JP2002091427A - Device and method for processing picture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture processor and a method therefor which use a built-in multi-window system operating on a real time operating system, efficiently switch double buffers without considering an exclusive control of plotting in window units, and control flickers at the time of plotting. SOLUTION: This is a display device 100 using a built-in window system which has two VRAM 801, 802 and operates on a real time operating system, and comprising a plotting part 500 for plotting in the VRAM for writing, and a plotting request count part 700 for judging whether or not plotting is being performed by the plotting part 500, and characterized by changing over an updated information accumulation part 600 for accumulating and holding updated information by plotting when it is judged that plotting is being performed, and changing over the VRAM for writing to VRAM for displaying when it is judged that plotting is not being performed, and then transferring the updated information accumulated by the updated information accumulation part 600 from the VRAM for display to the VRAM for writing.

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 an image processing method using a writing image storage medium and a display image storage medium.

[0002]

2. Description of the Related Art Conventionally, as an image processing apparatus of this type, when writing is performed to directly draw a figure or the like on an image storage medium such as a VRAM mapped to a display device such as a liquid crystal such as a copying machine or a camera. There was a phenomenon that the drawing process was visible or flickering. In order to suppress this, a device of a double buffer system in which two VRAMs are mounted and one is alternately switched for display and one for writing is generally used.

The details of the general double buffer method are as follows. First, drawing is performed on a writing VRAM that is not reflected on the display device (because the drawing process is not reflected on the display device,
No flickering). Next, when the drawing is completed, the writing VRAM and the display VRAM are switched. At this point, the drawing result is instantly reflected on the display device. Further, in preparation for the next drawing, the image of the entire VRAM is transferred from the switched display VRAM (holding the latest drawing result) to the writing VRAM. When the transfer is completed, the VRAM for writing
Can be drawn.

[0004] The next drawing is performed from the display VRAM to the write VR.
Since it can be done only after the transfer to AM is completed,
Various methods have been proposed to increase the transfer efficiency, such as transferring only the updated difference in order to eliminate the time lag of drawing.

On the other hand, a system in which a built-in window system that operates on a real-time OS is mounted on a device, a plurality of window application tasks are operated on the window system, and each of them performs drawing at random has become widespread. In this case, a drawing or drawing completion double buffer switching request is randomly generated from a plurality of window application tasks. Therefore, if no special measures are taken, the drawing result is not reflected on the display device, or the drawing process is performed on the display device while drawing is in progress. Is reflected and flickering appears. Therefore, the following method is generally used to coexist a plurality of window application tasks with the double buffer method.

(1) The number of window application tasks that can use the double buffer is fixed to one.

(2) When a double buffer is used by a plurality of window application tasks, exclusive control is performed while the double buffer is used.

(3) By logically allocating a write VRAM and a display VRAM for each window application, and managing an update state and a visible area for each window,
The mapping is performed with the physical write VRAM and display VRAM (special registration 2690925).

[0009]

However, the conventional techniques (1), (2), and (3) have the following problems.

(1) Since the number of window application tasks that can use the double buffer is fixed at one,
Drawings of other window application tasks will flicker.

(2) If the window application task 1 switches to the window application task 2 by an asynchronous event while acquiring the exclusive control right to use the double buffer, the window application task 2 sets the exclusive control right to use. It cannot be acquired and transits to the suspended state. After the task switch to window application task 1, window application task 1
Completes the drawing and releases the exclusive control use right, and then switches the task to the window application task 2 again. In this way, a useless task switch occurs and increases the load on the system.

(3) A write VRAM and a display VRAM are logically assigned to each window application, and an update state and a visible area for each window are assigned to perform mapping with the physical write VRAM and the display VRAM. Therefore, it is necessary to know the inside of the window system for embedding, and it is difficult to use a commercially available window system for embedding.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art.
An image processing apparatus and an image processing method that efficiently switch a double buffer and suppress flickering at the time of drawing by using an embedded multi-window system that operates on the above, without being aware of exclusive control of drawing on a window basis. To provide.

[0014]

In order to achieve the above-mentioned object, an apparatus according to the present invention has an image storage medium for writing and an image storage medium for display, and has a built-in window operating on a real-time OS. An image processing apparatus using a system, comprising: a drawing unit configured to perform drawing on the writing image storage medium; a determination unit configured to determine whether drawing is performed by the drawing unit; When it is determined that drawing is performed, update information accumulating means for accumulating and holding update information by drawing, and the determination means,
If it is determined that drawing is not performed, the writing image storage medium and the display image storage medium are switched, and the update information accumulated by the update information accumulation means is transferred from the display image storage medium to the writing image storage medium. It is characterized by comprising control means for transferring.

The image processing apparatus further comprises an image display means.

[0016] The drawing means is characterized in that drawing is performed on the image storage medium for writing at asynchronous timing.

The determining means includes a counting means for counting the number of windows in which the drawing means is performing drawing, and the update information accumulating means changes the number of windows counted by the counting means from 0 to 1. From the point in time, the update information by drawing starts to be accumulated, and the control means determines that the number of windows counted by the
At the time when the value changes from 0 to 0, the writing image storage medium and the display image storage medium are switched, and the update information is transferred from the display image storage medium to the writing image storage medium.

After all the tasks on the real-time OS are interrupted, the control means transfers the update information accumulated by the update information accumulating means from the display image storage medium to the writing image storage medium. It is characterized by being transferred to

[0019] The update information accumulating means is means for accumulating and holding, as the update information, information on the area where the drawing has been updated as rectangular information. Is a fixed value without accumulation, and accumulates only in the other axial direction.

The present invention is characterized in that round robin scheduling is performed only for a group of window application tasks on a real-time OS.

It is characterized in that a series of drawing instructions from a group of window application tasks on the real-time OS are executed only in a redrawing event handler in each window application task.

In order to achieve the above object, a storage medium according to the present invention stores an image processing program that is executed by a computer so that the computer operates as the image processing apparatus described above. .

