JP4952285B2 - Image processing apparatus, image processing method, and program - Google Patents

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program.

  Characters such as characters and figures displayed on the screen of games, car navigation systems, AV amplifiers, and the like use pattern data composed of a plurality of dots. Alpha blending processing is performed to superimpose. At that time, anti-aliasing processing may be performed in order to express the edge portion smoothly.

  An image processing apparatus that performs alpha blending processing and anti-aliasing processing stores, for each pattern data to be displayed, mixing ratio data (hereinafter referred to as alpha data) indicating a mixing ratio for each dot. Then, at the mixing ratio indicated by the alpha data, image data indicated by the pattern data for each dot (color data added to the pattern data; data consisting of RGB data for each dot) and the pattern. When displaying data, background image data (data consisting of RGB data for each dot) displayed on the background is mixed. As a result, the pattern data before and after can be synthesized, the color change at the edge portion can be reduced, and the edge portion can be expressed smoothly. Patent Document 1 discloses an example of this antialiasing process.

Patent Document 2 discloses bilinear processing which is a kind of interpolation processing for performing enlargement processing on pattern data.
JP 2004-213464 A JP 2006-18382 A

  However, in the above-described conventional technique, it is necessary to store both pattern data and alpha data for each character, and there is a problem that memory consumption is large.

  Accordingly, one of the objects of the present invention is to provide an image processing apparatus, an image processing method, and a program that can reduce the amount of memory required for performing alpha blending processing or anti-aliasing processing. .

An image processing apparatus according to the present invention for solving the above-described problem obtains display color data when a character to be drawn is a character , and handles the character when the character to be drawn is other than a character. Pattern data acquisition means for acquiring pattern data to be obtained, first alpha data acquisition means for acquiring a plurality of first alpha data corresponding to a plurality of dots, and a plurality of image data corresponding to the plurality of dots, respectively. The image data buffer to be stored, the display color data or the pattern data acquired by the pattern data acquisition unit for each dot, and the image data corresponding to the processing target dot are mixed based on the first alpha data Mixing means for mixing at a ratio and overwriting the image data buffer
According to this, since alpha blending processing or anti-aliasing processing can be performed only with alpha data without using pattern data, it becomes unnecessary to store pattern data, and is necessary for performing alpha blending processing or anti-aliasing processing. A reduction in the amount of memory is realized.

The image processing apparatus further includes second alpha data acquisition means for acquiring second alpha data obtained by enlarging each first alpha data acquired by the first alpha data acquisition means by interpolation processing, The mixing means may be configured to perform mixing at a mixing ratio based on the second alpha data instead of the first alpha data.
When the enlargement process by bilinear interpolation is performed on the mixture ratio pattern indicated by the first mixture ratio pattern data, the same enlargement effect as that obtained by performing the enlargement process by bilinear interpolation on the pattern data according to the prior art can be obtained.

The image processing method according to the present invention includes a pattern data acquisition unit, a first alpha data acquisition unit, an image data buffer that stores a plurality of image data respectively corresponding to a plurality of dots, and a mixing unit. An image processing method in an image processing apparatus, wherein the pattern data acquisition means acquires display color data when a character to be drawn is a character, and the character when the character to be drawn is other than a character. Pattern data acquisition step for acquiring pattern data corresponding to the first alpha data acquisition step, wherein the first alpha data acquisition means acquires a plurality of first alpha data respectively corresponding to a plurality of dots, and the mixing means, for each dot, the display obtained in the pattern data acquiring step And data or the pattern data, and those corresponding to the dot of the respective image data stored in the image data buffer, and mixed at a mixing ratio based on the first alpha data, overwrites the image data buffer And a mixing step.

In the image processing method, the image processing apparatus further includes a second alpha data acquisition unit, and the second alpha data acquisition unit acquires the first alpha data acquired in the first alpha data acquisition step. A second alpha data acquisition step of acquiring second alpha data obtained by enlarging the first alpha data by interpolation processing, wherein the mixing step mixes at a mixing ratio based on the second alpha data instead of the first alpha data It is also possible to do that.

The program according to the present invention obtains display color data when the character to be drawn is a character, and obtains pattern data corresponding to the character when the character to be drawn is other than a character. Data display means, first alpha data acquisition means for acquiring a plurality of first alpha data respectively corresponding to a plurality of dots, and the display color data or pattern data acquired by the pattern data acquisition means for each dot And the image data stored in the image data buffer storing the plurality of image data respectively corresponding to the plurality of dots are mixed at the mixing ratio based on the first alpha data. And the computer functions as a mixing means for overwriting the image data buffer. It is a program for.

