JP3876163B2 - Image output device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image output apparatus, and more particularly to an image output apparatus capable of drawing a mask pattern as intended by a user when drawing a mask pattern in an arbitrary graphic shape.
[0002]
[Prior art]
In many graphic applications and DTP applications, a method of drawing a mask pattern within an arbitrary figure specified by the user is prepared. For example, it is a method of creating a figure that becomes translucent by leaving a specified color for pixels with bits ON in the mask and a background for pixels with bits OFF in the mask. Also, in a printing apparatus having a low gradation expression capability, a technique of expressing a pseudo gradation using a certain area for a color density designated using a dither pattern or the like is often used. In this case, in order to express the designated color on the mask, an AND operation of the mask and the dither pattern is performed (Prior Art 1).
As this prior art 1, there is a proposal of “dot reduction method in an ink jet printer”, for example, Japanese Patent Laid-Open Nos. 2000-203010 and 2000-270214.
This proposal changes the thinning rate (and the corresponding mask pattern) according to the color density.
[0003]
Also, printers often provide a function for saving printing color materials such as toner and ink. For this purpose, a method of reducing the number of drawn dots on the entire page with a certain mask pattern is generally used (Prior Art 2).
As this prior art 2, for example, there is a proposal of “Image forming method and apparatus” in Japanese Patent Application Laid-Open No. 09-245150.
This proposal is a method of preparing a plurality of reduction patterns and allowing the user to select a pattern so as not to obtain an excessive reduction result. For example, in FIG. 3, paragraph number 0031 in the first embodiment, if the pattern B1 is used, the diagonal line pattern B2 does not remain at all. In such a case, the problem can be avoided by selecting A1. Yes.
[0004]
[Problems to be solved by the invention]
However, in the prior art 1, a bitmap pattern necessary for pseudo gradation expression cannot be obtained by the above-described calculation, and printing may be performed at a density lower than a designated density. The closer the both repetition frequencies, the larger the error, and the greater the possibility that the error will be the maximum when the frequencies match, that is, have the same width and height. Depending on the mask and dither pattern, printing may not be performed at all (density 0). In the case of the above-mentioned JP-A-2000-203010 and JP-A-2000-270214, it is impossible to avoid when the pattern is limited like the pattern specified by the user application.
[0005]
Further, in the prior art 2, there are cases where the amount of dots to be reduced is large depending on the drawing graphic, and in some cases it is far from the original graphic, such as not being printed at all. In the case of the above-mentioned Japanese Patent Application Laid-Open No. 09-245150, being able to select the pattern itself is a means for avoiding the complete disappearance problem, but the pattern is limited to a pattern specified by the user application. The case is impossible to avoid.
[0006]
Accordingly, an object of the present invention is to provide an image output apparatus capable of drawing a mask pattern as intended by a user when drawing a mask pattern in an arbitrary graphic shape.
[0007]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, the invention of claim 1 is directed to a graphic drawing command for image data applied to the image output apparatus, a command for specifying an arbitrary graphic range on a page memory, and a command for specifying a gradation density. And a graphic drawing command comprising: an instruction for filling the specified range with the specified gradation density; an instruction for specifying a mask pattern; and an instruction for performing a mask operation on the specified range with a mask pattern. Graphic drawing command interpreting means for interpreting the graphic drawing means, graphic drawing means for drawing the graphic drawing command in the page memory in accordance with the designation of the drawing attribute command, and page memory for passing the page memory drawing obtained by the graphic drawing means to the output means A drawing transfer means; a bitmap pattern acquisition means for acquiring a bitmap pattern corresponding to the specified gradation density; and the specified A spread drawing means for drawing a bitmap pattern corresponding to the specified gradation density in a range, and a first mask calculation for masking the specified range using the specified mask pattern Means and, A mask pattern designating unit for designating a mask pattern, and a mask operation using the mask pattern designated by the mask pattern designating unit and the bitmap pattern ( AND Second mask calculation means for performing calculation), mask pattern start position calculation means for calculating the start position of the mask pattern designated by the mask pattern designation means, and bits resulting from mask calculation of the bitmap pattern and the mask pattern ON Maximum mask pattern start position calculating means for calculating the start position of the mask pattern having the maximum number of pixels;It is provided with.
