JPH0944693A - Graphic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a graphic display device which is capable of reducing the capacity of memory for saving for returning to previous screen state. SOLUTION: When a storage device 4 display a prescribed image instructed by an input device 1, the device 4 stores the kind of the image, graphic parameter and the plotting color data of a video memory 5 before the image is plotted. When the instruction for restoration of a screen is given by an input device 1, a controller 2 reads the kind of the image and the graphic parameter from the storage device 4, supplies them to a graphic plotting algorithm generator 3 and writes the plotting color data read from the storage device 4 at the address of the video memory 5 corresponding to the plotting coordinates obtained by this supply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic display device having a video memory, and more particularly to a graphic display device for saving the contents of the video memory in order to restore the state before drawing.

[0002]

2. Description of the Related Art In a graphic display device having a video memory, after displaying a certain graphic and setting a certain screen state,
When it is necessary to restore the screen state before displaying the figure, the contents of the video memory in the previous screen state must be saved in the storage device in advance. In a conventional graphic display device, for example, when drawing a straight line as shown in FIG. 5, it is preferable to save the contents of a minimum rectangular area (minimum rectangle) that is parallel to the coordinate axes and surrounds the graphic to be drawn in a storage device. It is common.

[0003]

In such a conventional graphic display device, as described above, a small number of pixels (see FIG. 5) are used.
In the case of drawing a figure having only 13 pixels), the minimum rectangle forming 13 × 13 = 1
There is a problem that a memory for 69 pixels is required. The present invention has been made in view of such problems, and an object of the present invention is to provide a graphic display device capable of reducing the capacity of a save memory for returning to a previous screen state.

[0004]

In order to solve the above-mentioned problems of the prior art, the present invention provides a graphic display device for displaying a graphic of a predetermined drawing color on a monitor device, in which a graphic is drawn on the monitor device. , Input means for instructing the type of figure to be drawn, figure parameters, drawing color, screen restoration, control means for inputting an instruction signal from the input means, and by the control of the control means, by the input means By the graphic drawing algorithm generating means for generating the drawing coordinates corresponding to the instructed graphic and the control of the control means,
A video memory in which drawing color data representing the drawing color instructed by the input means is written at an address corresponding to the drawing coordinates obtained by the graphic drawing algorithm generating means, and the monitor device is instructed by the input means. When displaying a given figure, the type of the figure,
A saving means for storing drawing parameter and drawing color data of the video memory before drawing the drawing is provided, and when the screen restoration is instructed by the input means,
The control means reads out the type of the figure and the figure parameter from the storage means and supplies them to the figure drawing algorithm generating means, whereby the video memory corresponding to the drawing coordinates obtained from the figure drawing algorithm generating means. The present invention provides a graphic display device, characterized in that the drawing color data read from the storage means is controlled to be written in an address.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The graphic display device of the present invention will be described below with reference to the accompanying drawings. 1 is a block diagram showing an embodiment of the graphic display device of the present invention, and FIGS. 2 and 3 are flow charts for explaining the operation of the graphic display device of the present invention.
FIG. 4 is a diagram for explaining the save memory used in the graphic display device of the present invention.

First, the configuration of the graphic display device of the present invention will be described with reference to FIG. In FIG. 1, an instruction signal from an input device 1 including a keyboard and a mouse is input to the control device 2. The input device 1 instructs, for example, drawing and restoration of a figure (returning to a state before drawing a figure), shape (type) of a figure to be drawn, drawing color, and the like. The control device 2 controls the graphic drawing algorithm generating device 3, the storage device 4 as a save memory, and the video memory 5 based on the data input from the input device 1 in order to draw and restore the graphic.

The graphic drawing algorithm generator 3 should draw based on the graphic type information (triangle, rectangle, circle, etc.) input from the controller 2 and graphic parameters such as coordinate data for determining the shape. Coordinate data of points (drawing coordinates) are sequentially output. The storage device 4 stores type information of a figure to be drawn, figure parameters, and drawing color data of the video memory 5 before drawing. The data output from the control device 2 is written in the video memory 5 and displayed on the monitor device 6.

The operation of the graphic display device of the present invention at the time of graphic drawing and restoration will now be described. First, at the time of drawing a figure, in FIG. 2 showing the operation at the time of drawing a figure, the control device 2 acquires information on the type of a drawing to be drawn from the input device 1 (step S1). The figure type information is identification data such as a triangle, a rectangle, a circle, and an ellipse. The control device 2 acquires, from the input device 1, graphic parameters according to the type of graphic acquired in step S1. For example, when the type of figure is a rectangle, figure parameters such as drawing color, width and height of the rectangle, and coordinate values of reference points are acquired (step S2). The graphic to be displayed on the monitor device 6 is determined by the type of graphic acquired in step S1 and the graphic parameter acquired in step S2.

Further, the control device 2 stores the graphic type data acquired in step S1 in a predetermined area of the storage device 4 (step S3). For example, a triangle is 0, a rectangle is 1, a circle is 2, and so on. Continuing on, the controller 2
The graphic parameter acquired in step S2 is stored in a predetermined area of the storage device 4 (step S4). For example, in the case of a rectangle, the drawing color, the width, the height, the X coordinate of the reference point, and the Y coordinate are expressed in the order of 2 bytes, and the values are stored.