  In the above program, the computer functions as second alpha data acquisition means for acquiring second alpha data obtained by enlarging the first alpha data acquired by the first alpha data acquisition means by interpolation processing. The mixing means may be configured to mix at a mixing ratio based on the second alpha data instead of the first alpha data.

Embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
FIG. 1 is a block diagram showing a system configuration of an image processing apparatus 1 according to the first embodiment of the present invention. As shown in the figure, the image processing apparatus 1 is connected to a CPU (Central Processing Unit) 10, a pattern memory 20, and a CRT (Cathode Ray Tube) 40, and displays an image as a whole. The apparatus 30 is configured. The image processing apparatus 1 includes a CPU interface 50, a pattern memory interface 51, a sprite attribute table 53, a register 54, a sprite drawing unit 55a, a sprite generation unit 56, a line buffer 57, a pixel data control unit 58, and a CRT control. Section 59, clock generation section 60, and three D / A converters (Digital / Analog converters) 61-1 to 61-3.

The CRT 40 is a display device that displays image data on a two-dimensional coordinate space using a cathode ray tube. Instead of the CRT 40, an LCD (Liquid Crystal Display), an EL (Electro Luminescence) display, or the like may be used.
The two-dimensional coordinate space is composed of a large number of dots arranged in a matrix. Each combination of dots corresponding to a matrix row constitutes one scanning line, and the CRT 40 receives input of image data for each scanning line.

  The image data is composed of image data (RGB data) for each dot. Here, the RGB data is data indicating the luminance of each of the three primary colors of red, green, and blue in 256 gradations, and specifically includes three 8-bit data corresponding to each of red, green, and blue. Is done. The CRT 40 performs display processing for displaying image data by causing each dot to shine according to each image data. The CRT 40 performs this display process for each scanning line.

  The image processing apparatus 1 performs a drawing process for generating the image data composed of RGB data for each dot, and outputs the generated image data to the CRT 40. Here, in particular, the image processing apparatus 1 generates image data to be output to the CRT 40 by drawing several sprites (image data) in an overlapping manner. Details of the processing of the image processing apparatus 1 will be described later.

The pattern memory 20 stores pattern data for each character other than characters among the characters to be drawn, and stores a plurality of first alpha data respectively corresponding to a plurality of dots for each character. Each first alpha data is data composed of 4-bit numerical values (coefficients), and each indicates a mixing ratio (a ratio of a background image (described later) to a sprite (described later)) described later.
The pattern memory interface 51 of the image processing apparatus 1 controls data exchange between the pattern memory 20 and each part of the image processing apparatus 1.

  The CPU 10 instructs the image processing apparatus 1 on the specific contents of the drawing process to be performed. That is, the CPU 10 specifies a character to be drawn, instructs the image processing apparatus 1 to start drawing, and also specifies the address position of the pattern memory 20 where the first alpha data corresponding to the character is stored, and the above 2 of the character. Data (sprite attribute data) for designating the position in the dimensional coordinate space and the enlargement / reduction ratio of the character is output to the image processing apparatus 1. When the character is a character, the CPU 10 also outputs display color data (RGB data) indicating the color of the character instructed to be drawn by the instruction information to the image processing apparatus 1.

  The CPU interface 50 of the image processing apparatus 1 controls data exchange between the CPU 10 and each unit of the image processing apparatus 1. The CPU 10 writes the sprite attribute data in the sprite attribute table 53 of the image processing apparatus 1 and the display color data in the register 54 via the CPU interface 50.

Details of the image processing apparatus 1 will be described below.
The sprite attribute table 53 stores sprite attribute data written from the CPU 10. The register 54 stores various data such as the number of scanning lines of the CRT 40 in addition to the display color data written from the CPU 10.

  The sprite generation unit 56 acquires the address position of the pattern memory 20 included in the sprite attribute data stored in the sprite attribute table 53 and outputs the acquired address position to the sprite drawing unit 55. In addition, the timing control of each process performed by the sprite drawing unit 55 and the exchange of various data between the sprite drawing unit 55 and the sprite attribute table 53 and the register 54 are performed.

