JP2002244643A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely transfer data in timing to the output of an output device even when complicated plotting process is included. SOLUTION: This image processor is equipped with a 1st plotting time prediction part 6 which performs prediction from a display list format, an edge list generation part 7 which generates an edge list from the display list, a 2nd plotting time prediction part 9 which performs prediction from the edge list format, an edge list conversion part 10 which converts the edge list into a format of a shorter plotting time, and a plotting part 12 which performs plotting in the format obtained by converting the display list and edge list.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for drawing characters and images represented by input figures and outline data for the purpose of print output or display output to a printer or a display device. .

[0002]

2. Description of the Related Art In an editor, a CAD / CAM system, or the like that handles a character represented by a figure or outline data, a drawing process is performed to output the figure to a printer or a display device. The processing of such drawing is advanced using, for example, blocks as shown in FIG.

In FIG. 9, first, when a drawing command of a figure, character, or image is input by a user's instruction or an external input, the drawing command input is interpreted by a command interpreting unit 1 and a vector data generating unit 2 is interpreted. Is input to In the case of a character, the vector data generation unit 2 requests the font management unit 3 to acquire vector data representing the outline of the character. In the case of a stroke (line) figure, it is converted into vector data having a contour as shown in FIG. 10, for example, based on the thickness and the shape of the connection portion.

[0004] The characters, stroke figures, and fill (fill) figures converted in this way are input to the display list generation unit 4. It should be noted that the image is treated as a fill graphic that is filled with a different color for each pixel.

[0005] The display list generation unit 4 first approximates a curve portion represented by a Bezier, a spline, or the like with a minute straight line, and converts it into polygonal vector data as shown in FIG.

Next, the data is converted into a display list format as shown in FIG. The display list includes D as an example of data related to the vectors constituting the polygon.
ir: direction flag (+1 for upward, -1 for downward), Xs: X coordinate of vector start point, Ye: Y coordinate of vector end point, Dx: X change amount with +1 increase of Y coordinate ( Slope)). The conversion from the polygon to the display list will be described later in detail.

[0007] The display list data thus generated is input to the drawing processing unit 12. The drawing processing unit 12 calculates the coordinates of the intersection of each side of the input display list and each scan line of the output device with a DDA.
(Digital Differential Ana
lyzer), and sorts the X-coordinate values for each scan line to determine the correspondence between the start point and the end point of the fill. A line segment parallel to the scan line corresponding to the section (hereinafter, this Is called an edge) on the memory unit 13. The memory data drawn in this manner is transferred to an output device 14 such as a printer or a display device, so that printing or display is performed.

In such graphic processing, the operation of the drawing processing unit 12 is heavy because it involves DDA, sorting, and memory drawing for each side, and in particular, draws complicated figures including overlaps such as gradation. When you do
Overwriting occurs in the same area on the memory unit 13 many times, which is a major factor in reducing the overall processing speed.

Further, unlike a recent printer, a page memory is reduced by storing drawing commands at a level such as a polygon, a display list, and an edge list, and image formation is performed in real time in accordance with the printing speed of the printer. In the case of outputting while performing, there is a possibility that image formation may not be completed in a complicated portion having many overlaps and picture omission may occur.

Conventionally, as an attempt to solve such a problem, there has been proposed a method of performing high-speed processing or real-time drawing by removing overlaps from drawing elements. As a conventional technique using such a concept, Japanese Patent Application Laid-Open No. Hei 8-2
JP-A-79050, JP-A-9-62851, JP-A-9-171563, JP-A-9-281953, and JP-A-2000-149036.

[0011]

Problems to be Solved by the Invention
Japanese Patent Publication No. 0 and Japanese Patent Application Laid-Open No. Hei 9-62851 are directed to accumulating drawing elements in the form of an edge list, and comparing edge information for drawing on the same scan line and removing any overlap. However, the accumulation of drawing elements in the edge list has disadvantages such as an increase in resolution, as in recent printers, in which the amount of data to be accumulated becomes enormous and the memory cost increases.

[0012] Japanese Patent Application Laid-Open No. 9-171563 and
Japanese Patent Application Laid-Open No. -281953 accumulates drawing elements in the form of polygon data, performs overlap determination on two polygons,
If there is an overlap, this is removed. However, in order to perform overlap removal at the polygon level, it is necessary that the polygon has a simple convex shape. For polygons including concave shapes and intersections of sides, this is divided into convex shapes. Pre-processing is required. Although the target is narrowed down by overlap judgment / overlay graph, etc.
Since the overlap between two polygons is removed, N! Times of processing is required.