Thereafter, the control device 2 inputs the graphic type data and the graphic parameters acquired in steps S1 and S2 to the graphic drawing algorithm generating device 3 (step S).
5). As a result, the graphic drawing algorithm generator 3 outputs the coordinate data indicating the position of the point to be drawn until the graphic drawing is completed. The controller 2 acquires the coordinate value of the position of the point to be drawn from the drawing algorithm generator 3 (step S6). The control device 2 reads the data of the address on the video memory 5 corresponding to the drawing coordinates acquired in step S6, and saves this data in the storage device 4 (step S7).

Further, the control device 2 writes the drawing color data acquired in step S2 into the address on the video memory 5 corresponding to the drawing coordinates acquired in step S6 (step S8). As a result, the color of the corresponding point on the monitor device 6 changes to the drawing color designated by the input device 1. Then, it is determined whether the drawing is completed (step S
9), if completed, end. If not,
The operations of steps S6 to S8 are repeated until the drawing is completed. As a result, the graphic specified by the input device 1 is displayed on the monitor device 6 in the specified drawing color.

Next, at the time of restoration, in FIG. 3 showing the operation at the time of restoration, the control device 2 reads the data of the graphic type stored in the storage device 4 (step S11) and the data of the graphic parameter. (Step S12).
Then, the control device 2 inputs the graphic type data and the graphic parameters read in steps S11 and S12 to the graphic drawing algorithm generating device 3 (step S13).

The control device 2 acquires the coordinate value of the position of the point to be drawn from the drawing algorithm generating device 3 (step S14). The control device 2 reads the drawing color data before drawing, which is saved in advance from the storage device 4, for one pixel (S).
15). Then, the control device 2 writes the drawing color data read in step S15 in the address on the video memory 5 corresponding to the drawing coordinates acquired in step S14 (step S16). As a result, the color of the corresponding point on the monitor device 6 returns to the color before drawing.

Further, it is judged whether or not the restoration is completed (step S17), and if completed, the processing is ended. If not completed, the operations of steps S14 to S16 are repeated until the restoration is completed. As a result, the restored screen is displayed on the monitor device 6.

When storing the graphic type data, the graphic parameter, and the drawing color data in the storage device 4, the graphic type data is stored in the first area and the graphic parameter is stored in the second area, as shown in FIG. The drawing color data may be stored in the third area.

[0016]

As described in detail above, the graphic display device of the present invention is used to input a graphic on the monitor device, a type of graphic to be drawn, a graphic parameter, a drawing color, and an instruction for restoring the screen. Means, control means to which an instruction signal from this input means is input, graphic drawing algorithm generating means for generating drawing coordinates corresponding to the graphic instructed by the input means under the control of this control means, and control of the control means Thus, the video memory in which the drawing color data representing the drawing color instructed by the input means is written in the address corresponding to the drawing coordinates obtained by the graphic drawing algorithm generating means, and the predetermined amount instructed by the input means in the monitor device. When displaying a figure, the type of the figure, figure parameters and drawing color data of the video memory before drawing the figure are stored. When a screen restoration is instructed by the input means, the control means reads out the type of figure and figure parameters from the storage means and supplies them to the figure drawing algorithm generating means. Since the drawing color data read from the storage means is controlled to be written in the address of the video memory corresponding to the drawing coordinates obtained from the drawing algorithm generating means, the capacity of the saving storage means can be reduced. Further, when the screen is restored, the number of writings to the video memory is minimized, so that the restoration can be performed at high speed.

[Brief description of drawings]

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

FIG. 2 is a flow chart for explaining the operation of the present invention.

FIG. 3 is a flowchart for explaining the operation of the present invention.

FIG. 4 is a diagram for explaining a save memory used in the present invention.

FIG. 5 is a diagram for explaining a conventional example.

[Description of Reference Signs] 1 input device (input means) 2 control device (control means) 3 graphic drawing algorithm generation device (graphic drawing algorithm generation means) 4 storage device (storage means) 5 video memory 6 monitor device

Claims (1)

[Claims] 1. A graphic display device for displaying a graphic of a predetermined drawing color on a monitor device, comprising: drawing a graphic on the monitor device;
Input means for instructing drawing parameters, drawing color, screen restoration, control means for inputting an instruction signal by the input means, and control by the control means to correspond to the figure instructed by the input means. Graphic drawing algorithm generating means for generating drawing coordinates, and a drawing color representing a drawing color designated by the input means at an address corresponding to the drawing coordinates obtained by the graphic drawing algorithm generating means under the control of the control means. A video memory into which data is written, and a drawing color data of the video memory before drawing the type of the figure, a figure parameter and the figure when the predetermined figure instructed by the input means is displayed on the monitor device. And a storage means for storing the information, and when the input means gives an instruction to restore the screen, The control means reads out the type of the figure and the figure parameter from the storage means and supplies them to the figure drawing algorithm generating means, whereby the address of the video memory corresponding to the drawing coordinates obtained from the figure drawing algorithm generating means. A graphic display device, characterized in that the drawing color data read from the storage means is controlled to be written into the drawing display device.