  The sprite drawing unit 55 obtains the first alpha data from the pattern memory 20 based on the address position input from the sprite generation unit 56, and performs a drawing process including a process of performing mixing at the mixing ratio indicated by the first alpha data. As a result, image data is generated for each scanning line of the CRT 40 and stored in the line buffer 57. The processing of the sprite drawing unit 55 will be described in detail later.

  The line buffer 57 is an image data buffer having a double buffer configuration composed of the line buffers 57-1 and 2. While the sprite rendering unit 55 performs image data rendering processing using one of them, pixel data control described later is performed. The unit 58 reads out image data using the other. That is, the sprite drawing unit 55 and the pixel data control unit 58 use the line buffer 57 while alternately switching the line buffer 57. Each line buffer 57 includes a storage area for the number of dots constituting one scanning line of the CRT 40, and stores image data corresponding to each dot in each storage area.

  The pixel data control unit 58 reads image data for the number of dots constituting one scanning line of the CRT 40 from one of the line buffers 57 and outputs the image data to the CRT 40. There are CRTs 40 that accept analog signal input and digital signal input depending on the model. When the CRT 40 that accepts an analog signal input is used, each image data output from the pixel data control unit 58 is converted into an analog signal by the D / A converters 61-1 to 61-3 and then input to the CRT 40. Each D / A converter 61-1 to 6-3 corresponds to red (R), green (G), and blue (B), respectively. On the other hand, when the CRT 40 that accepts input of a digital signal is used, the image data output from the pixel data control unit 58 is input to the CRT 40 as it is.

The CRT control unit 59 synchronizes the timing at which the pixel data control unit 58 reads out image data from one of the line buffers 57 and outputs the image data to the CRT 40 and the timing at which the CRT 40 performs display processing.
The clock generation unit 60 generates a clock pulse and outputs it to each unit of the image processing apparatus 1. Each unit performs each process in synchronization with this clock pulse.

Hereinafter, the processing of the sprite drawing unit 55 will be described in detail.
FIG. 2 is a functional block diagram of functional blocks of the sprite drawing unit 55 according to the first embodiment. As shown in the figure, the sprite drawing unit 55 includes an alpha data acquisition unit 551, an alpha blending unit 553a, and a pattern data (display color data) acquisition unit 554.

  When a sprite attribute pattern indicating a character drawing instruction is written in the sprite attribute table 53 from the CPU 10, the sprite drawing unit 55 starts drawing processing using each unit.

  The alpha data acquisition unit 551 acquires the first alpha data by reading the first alpha data corresponding to the drawing target character from the pattern memory 20 based on the address position input from the sprite generation unit 56 for the drawing target character. It functions as first alpha data acquisition means.

  The pattern data acquisition unit 554 functions as display color data acquisition means for acquiring display color data relating to the drawing target character from the register 54 when the drawing target character is a character. If the character to be drawn is something other than characters, the pattern data acquisition unit 554 acquires pattern data stored in the pattern memory 20.

  For each dot in the two-dimensional coordinate space, the alpha blending unit 553a displays the display color data acquired by the pattern data acquisition unit 554 and the image data stored in the line buffer 57 corresponding to the dot. The mixture data is generated by mixing at the mixture ratio indicated by the first alpha data acquired by the alpha data acquisition unit 551. The mixed data functions as a mixing unit that overwrites the line buffer 57.

Specifically, the alpha blending unit 553a generates mixed data by performing the calculation of the formula (1) or the formula (2) for each color of red (R), green (G), and blue (B). . When the first alpha data is 0 or more and 7 or less, Expression (1) is used, and when the first alpha data is 8 or more and 15 or less, Expression (2) is used. However, (for layer) is display color data, and (back layer) is image data stored in the line buffer 57. The reason why different formulas are used depending on the value of the first alpha data is to realize the mixing ratio classified into 17 levels using the first alpha data which is 4-bit information.
Mixed data = (fore layer) × (16−first alpha data) / 16 + (back layer) × first alpha data / 16 (1)
Mixed data = (fore layer) × (16−first alpha data−1) / 16 + (back layer) × (first alpha data + 1) / 16 (2)

Note that the alpha blending unit 553a performs the above mixing for each scanning line of the CRT 40 with respect to the coordinates of the overlapping portion of the first alpha data with the scanning line.
As a result, the alpha blending unit 553a, as a result, uses the display color data acquired by the pattern data acquisition unit 554 as pattern data corresponding to each dot in the image data stored in the line buffer 57. Sprite).

