JP3374449B2 - Scroll control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll control device for rapidly scrolling characters and the like on a display screen.

[0002]

2. Description of the Related Art Conventionally, in a scroll control device which expands document data in which characters, graphics, and the like are mixed into display data in a bitmap format and scrolls the display data as needed, a new scroll data is added each time the scroll is performed. The entire screen, including the document data that appeared, had to be re-expanded into a bitmap, which resulted in very slow scrolling.

On the other hand, in the method disclosed in Japanese Laid-Open Patent Publication No. 2-310592, display data for several screens before and after the currently displayed screen is stored in a buffer in advance,
A relatively high speed scroll is realized by transferring the display data to the VRAM in response to a scroll request.

[0004]

However, when color display has become common, the capacity of the VRAM is greatly increased to express multiple colors, and the buffer for storing the display data of several screens is also very large. In addition to requiring a large capacity, the time for transferring the contents of the buffer to the VRAM cannot be ignored because of the large capacity.

The scroll control device of the present invention solves such a problem and realizes extremely high-speed scrolling without requiring a large amount of buffers even for a multicolor color display screen. The purpose is to do.

The scroll control device of the present invention transfers document data including code information such as characters and figures and attribute information attached to the code information to the VRAM as bit map data, and the transferred bit map. The data is controlled to be displayed on the display unit, and the VRA is displayed in response to the scroll of the document data.
In a scroll control device for rewriting bitmap data on M, a scroll buffer for storing monochrome data corresponding to the document data for several screens including a screen corresponding to the bitmap data on the current VRAM, and a scroll When it occurs, one of the plurality of planes forming the VRAM is selected, the data of the selected plane is erased, and the scroll buffer corresponding to the document data newly displayed by scrolling is selected. A control unit that transfers monochrome data to the selected plane, invalidates the planes other than the selected plane, and controls to display based on the monochrome data transferred to the selected plane. It is characterized by having.

Further, when the monochrome data is transferred to the VRAM by the monochrome data transfer means, a timer means for measuring a predetermined time is provided, and when a new scroll does not occur within the predetermined time, The control means expands the document data corresponding to the monochrome data on the VRAM into the VRAM as bit map data capable of color display.

[0008]

EXAMPLES In order to further clarify the constitution of the present invention described above, preferred examples of the present invention will be described below. FIG. 1 is a block diagram showing a schematic configuration as an embodiment of the present invention. A CPU 2 for controlling the entire apparatus, a ROM 6 for storing a basic control program, an RAM, a RAM 4 in which an OS, application programs and the like are expanded, and buffers and parameters used by each are stored, and a display unit 12
The VRAM 10 and the timer 8 to which the display data of the bitmap format displayed in the above are written are mutually connected by the system bus 14.

FIG. 2 is a diagram showing the flow of display data in this embodiment. The document area 30 in the RAM 4 is a character code created by an application program or the like,
This is an area for storing document data including ruled line codes, attributes, image data, and the like. The upper part of the figure is the beginning of the sentence, and the lower part is the end of the sentence. Further, the inside thereof is divided into a document area 32 corresponding to the current screen, a document area 34 corresponding to the previous screen, and a document area 36 corresponding to the previous-previous screen.

The VRAM 10 is the R plane 5 in this embodiment.
4, G plane 55, B plane 56, I (Inten
It is divided into 4 planes of the (plane: light and dark data) plane 57, and 4 bits are distributed per 1 DOT of the display screen, and 16 colors can be displayed. It is also possible to use a so-called packed pixel type VRAM in which the number of planes is increased to make it more multicolored, or several bits representing 1 DOT are arranged next to each other.

Normally, the document data in the document area 32 corresponding to the current screen is developed by expanding an internal character code or the like into bit data corresponding to an actual display character and selecting a plane according to a designated color. While being written to the VRAM 10. For example, D with white specified
In case of OT, all corresponding bits of R plane 54, G plane 55, B plane 56, I plane 57 are 1
And all zero if black. In addition, each plane has a corresponding pallet register (not shown), and by manipulating the data in the pallet register, the role of each plane can be freely changed to R, G, B, light red, dark green, black, or the like. it can. Further, it is possible to invalidate each plane (not to display it even if data is drawn).

The scroll buffer 40 is an essential part of the present invention, and is an area for storing several screens of monochrome data corresponding to the document area 30. The current screen buffer 42 stores monochrome data corresponding to the document area 32 corresponding to the current screen, the previous screen buffer 44 corresponds to the document area 34 corresponding to the previous screen, and the pre-previous screen buffer 46 is Monochrome data for a total of three screens is buffered so as to correspond to the document area 36 corresponding to the screen before the screen.

Monochrome data is data before character code data or the like in the document area 30 is expanded into bitmap data and colored (distributed to each plane data of VRAM). It is possible to select only ON-OFF (white, black) of the display DOT with a corresponding data amount. Therefore, the memory area of the RAM 4 can be greatly saved.

The new area 48 is a scroll buffer added when scrolling reaches an area which is not covered by the current screen buffer 42, the previous screen buffer 44, and the pre-previous screen buffer 46. The old area 50 is a buffer area that is deleted as the new area 48 is added. In the figure, the data is scrolled downward, one line of data below is read from the document area 30, developed, and added as a new area 48.