In Japanese Patent Application Laid-Open No. 2000-149036, the processing time required for the drawing processing is predicted from drawing elements expressed in the display list format, and if it is determined that the processing time cannot be reached, the display list format is used. And a method for removing overlap between drawing elements, which can be executed in N times for N processing targets.

However, Japanese Patent Application Laid-Open No. 2000-14903
In the method described in Japanese Patent Application Laid-Open No. 6 (1994), since the processing time is predicted based on the circumscribed rectangle information of the display list, the prediction error may increase depending on the description method of the drawing command and the like. And there is a problem that unnecessary overlap removal processing is performed even for an object that is actually in time.

Further, Japanese Patent Application Laid-Open No. Hei 8-279050 and Japanese Patent Application Laid-Open No. 2000-149036 are based on the premise that as a result of performing the overlap removal, it is possible to form an image without fail in time for the printing speed of the printer. Is GDI (Gr.
aphic Device Interface) and Hewlett-Packard's page description language P
CL (Printer Control Language)
e) ROP (RasterOperat)
In the case of drawing that requires a logical operation between a base and a drawing element, which is called “ion), there is a case where the underlying portion cannot be removed. is there.

The present invention has been made in consideration of the above-mentioned problems of the prior art, and includes a drawing time predicting means from a display list format, an edge list generating means for generating an edge list from a display list, There is no drawing time estimating means from the edge list format, an edge list converting means for converting the edge list into a format having a shorter drawing time, and a drawing processing means for performing a drawing process on the display list and the converted edge list. A high-speed image processing apparatus that can reduce the amount of processing required, guarantee that ROPs are included in time, and can store / transfer with a small amount of memory even in the case of high resolution compared to the edge list. It is intended to be realized.

[0017]

SUMMARY OF THE INVENTION The present invention relates to an image processing apparatus for achieving the above object. That is, the present invention converts, in an image processing apparatus that performs a drawing process of a graphic, vector information describing a drawing element or a clip element of the graphic into a set of linear vectors approximated by a polygon, and includes Display list generating means for sorting a straight line according to its start scan line coordinate value and generating a display list to which direction, inclination, and length information are added in accordance with a drawing element, and a display list storage for storing the generated display list Means, first drawing time estimating means for estimating the drawing processing time from the accumulated display list, and calculating the intersection of each straight line in the display list with the output scan line, and calculating the intersection of each scanning element for each drawing element. List generating means for generating a list of edges composed of a pair of a drawing start position and a drawing length Edge list accumulating means for accumulating the generated edge list, second drawing time estimating means for estimating the drawing processing time from the stored edge list, and edge list for converting the edge list into a format having a shorter drawing time. A conversion unit, a conversion data storage unit for storing data converted by the edge list conversion unit, and an image generated by processing the display list, the edge list, and the drawing element converted by the edge list conversion unit. Image drawing means.

Further, in the image processing apparatus of the present invention,
The edge list conversion means removes an edge or a part thereof which does not affect the drawing result due to the overlap between the drawing elements.

Further, in the image processing apparatus of the present invention,
The edge list converting means performs a drawing process on a drawing element represented by an edge list to convert the drawing element into an image.

Further, in the image processing apparatus of the present invention,
The first drawing time estimation means performs an estimation process using at least the number of pixels of a circumscribed rectangle of a drawing element represented by a display list, and the second drawing time estimation means includes:
The estimation process is performed by using at least the number of pixels of the drawing element represented by the edge list.

Further, in the image processing apparatus of the present invention,
If the drawing time estimated by the first drawing time estimating means is equal to or less than a first threshold, a display list is input to the image drawing means for processing, otherwise, the display list is processed by the edge list generating means. The display list is converted into an edge list, and when the drawing time estimated by the second drawing time estimating means is less than or equal to a second threshold, the edge list is input to the image drawing means for processing. In this case, the result of converting the edge list by the edge list converting means is input to the image drawing means for processing.

Further, in the image processing apparatus of the present invention,
The display list generating unit, the display list storing unit, the first drawing time estimating unit, the edge list generating unit, the edge list storing unit, the second drawing time estimating unit, the edge list converting unit, the converted data storing unit, and the image drawing Each processing by the means is independently performed for each partial region obtained by dividing the entire image to be formed.

Further, in the image processing apparatus of the present invention,
Display list generating means, display list storing means, first drawing time estimating means, edge list generating means, edge list storing means, second drawing time estimating means,
Further, the edge list conversion means is constituted by software described by a program, and the image drawing means is constituted by hardware.