[0008]
  In this way, since the density of the result pattern obtained by the combination of the source pattern and the mask pattern always calculates the mask pattern start position where the maximum density of the mask pattern is obtained, the output result is lower than the theoretical density. It is possible to avoid the problem of density and the problem of worst-case rendering (density 0). In addition, since the density of the result pattern obtained by the combination of the source pattern and the mask pattern always calculates the mask pattern start position where the density closest to the theoretical density value in the mask pattern is calculated, the output result is higher than the theoretical density. It is possible to avoid problems such as low density and high density, and problems that are not completely drawn (density 0).
[0010]
  Also,Since the density of the result pattern obtained by the combination of the source pattern and the mask pattern always calculates the mask pattern start position where the highest density in the mask pattern is calculated, the problem that the output result is lower than the theoretical density, It is possible to avoid a problem that the worst drawing is not complete (density 0). In addition, since the density of the result pattern obtained by the combination of the source pattern and the mask pattern always calculates the mask pattern start position where the density closest to the theoretical density value in the mask pattern is calculated, the output result is higher than the theoretical density. It is possible to avoid problems such as low density and high density, and problems that are not completely drawn (density 0).
[0011]
  Also,Maximum mask pattern start position calculation means for calculating the start position of the mask pattern that maximizes the number of bit ON pixels as a result of masking the bitmap pattern and mask patternAndBecause the density of the result pattern obtained by the combination of the source pattern and the mask pattern always calculates the mask pattern start position where the maximum density in the mask pattern is calculated, there is a problem that the output result is lower than the theoretical density Thus, it is possible to avoid a problem that the worst drawing is not complete (density 0).
[0012]
  The image output apparatus according to claim 2, instead of the maximum mask pattern start position calculation unit of the apparatus,A minimum mask pattern start position calculating means for calculating a mask pattern start position that minimizes a difference between a density expressed by a mask calculation result of a bitmap pattern and a mask pattern and a density specified by a drawing command; It is characterized by having. In this way, the mask pattern start position at which the density of the result pattern obtained by the combination of the source pattern and the mask pattern is always the closest to the theoretical density value in the mask pattern is calculated. However, it is possible to avoid the problem that the density becomes lower or higher than the theoretical density, or the problem that the worst case is not drawn (density 0).
[0013]
  Also,Claim 3Then, claim 1Or 2The image output apparatus according to any one of the above, wherein the specified gradation density is an integer density value from 0 to 255 that can be expressed by 8 bits, and the bitmap pattern is a dither pattern that represents a pseudo gradation. To do. In this way, the dither pattern is used to express the pseudo gradation by using the dot aggregation pattern in the image output apparatus having a low gradation expression capability with one pixel. Normally, the dither pattern is a bitmap for the number of density types that can be specified (256 patterns of 0 to 255 that can be expressed normally by 8 bits), and is drawn by laying it out in a tile shape. The dither pattern is applicable to the bitmap pattern of the present invention, and if applied, the claim 1.Or 2Since the effect of any of the inventions can be expected, an equivalent effect can be obtained.
[0014]
  Also,In Claim 4, Claim 3 is describedThe image output apparatus according to claim 1, further comprising a dither pattern switching unit that has a dither pattern for each type of graphic (character, graphic, image, etc.) to be drawn and switches a plurality of dither patterns for each drawing command. To do. In this way, even in an image printing apparatus having a plurality of dither patterns capable of switching dither patterns for each type of graphic (character, graphic, image, etc.) to be drawn, each dither patternClaim 3The same effect can be obtained by applying the drawing method.