When scrolling occurs, the data in the R plane 54 of the VRAM 10 is erased and the monochrome data in the scroll buffer 40 of the scroll destination is written in the R plane 54. The R plane 54 is set so as to develop black according to the value of the palette register, and the remaining planes are invalidated, so that a monochrome display corresponding to the R plane 54 is displayed on the display unit 12. In this case, since the drawing is performed on only one plane, very high speed drawing is possible.

FIG. 3 is a flow chart showing the procedure of the high speed scroll of the present embodiment, which will be described with reference to FIG. When there is a screen scroll request in S1, it is determined in S2 whether or not the scroll destination data has already been created in the scroll buffer 40, and if "No" (if scrolling downward in FIG. 2), then in S4. Scroll buffer 40
Check if you are using all, and if "Yes",
In S5, the old area 50 having the data farthest from the scroll position is discarded. If “No”, in S6, the new area 48
, And newly create the image data of the scroll destination in monochrome.

In the case of "Yes" in S2 (in the case of scrolling upward in FIG. 2), the document area 34 corresponding to the previous screen is displayed.
Confirm that the data has been changed, and if “Yes”, the determination of S4 starts. In this case, it is determined “No”, and the new data is overwritten on the previous screen buffer 44 in S6. become. In the case of "No" in S3, the process directly proceeds to S7 without creating new monochrome image data.

In S7, of the scroll buffer 40,
The image data of the scroll destination is transferred to the R plane 54. At this time, the R plane 54 is set to a monochrome plane, and the other planes are invalidated. In step S8, the timer 8 waits for a certain period of time, and if there is no scroll request, the VRAM
After returning the palette register of each plane of 10 to the original, in S9, the scroll destination data of the document area 30 is expanded and the color information is extracted, and the R plane 54, the G plane 55, the B plane 56, and the I plane 57 are extracted. Redraw.

If a VRAM buffer for backing up all the planes of the VRAM 10 is provided, the image data in the VRAM buffer is transferred from the VRAM buffer to each plane of the VRAM 10 when a few lines are scrolled, and only the newly appearing image is transferred. , Monochrome data can be transferred from the scroll buffer 40 to the VRAM 10. In this case, the entire screen does not become monochrome, which is effective when it is desired to scroll the end of the screen by several lines.

If the RAM 4 has enough space, the scroll buffer 40 can be divided into more screens or can be added for horizontal scrolling. If two scroll buffers 40 are provided, four-color display can be performed at high speed. Scrolling is also possible. For example, use the "arrow" key to scroll normally,
If the "Shift" + "arrow" keys are used for high-speed scrolling on a monochrome screen, and the "Ctrl" + "arrow" keys are used for semi-high-speed scrolling on a 4-color screen, the usability is further improved.

As described above, according to the present embodiment, high speed scrolling is enabled by temporarily displaying a part or all of the display screen in monochrome, and color display is performed when a predetermined time has elapsed after scrolling. Can be rewritten.

Further, since most of the documents for normal printing are composed in monochrome, there is no problem in practical use if they are temporarily returned to color display even if they are temporarily displayed in monochrome during scrolling.

[0023]

As described above, the scroll control device of the present invention has the scroll buffer for storing the monochrome data corresponding to the document data. Therefore, when scrolling, the monochrome data is transferred from the scroll buffer. For example, the display screen can be rewritten very quickly, and as a result, high-speed scrolling is possible.

Further, since the scroll buffer is composed of monochrome data, RAM consumption can be suppressed.

Furthermore, if the color display is restored again at a predetermined time after scrolling, a more natural operation feeling can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration as an embodiment of the present invention.

FIG. 2 is a diagram showing a flow of display data according to the present embodiment.

FIG. 3 is a flow chart showing a procedure of high-speed scroll according to the present embodiment.

[Explanation of symbols]

2: CPU 4: RAM 6: ROM 8: Timer 10: VRAM 12: Display 14: System bus 30: Document area 32: Document area corresponding to the current screen 34: Document area corresponding to previous screen 36: A document area corresponding to the screen before two 40: scroll buffer 42: Current screen buffer 44: Previous screen buffer 46: Screen buffer before last 48: New field 50: Old area 54: R plane 55: G plane 56: B plane 57: I plane

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Claims (2)

(57) [Claims] 1. Document data composed of code information such as characters and figures and attribute information attached to the code information is transferred as bit map data to a VRAM, and the transferred bit map data is displayed on a display unit. In the scroll control device for controlling the control so that the bitmap data on the VRAM is rewritten in response to the scroll of the document data, a screen for several screens including a screen corresponding to the current bitmap data on the VRAM is displayed. A scroll buffer for storing monochrome data corresponding to document data, and when scrolling occurs, one of the plurality of planes forming the VRAM is selected, data of the selected plane is erased, and scrolling is performed. Corresponds to the document data newly displayed by Control to transfer monochrome data on the scroll buffer to the selected plane, invalidate the planes other than the selected plane, and display based on the monochrome data transferred to the selected plane And a control means for controlling the scroll control device. 2. The scroll control device according to claim 1, further comprising timer means for measuring a predetermined time after the monochrome data transfer means transfers the monochrome data to the VRAM. In the case where a new scroll does not occur, the control means expands the document data corresponding to the monochrome data in the VRAM on the VRAM as bitmap data that can be displayed in color. Control device.