JPS6223333B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a CRT display device that displays a pattern according to data written in a digital memory, and in particular, when a light pen is placed facing a CRT screen, a digital memory allocated to correspond to the facing position, that is, the display position. An object of the present invention is to provide a video instruction device that can write data to be displayed at the specified position to the address of the specified position. In this type of video display system, by moving the light pen's indicated position, color display information is written one after another at the address of the digital memory according to the movement trajectory, and the CRT displays according to the written content. . In order to display a straight line on such an image display device, it is naturally necessary to move the light pen in a straight line, but this is extremely difficult to do manually by an operator, and nearly impossible in a high-resolution device. . Therefore, a device has been proposed that has a function called straight line writing so that the straight line moves in the specified direction while the light pen is outputting the specified information on straight line writing.
It was difficult to draw detailed straight lines. The present invention has been made in view of the above circumstances, and provides a video display device having a detailed linear writing function. do. FIG. 1 is a block diagram showing the main parts of a video display device according to the present invention, FIG. 2 is an instruction pattern diagram for explaining various instruction areas on a CRT screen, and FIGS. 3 and 4 are diagrams of various signals. FIG. 1st
In Fig. 2, 1 is a CRT indicating device;
Consider an orthogonal X-Y coordinate system in which the horizontal direction of the CRT1 screen is viewed as the X axis and the vertical direction as the Y axis, and each pixel is expressed by the coordinate values (X, Y) of this coordinate system. The address system of the memory in which data to be displayed on the screen of the CRT 1 is written is configured to correspond 1:1 to these coordinate values. That is, the horizontal address of the memory defines the coordinate value X, and the vertical address defines the coordinate value Y.
In addition, the portion of the CRT 1 screen where 0≦X≦X6 and 0≦Y≦Y1 is assigned as a writing area A, so that a desired color pattern can be displayed in this area A. Color instruction information can be written to the memory address corresponding to . Also, the area where X1≦X≦X3 and Y2≦Y≦Y4 is designated as the straight line writing designated area B, and X4≦X≦
The area where Y2≦Y≦Y4 at X5 is assigned as the color designated area C. Color display information to be displayed in the writing area A is written to an image memory 2 consisting of a RAM having addresses corresponding to the coordinate values of pixels in the writing area A. Writing can be performed using pen 3. On the other hand, the data related to the display of color specified area C (color specification information) and the data related to the display of straight line writing specified area B (straight line writing specification information) are the coordinate values of pixels in these areas C and B. It is written in advance in the corresponding ROM 4, and the light pen 2 is written in these areas B and C.
A predetermined display is always displayed regardless of the operation. The linear writing designation area B is divided into four equal parts in the shape of a square, and the coordinate range display of each division and the function when each division is specified, which will be described later, are as shown in the table below. In other words, data for displaying arrows pointing in four directions in each section is written in the corresponding address of the ROM 4. Note that the display pattern in these sections is not limited to the illustrated arrow mark, but any appropriate pattern may be used, and any color may be used.

【table】

[Table] The color instruction area C is horizontally divided into eight sections, and each section displays colors of red, green, blue, yellow, cyan, magenta, black and white (or gray). That is, in each address of the ROM 4 corresponding to each section of the color designation area C, 3-bit data indicating the respective display color is written. The areas other than the writing area A, the linear writing designated area B, and the color designated area C are displayed in a constant color,
The operation using the light pen 3 is not illustrated. Now, the configuration of the apparatus of the present invention will be explained based on FIG. The light pen 3 emits two types of signals as is well known. One is the switch signal SW that reports that the light pen 3 is pressed against the CRT 1;
SW=1 (high level) when pressing the light pen 3 as shown in the timing chart in the figure.
becomes. This switch signal SW is applied to the address determining circuit 5. The other signal is a signal that reports the indicated position on the CRT 1 screen by the light pen 3. This signal is emitted when the light receiving section of the light pen 3 captures the raster line passing through the indicated position, and the switch signal SW is "1". ”, the signal is input to the address determination circuit 5 which operates only when ``, and is converted into a signal corresponding to the coordinate values (X0, X0) of the indicated position of the light pen 3, and is input to the address determination circuit 6. The address determination circuit 6 generates six types of output signals, and which signal to generate is determined by the input signal, that is, the coordinate values (X0, Y0) of the light pen indicated position. First, the first signal is a color information capture signal a, which is generated when the light pen 3 indicates a color designation area C, and is given to the register 7 as a control signal. The second signal is a 3-bit color signal b, which has data content corresponding to the designated color of the designated section when the light pen 3 designates the color designated area C, and is stored in the 3-bit parallel register 7. It is beginning to be given to The third signal is an address signal C, which is emitted when the light pen 3 indicates a writing area, and has content representing the coordinate values (X0, Y0) of the indicated position, that is, input content from the address determination circuit 5. is input as is to the selection circuit 8 and the addition/subtraction circuit 9. The fourth signal is an addition/subtraction instruction signal d, which is emitted when the light pen 3 specifies the designated area B for linear writing, and has 2-bit data content corresponding to the specified section, and is sent to the addition/subtraction circuit 9. It is given as a signal specifying four types of addition/subtraction modes.
