JP3018426B2 - Character / graphic drawing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a character / graphic drawing apparatus that develops outline fonts into bitmaps and draws them.

[Prior art]

An outline method is conventionally known for representing characters and figures. The outline method is a method in which the coordinates of outlines of characters and figures are widened and the characters and figures are expressed by interpolating them with line segments and curves. In order to output and display the characters and figures of the outline data, a process of drawing an outline using the outline data (outline font) and filling the inside is performed. That is, when this outline font is developed into a bitmap, the outline font is enlarged and enlarged so as to become a bitmap of a desired size.
A method is used in which conversion (affine transformation) such as reduction and rotation is performed, and then the outline is filled using the outline information.

[Problems to be solved by the invention]

In this outline method, when the character size is small or the resolution of the output device is low, interpolation cannot be performed well even if the outline data is expanded to a bitmap, and the character shape is greatly affected by the print characteristics of the output device. Problems. For example, if there is a portion where the width of the outline font is smaller than the minimum stroke width Wiot that can be expressed by the output device as shown in FIG. In addition, as shown in FIGS. 7B and 7D, a missing or interrupted font may occur, and the original shape may not be correctly represented. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the prior art, and to reduce the size of characters and graphics or the resolution of an output device so that there are few omissions or breaks in the original shape. Characters that can well represent
It is an object of the present invention to provide a graphic drawing device.

[Means for Solving the Problems]

The character / graphic drawing apparatus of the present invention comprises a stroke width extracting means (FIG. 1) for obtaining the minimum stroke width of the character / graphic from the outline data, and the minimum stroke width obtained by the stroke width extracting means (4). And an outline data correcting means (FIG. 1) for comparing the minimum stroke width and the minimum stroke width that can be displayed on the output device, and correcting the stroke width based on the result of the comparison.

[Action]

According to the present invention, when the stroke width indicated by the outline data is smaller than the minimum stroke width (resolution of the output device) that can be displayed on the output device, missing or broken fonts occur when the data is developed into a bitmap. Correct the data. More specifically, the minimum stroke width (W in FIGS. 4 and 6) of the outline data is extracted by the stroke width extracting means (4). When the extracted minimum stroke width (W) is smaller than the minimum stroke width (Wiot in FIGS. 4 and 6) that can be displayed on the output device, the outline data correction means (5, 6) changes the font width. Correct the outline data so that it expands. FIG. 6 shows an example of the correction, in which the outline font represented by the outline data is widened as shown by a broken line in FIG.
By making the minimum stroke width (W) larger than the minimum stroke width (Wiot) that can be displayed on the output device, font omission is eliminated as shown in FIGS.