In the present invention, the first drawing time estimating means estimates the drawing processing time at the stage of the display list, and if it is determined that the estimated drawing processing time is sufficient for the output, the display list is estimated. Is transferred to the image drawing means. If the output cannot be completed in the estimated drawing processing time, an edge list is generated and the second list is generated.
The accurate drawing processing time is estimated by the drawing time estimating means, and if it is determined that the time is enough, the edge list is transferred to the image drawing means. Also, if the drawing processing time estimated by the second drawing time prediction means is not enough,
The data is converted into a format having a shorter drawing time than the edge list and transferred to the image drawing means. As a result, data can be transferred in time for output even in a complicated drawing process.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image processing apparatus according to the present invention will be described below with reference to the drawings. Figure 1
1 is a block diagram illustrating an embodiment of an image processing apparatus according to the present invention. In the figure, the image processing apparatus includes an instruction interpreting unit 1, a vector data generating unit 2, a font managing unit 3, a display list generating unit 4, a display list storing unit 5, a first drawing time predicting unit 6, An edge list generating unit 7, an edge list storing unit 8, a second drawing time predicting unit 9, an edge list converting unit 10, a converted data storing unit 11, a drawing processing unit 12, a memory unit 13, ,
And an output device 14.

The outline and operation of each component of this embodiment will be described below. That is, the command interpreter 1
It interprets the input drawing command of a figure or character and converts it into a format that the next vector data generation unit 2 can understand. In a page description language such as PostScript (trademark of Adobe Systems, Inc.) or PCL, these drawing instructions are given as a character string or a binary string. In such a case, the instruction interpreting unit 1 cuts out a token, It interprets and converts it into an internal drawing command.

The vector data generating unit 2 includes an instruction interpreting unit 1
, And generates vector data. If the input is a fill (filled) figure, the instruction interpreting unit 1 indicates a vector representing the outline of the figure, a fill rule such as an even-odd rule / non-zero rule, and a flatness indicating the precision when a curve is linearly approximated. (Flatness) value, drawing color, and the like are given, and the information is output as it is.

When the input is a stroke (line) graphic,
A vector expressing a line, line attributes such as line width / line type / termination shape / connection shape, a flatness value indicating the accuracy when a curve is approximated by a straight line, a drawing color, and the like are given. Figure 1 using the vector and line attribute information
A contour vector as shown in FIG. 0 is generated and output together with the remaining information.

When the input is a character, a character code, a font ID, and information such as a drawing position and a drawing color are given. To obtain the outline vector of the character and output it together with the remaining information.

The font management unit 3 stores outline vector data for various fonts, and provides outline vector data for the character in accordance with a given character code and font ID.

By the above-mentioned processing, all the input figures / characters are converted into vector data representing contours, drawing colors (image data in the case of images), flatness values, and information on filling rules.

When a curve is included in the input vector data, the display list generating unit 4 first sets the curve portion so that the error is equal to or less than the precision specified by the flatness value. , A process of approximating with a minute linear vector is performed.

For example, in the case of a curved vector, 4 shown in FIG.
A Bezier curve represented by two control points is used. In this case, the linear vectorization process recursively divides the Bezier curve as shown in FIG. 2, and ends the division when the height (distance d) becomes smaller than the flatness value (flat).
Then, by connecting the start point and the end point of each of the divided Bezier curves in order, the linear vectorization is completed.

Based on the vector data linearly approximated in this manner, the display list generating unit 4 converts the vector data into a display list format expression. Here, the display list is, for example, as shown in FIG. The input polygon vector is first converted so that the Y coordinate of each vertex is an integer.

Specifically, for each side, the vertex with the smaller Y coordinate is rounded up, the vertex with the larger Y coordinate is rounded down, and the integer error is corrected with the X coordinate value so that the inclination of each side does not change. After converting the Y coordinate values into integers in this way, sides having the same start Y coordinate are collected and connected in a list.

Each element of the list has a direction flag Dir indicating whether the direction of the side is upward or downward by + 1 / -1;
The X coordinate value Xs at the start point Ys, the Y coordinate value Ye at the end point, and the slope Dx of the side represented by the amount of change in the X coordinate value with respect to the +1 increase of the Y coordinate value are stored. Note that those that do not cross any scan lines, such as sides that are nearly horizontal, are not registered as elements in the display list.

As shown in FIG. 3, the display list generated as described above is divided into partial areas (hereinafter, referred to as bands) obtained by dividing a page by a predetermined width.
The data is stored in the display list storage unit 5 for each band.