[0015]
  Also,In Claim 5, Claim 3 is describedIn this image output apparatus, the specified parameters are CMYK color densities used for color printing, and the bitmap pattern is a CMYK dither pattern representing a pseudo gradation. In this way, the dither pattern is generally used in a color printing apparatus using CMYK as a color material. Each color material has a dither pattern, a page memory is generated for each color material, and they are printed by overlapping them at the time of output. For each dither pattern for each colorantClaims 1 and 2If applied, the mask pattern start position for each color material will be different, and if they are superimposed, the expected result will be different. Therefore, by calculating the number of bits ON pixels for all color materials at the time of mask pattern start position calculation, a mask pattern start position common to all color materials can be obtained.Claims 1, 2The same effect can be obtained.
[0016]
  Also,In claim 6, claims 3, 4, and 5Any one of the image output apparatuses described above includes a dither pattern creating unit that creates a dither pattern from a threshold (order) table. In this way, one dither pattern is required for each density value, and the amount of data increases. Therefore, a threshold value (order) having a threshold value for the density value at which the bit of the dither pattern changes from OFF to ON. Typically created from a table. Even in an apparatus for obtaining a dither pattern using a threshold table,Claim 3The same effect can be obtained by applying the drawing method.
[0017]
  Also,In claim 7, claims 3, 4 and 5In any one of the image output apparatuses described above, the mask pattern is a pattern for saving printing color material. In this way, the mask pattern may be used to save printing color materials such as toner and ink. In this case, since the mask pattern is applied to the entire page, the present invention is applicable to normal graphic drawing processing using the saving mask pattern.
[0018]
  Also,In claim 8, Claim 1Or 2In the described image output apparatus, one pixel of the bitmap pattern is expressed by multiple values. In this way, if one pixel of the bitmap pattern is expressed by multiple values with multiple bits instead of the binary value of bit ON / OFF, the bit ON is used instead of the number of bit ON pixels. The present invention can be applied by targeting the number of bits.
[0019]
  Also,In claim 9, Claim 1Or 2The image output apparatus described above is characterized in that the output means is a laser printer. In this way, when the page memory is generated on the printer side as in a laser printer, the present invention can be applied to processing on the printer side that generates the page memory from each drawing command.
[0020]
  Also,In claim 10, Claim 1Or 2The image output apparatus described above is characterized in that the output means is an ink jet printer. In this way, when the page memory is generated on the host computer side as in the case of the ink jet printer, the present invention can be applied to processing on the host computer side that generates the page memory from each drawing command.
[0021]
  Also,In claim 11, Claim 1Or 2The described image output apparatus is characterized in that arithmetic processing up to page memory generation is performed by a dedicated ASIC such as a graphic accelerator. In this way, when the page memory is generated not by software processing using the CPU on the printer side but by a dedicated ASIC such as a graphic accelerator, the present invention is applied to processing in the ASIC that generates page memory from each drawing command. Applicable.
[0022]
  Also,In claim 12, Claim 1Or 2In the described image output apparatus, the host computer side performs arithmetic processing up to page memory generation. In this way, regardless of the output device, when the page memory is generated on the host computer side, the present invention can be applied to the processing on the host computer side that generates the page memory from each drawing command.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described based on the illustrated embodiments.
  (1) First embodimentClaim 1Correspondence
  FIG. 1 is a configuration diagram of an image output apparatus system GS to which a first embodiment and a second embodiment described below are applied. As shown in FIG. 1, the image output device system GS includes a data input device 10, an image output device 20, and an output device 30 that is an “output unit”. The data input device 10 inputs drawing data to the image output device 20. The image output device 20 includes an interpreter 21 that is a “graphic drawing command interpretation unit”, a mask coordinate calculation process 22 that is a “mask pattern start position calculation unit, a maximum mask pattern start position calculation unit, and a minimum mask pattern start position calculation unit”. A figure drawing process 23 which is “figure drawing means, page memory drawing transfer means, bitmap pattern acquisition means”, a mask drawing which is “mask pattern designation means, first mask calculation means, second mask calculation means, spread drawing means” The processing 24, CPU 25, intermediate data memory 26, mask pattern memory 27, bitmap pattern memory 28, and page memory 29 are configured to output to the output device 30.
[0024]
The drawing data input to the image output device 20 is input to the interpreter 21, interpreted as intermediate data suitable for subsequent drawing processing, and stored in the intermediate data memory 26. The CPU 25 performs the calculation process. The intermediate data includes a drawing range designation command, a drawing color designation command, and the like, and includes a mask pattern designation command. The mask pattern designation command stores data in the mask pattern memory 27.