  FIG. 3 is an explanatory diagram for explaining the above-described processing of the sprite drawing unit 55. The figure shows the above processing for one color of red (R), green (G), and blue (B). FIG. 3A shows display color data acquired by the pattern data acquisition unit 554. The numerical value shown in FIG. FIG. 3B shows the first alpha data for 4 × 4 dots acquired by the alpha data acquisition unit 551. Each square in the figure represents a dot, and the numerical value corresponding to each square is the first alpha data. FIG. 3C shows image data for 4 × 4 dots stored in the line buffer 57. The squares in the figure also indicate dots, and the numerical value corresponding to each is luminance. FIG. 3C shows four scanning lines side by side.

FIG. 3 (d) shows the display color data shown in FIG. 3 (a) and the image data shown in FIG. 3 (c), with the mixing ratio indicated by the first alpha data shown in FIG. 3 (b). FIG. 6 shows each mixing data (mixing result of the alpha blending unit 553a) obtained by mixing each dot. For example, when attention is paid to the second dot from the left and the third dot from the top, Equation (1) is calculated as Equation (3) below.
Mixed data = 100 × (16−7) / 16 + 50 × 7 / 16≈78 (3)

On the other hand, when attention is paid to the dot in the lower right corner, the equation (2) is calculated as the following equation (4). The mixed data calculated by the equation (4) is the same as the image data. This is because the mixing ratio is 1 (first alpha data is 15), and the contribution to the first alpha data of (fore layer) is This is because it is 0%.
Mixed data = 100 × (16−16) / 16 + 50 × 16/16 = 50 (4)

  As described above, since only the display color data is required for the processing of the sprite drawing unit 55 for characters, it is not necessary to store the pattern data in the pattern memory 20.

[Embodiment 2]
In the second embodiment, the inside of the sprite drawing unit 55 of the first embodiment is changed. FIG. 4 is a schematic block diagram illustrating functional blocks of the sprite drawing unit 55 according to the second embodiment. As shown in the figure, the sprite drawing unit 55 includes a bilinear processing unit 555b between the alpha data acquisition unit 551 and the alpha blending unit 553a. Hereinafter, differences from the first embodiment will be described.

  The bilinear processing unit 555b functions as a second alpha data acquisition unit that acquires second alpha data obtained by enlarging the first alpha data acquired by the alpha data acquisition unit 551 by interpolation processing. The alpha blending unit 553a performs mixing at the mixing ratio indicated by the second alpha data.

  That is, before the enlargement, each first alpha data corresponds to the coordinates where the dots in the two-dimensional coordinate space are located (hereinafter referred to as dot coordinates). However, after the enlargement, the correspondence between the first alpha data and the dot coordinates is lost, and there are dot coordinates that do not have corresponding alpha data. Therefore, the bilinear processing unit 555b generates alpha data (second alpha data) corresponding to each dot coordinate by interpolation processing, and outputs it to the alpha blending unit 553a. Details will be described below.

FIG. 5 is a diagram for explaining the principle of generating the second alpha data from the first alpha data by the bilinear processing unit 555b. Here, in the figure, the x mark is the coordinate corresponding to the second alpha data, A, B, C, and D are the coordinates corresponding to the first alpha data, xd is the horizontal distance from A to X, and yd is Assuming a vertical distance from A to X, the second alpha data is
Second alpha data = (1−xd) × (1−yd) × A + xd × (1−yd) × B + (1−xd) × yd × C + xd × yd × D (5)
Can be obtained by performing the following calculation.
If the second alpha data does not become an integer value by the calculation of the equation (5), the integer value may be obtained by rounding off or rounding up or down after the decimal point.

  For each dot, the alpha blending unit 553a displays the display color data acquired by the pattern data acquisition unit 554 and the image data stored in the line buffer 57 corresponding to the dot from the bilinear processing unit 555b. Mixing data is generated by mixing at the mixing ratio indicated by the input second alpha data.

  As described above, according to the image display device 30, the second alpha data corresponding to each dot one-to-one is generated based on the mixture ratio pattern after the enlargement process. , Mixing by the alpha blending unit 553a becomes possible.