The band is divided by drawing / outputting by the double buffer method, so that the capacity of the memory unit 13 is reduced to two.
This is for reducing the number of bands. One page to be drawn is divided into, for example, a band-shaped partial region as shown in FIG. 3 (hereinafter, this partial region is referred to as a band), and for each drawing command, information is drawn on a band in which a drawing element is drawn. The image data already drawn in the memory unit 13 is output in accordance with the printing speed of the printer in parallel with the drawing processing of the next band by the drawing processing unit 12. The unit 13 does not require a memory capacity capable of drawing the entire page, and can be configured with a minimum of two bands.

The first drawing time prediction unit 6 reads out the display list for each band stored in the display list storage unit 5 and calculates the processing time for drawing the band by the drawing processing unit 12 from the display list information. It is estimated and compared with a predetermined first threshold value. The drawing time prediction from the display list will be described later in detail.

When the predicted drawing time by the first drawing time prediction unit 6 is equal to or less than the first threshold value, no special processing is performed on the band, and the display list stored in the display list storage unit 5 is deleted. It is set to transfer to the drawing processing unit 12. In other cases, the display list of the band is converted into an edge list by the edge list generation unit 7 and stored in the edge list storage unit 8.

Here, the edge list is, for example, as shown in FIG. In the input display list, the coordinates of the intersection with each scan line are obtained by a method such as DDA. The obtained intersection coordinates are sorted in ascending order of the coordinate values for each scan line, and the starting point / point is determined in different ways according to the filling rule (even-odd rule, non-zero rule).
The correspondence between the end points is determined, and a space between the corresponding points becomes one edge, and is represented by, for example, a set of a start point Xs and an edge length Len. Edges drawn on the same scan line are collected and connected in a list, and a set of all edges obtained by converting the input display list becomes an edge list.

The second drawing time predicting section 9 reads out the edge list for each band stored in the edge list storage section 8 and draws that band from the edge list information.
The processing time for performing the drawing processing is estimated and compared with a predetermined second threshold value. The drawing time prediction from the edge list will be described later in detail.

If the predicted drawing time by the second drawing time prediction unit 9 is equal to or less than the second threshold, the edge list storage unit 8
, The edge list of the band stored in the display list storage unit 5 is deleted, and the display list of the band stored in the display list storage unit 5 is set to be transferred to the drawing processing unit 12. In other cases, the edge list of the band is converted by the edge list conversion unit 10 so as to reduce the drawing time, then stored in the conversion data storage unit 11, and transferred to the drawing processing unit 12. Is set. The conversion process in the edge list conversion unit 10 will be described later in detail.

For all the bands constituting the page,
When the above processing is completed, data is transferred from the display list storage unit 5 or the conversion data storage unit 11 to the drawing processing unit 12 in the drawing order of the bands according to the setting of each band.

The drawing processing unit 12 sequentially processes drawing elements in the display list format for each band transferred or the format converted from the edge list, and stores the drawing elements in a memory area corresponding to the band in the memory unit 13. Draw image data. The processing in the drawing processing unit 12 will be described later in detail.

When all the drawing elements in the band are drawn in the memory unit 13, the result is output to the output device 14 and printed or displayed on a printer or a display. This process is sequentially performed until all bands constituting the page are completed.

With such an image processing apparatus, the first drawing time predicting section 6 estimates the drawing processing time at the stage of the display list. If the estimated drawing processing time is equal to or less than the threshold, it is determined that the output can be completed. Upon determination, the display list is transferred to the drawing processing unit 12.

If the estimated drawing processing time exceeds the threshold, it is determined that there is a possibility that the output may not be completed in time.
The edge list generation unit 7 generates an edge list, and the second drawing time prediction unit 9 estimates an accurate drawing processing time. If the estimated rendering processing time is equal to or less than the threshold, it is determined that output is in time, and the display list is transferred to the image rendering means.

If the drawing processing time estimated by the second drawing time prediction section 9 exceeds the threshold value, there is a possibility that the output may not be enough for the output. The data is converted into a smaller format and transferred to the drawing processor 12. As a result, data can be transferred in time for output even in a complicated drawing process.

The outline of the image processing apparatus of the present invention has been described above. Although the description so far has been made only with respect to the drawing element, if a clip element indicating a clip area for limiting the drawing range of the drawing element is added, the same processing is performed for the clip element. The processing when a clip element exists is described in JP-A-2000-
Since it is described in detail in Japanese Patent No. 149036, only the drawing elements will be described below to simplify the description.

In addition, here, for the sake of simplicity of description, the above-described units are described as existing as hardware blocks, but the present invention is not limited thereto.