【Example】

FIG. 1 is a functional block diagram of an embodiment of the present invention. This device stores an input unit 1 for inputting or storing character and graphic data to be output and displayed, an outline data storage unit 2 for storing outline data corresponding to the input data, and data indicating the resolution of the output device. An output resolution data holding unit 3 and a stroke data extracting unit 4 for obtaining a minimum value of a stroke width from outline data
And a correction determining unit 5 that compares the extracted minimum stroke value with the output device resolution data to determine whether or not the outline data needs to be corrected. An outline data correction unit 6 for correcting outline data based on output resolution data, a bitmap development unit 7 for developing outline data output from the outline data correction unit 6 into a bitmap, a printer, a display, and the like. And an output unit 8. FIG. 2 is an operation flowchart for explaining the correction of the outline data according to the present embodiment. The specific character used to extract the minimum stroke width W of the outline data is read and stored in the outline data storage unit 2 (step 201). Next, the minimum value Wiot of the stroke width that can be displayed on the device of the output unit 8 currently used is read into the output unit resolution data holding unit 3 (step 202). The minimum value of the stroke width is extracted from the outline data in the outline data holding unit 2 (step 203).
It is easier to use a special character for the extraction. For example, since the upper part of “0”, “8”, “9”, etc. generally has the minimum stroke width, it is suitable for use as a specific character for extracting the minimum width. The extraction process of the minimum stroke width will be described using the character “8” as an example. As shown in FIG. 3, the minimum rectangle surrounding each of the closed curves 31, 32, 33 is obtained, and the maximum value a, b,
Find c. In the case of "8", it is desired to be constituted by three closed curves, so that three maximum values are obtained. Sort these maximums in descending order. The difference between the largest maximum value and the next largest maximum value is defined as the minimum stroke width W. In the example of FIG. 3, W = ab. Next, it is determined whether or not the stroke data is to be corrected, that is, whether or not to make the stroke thicker.
204). That is, the minimum stroke width W of the outline data extracted by the stroke width extracting unit 4 is compared with the minimum stroke width Wiot that can be displayed on the output device. As a result of the comparison, when W ≧ Wiot, the stroke is not lost or interrupted when developed into a bitmap, so that it is determined that no correction is necessary, and processing for developing into a bitmap is performed (step 207). . As a result of the comparison, when W <Wiot, since the fineness of the stroke cannot be represented by the resolution of the output device, it is determined that the outline data should be corrected to increase the stroke, and the value to be increased. Calculate T (step
205). As shown in FIG. 5, the thickening value T is obtained by subtracting the minimum stroke width W of the outline data from the displayable minimum stroke width Wiot of the device of the output unit 8. That is, T = Wiot-W. Next, a process of thickening the outline data is performed (step 206). For this purpose, the outline data to be output is transferred from the outline data holding unit 2 to the outline data correction unit 6.
And the data is subjected to a thickening process using the thickened value T obtained as described above. It does the following. Find the normal vector of each segment. For the curve, an approximate normal vector is obtained from the start point and the end point for the curve. Assuming that the normal vector and the inclination of the x-axis are θ, and the thickening value is T, the x-axis component X and the y-axis component Y of the actually thickening value are obtained by X = T * cosθ Y = T * sinθ . The stroke of the outline data is thickened by adding the values X and Y for thickening the stroke thus obtained to each control point. When the outline data has been corrected in steps 205 to 206, the corrected outline data is bitmap-deployed by the bitmap developing unit 7 (step 207). The bitmap data obtained in this manner is sent to an output unit (for example, a printer) 8 so that characters and figures without missing or missing strokes can be output and displayed. Fifth
Figures (a) and (b) show the outline font when no correction is made, and Figures (b) and (d) show the characters obtained by bitmap expansion, and the stroke width of the outline font is printed by the output device. The smallest possible dot width Wi
Missing fonts occur in parts smaller than ot. On the other hand, according to the present embodiment, the font can be prevented from being lost as shown in FIGS. 6B and 6D by making the font thicker as shown in FIGS. 6A and 6C. In the embodiment described above, an example in which the minimum stroke width of the outline data is automatically extracted has been described. However, this may be configured to be semi-automatically extracted.
That is, the minimum stroke width is extracted in advance by an operator's manual operation, and is input as an attribute parameter in the outline data. Then, when converting the outline data into bitmap data, the minimum stroke width information input as the above-mentioned attribute parameter may be extracted from the outline data, and a correction process may be performed.

【The invention's effect】

According to the present invention, when the size of characters or graphics in the outline data is relatively small compared to the resolution of the output device, or when the resolution of the output device is low compared to the size of the characters or graphics, the omission or interruption occurs. It is possible to draw few characters and figures.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an embodiment of the present invention. FIG. 2 is an operation flowchart showing the outline data correction processing of this embodiment. FIG. 3 is a diagram for explaining a minimum stroke width extraction process. FIG. 4 is a diagram for explaining the calculation of the value to be thickened. FIGS. 5 (a) to 5 (d) are diagrams showing examples in which strokes are lost or interrupted when outline data is developed into a bitmap by a conventional technique. FIGS. 6 (a) to 6 (d) are diagrams showing an example in which the outline data is expanded according to the present invention and bitmap-expanded, thereby preventing the occurrence of missing or interrupted strokes. 1 ... input unit, 2 ... outline data holding unit, 3 ...
... Output section resolution data storage section, 4... Stroke width extraction section, 5... Correction determination section, 6... Outline data correction section, 7.

Claims (1)

(57) [Claims] 1. A stroke width extracting means for obtaining a minimum stroke width of a character or figure from outline data, and comparing the minimum stroke width obtained by the stroke width extracting means with a minimum stroke width which can be displayed on an output device. A character / figure drawing device comprising: an outline data correcting unit for correcting the stroke width to be increased based on the result of the comparison.