In order to achieve the above object, a method according to the present invention is directed to an image processing method using an embedded window system having a writing image storage medium and a display image storage medium and operating on a real-time OS. A drawing step of drawing on the writing image storage medium; a determining step of determining whether or not drawing is performed by the drawing step; and drawing is performed by the determining step. Is determined, the update information accumulating step of accumulating and holding the update information by drawing, and if the determination step determines that drawing is not performed, the writing image storage medium and the display image storage medium And a control step of transferring the update information accumulated in the update information accumulation step from the display image storage medium to the writing image storage medium.

A computer readable memory storing an image processing program, utilizing an image storage medium for writing, an image storage medium for display, and a built-in window system operating on a real-time OS. It is determined that drawing is performed by the code of a drawing step of performing drawing on the embedded image storage medium, the code of a determining step of determining whether or not the drawing is performed by the drawing step, and the determining step. Then, the code of the update information accumulation step of accumulating and holding the update information by drawing, and the determination step,
If it is determined that drawing is not performed, the writing image storage medium and the display image storage medium are switched, and the update information accumulated in the update information accumulation step is transferred from the display image storage medium to the writing image storage medium. And a code for a control process to be transferred.

[0025]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the relative arrangement of components described in this embodiment, formulas, numerical values, etc., unless otherwise specified,
It is not intended to limit the scope of the present invention only to them.

(First Embodiment) In a first embodiment of the present invention, a real-time O
A description will be given of a display device equipped with a built-in window system that operates on the S, executes a plurality of window application tasks on the window system, and performs double-buffer control so that each performs random drawing.

<Overview> The display device according to the present embodiment has a display device such as a liquid crystal display such as a copying machine or a camera.
A built-in window system that operates on a real-time OS is mounted, a drawing mechanism that performs primitive drawing at specified coordinates on a writing VRAM at asynchronous timing, and a number of windows during execution of a series of drawing commands. A drawing request counting mechanism for counting, an update rectangle accumulating mechanism for accumulating update area information by primitive insertion from the point in time when the number of windows counted by the drawing request counting mechanism changes from nothing to existence and holding the information as rectangle information, and a drawing request count The writing VRAM and the display VRAM are switched when the number of windows counted by the mechanism changes from existence to non-existence, and only the image area indicated by the rectangle information accumulated by the update rectangle accumulation mechanism is written from the display VRAM. A double buffer switching mechanism for transferring data to the VRAM is provided. When there is a drawing request command from the embedded window system, the drawing request counting mechanism counts the number of windows to be counted (initial value =
0) is incremented by one, and the accumulated rectangle information managed by the update rectangle accumulation mechanism is cleared when the number of windows to be counted changes from nothing to existence. Next, when a series of drawing commands are called from the built-in window system, the drawing mechanism performs primitive (window overlapping, position, VRAM that does not require clipping information) to the designated coordinates on the writing VRAM. (Points, parallel lines, vertical lines, bitmaps) by specifying the absolute coordinates with respect to, and at the same time, the update area information at that time is added to the accumulation rectangle information managed by the update rectangle accumulation mechanism. Finally, when there is a drawing completion command from the embedded window system indicating that a series of drawing has been completed, the drawing request counting mechanism decreases the number of windows to be counted by one, and the number of windows to be counted is changed from existence to none. At that point, the double buffer switching mechanism is activated. When activated, the double buffer switching mechanism switches between the write VRAM and the display VRAM, and switches only the image area indicated by the accumulated rectangle information managed by the updated rectangle accumulation mechanism from the display VRAM (holding the latest drawing result). Transfer to the write VRAM.

By providing the above mechanism, even if there are drawing request commands from a plurality of window application tasks on the embedded window system, when the number of windows is present, all the window application tasks are executed by the drawing request counting mechanism. Is written in the write VRAM and is not reflected on the display device until the number of windows becomes zero, so that flicker can be suppressed.

Further, since the consistency of the drawing between the window application tasks is maintained by the drawing request counting mechanism, there is no need to perform exclusive control, and while the window application task 1 is drawing, an asynchronous event When the task is switched to the window application task 2, the window application task 2 starts drawing without transiting to the suspended state, and after the drawing is completed, switches the task to the window application task 1 and continues the original drawing. When the window application task 1 completes the drawing, the number of windows counted by the drawing request counting mechanism changes from existence to no existence, and the drawing results of the window application task 1 and the window application task 2 are collectively reflected on the display device. As described above, unnecessary task switching does not occur, and the load on the system can be reduced.

In the drawing mechanism, primitives (points, parallel lines, vertical lines, and the like based on the absolute coordinates specified for a VRAM that does not require clipping information, and the primitive (window overlapping, position, clipping information) (Bitmap) Since only drawing is performed, the overlapping rectangle position, the position, and the clipping information are not required even in the update rectangle accumulation mechanism and the double buffer switching mechanism in order to realize the double buffer switching. Therefore, it is easy to use a commercially available window system for installation.

<Specific Configuration> FIG. 1 is a block diagram showing a schematic configuration of a display device according to the present embodiment.

In FIG. 1, a display device 100 has a CPU
CPU 210, ROM 220, RAM 3
00, operation buttons 110, and a display device 900 are connected.

Of these, the ROM 220 has a double buffer control unit 400 and a window system 31 for embedding.
0, object codes for the window application task 320 and the window application task 330 are stored, and the real-time OS and the RAM 300
Expanded above. When the CPU 210 is reset,
Among the object codes on the ROM 220, the double buffer control unit 400, the window system 310 for embedding,
The code corresponding to the window application task 320 and the window application task 330 is R
The data is copied to the AM 300, the real-time OS on the ROM 220 is started, and the window system for embedding 310 is started on the RAM 300.

In the double buffer control unit 400,
First, the double buffer switching unit 800 is activated, and VR for displaying the drawing results of the window application task 320 and the window application task 330 is displayed.
AM 801 and VRAM 802 are cleared and display switching 8
04 maps the VRAM 801 to the display VRAM, and the write switch 803 maps the VRAM 802 to the write VRAM. At this stage, a window application task 320 and a window application task 330 for drawing are activated on the embedded window system 310.