The graphic drawing process 23 draws the graphic contained therein according to the contents of the intermediate data memory 26. A bitmap pattern corresponding to the designated color is acquired from the bitmap pattern memory 28 and drawn in the page memory 29. In the case of a figure using a mask pattern, the mask drawing process 24 performs a drawing process using the mask pattern stored in the mask pattern memory 27, the specified drawing range, and drawing color. At this time, the start coordinate of the mask pattern is calculated using the mask coordinate calculation process 22. When the drawing command for one page is completed, the contents of the page memory 29 are output to the output device 30.
[0025]
A simple example of the mask calculation performed in the mask drawing process 24 of FIG. 1 will be described with reference to FIG. First, a source pattern S (FIG. 2 (a)) as an operation source is obtained from the bitmap pattern memory 28 of FIG. This is a bitmap corresponding to the drawing color designated by the drawing color designation command. The size is 64 pixels of 8x8. Set the white part to bit OFF and the black part to bit ON. Further, a mask pattern M (FIG. 2B) is obtained from the mask pattern memory 27. This is a bitmap corresponding to the mask pattern designation command. For simplicity, it is the same size as the source pattern S. The result of ANDing the same position of the source pattern S and the mask pattern M is a result pattern D (FIG. 2C). This is drawn in a specified range on the page memory 29 using a calculation method with the specified page memory (for example, SET calculation if overwriting). In actual drawing, calculation is performed on a pattern set in which source patterns S are tiled vertically and horizontally and a pattern set in which mask patterns M are vertically and horizontally arranged in accordance with the drawing range.
[0026]
  In the present embodiment, the start position coordinates of the mask pattern M are moved so that the result pattern D has the maximum density (the number of bits ON is the maximum number). Since the mask pattern is used repeatedly vertically and horizontally, the pattern itself does not change even if the start position coordinates are moved.does not change.
[0027]
FIG. 3 shows a process flow of the start position coordinates calculated by the mask coordinate calculation process in FIG.
In Step 1, the bit ON maximum pixel number Dmax and the coordinates (Dx, Dy) for the maximum pixel number are initialized to zero. These are used in Step5.
In Step 2, initialize y which is Y coordinate of mask pattern to 0.
In Step 3, initialize x which is the X coordinate of the mask pattern to 0.
[0028]
In Step4, shift the origin of the mask pattern by (x, y) (lower right). Since the mask pattern is used repeatedly in the vertical and horizontal directions, the protruding portion circulates by shifting. For example, when shifting vertically by one pixel (y = 1), after shifting all pixels vertically by one pixel, the protruding last line moves to the first line. If the pixel is shifted horizontally by two pixels (x = 1), after shifting all the pixels horizontally by two pixels, the two pixels from the right that protrude are moved from the left to the two pixels as they are. Mask operation (AND) is performed with the generated mask pattern and source pattern S, the number of pixels with bit ON is counted, and it is set to the variable Dnum.
In Step 5, the Dnum counted in Step 4 is compared with the bit ON maximum pixel count Dmax so far. If Dnum is larger, go to Step 6, and if it is below, go to Step 7.
[0029]
In Step 6, since it was determined that Dnum> Dmax in Step 5, Dnum, x, and y are stored in Dmax, Dx, and Dy, respectively. This is the number and position where the bit-on pixel is the maximum at the present time.
In Step 7, x is incremented by one, and when the rightward shift on the same line (y) is completed for all patterns, the process proceeds to Step 8, and in the middle, returns to Step 4.
In step 8, y is incremented by one. When all patterns are shifted downward, the process ends.
The (Dx, Dy) at the end of the processing is the shift amount of the mask pattern M that maximizes the bit ON pixel, that is, the start coordinate point of the mask pattern M.
