JPH06162182A - Image data rotating process system - Google Patents

Abstract

PURPOSE:To shorten the processing time of a rotating process by shortening the required time from the angle input of the rotation of image data, specially, optional-angle rotation to displaying on a display screen. CONSTITUTION:The amount of data to be rotated is decreased by an image data reducing process (S4) so as to shorten the rotating process. Further, display data (D4) to be displayed are generated and then displayed by a reduced data thinning-out process (S5) and a thinned-out data rotating process (S6) to shorten the necessary time from the angle input to the display of the rotation result on the display screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data rotation processing system capable of rotating image data of bit map data at an arbitrary angle.

[0002]

2. Description of the Related Art Generally, there are two types of graphics software, a draw type that handles vector data and an image type that handles bitmap data. Vector data can handle a drawn figure as one object and is represented by coordinate data. Therefore, the vector data can be easily edited by calculation. In the bitmap data editing function, in order to support the editing function similar to that of the vector data, a high-level bitmap processing is required, and the processing time for editing one bit map is also required. However, bitmap data is required to have the same editing function as vector data, and its performance is also required. Due to this tendency, the arbitrary angle rotation function of bitmap data is also required as one of the data editing functions.

A conventional image data rotation method based on bitmap data will be described with reference to the drawings. In step S1 of FIG. 4, the range to be rotated in all the image data is input. Image data D1 in the input range
Is cut out into the bit map (step S2).
When an arbitrary rotation angle θ (0 ° <θ <360 °) is input (step S3) and the rotation angle θ is determined, the image data D1 which is the rotated data is rotated by the angle θ (step S10).

The image data D6 subjected to this rotation processing (step S10) is enlarged. The reason for enlargement will be described with reference to FIG. When the image data shown in FIG. 2A is rotated at an arbitrary angle θ (described as θ = 45 °), the rotation data shown in FIG. 2B is obtained. Further, the rotation data is rotated by an arbitrary angle θ. Since the image data cannot be treated as an object like the vector data in the editing of the image data, the rotation data is subjected to the rotation processing by designating the range shown in FIG. The result is magnified like the rotation data shown in FIG. 2D, and the image data shown in FIG.
The result is different from the rotation data of FIG. 2 (e) which is rotated.

If the rotation processing other than the 90 ° unit rotation is performed in this way, the image data will be enlarged, so that rotation data reduction processing is required. The holding data D5 can be generated by calculating the reduction ratio from the data enlargement ratio by the arbitrary angle θ and performing the rotation data reduction process (step S11). The holding data D5 is pasted (step S9) to the image data subjected to the image data cutting process (step S2), and the holding data D5 is displayed on the screen by the holding data display process (step S12).

[0006]

In the conventional image data rotation processing method, since the image data is rotated as it is, the rotation processing, reduction processing, and display processing require a large amount of data. Since there is a large amount of data, there is a drawback that the processing time is long. Further, since the processing time is long, it takes a long time from the input of the rotation angle to the display of the result.

[0007]

SUMMARY OF THE INVENTION The present invention is an image data rotation processing method for rotating image data by bit map data in which image data is enlarged at a rate according to a rotation angle, at a rate according to a rotation angle. It is characterized in that the image data is reduced and then the image data is rotated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a flow chart showing an embodiment of the present invention.

In FIG. 1, in step S1, the operator inputs the range to be rotated in all the image data,
Determine the rotation range. Image data of the determined rotation range is obtained from all the image data, and a bitmap for rotation is created. This is the image data D1. After inputting the rotation range (step S1), the operator inputs the rotation angle (step S3). The rotation angle that can be specified by the operator is an arbitrary angle θ (0 ° <θ <359 °). In the following description, θ = 45 degrees in the examples.

After inputting the rotation angle (step S3), the image data D1 is reduced (step S4). The reason why the reduction processing (step S4) is performed before the rotation is that the image data of FIG. 2A is rotated 45 ° twice twice as described above with reference to FIG. The data is different from the image data shown in FIG. 2E rotated by 90 °. Therefore, reduction processing is required to correct the enlargement.

Magnification ratio is 45 °, 135 °, 225 units, 3
When rotated by 15 °, the maximum value is 1.414 (square root of 2) times. The reduction ratio for correcting the enlargement can be determined by the relationship shown in FIG. When the rotation angle θ is 45 °, the reduction rate is _COS θ
= 1 / 1.414. Image data reduction processing (step S4) is performed at the obtained reduction ratio. The reduction processing is performed by the method of thinning out the dots of the image data, and the reduction data D
Generates 2.

The higher the resolution (the number of bits in 1 inch) of the image data, the more beautiful the data can be expressed.
Although the resolution differs depending on the screen and the printer, the resolution of the screen is lower than that of the printer, so the data displayed on the screen is coarser than the data to be printed. Therefore, when displayed on the screen, rough data for display is required, and for printing, high density data for expressing more beautiful data is required.

The coarse data for display is subjected to reduced data thinning processing (step S5) so that the image data has a screen resolution of 1: 1. In this embodiment, the image data to be held and the density of the screen will be explained as 4: 1.
By the reduced data thinning process (step S5), the reduced data D2 is thinned to 1/4 to generate thinned data D3 having a screen density of 1: 1.

The data amount of the thinned-out data D3 is 1 / (4 × 1.414) times the D1 of the image data, and the rotation processing of the thinned-out data D3 is significantly faster than the rotation of the image data D1 (step). It is possible to perform S6). The display data D4 generated by the thinning-out data rotation process (step S6) is displayed on the screen at a ratio of 1: 1 (step S7). At this point, the operator can see the rotation result on the screen.

After displaying the rotation result on the screen, the reduction data D2 is rotated (step S8) to generate the holding data D5 to be reflected in all the image data.
This holding data D5 is pasted to all the image data whose rotation range has been cut out (step S9), and a series of rotation processing is completed.

In the embodiment, since the amount of data for rotation processing can be reduced by reducing the image data before the rotation, the rotation processing time can be greatly shortened, and the reduced data can be displayed instead of displaying the held data. By displaying the rotation display data which is thinned and rotated, the processing time from the angle input to the display can be reduced.

[0018]

According to the image data rotation processing method of the present invention, since the amount of data to be rotated can be reduced by reducing the image data before rotation, the rotation processing time can be greatly shortened. .

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a rotation process of image data.

FIG. 3 is a diagram showing a relationship between reduction ratios in the rotation process of step S8 and the reduction process of step S4 shown in FIG.

FIG. 4 is a flowchart showing a conventional image data rotation processing method.

Claims (1)

[Claims] 1. An image data rotation processing method for rotating image data according to bit map data, wherein image data is enlarged at a rate according to a rotation angle, and the image data is reduced at a rate according to a rotation angle. An image data rotation processing method characterized by performing data rotation processing.