Window application task 320
The window application task 330 activates the drawing request counting unit 700 by the drawing request command 407 before starting drawing by the series of window operation commands 340 and the drawing command 350 in the window, and after completing the series of drawing, the drawing completion command. In step 408, the drawing request count unit 700 is activated.

The drawing request counter 700 increments the drawing request counter 701 held therein,
When the number has changed from 0 to 1, the update rectangle accumulation unit 600 is activated by the update start event 401. When the drawing request command 407 is received from a plurality of window application tasks, the drawing request counter 701 is incremented by one each time.

Here, the drawing request counting section 700
Uses the drawing request counter 701 to count the number of windows that are currently performing a series of drawing, but the counting method is not limited to the numerical counter. For example, it is also possible to manage the presence / absence of the number of windows by using the increase and decrease of the stack.

The update rectangle accumulation section 600 clears the accumulation rectangle information 405 held therein. The update rectangle accumulating unit 600 is activated each time a primitive drawing is performed from the drawing unit 500, receives update region information 403 indicating a rectangular region updated by drawing, and receives cumulative rectangle information 405.
Is added to and accumulated.

After issuing the drawing request command 407, the window application task 320 and the window application task 330 execute a series of drawing commands (the window operation command 340 and the in-window drawing command 35).
0) is issued. Normally, this series of drawing commands are clipped by the embedded window system 310 due to overlapping windows, and then decomposed into primitive drawing requests (points, horizontal lines, vertical lines, bitmap processing requests) at the bottom layer. Is done. The rendering command 406 is a generalization of this. The drawing unit 500 is activated by the drawing command 406 and requested primitive drawing (point drawing processing, horizontal line drawing processing, vertical line drawing processing, bitmap processing) for the write VRAM (the current VRAM 802 is mapped). Rendering processing). At the same time, the update rectangle accumulator 600 is activated, and a request is made to accumulate the update area information 403 by drawing for each primitive drawing.

Window application task 320
The window application task 330 executes a drawing completion command 408 after a series of window operation commands 340 and drawing in a window drawing command 350 are completed.
Activates the drawing request counting unit 700.

The drawing request count unit 700 decrements the drawing request counter 701 and activates the double buffer switching unit 800 when it changes from 1 to 0. In the drawing request counting unit 700, when receiving a drawing request command 407 from a plurality of window application tasks,
Even when the drawing completion command 408 is received, the drawing request counter 70
Until 1 changes from 1 to 0, it is guaranteed that the drawing result is not reflected on the display device 900.

The double buffer switching section 800 maps the VRAM 802 to the display VRAM by the display switching section 804 and maps the VRAM 801 to the write VRAM by the write switching section 803.
Swap the mapping of M. In the case of FIG.
01 is reflected on the display device 900. Further, thereafter, in order to enable drawing on the VRAM 802 mapped as the write VRAM, the cumulative update information 405 is obtained from the update rectangle accumulating unit 600, and only that area is displayed in the display VRAM (VRAM in FIG. 1).
801 is mapped), the write VRAM
(The VRAM 802 is mapped in FIG. 1).

As a result, the embedded window system 3
Multiple Window Application Tasks 32 on 10
Even if there is a drawing request command 407 from 0, 330, when the value of the drawing request counter 701 is other than 0, the drawing command 406 of all the window application tasks 320, 330 is written by the drawing request counting unit 700.
Is not reflected on the display device 900 until the value of the drawing request counter 701 becomes 0, thereby making it possible to suppress flickering.
Since the consistency of the drawing between 0 and 330 is maintained, there is no need to perform exclusive control, and when the window application task 320 switches to the window application task 330 by an asynchronous event during drawing, Window application task 33
0 starts the drawing as it is without transition to the suspended state, and after the drawing is completed, the window application task 3
The task is switched to 20, and the original drawing is continued. When the window application task 320 completes drawing,
The value of the drawing request counter 701 of the drawing request counting unit 700 changes from 1 to 0, and the window application task 320 and the window application task 33
0 drawing results are collectively reflected on the display device 900. In this way, it is possible to reduce the load on the system without generating useless task switches.
00, only primitive (points, parallel lines, vertical lines, and bitmaps, designated by absolute coordinates for a VRAM that does not require clipping information, to a specified coordinate on a write VRAM) are drawn. Therefore, in order to realize double buffer switching, the update rectangle accumulating unit 600 and the double buffer switching unit 800
Does not require window overlap, position, or clipping information. For this reason, commercially available window systems for embedded 3
10 can be easily used.

That is, this embodiment is a real-time O
Using a commercially available embedded multi-window system that operates on S, it is possible to switch the double buffer efficiently without being aware of exclusive control of drawing in window units.
Double-buffer control that suppresses flickering during drawing becomes possible. In order to realize this system, it is not necessary to develop new dedicated hardware, only a general-purpose inexpensive video controller supporting a double buffer is required, and all other parts can be realized by software. In addition, low cost and efficient double buffer control of the embedded window system can be realized.

Hereinafter, the present embodiment will be described in more detail with reference to the drawings.

<Initialization Processing> The initialization processing of the double buffer switching unit 800 will be described with reference to FIGS.

FIG. 2 is a diagram showing information stored in the VRAMs 801 and 802.

An address (1 byte) represents information of one pixel, and is relatively shifted from an address 0 to 30719 from a base address.
By having the address 9, an image having a width of 640 and a height of 480 can be stored. The base address of the VRAM 801 is represented by VRAM1_TOP and 100000
Address. The base address of VRAM 802 is VRAM
It is represented by 2_TOP and is at address 500,000.

At each address (pixel), a color index value of 0 to 255 is stored in hexadecimal notation, and 256 colors are expressed by the color index value. For example,
In FIG. 2, the color index 01 is stored at address 0, which indicates that the color of the image at the coordinates of (x, y) = (0, 0) is brown.

FIG. 3 shows the double buffer switching section 80 in FIG.
11 is a flowchart showing initialization processing of 0.

The VRAM 801 and VRAM 802 are cleared in order to initialize the double buffer switching unit 800 and display the drawing results of the window application task 320 and the window application task 330, and the VRAM 801 is displayed by the display switching unit 804.
The RAM / write switching unit 803 maps the VRAM 802 to the write VRAM.