[0030]
FIG. 4 shows an application example of this embodiment. First, when the source pattern S of FIG. 4A and the mask pattern M of FIG. 4B are used as inputs and calculated using the flow of FIG. 3, a result of (Dx, Dy) = (3, 3) is obtained. The result of shifting the mask pattern M by (3, 3) is the mask pattern M ′ in FIG. When the mask operation is performed with this and the source pattern S, the result pattern of FIG. 4D is obtained. This is because the 2 × 2 bit ON pixel (2 in FIG. 4 (b)) at the upper left of the mask pattern M moves to the position 3 in FIG. 4 (c) of the mask pattern M ′, and the center of the source pattern S 2 × 2 bit ON pixels (1 in FIG. 4A) overlap each other, and in the result pattern D, the bit ON pixels become 4 pixels.
[0031]
Effects of this embodiment
In this way, by calculating the mask pattern start position where the density of the result pattern obtained by the combination of the source pattern and the mask pattern is always the highest density in the mask pattern, the output result is lower than the theoretical density. It is possible to avoid problems and problems that are not completely drawn (density 0). For example, if the mask pattern M in FIG. 2B is mask-calculated with a pattern shifted by 2 pixels horizontally and the source pattern S, all pixel bits are turned OFF, and nothing is drawn in the figure drawing using this combination. If this embodiment is used, as shown in FIG. 4 (d), the image is drawn at a density of 4/64 for 4 pixels.
[0032]
In the present embodiment, the calculation is performed so that the resulting pattern density becomes the maximum density, so that a difference from the theoretical density value occurs. The theoretical density is a value Ls × Lm obtained by multiplying the density Ls corresponding to the source pattern S and the density Lm of the mask pattern M. Since this difference is a difference to the higher density (the darker one), the pattern may be drawn with a pattern darker than the theoretical density. For example, in Fig. 4, Ls = 8/64 and Lm = 8/64, so the theoretical density is 1/64. Theoretically, 64 pixels and 1 pixel should be bit ON. If the form is used, the four pixels in FIG. 4 (d) are turned on, and the difference of three pixels is darkened.
[0033]
Although it is unsuitable for applications that require accuracy in the output density of figures using mask patterns, mask patterns used for painting charts and graphs as found in general business documents may have slight density differences. Output at density 0, where nothing is output, is avoided, and even if the mask pattern is different, if the mask pattern density Lm is the same, the specified density Ls corresponding to any source pattern, the same density at any position Is required to be output. Applying this example to such applications satisfies the requirements.
In this example, the number of gradations that can be expressed by one pixel of the source pattern is binary (1 bit), but multi-values such as 2 bits, 4 bits, 8 bits, etc. can be similarly applied.
[0034]
  (2) Second embodiment ...Claim 2Correspondence
  In the first embodiment, the start position coordinates of the mask pattern M are calculated so that the result pattern D has the maximum density (the maximum number of bits ON). However, in the present embodiment, it corresponds to the source pattern S. From the density Ls and the density Lm of the mask pattern M, the start position coordinates of the mask pattern M are calculated such that the density Ld of the result pattern D is the density closest to the theoretical density Ls × Lm. The configuration diagram of the image output device system GS is the same as FIG.
[0035]
FIG. 5 shows a process flow of the start position coordinates calculated by the mask coordinate calculation process in FIG.
In Step 0, the number of bit ON pixels Dt of the pattern closest to the theoretical density Ls × Lm is calculated. When Ls is the input density value (0.0 to 1.0), Lm is the bit ON pixel ratio of the specified mask pattern M (bit ON pixel number ÷ total number of pixels), and Dw and Dh are the width and height of the mask pattern M, respectively, Calculate Dt from the following formula.
Dt = (Ls × Lm) × (Dw × Dh) (Formula 1)
Since Dt is a decimal, it is rounded up to the nearest whole number by rounding up, rounding down, or rounding (the method is arbitrary).
The start position coordinates that are the closest number of bit ON pixels are searched in the following steps.
[0036]
In Step 1, the nearest bit ON pixel count Dave is initialized to (Dw × Dh) and the coordinates (Dx, Dy) are initialized to 0, respectively. These are used in Step5.
In Step 2, initialize y which is Y coordinate of mask pattern to 0.