The fifth signal is a straight line writing instruction signal e, and as shown in FIG.
When ``1'' is specified, the counter A10 becomes ``1''.
The counter B11 is input to the selection circuit 8 and the gate circuit 12. The sixth signal is a write area signal f, which is generated when the address (X0, Y0) is in the write area A, and is input to the addition/subtraction circuit 9, the selection circuit 8, and the gate circuit 12. Register 7 captures color signal b when color information capture signal a is input,
This is stored and output to the image memory 2 as write data. As shown in FIG. 3, when the counter A10 receives the linear writing instruction signal e, the output signal h becomes "1", and the vertical synchronizing signal V
starts counting, and the count reaches the set value m.
When the output signal h of the counter A10 reaches "0"
becomes. As shown in FIG. 3, the counter B11 starts counting the vertical synchronizing signal V when the linear writing instruction signal e is input, and when the count reaches the set value n, the output signal i of the counter B11 becomes "1". This state is maintained until the straight line writing instruction signal e becomes "0". The output signal h of the counter A10 and the output signal i of the counter 11 are OR
The output of the gate 13 receives the clock from the clock B14 as one input.
It is used as the other input of AND gate 15. The addition/subtraction circuit 9 receives the address signal C when the write area signal f is input, and also outputs the AND gate 1.
At the timing when the output signal of 5 becomes "1", X0 or Y0 of the fetched address (X0, Y0) is +1 or -1 according to the contents of the addition/subtraction instruction signal d, and the addition or subtraction result is stored internally. At the same time, this is output to the selection circuit 5 as an address (X1, Y1). 16 is a display address counter for reading the contents of the image memory 2 and ROM 4 and displaying them on the CRT 1, and uses the clock from the clock A17 shown in the timing chart of FIG. The content of the count is changed accordingly, and the content of the count is output to the selection circuit 8 as a read address (X2, Y2). The content of this count, that is, the read address of image memory 2 and ROM 4 is
Since it corresponds to the X-Y coordinates of the CRT1 screen,
This is sent via the selection circuit 8 to the image memory 2 and
When given to the ROM 4, the 3-bit color information written at this address is converted into serial data by a parallel-to-serial converter circuit (abbreviated as P/S converter circuit) 17, and then sent to a D/A converter circuit 18. The color information is inputted here, converted to an analog video signal, and inputted to the CRT 1, where a display based on this color information is performed at the coordinates (X2, Y2) on the screen. The vertical synchronizing signal V shown in FIG. 3A and the horizontal synchronizing signal H shown in FIG.
Figure 4 (b) shows the display period signal D, which is a signal that is used for synchronization control of the display in step 1. It becomes "1" during the period except for this, and an image is displayed during the period when it is "1".
Therefore, the clock A is a signal that appears as many times as the number of pixels in one raster line while D="1". Note that the display period signal D is applied to the selection circuit 8 and the gate circuit 12. The selection circuit 8 receives input signals from the address judgment circuit 6 addition/subtraction circuit 9 and the address counter 16 in accordance with a combination of the write area signal f, the linear write designation signal e, and the display period signal D input as control signals to the selection circuit 8. It selectively selects address signals (X0, Y0), (X1, Y1) (X2, Y2), and outputs them as addresses (X, Y) for writing or reading to the image memory 2 and ROM 4. This output address (X, Y) is expressed by the following logical formula. (X, Y) = (X0, Y0)・f・+(X1, Y1)・e・+(X0, Y2)・D In other words, during the image display period (D="1"), the image memory 2 and ROM4 Select the output (X2, Y2) of the address counter 16 for displaying the contents, specify the writing area 1 with the light pen 3, and write the writing area f.