The steps will be described below. This process is executed without interrupts. First, the physical base address 100000 of the VRAM 801 is substituted for the variable VRAM1_TOP (step S811). Next, the variable VRAM2_
The physical base address 5000 of VRAM802 in TOP
00 is substituted (step S812). Next, write V
640 is substituted for the RAM width (step S813). Next, 640 is substituted for the display VRAM width (step S
814). Next, the VRAM 801 is cleared (step S815). Next, the VRAM 802 is cleared (step S816). Next, OK is set for synchronization (step 817). As a result of drawing, VRAM 801 and VRAM 8
02, there is a DIRTY
Is set. Next, V is set to the write VRAM base address.
RAM2_TOP is set (step S818).
Next, the write switching unit 803 is switched and mapped by setting the write VRAM to the VRAM 802 (step S8).
19). Next, VRAM1 is set in the display VRAM base address.
_TOP is set (step S820). Next, the display switching unit 804 is switched and mapped by setting the display VRAM to the VRAM 801 (step S819).

<Point Drawing Processing> FIG. 4 shows the drawing unit 50 in FIG.
9 is a flowchart showing a point drawing process performed at 0.
Activated by the drawing command 406, the designated x coordinate, y
A point is drawn in the writing VRAM with the coordinates and the RGB color values, and finally the updated area information 40 updated by the point drawing
In order to add 3 to the accumulated rectangle information 405, the update rectangle accumulation unit 600 is started.

The steps will be described below. First, the designated RGB color values are converted into color index values (step S560). Next, a drawing offset address is obtained from the write VRAM width and the designated x-coordinate and y-coordinate (step S511). Next, the sum of the VRAM base address for writing and the drawing offset address set in step S511 is obtained and set to the drawing address (step S5).
12). Next, the content of the pointer indicating the drawing address is updated to the color index value obtained in step S560 (step S513). Step S513 corresponds to point drawing at the designated coordinates on the writing VRAM. Finally,
In order to add the updated area information 403 updated by drawing to the accumulated rectangle information 405, the updated rectangle accumulation unit 600 is activated and communication area addition processing is performed (step S620). Since a region including a point is designated as a parameter at this time, a calling sequence of AddUpdateRect (x coordinate, y coordinate, 1, 1) is used.

Next, the color index acquisition processing performed in step S560 will be described in more detail.

FIG. 5 is a diagram showing color pallet information. Stores the Palette RGB array and 256
By specifying the color index of a color as a subscript of the Palette RGB array, RGB RGB
The B color value can be obtained. PaletteR
The color index value indicating the GB array is the VRAM80
1 and the color data of each pixel of the VRAM 802.

FIG. 6 is a flowchart showing the color index acquisition process. This process is started by a point drawing process, a horizontal line drawing process, and a vertical line drawing process. The specified RGB color value is converted into a color index value and returned as a return value. The steps will be described below. First, the color index upper limit value is set to 255 (step S561). The color index is set to 0 (step S562). Next, using the table of FIG. 5, the designated RGB color value and Palette
The eRGB [color index] is compared (step S564).

If not equal in step S564, the color index is incremented to search for the next color index (step S565). From step 0 to the color index upper limit, these steps S564,
Repeat 565. If they are equal in step S564, the repetition is terminated, and the matched current color index is returned as a return value (step S566).

Further, here, step S6 in FIG.
The update area adding process in 20 will be described in detail.

FIG. 7 is a flowchart showing an update area adding process of the update rectangular area accumulation unit 600. The drawing unit 500 is activated by a point drawing process, a horizontal line drawing process, a vertical line drawing process, or a bitmap drawing process in the drawing unit 500 due to a series of drawing commands 406 from the embedded window system 310, and is updated by drawing for each primitive drawing. The area information 403 (start x coordinate, start y coordinate, width, height)
Add to the cumulative rectangle information 405 (rectangle start x coordinate, rectangle start y coordinate, rectangle width, rectangle height), and include 1 including two rectangles
Find a rectangle. However, in the coordinate system, (x, y) =
With the origin at (0,0), it grows positively in the lower right direction. The rectangle has a starting point (x, y) at the upper left and a width and height in the lower right direction. Therefore, the start x coordinate, start y coordinate, width, height, rectangle start x coordinate, rectangle start y coordinate, rectangle width, and rectangle height are:
Neither should be a negative value.

The steps will be described below. This process is executed without interrupts. First, it is compared whether the rectangular width or the rectangular height is equal to 0 (step S621). Step S6
If they are equal to each other, the accumulated rectangle information 405 is cleared, and then it is determined that the update area is to be added for the first time.
The update area information 403 (start x coordinate, start y coordinate, width, height) is substituted for (rectangle start x coordinate, rectangle start y coordinate, rectangle width, rectangle height), and the process ends (step S622, step S622). 623, 624, 625). Step S
If they are not equal in 621, it is determined that a valid value has already been entered in the accumulated rectangle information 405, and the following addition processing is performed. First, the update area information 403 (start x
From the coordinates, start y coordinate, width, height and the accumulated rectangle information 405 (rectangle start x coordinate, rectangle start y coordinate, rectangle width, rectangle height) already stored, a newly added rectangle (start x coordinate, A start y coordinate, an end x coordinate, and an end y coordinate) and an existing cumulative rectangle (rectangle start x coordinate, rectangle start y coordinate, rectangle end x coordinate, rectangle end y coordinate) are obtained (steps S626, S6).
27,628,629). Next, the calculation of the existing cumulative rectangle = the existing cumulative rectangle + the newly added rectangle is performed (step S630).
To S639). In this calculation, first, a rectangle start x coordinate is obtained (steps S630 and S631). Next, a rectangle start y coordinate is obtained (step S632, step S633). Next, a rectangle end x coordinate is obtained (step S634, step S635). Next, end rectangle x
A rectangle width is determined from the coordinates and the rectangle start x coordinate determined in steps S630 and 631 (step S636). Next, a rectangle end y coordinate is obtained (step S637, step S637).
638). Next, the rectangle end y coordinate and step S632,
A rectangle height is obtained from the rectangle start y coordinate obtained in step S633 (step S636). As described above, the addition result is the cumulative rectangle information 405 (rectangle start x coordinate, rectangle start y coordinate,
(Rectangle width, rectangle height).

