (Y), magenta (M), and cyan (C), the erasure code is generated during the drawing process of each color plane. The erase code holding unit 9 holds the input erase code, and transfers the erase code to the drawing unit 6 when the drawing unit 6 erases the drawing buffer 7.

The structure of the erase code generator 8 will be described in more detail. FIG. 7 is a functional block diagram of a main part of the erasure code generation unit 8. Here, it is assumed that processing is performed when the K plane is drawn. 7, the color component determination unit 12 extracts a drawing code in which the value of the color information of K color is “0”. If the value of the K color is “0”, the image data of the K color is not drawn at the coordinate value indicated by the drawing code.
This is because there is no need to generate an erasure code and perform drawing for erasure. That is, the drawing code having the K color value “0” is not used for generating the K-plane erase code.

The continuous cell discriminating section 13 is a cell which is continuous in the X direction to be described later (see FIG. 3) in the input drawing code.
Is detected. The continuous cell combining unit 14 combines the detected continuous cells and converts them into one cell. Color information replacement unit 15
Replaces all the values of the color information described in the header of each drawing data with “0”. The erase code of the K plane generated in this manner is stored in the erase code holding unit 9 of the erase code holding unit 9. Such an erasure code generation function is common to the processing of each color plane.

FIG. 3 is a diagram showing an example of the configuration of the drawing code. FIG. 1A is a schematic diagram showing the relationship between two cells. The drawing code 11 expresses the coordinate value of the current cell 11b based on the previous cell 11a. However, the first cell is represented by a coordinate value based on the origin of the coordinates of the drawing buffer 7.

As shown in FIG. 3B, the drawing code 11 includes a header section 110 and a data section 120.
As shown in FIG. 3C, the header section 110 includes the number N of cells.
um, the value Col of the color information of each color of KYMC for the color image
or, the size of the drawing code. The data section 120 is a set of a plurality of cells.
As shown in (d), it is composed of a difference X in the X direction from the previous cell, a difference Y in the Y direction from the previous cell, and a run length RL of the cell. The cell difference and run length are shown in FIG.
The present invention is not limited to the method shown in FIG.

FIG. 4 is an example of a bitmap image using a drawing code. FIG. 3 shows bitmap images I1, I2, I3, and I4 drawn on the drawing buffer 7 based on four drawing codes.

FIG. 5 shows the bitmap images I1, I
It is a figure which shows the drawing code corresponding to 2, I3, I4.
Drawing code DC1 corresponding to bitmap image I1
According to the header part, the bitmap image I1
Indicates that the number of cells is 5, the K color is “0”, the Y, M, and C colors are each “128”, and the total size of the drawing code is represented by a drawing code of 25 bytes. .

According to the data section of FIG. 5, first, a line segment of run length "2" is drawn from the coordinate values (5, 5), then the X coordinate is moved by "-2", and the Y coordinate is moved to "1". Move to draw a line segment of run length “2”. Further, the X coordinate is changed to "-
2 ”, the Y coordinate is moved by“ 1 ”, and a line segment of run length“ 2 ”is drawn. Thereafter, by executing the same processing, a vertically long rectangle having an X-direction length “2” and a Y-direction length “5” as shown in FIG. 4 is drawn. Similarly, bitmap images I2, I3, and I4 are represented by drawing codes DC2, DC3, and DC4, respectively.

FIG. 6 is a diagram showing an erasure code for each color plane generated based on the drawing codes DC1 to DC4. The K-plane erasure code Ke is generated using the drawing codes DC2, DC3, and DC4 except for the drawing code DC1 in which the value of the K color information is “0”. That is, the bitmap images I2, I3,
A value "0" of K color information is drawn in a range where I4 is drawn, and an erasure code Ke is generated so as to erase the K component of the bitmap images I2, I3 and I4.

Further focusing on the continuity of the cells of the drawing codes DC2 to DC4 in the X direction, the drawing code DC2
The first cells of D4 are continuous with each other. Similarly, the second cell, third cell, fourth cell, and fifth cell of the drawing codes DC2 to D4 are also continuous with each other. Thus, these consecutive cells have been combined into a single cell. For example, the first cells “7, 5, 2” of the drawing codes DC2 to D4,
“9, 5, 2” and “11, 5, 2” are converted into a single cell “7, 5, 6”. Similarly, Y, M, C
Erasure codes Ye, Me, and Ce for the plane have been generated.