In Step 3, initialize x which is the X coordinate of the mask pattern to 0.
In Step4, shift the origin of the mask pattern by (x, y) (lower right). Since the mask pattern is used repeatedly in the vertical and horizontal directions, the protruding portion circulates by shifting. For example, if shifting vertically by one pixel (y = 1), after shifting all pixels vertically by one pixel, the last protruding line moves to the first line. If the pixel is shifted horizontally by two pixels (x = 1), after shifting all the pixels horizontally by two pixels, the two pixels from the right that protrude are moved from the left to the two pixels as they are. Mask operation (AND) is performed with the generated mask pattern and source pattern S, the number of bit ON pixels is counted, and it is set to the variable Dnum.
[0037]
In Step 5, the Dnum counted in Step 4 is compared with the absolute value of the difference between the bit ON maximum pixel number Dave closest to Dt so far. If Dave is larger, the process proceeds to Step 6, and if it is smaller, the process proceeds to Step 7.
In Step 6, since it is determined in Step 5 that Dave is closest to Dt, Dnum, x, and y are stored in Dave, Dx, and Dy, respectively. This is the number and position of the bit ON pixels closest to Dt at the present time.
In Step 7, x is incremented by one, and when the rightward shift on the same line (y) is completed for all patterns, the process proceeds to Step 8, and in the middle, returns to Step 4.
In step 8, y is incremented by one. When all patterns are shifted downward, the process ends.
(Dx, Dy) at the end of the processing is the shift amount that becomes the mask pattern M having the number of bit ON pixels closest to the theoretical density, that is, the start coordinate point of the mask pattern M.
[0038]
FIG. 6 shows an application example of this embodiment. Here, it is assumed that the source pattern S of FIG. 6A is obtained from the bitmap pattern memory from the input data of Ls = 8/64. Further, the density of the mask pattern M in FIG. 6B is Lm = 8/64. Further, Dw = Dh = 8. When these values are applied to Equation 1 of Step 0 in FIG. 5, Dt = 1. If calculation is performed using the flow shown in FIG. 5, the result (Dx, Dy) = (3, 1) is obtained. The result of shifting the mask pattern M by (3, 1) is the mask pattern M ′ in FIG. When the mask operation is performed with this and the source pattern S, the result pattern of FIG. 6D is obtained. This is because the 2 × 2 bit ON pixel (2 in FIG. 6B) at the upper left of the mask pattern M moves to the position 3 in FIG. 6C of the mask pattern M ′, and the source pattern S The top bit ON pixel (1 in FIG. 6A) overlaps, and the result pattern D is a position where the bit ON pixel becomes one pixel.
[0039]
Effects of this embodiment
In this way, by calculating the mask pattern start position where the density of the result pattern obtained by the combination of the source pattern and mask pattern is always close to the theoretical density, the output result will be different from the theoretical density. In addition, it is possible to avoid a problem that is not completely rendered completely (density 0). For example, the density of the source pattern S in FIG. 4 or 6 is Ls = 8/64, and the density of the mask pattern is Lm = 8/64, so the theoretical density is 1/64. If this example is not used, the density of the resulting pattern D will be 2/64 as shown in FIG. 2 (c), where the bit ON pixels will be 2 pixels, and if the first embodiment is used, 4 / 64, and there is a difference between the theoretical density and the actual output density.
[0040]
Applying this example to applications that require accuracy in the output density of a figure using a mask pattern will satisfy the requirements.
In this example, the number of gradations that can be expressed by one pixel of the source pattern is binary (1 bit). However, multi-values such as 2 bits, 4 bits, and 8 bits can be similarly applied.
[0041]
In each of the above embodiments, the case of a rectangle has been described. However, the present invention can be applied to a figure having an arbitrary shape such as a circle or an ellipse.
[0042]
【The invention's effect】
  As described above, according to the present invention, the following effects can be exhibited.
(1)According to claim 1Thus, it is possible to avoid the problem that the output result is lower than the theoretical density and the problem that the worst rendering is not complete (density 0).