<Horizontal Line Drawing Process> FIG. 8 is a flowchart showing the horizontal line drawing process. It is started by a drawing command 406. A horizontal line is drawn in the writing VRAM with the specified x-coordinate, y-coordinate, length, and RGB color value. Finally, the update area information 403 updated by the horizontal line drawing is added to the accumulated rectangle information 405. Rectangle accumulator 600
Start

The steps will be described below. First, the designated RGB color values are converted into color index values as shown in FIG. 6 (step S560). Next, a drawing offset address is obtained from the write VRAM width and the designated x-coordinate and y-coordinate (step S521). Next, the sum of the VRAM base address for writing and the drawing offset address set in step S521 is obtained and set to the drawing address (step S522). Next, the following processing (steps S524 and 525) is repeated for the designated length (step S523). The content of the pointer indicating the drawing address is updated to the color index value acquired in step S560 (step S524). Step S5
Reference numeral 24 corresponds to point drawing at designated coordinates on the writing VRAM, and by repeating this, line drawing is performed. The drawing address is incremented for repetition (step S52).
5). When the repetition is completed, finally, in order to add the update area information 403 updated by drawing to the cumulative rectangle information 405, the update rectangle accumulation unit 600 is activated, and the update area adding process is performed as shown in FIG. S620).
In this process, since a region including a horizontal line is specified as a parameter, a calling sequence of AddUpdateRect (x coordinate, y coordinate, length, 1) is used.

<Vertical Line Drawing Process> FIG. 9 is a flowchart showing the vertical line drawing process. It is started by a drawing command 406. To draw a vertical line in the write VRAM with the specified x-coordinate, y-coordinate, length, and RGB color value, and finally add the updated area information 403 updated by the vertical line drawing to the cumulative rectangle information 405 , Updated rectangle accumulator 600
Start

The steps will be described below. First, the designated RGB color values are converted into color index values as shown in FIG. 6 (step S560). Next, a drawing offset address is obtained from the write VRAM width and the designated x and y coordinates (step S531). Next, the sum of the VRAM base address for writing and the drawing offset address set in step S531 is obtained and set to the drawing address (step S532). Next, the following processing (steps S534 and 535) is repeated for the designated length (step S533). The content of the pointer indicating the drawing address is updated to the color index value obtained in step S560 (step S534). Step S5
Numeral 34 corresponds to point drawing at designated coordinates on the writing VRAM, and by repeating this, line drawing is performed. The drawing address is incremented by the write VRAM width for repetition (step S535). When the repetition is completed, finally, the update rectangle accumulation unit 600 is started to add the update area information 403 updated by drawing to the accumulation rectangle information 405, and the update area addition processing is performed as shown in FIG. 7 ( Step S620). Since a region including a vertical line is specified as a parameter at this time, a calling sequence called AddUpdateRect (x coordinate, y coordinate, 1, length) is used.

<Bitmap Drawing Processing> FIG. 10 is a flowchart showing bitmap drawing processing. It is started by a drawing command 406. The specified bitmap width,
The bitmap height and the bitmap indicated by the bitmap head address are designated as x coordinates and y in the write VRAM.
In order to copy the coordinates to the coordinates and finally add the update area information 403 updated by the bitmap drawing to the accumulation rectangle information 405, the update rectangle accumulation unit 600 (the update area addition processing in FIG. 13) is activated.

The steps will be described below. First, a drawing offset address is obtained from the write VRAM width and the specified x and y coordinates (step S541). Next, the sum of the write VRAM base address and the drawing offset address set in step S541 is obtained, and set to the drawing address (step S542). Next, the start address of the designated bitmap of the transfer source is set to the current pixel address (step S543). Next, the following processing is performed for the designated bitmap height (steps S545 and 549).
Is repeated (step S544). Further, the following processing is performed by the nesting for the designated bitmap width (step S
546, 547, and 548) (Step S54)
5). The contents of the pointer indicating the drawing address are updated to the contents of the pointer indicating the current pixel address (step S546). Step S546 is the write VRAM
This corresponds to one pixel copy to the above designated coordinates, and by repeating this for the bitmap width and the bitmap height, bitmap drawing is performed. In order to repeat the width, the drawing address is incremented (step S547), and the current pixel address is incremented (step S548).
In order to repeat the height, the drawing address is written in the VRA for writing.
Increment by M width and decrement by the specified bitmap width (step S549). When the repetition is completed, finally, the update rectangle accumulation unit 600 is started to add the update area information 403 updated by drawing to the accumulation rectangle information 405, and the update area addition processing is performed as shown in FIG. 7 ( Step S620). Since the area including the bitmap is specified as a parameter at this time,
A calling sequence called DrawBitmap () (x coordinate, y coordinate, bitmap width, bitmap height) is taken.

<Drawing Request Accepting Process> FIG. 11 is a flowchart showing the drawing request accepting process of the drawing request counting unit 700 in FIG.

Window application task 320
And in response to the series of window operation instructions 340 and in-window drawing instructions 350 from the window application task 330, before the drawing unit 500 starts drawing,
The drawing request command unit 407 starts the drawing request counting unit, and performs a drawing request reception process. When the internally stored drawing request counter 701 is incremented and changes from 0 to 1, an update start event 401 causes the update rectangle accumulation unit 600 to perform update start processing. Drawing request command 407 from a plurality of window application tasks
Upon receiving this, the drawing request counter 701 is incremented by one each time.

The steps will be described below. This process is executed without interrupts. First, the drawing request counter 701 is incremented (step S711). Next, it is determined whether the drawing request counter 701 is equal to 1 (step S712). If not equal in step S712, the plurality of window application tasks 320,
It is determined that the drawing request command 407 has arrived in parallel from 330, and the processing is terminated as it is. If they are equal in step S712, it is determined as the first drawing request command 407 from one of the plurality of window application tasks 320 and 330, and the following processing is executed. First, since the image of the writing VRAM and the image of the display VRAM may not match due to the drawing command 406 that may be executed thereafter, the synchronization is set to DIRTY (step S713). Finally, by activating the update start process of the update accumulation unit 600, the accumulation rectangle information 405 is cleared (step S610).