Rather, the drawing processing unit 12, the memory unit 13,
Since the components other than the output device 14 are configured by hardware, the design becomes complicated and costly. Therefore, it is preferable that the components are configured as software modules.

In that case, the display list storage unit 5,
The edge list storage unit 8 and the conversion data storage unit 11 are provided with a CPU (Central Processing Unit) of a computer system on which the software module operates.
(nit: central processing unit) may be shared.

Next, the details of the main part of the image processing apparatus will be described. FIG. 5 is a block diagram illustrating an example of a configuration of the first drawing time prediction unit 6. In the figure,
The first prediction processing unit 60 predicts the processing time in the drawing processing unit 12 based on the input display list.

The first determination processing section 61 accumulates / corrects the result of the prediction processing in the first prediction processing section 60, compares the result with a predetermined threshold value, determines the magnitude relationship, and outputs the result. . The first parameter storage unit 62 stores processing parameters required by the first prediction processing unit 60 and the first determination processing unit 61.

As described above, the display list storage unit 5 stores a display list of drawing elements for one page, divided for each band. After the above processing is completed, the first drawing time prediction unit 6 reads the display list, calculates a predicted value of the drawing time for each band, compares it with a predetermined threshold value, and outputs the result.

When the predicted value of the band drawing time is larger than the threshold value, each drawing element of the band is converted from the display list format to the edge list format by the edge list generation unit 7.

When the display list is input to the first prediction processing unit 60, the first prediction processing unit 60 obtains at least the number of pixels of a circumscribed rectangle of the figure drawn by the display list, and The coefficient stored in the storage unit 62 is read out, and the drawing time is predicted by a predetermined formula using the coefficient and the number of pixels of the circumscribed rectangle as arguments.

When the drawing process is executed by hardware,
Normally, writing to the memory unit 13 becomes a bottleneck in processing. Writing to the memory is proportional to the drawing area, and if there is an overhead such as memory access mode switching for writing for each scan line,
The height of the drawing area also affects the drawing time. For example, in such a case, the drawing time is predicted by calculation as in the following equation (1).

(Estimated drawing time) = a × (number of pixels of circumscribed rectangle) + b × (height of drawing area) + c (1)

The coefficients a, b, and c are obtained in advance by a statistical method or the like, and are supplied from the first parameter storage unit 62 to the first prediction processing unit 60.

The above equation (1) shows a case where a character / figure is drawn in a fixed color. However, when drawing an image, it is necessary to read and draw different color values for each pixel. , Coefficients a, b, and c have different values. If the drawing processing unit 12 is configured to share a bus for drawing and image reading, the bus band is consumed for image reading and the drawing time is affected. And so on must be included in the prediction formula.

The first prediction processing unit 60 sends the predicted drawing time for each drawing element thus obtained to the first determination processing unit 61. The first determination processing unit 61 adds up the predicted drawing time for the drawing elements in the band, performs correction according to the configuration of the drawing processing unit 12, and obtains the final predicted value of the band drawing time.

Here, the correction according to the configuration of the drawing processing unit 12 means, for example, that the drawing processing unit 12 is configured by hardware and the memory unit 13 is a DRAM (Dynamic R).
In the case of a configuration using an Random Access Memory, the effect of a bus band consumed for memory refresh or an influence of a bus band consumed for outputting image data from the memory unit 13 to the output device 14. It is for taking into account.

The final predicted drawing time obtained in this way is compared with a threshold value stored in advance in the first parameter storage section 62 to determine the magnitude relationship, and the result is output. The threshold used here is determined in consideration of a prediction error obtained in advance by a statistical method or the like. For example, the upper limit of the drawing time per band is 100 milliseconds, and the error is ± If there is about 30 milliseconds, a value such as 60 to 70 milliseconds is set as the threshold.

Next, the operation of the second drawing time prediction section 9 will be described. FIG. 6 is a block diagram illustrating an example of the configuration of the second drawing time prediction section 9. In the figure, the second prediction processing unit 90 predicts the processing time in the drawing processing unit 12 based on the input edge list.

The second determination processing section 91 accumulates / corrects the result of the prediction processing in the second prediction processing section 90, compares the result with a predetermined threshold value, determines the magnitude relationship, and outputs the result. . The second parameter storage unit 92 stores processing parameters required by the second prediction processing unit 90 and the second determination processing unit 91.

As described above, the edge list storage section 8 stores the edge list of the drawing elements of the bands for which the first drawing time predicting section 6 has determined that the predicted drawing time is larger than the predetermined threshold. ing.