[Embodiment 3]
In the third embodiment, the inside of the sprite drawing unit 55 of the second embodiment is changed, and a plurality of pattern data respectively corresponding to a plurality of dots is stored in the pattern memory 20. Each pattern data is data composed of a 1-bit numerical value, which indicates that “1” is a colored dot and “0” is a transparent dot. The pattern memory 20 stores the pattern data for each character to be drawn.

  FIG. 6 is a schematic block diagram showing functional blocks of the sprite drawing unit 55 according to the present embodiment. As shown in the figure, the sprite rendering unit 55 according to the present embodiment includes an alpha data acquisition unit 551, a bilinear processing unit 555b, and an alpha blending unit 553a in the sprite rendering unit 55 according to the second embodiment. The pattern data acquisition unit 556, the bilinear processing unit 555c, and the alpha blending unit 553c are replaced. Hereinafter, differences from the second embodiment will be described.

  The pattern data acquisition unit 556 reads pattern data corresponding to the drawing target character from the pattern memory 20 based on the address position input from the sprite generation unit 56 for the drawing target character, thereby acquiring pattern data. Function as.

  The bilinear processing unit 555c functions as an alpha data acquisition unit that acquires alpha data obtained by enlarging the pattern data acquired by the pattern data acquisition unit 556 by interpolation processing. Specifically, the pattern data is acquired from the pattern data acquisition unit 556 and the enlargement ratio is acquired from the sprite attribute table 53. Then, after inverting each dot of the pattern data, a plurality of alpha data corresponding to each dot coordinate is generated by applying the formula (5) to these, and output to the alpha blending unit 553c. The processing of the bilinear processing unit 555c is the same as that of the bilinear processing unit 555b except that the input data is pattern data. However, the alpha data in the present embodiment is not a 4-bit (0-15) value but a decimal value.

The alpha blending unit 553c performs the same processing as the alpha blending unit 553a and functions as a mixing unit. However, the following formula (6) is used instead of the formulas (1) and (2). This is because alpha data is a decimal value.
Mixed data = (fore layer) × (1−alpha data) + (back layer) × alpha data (6)

  FIG. 7 is an explanatory diagram for explaining the above processing of the sprite drawing unit 55. The figure shows the above processing for one color of red (R), green (G), and blue (B). 7A and 7E are the same display color data as in FIG. 3A. FIG. 7C shows the same image data as FIG. 3C, and FIG. 7G shows the background image data of 7 × 7 dots stored in the line buffer 57. FIG. 7B shows an inverted version of each dot of the pattern data acquired by the pattern data acquisition unit 556. Further, FIG. 7F shows alpha data generated by the bilinear processing unit 555c. The alpha data shown in the figure is generated based on the pattern data shown in FIG. 7B, and the enlargement ratio is 4/7. Also, the numerical value with the underline in the figure is alpha data other than alpha data located on the dot coordinates after enlargement.

  FIG. 7D shows, based on the equation (6), the display color data shown in FIG. 7A and the image data shown in FIG. 7C, the pattern data shown in FIG. 7B. The mixing data (mixing result of the alpha blending unit 553c) obtained by mixing for each dot at the mixing ratio indicated by is shown.

  On the other hand, FIG. 7H shows the display color data shown in FIG. 7E and the image data shown in FIG. 7G based on the equation (6) in FIG. The mixed data (mixing result of the alpha blending unit 553c) obtained by mixing for each dot at the mixing ratio indicated by the alpha data configured based on the pattern data is shown. Thus, according to the present embodiment, an anti-aliasing effect can be obtained at the time of enlargement.

  As described above, according to the third embodiment, for example, when the user gives an instruction to enlarge the size of the character to be displayed, alpha data can be generated from the pattern data, and this can be performed by the alpha blending unit 553c. The mixing ratio used can be set. That is, since anti-aliasing processing can be performed by storing 1-bit / dot pattern data instead of alpha data, it is possible to further reduce the amount of memory required.

  For example, when alpha blending processing is performed to make the entire character translucent, multi-bit / dot alpha data must be stored. However, when alpha blending processing is performed only for anti-aliasing processing, As shown in the third embodiment, 1-bit / dot pattern data can be stored instead of alpha data. And by doing in this way, a required memory amount can be reduced.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and the present invention can of course be implemented in various forms without departing from the scope of the present invention. It is.