FIG. 12 is a flowchart showing the update start processing of the update rectangular area accumulator 600. The drawing request counter 700 is activated when the drawing request counter 701 is incremented and changes from 0 to 1. A series of drawing commands 40 from the built-in window system 310
Before the point drawing process, the horizontal line drawing process, the vertical line drawing process, and the bitmap drawing process in the drawing unit 500 according to 6 are started, the accumulated rectangle information 405 is cleared.

This process is executed without interrupts. The rectangle start x coordinate, rectangle start y coordinate, rectangle width, and rectangle height of the accumulated rectangle information 405 held by the update rectangle accumulation unit 600 are all 0.
(Step S611).

<Drawing Completion Accepting Process> FIG. 13 is a flowchart showing the drawing completion accepting process of the drawing request counting unit 700 in FIG. The window application task 320 and the window application task 330 are activated by a drawing completion command 408 after a series of window operation commands 340 and drawing in the window drawing command 350 are completed. When the drawing request counter 701 is decremented and changes from 1 to 0, the double buffer switching unit 800 performs a switching process. If the drawing request command 407 has been received from a plurality of window application tasks, it is guaranteed that even if the drawing completion command 408 is received, the drawing result is not reflected on the display device 900 until the drawing request counter 701 changes from 1 to 0. You.

The steps will be described below. This process is executed without interrupts. First, the drawing request counter 701 is decremented (step S721). Next, it is determined whether the drawing request counter 701 is equal to 0 (step S).
722). If not equal in step S712,
Multiple window application tasks 320, 33
It is determined that the drawing request command 407 has arrived in parallel from 0, and the processing ends as it is. If equal in step S722, a plurality of window application tasks 3
Last drawing completion command 40 from one of 20, 330
8 and activates the switching process of the double buffer switching unit 800 to reflect the latest result drawn in the writing VRAM on the display device 900 by exchanging the mapping between the writing VRAM and the display VRAM. (Step S830).

Next, the switching process of FIG. 13 (step S83)
0) will be described in more detail.

FIG. 14 is a flowchart showing the switching processing of double buffer switching section 800. In the drawing request counting unit 700, the drawing request counter 701 is decremented, and is started when it changes from 1 to 0. V for writing
The latest result drawn in the RAM is reflected on the display device 900 by exchanging the mapping between the writing VRAM and the display VRAM. Furthermore, the VRA for writing
To make the VRAM mapped to M hold the latest drawing result, the image is transferred from the display VRAM (currently holding the latest drawing result) to the writing VRAM.

The steps will be described below. This process is executed without interrupts. First, write VRAM to VRAM
It is determined whether or not 801 is mapped (step S
831). If the VRAM 801 is mapped to the write VRAM, steps S832, 833, 83
According to 4,835, the VRAM is switched so that the VRAM 802 is mapped to the write VRAM and the VRAM 801 is mapped to the display VRAM. If it is determined in step S831 that the VRAM 801 is not mapped to the write VRAM, the process proceeds to steps S835 and 83.
According to 7, 838, 839, the VRAM is
801 is mapped to VRAM 80 for display VRAM.
Switching of VRAM is performed by mapping 2. The VRAM image mapped to the display VRAM is instantly reflected on the display device at this point. Finally, the VR mapped to the write VRAM by switching
In order to make the AM hold the latest drawing result, the display VRAM (currently holding the latest drawing result) is read from the writing VRAM.
The image is transferred to the RAM (Step S840).

Next, the transfer process of FIG. 14 (step S84)
0) will be described in more detail. FIG. 15 shows the transfer processing of double buffer switching section 800 (step S840).
5 is a flowchart showing in detail.

The switching process of the double buffer switching unit 800 is started when the buffer is switched. In order to make the VRAM mapped to the write VRAM hold the latest drawing result, the cumulative update information 405 is obtained from the update rectangle accumulating unit 600, and only that area is displayed from the display VRAM (currently holds the latest drawing result). Then, the image is transferred to the write VRAM.

The following is a step-by-step description. This process is executed without interrupts. The display VRAM is the transfer source, and the write VRAM is the transfer destination. First, the update rectangle accumulation unit 600
, The rectangle start x coordinate of the accumulated rectangle information 405 held in
The rectangle start y coordinate, the rectangle width, and the rectangle height are set to the x coordinate, the y coordinate, the transfer width, and the transfer height as update rectangle information (step S841). Next, a transfer offset address is obtained from the display VRAM width and the x and y coordinates acquired in step S841 (step S842). However, it is assumed that the display VRAM width and the write VRAM width are the same. Next, the sum of the display VRAM base address and the transfer offset address set in step S842 is obtained and set as the transfer source address (step S843). Next, write VRA
The sum of the M base address and the transfer offset address set in step S842 is obtained and set to the transfer destination address (step S844). Next, the following processing is performed by the transfer height set in step S841 (steps S846 and 85).
0, 851) is repeated (step S845). Further, the following processes (steps S847, 848, and 849) are repeated by the transfer width set in step S841 (step S846). The contents of the pointer indicating the transfer destination address are updated to the contents of the pointer indicating the transfer source address (step S847). Step S847
Corresponds to one pixel copy to the designated coordinates on the writing VRAM, and is repeated by the transfer width and transfer height to form a rectangular copy of the drawn image. In order to repeat the transfer width, the transfer destination address is incremented (Step S
848), the transfer source address is incremented (step S849). In order to repeat the transfer height, the transfer destination address is incremented by the write VRAM width and decremented by the transfer width (step S850). Further, the transfer destination address is incremented by the display VRAM width and decremented by the transfer width (step S851). When repetition for the transfer width and transfer height is completed, the write VRAM
And the image of the display VRAM completely match, so OK is set synchronously.