FIG. 8 is a flowchart showing the drawing erasing process. In the figure, in step S1, a drawing code generation unit 4 generates a drawing code based on document data, and stores it in a drawing code holding unit 5. In step S2, the erasure code generation unit 8 generates an erasure code for each plane of each color based on the drawing code, and stores the erasure code in the erasure code holding unit 9.
In step S3, the drawing code is read from the drawing code holding unit 5 in response to the write command, and the bitmap image is developed in the drawing buffer 7. This development is performed in a predetermined data unit, for example, a band unit in which one page is divided into a plurality of band-shaped regions.

When one band data is developed, the image data in the drawing buffer 7 is transferred to the image output device 22 in step S4. In step S5, the erasure code is read from the erasure code holding unit 9, and the bitmap image of "0" is developed in the drawing buffer 7. In step S6, it is determined whether or not output of all drawing codes has been completed. Until this determination is affirmative, step S3 is performed.
And the process ends if the determination is affirmative.

As described above, according to the present embodiment, an erasure code is generated based on a rendering code whose data amount has been reduced by detecting and eliminating color components that do not need to be erased for each plane from the rendering code. . In addition, the number of cells was reduced by connecting successive cells to each other. Therefore, a simplified erasure code containing no extra data can be obtained.

In this embodiment, the erase code for only the color component being drawn is generated, and the continuous cells are combined to reduce the number of cells. Alternatively, the erase code may be generated by a drawing code that has been subjected to data processing only by using one of them or by reducing the number of cells by combining them.

[0027]

As is apparent from the above description, according to the present invention, since the drawing buffer is erased by the erasing code based on the drawing code with the reduced data amount, the erasing time can be shortened. . As a result, data can be efficiently supplied to an image output device that is required to generate a bitmap image at high speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a laser printer according to an embodiment of the present invention.

FIG. 2 is a block diagram of an image forming system including a laser printer according to an embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a drawing code.

FIG. 4 is a schematic diagram showing an example of a bitmap image developed in a drawing buffer.

FIG. 5 is a diagram showing a specific example of a drawing code.

FIG. 6 is a diagram showing a specific example of an erasure code.

FIG. 7 is a block diagram illustrating a main function of an erasure code generation unit.

FIG. 8 is a flowchart of image processing according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Document creation apparatus, 2 ... Laser printer, 4 ... Drawing code generation part, 5 ... Drawing code holding part, 6 ... Drawing part, 7 ... Drawing buffer, 8 ... Erasure code generation part,
9: Erasure code holding unit, 12: Color component determination unit, 14
... Continuous cell connection unit, 15 ... Color information replacement unit

Claims (3)

[Claims] An image processing apparatus for generating and outputting image data for each color component of a color image, comprising: a drawing buffer for holding a bitmap image; and a drawing code generating means for generating a drawing code based on document data. Drawing means for drawing a bitmap image in the drawing buffer in accordance with the drawing code; color component extracting means for extracting only a color component of a drawing color from the drawing code; cells of the drawing code of the extracted color component Cell combining means for combining ones continuous with each other to generate one cell, and color information replacement for converting the color information value of the drawing code including the combined cells into zero data and outputting an erasure code Means for drawing, wherein the drawing means uses the erase code after drawing the bitmap image by the drawing code. The image processing apparatus characterized by being configured to erase the image buffer. 2. An image processing apparatus for generating and outputting image data for each color component of a color image, comprising: a drawing buffer for holding a bitmap image; and a drawing code generating means for generating a drawing code based on document data. Drawing means for drawing a bitmap image in the drawing buffer in accordance with the drawing code; color component extraction means for extracting only a color component of a drawing color from the drawing code; and color information of the drawing code of the extracted color component Color information replacing means for converting the value of the image data into zero data and outputting an erasure code, wherein the rendering means erases the rendering buffer using the erasure code after rendering the bitmap image by the rendering code. An image processing apparatus characterized by being configured as described above. 3. A drawing buffer for holding a bitmap image, drawing code generation means for generating a drawing code based on document data, drawing means for drawing a bitmap image in the drawing buffer according to the drawing code, A cell combining unit that combines ones of the cells of the drawing code that are continuous with each other to generate one cell; and converts a value of color information of the drawing code including the combined cells into zero data to generate an erasure code. Image processing, comprising: outputting color information replacing means; and wherein the drawing means is configured to delete the drawing buffer using the deletion code after drawing the bitmap image by the drawing code. apparatus.