(2)According to claim 2Therefore, it is possible to avoid the problem that the output result is a density lower or higher than the theoretical density, or the problem that the worst case is not drawn (density 0).
[0043]
  (3)Claim 3According to this, the dither pattern is used to express a pseudo gradation by using an aggregate pattern of dots in an image output apparatus having a low gradation expression capability with one pixel. Normally, the dither pattern is a bitmap for the number of density types that can be specified (256 patterns of 0 to 255 that can be expressed normally by 8 bits), and is drawn by laying it out in a tile shape. The dither pattern is applicable to the bitmap pattern of the present invention, and if applied, the claim.1, 2Since the effect can be expected, the same effect can be obtained.
[0044]
  (4)Claim 4Therefore, even in an image printing apparatus having a plurality of dither patterns capable of switching the dither pattern for each type of figure to be drawn, each dither patternClaim 3The same effect can be obtained by applying the drawing method.
(5)Claim 5According to this, since the mask pattern start position common to all the color materials can be obtained by calculating the number of bit ON pixels for all the color materials at the time of calculating the mask pattern start position, the same effect as in claims 3 and 4 can be obtained. can get.
[0045]
  (6)Claim 6Therefore, even in an apparatus for obtaining a dither pattern using a threshold table,Claim 3The same effect can be obtained by applying the drawing method.
(7)Claim 7According to this, when the mask pattern is used for saving printing color materials such as toner and ink, the mask pattern is applied to the entire page. The invention is applicable.
(8)Claim 8According to this, when one pixel of the bitmap pattern is expressed by multiple values of multiple bits instead of binary of bit ON / OFF, the number of bits that are turned on rather than the number of bits turned on The present invention is applicable by targeting.
[0046]
  (9)Claim 9Accordingly, when the page memory is generated on the printer side as in the case of a laser printer, the present invention is applicable to processing on the printer side that generates the page memory from each drawing command.
(10)Claim 10Therefore, when the page memory is generated on the host computer side as in an ink jet printer, the present invention can be applied to the processing on the host computer side that generates the page memory from each drawing command.
(11)Claim 11According to the present invention, the present invention can be applied to the processing in the ASIC that generates the page memory from each drawing command when the generation of the page memory is not performed by software processing using the CPU on the printer side but by a dedicated ASIC such as a graphic accelerator. It is.
(12)Claim 12Accordingly, when the page memory is generated on the host computer side regardless of the output device, the present invention can be applied to the processing on the host computer side that generates the page memory from each drawing command.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an image output apparatus system to which first and second embodiments of the present invention are applied.
FIGS. 2A and 2B are explanatory diagrams of a simple example of mask calculation performed in mask drawing processing in the image output apparatus system, where FIG. 2A is a source pattern, FIG. 2B is a mask pattern, and FIG. 2C is a result pattern; .
FIG. 3 is a processing flow of start position coordinates calculated by mask coordinate calculation processing in the first embodiment;
FIG. 4 is a diagram showing an application example of the first embodiment, where (a) is a source pattern, (b) is a mask pattern, (c) is a shifted mask pattern, and (d) is a result pattern. is there.
FIG. 5 is a processing flow of start position coordinates calculated by mask coordinate calculation processing in the second embodiment.
6 is a diagram showing an application example of the first embodiment, where (a) is a source pattern, (b) is a mask pattern, (c) is a shifted mask pattern, and (d) is a result pattern. is there.