FIG. 16 is a state transition diagram of the double buffer control unit 400. In the present embodiment, state A “VRAM
802 READY "→ Status B" VRAM 802 updating "
→ State C “VRAM801READY” → State D “VR
Only the four states of “AM update in progress” are repeated.

Note that only the window application tasks 320 and 330 may be round-robin scheduled on the real-time OS. Then, one window application task executes a series of drawing commands 406 after issuing the drawing request command 407,
Until the drawing completion command 408 is issued, no useless task switch is generated. Thereby, drawing can be performed efficiently.

To make the two window application tasks round-robin scheduled on the real-time OS, the real-time OS uses the generation system call 375 to generate the two tasks by disabling the same priority and time slice scheduling. do it.

The series of drawing commands 406 from the window application tasks 320 and 330 on the real-time OS may be executed only in the redrawing event handler in each window application task 320 and 330.

Here, the redraw event handler refers to a portion of the window processing function that processes the redraw event. The window processing function is a function of each window application task in a general embedded window system, and is for processing an event sent to its own window.

[0086] The redraw event corresponds to an Expose event in a general window system, for example, X11 of XWindow System, which is a registered trademark of the Massachusetts Institute of Technology in the United States. In a window system, a redraw event is often implemented with a lower priority for event transmission than other events.

Thus, if a series of drawing commands 406 from all the window application tasks are executed only in the redrawing event handler in each window application task, the drawing can be performed asynchronously with other events. And no preemption occurs. Therefore, until one window application task issues a drawing request command 407, executes a series of drawing commands 406, and issues a drawing completion command 408, no useless task switch occurs.
It is possible to realize efficient drawing.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described.

In the first embodiment, the transfer process is performed immediately after switching between the writing VRAM and the display VRAM by the switching process of the double buffer switching unit 800. However, in the present embodiment, the transfer process is performed. After the switching process, the real-time OS
When all of the above tasks are suspended, only the image area indicated by the accumulation rectangle information 405 held by the update rectangle accumulation unit 600 is displayed in the display VRAM as shown in FIG.
The image is transferred from (currently latest drawing result holding) to the writing VRAM. That is, the transfer process is started as the task with the lowest priority.

By performing the above processing, the state A “VRAM 802 READY” → the state B in FIG.
“Updating VRAM 802” → Status E “VRAM 802 →
Waiting for VRAM 801 transfer "→ State C" VRAM 801R
EADY ”→ State D“ Updating VRAM801 ”→ State F
A transition is made repeatedly by repeating the six states of “VRAM 801 → VRAM 802 transfer waiting”.

According to the present embodiment, the transfer processing of double buffer switching section 800 can be performed efficiently without increasing the load on the system.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described.

In this embodiment, in order to increase the processing speed, only the calculation in the y-axis direction is performed, and the x-axis direction is fixed as the display VRAM width.

That is, in the above-described embodiment, the update area information 403 (start x coordinate, start y coordinate, width, height) by drawing for each primitive drawing is stored in the cumulative rectangle information 405.
(Rectangle start x coordinate, rectangle start y coordinate, rectangle width, rectangle height) are added in both the x-axis direction and the y-axis direction. However, in this embodiment, only the y-axis direction is added and 2 A rectangle having a display VRAM width including two rectangles is obtained.

Specifically, in FIG. 7, step S6
If it is determined at 21 that the rectangle width or the rectangle height is equal to 0, after clearing the cumulative rectangle information 405, it is determined that an update area is to be added for the first time, and the rectangle start y coordinate and the rectangle height of the cumulative rectangle information 405) The start y coordinate of the update area information 403
The heights are respectively substituted (steps S623 and S62)
5). In step S622, 0 is substituted for the rectangle start x coordinate. In step S624, the display VRAM width is substituted for the rectangular width.

If it is determined in step S621 that they are not equal, it is determined that a valid value has already been entered in the cumulative rectangle information 405, and the following addition processing is performed. First, based on the update area information 403 (start y coordinate, height) passed as an argument and the accumulated rectangle information 405 (rectangle start y coordinate, rectangle height) already stored, a newly added rectangle (start y coordinate, end) y coordinate) and existing cumulative rectangle (rectangle start y coordinate, rectangle end y)
Is obtained (steps S627 and S629). Steps S626 and 628 are not executed.

Next, the calculation of the existing cumulative rectangle = the existing cumulative rectangle + the newly added rectangle is performed (steps S632, 633, 6).
37, 638, 639). Step S630, 631,
Steps 634, 635, and 636 are not executed. In this calculation, first, a rectangular start y coordinate is obtained (steps S632 and S63).
3). Next, a rectangle end y coordinate is obtained (step S63).
7,638). Next, the rectangle end y coordinate and step S63
A rectangle height is obtained from the rectangle start y coordinate obtained in 2,633 (step S636).

As described above, the addition result is the cumulative rectangle information 405
(Rectangular start x coordinate = fixed, rectangular start y coordinate, rectangular width = fixed, rectangular height).

As described above, according to the present embodiment, only the y (vertical) axis direction of the update area information is accumulated, and the x (horizontal) axis is stored as rectangular information having the width of the VRAM, thereby achieving processing. Can be speeded up.

In this embodiment, the width of the display VRAM is fixed in the x (horizontal) axis direction and accumulation is performed only in the y (vertical) axis direction. This is a case where it is assumed that addresses are continuous. For example, when addresses on the VRAM are continuous in the y (vertical) axis direction, the display VRAM width is fixed in the y (vertical) axis direction.
By accumulating only in the x (horizontal) axis direction, a similar high speed can be achieved.

(Other Embodiments) The present invention
The present invention may be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, and the like), or may be applied to a device including one device (for example, a copier, a facsimile device, and the like). .

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. The functions of the above-described embodiments are not only realized by the computer executing the readout program code, but also the operating system running on the computer based on the instructions of the program code.
It goes without saying that the (OS) or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the above-described flowcharts (shown in FIG. 14 and / or FIG. 15).

[0105]

According to the present invention, the double buffer is efficiently switched by using the built-in multi-window system operating on the real-time OS without being conscious of exclusive control of drawing in window units. It is possible to provide an image processing apparatus and an image processing method in which flicker is suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram showing information stored in a VRAM 801 and a VRAM 802.