For example, a program for realizing the function of each image processing unit is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed, whereby the above-described processes are performed. You may go.
Here, the “computer system” may include an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.
Furthermore, the “computer-readable recording medium” includes a volatile memory (for example, DRAM (DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Dynamic Random Access Memory)), etc., which hold programs for a certain period of time.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve each function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

1 is a block diagram showing a system configuration of an image processing apparatus according to a first embodiment of the present invention. It is a block diagram which shows the functional block of the sprite drawing part concerning Embodiment 1 of this invention. It is explanatory drawing for demonstrating the process of the sprite drawing part concerning Embodiment 1 of this invention. It is a block diagram which shows the functional block of the sprite drawing part concerning Embodiment 2 of this invention. It is explanatory drawing of the bilinear process concerning Embodiment 2 of this invention. It is a block diagram which shows the functional block of the sprite drawing part concerning Embodiment 3 of this invention. It is explanatory drawing for demonstrating the process of the sprite drawing part concerning Embodiment 3 of this invention.

Explanation of symbols

  1 image processing device, 10 CPU, 20 pattern memory, 30 image display device, 50 CPU interface, 51 pattern memory interface, 53 sprite attribute table, 54 register, 55 sprite drawing unit, 56 sprite generation unit, 57 line buffer, 58 pixels Data control unit, 59 CRT control unit, 60 clock generation unit, 61 A / D converter, 551 alpha data acquisition unit, 553a, 553c alpha blending unit, 554, 556 pattern data acquisition unit, 555b, 555c Bilinear processing unit.

Claims (6)

Pattern data acquisition means for acquiring display color data when the character to be drawn is a character, and acquiring pattern data corresponding to the character when the character to be drawn is other than a character ;
First alpha data acquisition means for acquiring a plurality of first alpha data respectively corresponding to a plurality of dots;
An image data buffer for storing a plurality of image data respectively corresponding to a plurality of dots;
For each dot, the display color data or the pattern data acquired by the pattern data acquisition unit and the image data corresponding to the processing target dot are mixed at a mixing ratio based on the first alpha data, and the image An image processing apparatus comprising: mixing means for overwriting a data buffer. The image processing apparatus according to claim 1.
Second alpha data acquisition means for acquiring second alpha data obtained by enlarging each first alpha data acquired by the first alpha data acquisition means by interpolation processing;
Including
The mixing means mixes at a mixing ratio based on the second alpha data instead of the first alpha data.
An image processing apparatus. An image processing method in an image processing apparatus comprising pattern data acquisition means, first alpha data acquisition means, an image data buffer for storing a plurality of image data corresponding to a plurality of dots, and a mixing means,
The pattern data obtaining means obtains display color data when the character to be drawn is a character, and obtains pattern data corresponding to the character when the character to be drawn is other than a character. Steps,
A first alpha data acquisition step in which the first alpha data acquisition means acquires a plurality of first alpha data respectively corresponding to a plurality of dots;
It said mixing means, for each dot, the display color data or the pattern data acquired in the pattern data acquiring step, and those corresponding to the dot of the respective image data stored in the image data buffer Mixing at a mixing ratio based on the first alpha data and overwriting the image data buffer;
An image processing method comprising: The image processing method according to claim 3.
The image processing apparatus further includes second alpha data acquisition means,
A second alpha data acquisition step in which the second alpha data acquisition means acquires second alpha data obtained by enlarging the first alpha data acquired in the first alpha data acquisition step by interpolation processing;
Including
The mixing step is to mix with a mixing ratio based on the second alpha data instead of the first alpha data.
An image processing method. Pattern data acquisition means for acquiring display color data when the character to be drawn is a character, and acquiring pattern data corresponding to the character when the character to be drawn is other than a character ;
First alpha data acquisition means for acquiring a plurality of first alpha data respectively corresponding to a plurality of dots; and for each dot, the display color data or the pattern data acquired by the pattern data acquisition means; The image data corresponding to the dots among the image data stored in the image data buffer storing a plurality of image data respectively corresponding to the dots is mixed at a mixing ratio based on the first alpha data, and the image Mixing means to overwrite the data buffer,
As a program to make the computer function as. The program according to claim 5,
Second alpha data acquisition means for acquiring second alpha data obtained by enlarging each first alpha data acquired by the first alpha data acquisition means by interpolation processing;
Function the computer as
The mixing means mixes at a mixing ratio based on the second alpha data instead of the first alpha data.
A program characterized by that.

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