After the above processing is completed, the second drawing time prediction section 9 reads the edge list, calculates the predicted value of the drawing time of the band, compares it with a predetermined threshold value, and compares the result with the threshold value. Output. If the predicted value of the band drawing time is larger than the threshold, each drawing element of the band is
The conversion is performed by the edge list conversion unit 10.

When the edge list is input to the second prediction processing section 90, the second prediction processing section 90 obtains at least the number of pixels of the figure to be drawn based on the edge list, and the second parameter storage section 92 Is read out, and the drawing time is predicted by a predetermined formula using the coefficient and the number of drawing pixels as arguments.

Unlike the display list, the accurate drawing pixel number can be obtained from the edge list only by integrating the values of Len shown in FIG. Therefore, a value with a much smaller prediction error than the predicted drawing time in the first drawing time prediction unit 6 can be obtained by the following equation (2).

(Estimated drawing time) = d × (number of drawing pixels) + e × (height of drawing area) + f (2)

The coefficients d, e, and f are obtained in advance by a statistical method or the like, similarly to the coefficients a, b, and c, and are supplied from the second parameter storage unit 92 to the second prediction processing unit 90. You.

Note that, like the first drawing time prediction section 6,
When drawing an image, the coefficients d, e, and f have different values.
If the drawing processing unit 12 is configured to share a bus for drawing and image reading, it is necessary to include the data amount of the image in the elements of the prediction formula.

The second prediction processing section 90 sends the predicted drawing time for each drawing element thus obtained to the second determination processing section 91. The second determination processing unit 91 calculates the final predicted value of the band drawing time by accumulating the predicted drawing time for the drawing elements in the band and performing correction according to the configuration of the drawing processing unit 12.

The final predicted drawing time obtained in this way is compared with a threshold value stored in advance in the second parameter storage section 92 to determine the magnitude relationship, and the result is output.

The threshold value used here is stricter than that used in the first drawing time prediction section, because the prediction error is small. For example, if the upper limit of the drawing time per band is 100 milliseconds and the error is about ± 5 milliseconds, a value such as 90 to 95 milliseconds is set as the threshold.

Next, the operation of the edge list conversion unit 10 will be described. FIG. 7 is a diagram illustrating the operation of the edge list conversion unit 10. As shown in the figure, the edge list conversion unit 10 removes the overlap of the edge list for the drawing element of the band for which the predicted drawing time is determined by the second drawing time prediction unit 9 to be larger than the predetermined threshold. I do.

More specifically, the drawing elements are taken out in order from the one drawn below, and for each edge included in the drawing element, the overlapping relationship with the edge included in the drawing element drawn higher is checked. , If there is overlap,
Remove that part.

For example, as shown in FIG. 7A, if there is no overlap, nothing is changed. As shown in FIG. 7B, when the portions overlap, the overlapping portion is removed from the edge of the lower drawing element.

As shown in FIG. 7C, when the edge of the upper drawing element is included in the edge of the lower drawing element, the lower edge is not covered by the upper edge. It is divided into two edges consisting of parts. As shown in FIG. 7D, when the edge of the upper drawing element covers the edge of the lower drawing element, the lower edge is deleted.

Such processing is performed on all drawing elements except the drawing element to be drawn on the top, and the resulting new edge list is stored in the conversion data storage unit 11.
To be stored.

Since the processing time in the drawing processing unit 12 depends on the number of pixels to be drawn, a non-overlapping edge list after conversion can be drawn faster than before processing.
In particular, bands that cannot be drawn by the drawing processing unit 12 often have enormous overlap due to gradation or the like, so that this processing greatly reduces the drawing processing time, and enables the drawing to be performed in time for the printing speed of the output device 14. It becomes possible.

Next, the operation of the drawing processing unit 12 will be described. FIG. 8 is a block diagram illustrating an example of a configuration of the drawing processing unit 12. In the figure, the shape processing circuit 120
Processes the display list input from the display list storage unit 5 or the edge list input from the conversion data storage unit 11, and outputs edge information to be drawn to the drawing circuit 123.

The color value generation circuit 121 supplies color value data for the drawing circuit 123 to draw in the memory unit 13.
For example, when the color value information is given by 8 bits each of RGB and the output device 14 is a printer of CMYK 1 bit input, the color value generating circuit 121 converts the RGB into CMYK.
Color space conversion, and then screen processing CM
YK 1-bit data is generated, and the shape processing circuit 120
Supplies the color value of the portion corresponding to the edge output to the drawing circuit 123 to the drawing circuit 123.