FIG. 3 is a flowchart illustrating an initialization process of a double buffer switching unit 800.

FIG. 4 is a flowchart illustrating a point drawing process of a drawing unit 500;

FIG. 5 is a diagram showing color palette information representing color data.

FIG. 6 is a flowchart showing a color index acquisition process of a drawing unit 500.

FIG. 7 is a flowchart illustrating an update area adding process of an update rectangle accumulating unit 600;

FIG. 8 is a flowchart showing a horizontal line drawing process of the drawing unit 500.

FIG. 9 is a flowchart illustrating a vertical line drawing process of the drawing unit 500.

FIG. 10 is a flowchart illustrating a bitmap drawing process of a drawing unit.

FIG. 11 is a flowchart showing a drawing request reception process of a drawing request counting unit 700.

FIG. 12 is a flowchart illustrating an update start process of the update rectangle accumulating unit 600;

FIG. 13 is a flowchart showing a drawing completion receiving process of the drawing request counting unit 700.

14 is a flowchart illustrating a switching process of a double buffer switching unit 800. FIG.

FIG. 15 is a flowchart showing a transfer process of a double buffer switching unit 800.

FIG. 16 is a state transition diagram of the double buffer control unit 400.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 display device 110 operation button 200 CPU bus 210 CPU 220 ROM 300 RAM 310 window system for embedding 320 window application task 1 330 operating on window system for embedding Window application task 2 330 operating on window system for embedding Window operation command 350 In-window drawing command 360 Button event 400 Double buffer control unit 401 Update start event 402 Point, horizontal line, horizontal line, bitmap writing process 403 Update area information of drawing by drawing unit 500 404 Update completion event 405 Cumulative rectangle Information 406 Drawing command 407 Drawing request command 408 Drawing completion command 500 Drawing unit 600 Update rectangle accumulation unit 700 Update request counting unit 701 Counter 8 0 window double buffer switching unit 801 VRAM 802 VRAM 803 Window 902 Window system for embedded to write selector switch 804 display switching switch 805 transfers image 900 displayed device 901 window system for embedded is displayed is displayed

Continued on the front page (72) Inventor Seiji Sasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Toshio Yabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. F term (reference) 5B069 BC02 CA13 5B098 AA08 GA02 GA04 GC02 GD05 GD14 5C082 AA01 BA12 BB15 BB25 BB26 CA62 CB01 DA22 DA53 DA87 MM02 MM10

Claims (11)

[Claims] 1. An image processing apparatus using an embedded window system that operates on a real-time OS and has two image storage media, and a drawing unit that performs drawing on one of the two image storage media. Determining means for determining whether or not drawing is being performed by the drawing means; and updating information accumulating means for accumulating and holding update information by drawing when the determining means determines that drawing is being performed. And control means for setting one of the two image storage media as a writing image storage medium on which drawing is performed by the drawing means and the other as a display image storage medium. When the determination means determines that drawing is not performed, the image information storage medium is switched between the writing image storage medium and the display image storage medium, and the update information accumulated by the update information accumulation means is An image processing apparatus for transferring from a display image storage medium to a writing image storage medium. 2. The image processing apparatus according to claim 1, wherein said image processing apparatus further comprises image display means. 3. The image processing apparatus according to claim 1, wherein said drawing means performs drawing on an image storage medium for writing at asynchronous timing. 4. The method according to claim 1, wherein the determining unit includes a counting unit that counts the number of windows in which the drawing unit is performing drawing, and the update information accumulating unit changes the number of windows counted by the counting unit from 0 to 1. At the time of the change, the update information by drawing starts to be accumulated. At the time when the number of windows counted by the counting means changes from 1 to 0, the control unit switches the writing image storage medium and the display image storage medium. The image processing apparatus according to claim 1, wherein the switching is performed, and the update information is transferred from the display image storage medium to the writing image storage medium. 5. The control means according to claim 1, wherein said update information accumulated by said update information accumulating means is transferred from said display image storage medium to said writing image after all tasks on said real-time OS are suspended. 2. The image processing apparatus according to claim 1, wherein the image is transferred to a storage medium. 6. The update information accumulating means is means for accumulating and holding, as the update information, information of a region updated and rendered as rectangular information, wherein one of the rectangular information in the vertical or horizontal axis direction is provided. The image processing apparatus according to claim 1, wherein a fixed value is not accumulated in the axial direction, and only the other axial direction is accumulated. 7. The image processing apparatus according to claim 1, wherein round robin scheduling is performed only for a group of window application tasks on a real-time OS. 8. The image processing apparatus according to claim 1, wherein a series of drawing instructions from a group of window application tasks on the real-time OS are executed only in a redrawing event handler in each window application task. . 9. A computer-readable memory storing an image processing program that is executed by a computer so that the computer operates as the image processing apparatus according to claim 1. Description: 10. An image processing method for performing drawing, wherein one of two image storage media is selectively used as a write image storage medium and the other is used as a display image storage medium. A drawing step of performing drawing in the drawing step; a determining step of determining whether or not the drawing is performed in the drawing step; and if the determining step determines that the drawing is performed, the update information by the drawing is accumulated. An update information accumulating step for storing and updating, and when it is determined that drawing is not performed in the determining step, the image information storage medium for writing and the display image storage medium are switched, and the update information accumulated in the update information accumulating step is obtained. Transferring the image data from the display image storage medium to the writing image storage medium. 11. A computer-readable memory storing an image processing program for performing drawing, wherein one of the two image storage media is selectively used as a write image storage medium and the other is used as a display image storage medium. A code for a drawing step for drawing on the image storage medium for writing, a code for a determination step for determining whether or not the drawing in the drawing step is performed; and a determination that the drawing is performed by the determination step Then, a code of an update information accumulating step for accumulating and holding update information by drawing, and when it is determined in the determining step that drawing is not performed, a writing image storage medium and a display image storage medium And a code for a control step of transferring the update information accumulated in the update information accumulating step from the display image storage medium to the writing image storage medium. Over data readable memory.