[Explanation of symbols]
GS: Image output device system
S: Source pattern
M ... Mask pattern
M ’… shifted mask pattern
D ... Result pattern
1 ... Position of the bit ON pixel at the top of the source pattern
2: Position of 2x2 bit ON pixel at the upper left of the mask pattern
3. Position of the 2x2 bit ON pixel at the upper left of the mask pattern after movement
10. Data input device
20. Image output device
21 ... Interpreter
22 ... Mask coordinate calculation processing
23. Drawing process
24. Mask drawing process
25 ... CPU
26: Intermediate data memory
27 ... Mask pattern memory
28 ... Bitmap pattern memory
29 ... Page memory
30 ... Output device

Claims (12)

The graphic drawing command for image data applied to the image output apparatus includes a command for designating an arbitrary graphic range on a page memory, a command for designating gradation density, and the designated floor within the designated range. It consists of a command to paint with tonal density, a command to specify a mask pattern, and a command to perform a mask operation with the mask pattern within the specified range,
Graphic drawing command interpreting means for interpreting the graphic drawing command;
Graphic drawing means for drawing the graphic drawing command in a page memory in accordance with a designation of a drawing attribute command;
Page memory drawing transfer means for passing page memory drawing obtained by the figure drawing means to output means;
Bitmap pattern acquisition means for acquiring a bitmap pattern corresponding to the specified gradation density;
A spread drawing means for drawing a bitmap pattern corresponding to the specified density within the specified range;
First mask calculation means for performing mask calculation within the specified range using the specified mask pattern ;
A mask pattern designating unit for designating a mask pattern , a second mask computing unit for performing a mask operation ( AND operation) between the mask pattern designated by the mask pattern designating unit and the bitmap pattern, and the mask pattern designating unit Mask pattern start position calculating means for calculating the start position of the mask pattern,
An image output apparatus comprising: a maximum mask pattern start position calculating unit that calculates a start position of a mask pattern that maximizes the number of bit ON pixels as a result of performing a mask operation on a bitmap pattern and a mask pattern . The graphic drawing command for image data applied to the image output apparatus includes a command for designating an arbitrary graphic range on a page memory, a command for designating gradation density, and the designated floor within the designated range. It consists of a command to paint with tonal density, a command to specify a mask pattern, and a command to perform a mask operation with the mask pattern within the specified range,
Graphic drawing command interpreting means for interpreting the graphic drawing command;
Graphic drawing means for drawing the graphic drawing command in a page memory in accordance with a designation of a drawing attribute command;
Page memory drawing transfer means for passing page memory drawing obtained by the figure drawing means to output means;
Bitmap pattern acquisition means for acquiring a bitmap pattern corresponding to the specified gradation density;
A spread drawing means for drawing a bitmap pattern corresponding to the specified density within the specified range;
First mask calculation means for performing mask calculation within the specified range using the specified mask pattern;
A mask pattern designating unit for designating a mask pattern, and a mask operation using the mask pattern designated by the mask pattern designating unit and the bitmap pattern ( AND Second mask calculation means for performing calculation), mask pattern start position calculation means for calculating the start position of the mask pattern designated by the mask pattern designation means,
A minimum mask pattern start position calculating means for calculating a mask pattern start position that minimizes a difference between a density expressed by a mask calculation result of a bitmap pattern and a mask pattern and a density specified by a drawing command; An image output apparatus comprising: 3. The image output apparatus according to claim 1, wherein the specified gradation density is an integer density value of 0 to 255 that can be expressed by 8 bits, and the bitmap pattern is a dither pattern that represents a pseudo gradation. An image output apparatus comprising: 4. The image output apparatus according to claim 3 , further comprising a dither pattern switching unit that has a dither pattern for each type of graphic (character, graphic, image, etc.) to be drawn and switches a plurality of dither patterns for each drawing command. An image output apparatus characterized by that. 4. The image output apparatus according to claim 3, wherein the designated parameter is a CMYK color density used for color printing, and the bitmap pattern is a CMYK dither pattern expressing a pseudo gradation. Output device. 6. The image output apparatus according to claim 3, further comprising dither pattern creating means for creating a dither pattern from a threshold (order) table. 6. The image output apparatus according to claim 3, wherein the mask pattern is a pattern for saving a printing color material. 3. The image output apparatus according to claim 1, wherein one pixel of the bitmap pattern is expressed in multiple values. 3. The image output apparatus according to claim 1, wherein the output means is a laser printer. 3. The image output apparatus according to claim 1, wherein the output means is an ink jet printer. 3. The image output apparatus according to claim 1, wherein the arithmetic processing up to page memory generation is performed by a dedicated ASIC such as a graphic accelerator. 3. The image output apparatus according to claim 1, wherein calculation processing up to page memory generation is performed on the host computer side.

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