The image processing circuit 122 processes the image data and supplies the color value data for the drawing circuit 123 to draw in the memory unit 13 when the drawing element is a filled figure by an image. Similarly to the color value generation circuit, the image processing circuit 122 performs a process of converting image data when given in a different color space, a different number of bits, and a different resolution from the output device 14, and performs shape processing. The circuit 120 supplies the drawing circuit 123 with the color values corresponding to the edges output to the drawing circuit 123.

The drawing circuit 123 calculates a corresponding address in the memory unit 13 from the edge information input from the shape processing circuit 120 and converts the color value data supplied from the color value generation circuit 121 or the image processing circuit 122 into the corresponding address. Write to address.

When this process is performed on all drawing elements included in the processing target band, a band image of the band is drawn on the memory unit 13. This is output device 1
4, the band is displayed or printed.

Although the input to the drawing processing unit 12 has been described so as to be sequentially input from the display list storage unit 5 or the conversion data storage unit 11 for each band, software before the drawing processing unit 12 is used. In the case of a network printer that is composed of modules, the drawing processing unit and subsequent parts are composed of hardware, and the network is connected by a narrow path such as a network, the network transfer may become a bottleneck and it may not be possible to print. Conceivable. In such a case, it is necessary to adopt a configuration in which a temporary storage circuit is provided inside the drawing processing unit 12, and drawing processing is started after data for one page is sent and stored in the temporary storage circuit.

Next, another embodiment of the present invention will be described. The block diagram for explaining this embodiment uses the same FIG. 1 as the above embodiment, and the operation of each block other than the edge list conversion unit 10, the conversion data storage unit 12, and the drawing processing unit 12 is the same as that of the above invention, Description is omitted.

In the above embodiment, the edge list conversion unit 1
In the case of 0, the edge list overlap removal processing is performed. However, when the ROP processing is performed as described above, the element drawn below cannot be removed depending on the ROP code, and it is ensured that the drawing processing can be performed in time. I can't.

Therefore, the edge list conversion unit 1 of this embodiment
0, a memory area capable of drawing a band-size image is secured in the conversion data storage unit 11, and the edge list storage unit 9
The band list is generated by sequentially reading the edge list of the processing target band stored in the conversion processing unit 12, performing a drawing process of generating an image equivalent to that performed by the drawing processing unit 12, and writing the image in the conversion data storage unit 11.

For example, if the output device 14 is CMYK (C
yan, Magenta, Yellow, blackK)
If the printer is a one-bit input printer, the drawing processing unit 12
1-bit images of CMYK are generated using the same screen processing as in the first embodiment.

At the time of transferring the band, the band image is output from the converted data storage unit 11 to the drawing processing unit 12. The drawing processing unit 12 includes a conversion data storage unit 11
Then, the band image input from is written to the memory unit 13 as it is, and the drawing process of the band is ended.

As described above, by performing the drawing process in advance for the band for which the drawing process cannot be completed in time by the edge list conversion unit 10, the data to the output device 14 can be reliably transmitted to the band including the ROP process. Supply can be made in time.

Here, the description will be made such that the edge list conversion unit 10 generates a band image for all the bands in which the prediction result of the second drawing time prediction unit 9 is larger than the second threshold value. Performed, but check the ROP code of the drawing element included in the band, and if the ROP code that requires the base is not included at all, or the area of the drawing element that has the ROP code that requires the base is small In such a case, the overlap removal described in the previous embodiment may be performed.

In order to reduce the data amount of the band image and shorten the transfer time to the drawing processing unit 12, the edge list conversion unit 10 generates a compressed band image by performing a compression process after generating the band image. Alternatively, the drawing processing unit 12 may configure a decompression circuit in the image processing circuit 122 shown in FIG. 8 to decompress the input compressed band image and write it to the memory unit 13.

If multi-valued image compression / expansion is possible and the data amount is reduced to 1 / n or less by compression, even if the output device 14 is a CMYK 1-bit input printer, Without performing screen processing, compression is performed with n bits (normally n = 8) of multi-valued, and the drawing processing unit 1
2 may be configured to perform decompression and screen processing.

[0099]

As described above, according to the present invention, even when it is difficult to accurately predict the drawing processing time from the information of the drawing elements represented in the display list format, unnecessary processing such as overlap removal is performed. As much as possible, it ensures that data is supplied in time for the printing speed of the printer even when ROP processing is included, and also has less memory even at high resolution compared to the edge list. It is possible to realize a high-speed image processing device capable of storing / transferring in a small amount.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an image processing apparatus according to an embodiment.

FIG. 2 is a diagram illustrating recursive division of a Bezier curve.