= “1”, select (X0, Y0) in a period other than the image display period (D = “0”),
In addition, when the light pen 3 is used to specify the straight line writing designation area B, and while the straight line writing indication signal e="1", (X1, Y1) is displayed in a period other than the image display period (D="0"). Select. The gate circuit 12 is a circuit for selectively switching the image memory 2 to read or write mode, and its output signal g is configured to be expressed by the following logic circuit. g=f.+e. This output signal g puts the image memory 2 into the write mode when g="1", and puts it into the read mode when g="0". Next, the operation of the device of the present invention will be explained. When displaying a pattern in the writing area A of the CRT 1, first, use the light pen 3 to indicate a section of the color designation area C in which a desired color is displayed. As a result, the address determining circuit 5 issues an address corresponding to this section, so the address determining circuit 6 receives this and outputs a color information acquisition signal a and a color signal b representing the color of the designated section. The register 7 stores color information represented by the color signal. Next, point the writing area A of the CRT 1 with the light pen 3. Then, the address (X0, Y0) corresponding to the coordinates of the indicated position is output from the address determination circuit 5 and input to the address determination circuit 6. In this case, the address (X0, Y0) corresponds to the coordinates within the write area A, so the address determination circuit 6 issues the write area instruction signal f and outputs the address (X0, Y0) to the selection circuit. do. The selection circuit 8 to which the write area designation signal f is input selects this (X0,
Y0) is selected and output to the image memory 2, and the gate circuit 12 also synchronously sets the image memory 2 to write mode by setting the write signal g="1", so this address (X0, Y0) is The color information stored in register 7 will be written. Then, in the next field, at the timing of D="1", the data written by the read address (X2, Y2) given from the address counter 16 via the selection circuit 8 is read out, and the data is read out from the address counter 16 to the pixel at the position indicated by the light pen. Dots of the desired color will be displayed. When the light pen 3 is moved within the writing area A of the CRT 1 in order to display a desired pattern, writing to the image memory 2 and display on the CRT 1 follow the movement trajectory. On the other hand, the write area designation signal f is also given to the adder/subtraction circuit 9, and when it is input, the address signal C is input and the address signal taken in when the write area designation signal f disappears, that is, (X0 , Y0) is held as the initial value of the straight line. Now, the linear writing which is the most characteristic feature of the apparatus of the present invention is carried out as follows. When the light pen 3 indicates the designated area B for straight line writing, the address determination circuit 6 outputs an addition/subtraction instruction signal d and a straight line instruction signal e. The addition/subtraction designation signal d has different contents depending on the four sections of the linear writing designation area B indicated by the light pen 3, and the above-mentioned initial values (X0, Y0) are +1 depending on the direction of the arrow. Or it operates to -1. These additions or subtractions are performed at the timing when the output signal of AND15 becomes "1". That is, as is clear from the timing chart in FIG. When the number of pulses of the synchronization signal V reaches (nm), addition or subtraction stops,
After that, addition or subtraction is performed as long as the light pen 3 continues to point to the linear writing designated area B. The result of addition or subtraction is the address signal (X1,
Y1) is output to the selection circuit 8, and in this case, since the linear writing instruction signal e="1", the address signal (X1, Y1) is selected during a period other than the image display period (D="0"). The color information stored in the register 7 is selected by the circuit 8, and at the same timing, the write signal g becomes “1” and the image memory 2 enters the write mode. The data is written and displayed during the image display period when D="1". As detailed above, according to the existing CRT display device, when the light pen indicates a designated area for straight line writing, the straight line continues to advance for that period. The timing of moving the line away from the designated area for straight line writing was an extremely difficult task. On the other hand, according to the present invention, since the straight line advances only during the period during which m pulses of the first vertical synchronization signal arrive, the value of m can be set so that, for example, one addition or subtraction is performed in m pulses. For example, by continuing to release the light pen until n pulses of the vertical synchronization signal arrive, the straight line can be advanced one address at a time. If you want to draw straight lines continuously, if you keep pointing the designated area for straight line writing with the light pen for at least the period during which n pulses of the vertical synchronization signal come, you can continue writing straight lines until you release the light pen. As mentioned above,
The CRT display device of the present invention finely extends the straight line and sets it to a predetermined length by repeating the operation of starting a straight line drawing operation with a light pen and then stopping the straight line drawing operation during the rest period of straight line drawing. , the length of the drawn straight line can be accurately set to the desired length. Furthermore, there is no need to enlarge the designated area for linear writing, and the writing area does not become narrow.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the device of the present invention;
FIG. 2 is a display pattern diagram for explaining the configuration of a CRT screen, and FIGS. 3 and 4 are timing charts for explaining the operation of the device of the present invention, in which 1 is a CRT, 2 is an image memory , 3 is a light pen, 4 is a ROM, 6 is an address judgment circuit, 7 is a register, 8 is a selection circuit, 9 is an addition/subtraction circuit, A is a writing area, B is a linear writing designated area, and C is a color designated area. shown respectively.

Claims (1)

[Claims] 1 Equipped with a CRT for displaying images, a readable and writable image memory, and a light pen,
A ROM in which linear writing specification information is written in a CRT display device that displays the contents of the image memory in the writing area allocated to the CRT screen.
means for displaying the contents of on a CRT screen, and an image memory address value corresponding to the position indicated by the light pen in the writing area of the CRT screen, and an address value corresponding to the time length of the input writing signal. a writing means that adds or subtracts one by one and writes display information in the area of the image memory specified by the address; and generates a first writing signal with a short initial period in response to a straight line writing instruction with the light pen. death,
A CRT display comprising a writing signal generating means for generating a second writing signal after a predetermined time delay from the end of the first writing signal until the end of the straight line writing instruction with the light pen. Device.