FIG. 3 is a diagram illustrating a band division method.

FIG. 4 is a diagram illustrating an edge list.

FIG. 5 is a block diagram illustrating an example of a first drawing time prediction unit in the image processing apparatus according to the present embodiment.

FIG. 6 is a block diagram illustrating an example of a second drawing time prediction unit in the image processing apparatus according to the present embodiment.

FIG. 7 is a diagram illustrating edge overlap removal.

FIG. 8 is a block diagram illustrating an example of a drawing processing unit in the image processing apparatus according to the present embodiment.

FIG. 9 is a block diagram illustrating an example of an existing image processing apparatus.

FIG. 10 is a diagram illustrating conversion of a line graphic into a filled graphic.

FIG. 11 is a diagram illustrating approximation of a curve with a minute straight line.

FIG. 12 is a diagram illustrating a display list.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Instruction interpretation part, 2 ... Vector data generation part, 3 ... Font management part, 4 ... Display list generation part, 5 ... Display list storage part, 6 ... First drawing time prediction part, 7
... Edge list generation unit, 8 ... Edge list storage unit, 9 ...
Second drawing time prediction unit, 10... Edge list conversion unit, 1
DESCRIPTION OF SYMBOLS 1 ... Conversion data storage part, 12 ... Drawing processing part, 13 ... Memory part, 14 ... Output device, 60 ... First prediction processing part,
61: first determination processing unit, 62: first parameter storage unit, 90: second prediction processing unit, 91: second determination processing unit, 92: second parameter storage unit, 120: shape processing circuit 121, a color value generation circuit, 122, an image processing circuit,
123 ... Drawing circuit

Claims (7)

[Claims] 1. An image processing apparatus for performing a drawing process of a graphic, comprising converting vector information describing a drawing element or a clip element of the graphic into a set of linear vectors approximated by a polygon. Display list generating means for sorting a straight line by its start scan line coordinate value and generating a display list to which direction, inclination, and length information are added corresponding to the drawing element; and a display list generated by the display list generating means. Display list accumulating means for accumulating the image data; first drawing time estimating means for estimating the drawing processing time from the display list accumulated in the display list accumulating means; Calculate and draw start position and drawing on each scan line for each drawing element Edge list generating means for generating a list of edges composed of a set of: an edge list storing means for storing the edge list generated by the edge list generating means; and an edge list stored in the edge list storing means. Second drawing time estimating means for estimating a drawing processing time, edge list converting means for converting an edge list into a format having a shorter drawing time, and conversion data storing means for storing data converted by the edge list converting means Processing the display list, the edge list, and the drawing element converted by the edge list conversion means based on the drawing processing time predicted by the first drawing time prediction means and the second drawing time prediction means. An image processing apparatus, comprising: an image drawing unit that generates an image by using the image processing unit. 2. The image processing apparatus according to claim 1, wherein the edge list conversion unit removes an edge or a part of the edge that does not affect a drawing result due to overlap between drawing elements. 3. The image processing apparatus according to claim 1, wherein said edge list conversion means performs a drawing process on a drawing element represented by an edge list to convert the drawing element into an image. 4. The first drawing time estimating means performs an estimating process using at least the number of pixels of a circumscribed rectangle of a drawing element represented by a display list, and the second drawing time estimating means includes at least an edge. 2. The image processing apparatus according to claim 1, wherein the estimation processing is performed using the number of drawing pixels of the drawing elements represented by the list. 5. When the drawing time estimated by said first drawing time estimating means is less than or equal to a first threshold, a display list is input to said image drawing means for processing, otherwise, said display list is processed. The display list is converted into an edge list by the edge list generating means, and when the drawing time estimated by the second drawing time estimating means is less than or equal to a second threshold, the edge list is input to the image drawing means and processed. In other cases, the result of converting the edge list by the edge list converting means is input to the image drawing means and processed. An image processing apparatus as described in the above. 6. The display list generating means, the display list storing means, the first drawing time estimating means, the edge list generating means, the edge list storing means, the second drawing time estimating means, the edge list 6. The image processing apparatus according to claim 1, wherein each processing in the conversion unit, the conversion data storage unit, and the image drawing unit is performed independently for each partial region obtained by dividing the entire image to be formed. The image processing apparatus according to claim 1. 7. The display list generation unit, the display list storage unit, the first drawing time estimation unit, the edge list generation unit, the edge list storage unit, the second drawing time estimation unit, and the edge The image processing apparatus according to any one of claims 1 to 6, wherein the list conversion unit is configured by software described by a program, and the image rendering unit is configured by hardware.