JP2010146255A - Vector graphics drawing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a vector graphics drawing device for eliminating processes with respect to a wasteful tile area, and for operating at a high speed. <P>SOLUTION: A curve-dividing unit 13 divides the curve of an outline into a plurality of minute straight lines. An outline drawing unit 14 acquires information on a cross point between a straight line and a scan line and holds in an outline buffer 15. A pixel-producing unit 18 produces a pixel by reading information of the outline buffer 15. A valid tile flag buffer 16 holds a flag, indicating which tile area is valid. A control unit 19 determines which tile area is to be processed next, by referring to the valid tile flag buffer 16 and controls the curve-dividing unit 13, the outline drawing unit 14, and the pixel-producing unit 18 so as to perform processing by a tile area unit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vector graphic drawing apparatus that divides a drawing area into a plurality of tile areas and draws a vector graphic whose contour is defined by a mathematical expression for each tile area.

  Vector graphics and outline fonts have contours defined by mathematical formulas, and can be easily deformed such as enlarged, reduced, and rotated, and the image quality does not deteriorate even when deformed. When displaying vector graphics and outline fonts on a display device such as a liquid crystal display, it is necessary to convert them to raster data. After converting the coordinates to the desired size, draw the contour according to the contour formula, The process of painting out is required. This processing is normally performed by software processing by the CPU, but there are cases where drawing is performed at high speed by hardware.

  Conventionally, in order to reduce the amount of work memory that stores outline information required for drawing processing of vector graphics and outline fonts, a small amount of work memory is built in, and the graphics or characters to be drawn exceed the work memory area. In some cases, there has been a method of drawing by dividing into tile units corresponding to the work memory area (see, for example, Patent Document 1).

JP-A-6-161420

  In the conventional graphic drawing apparatus as described above, the effective drawing area is divided into tile units, and the divided areas are sequentially processed. However, since the processing is sequentially performed in this way, a region where no graphic is present is similarly processed. As a result, depending on the shape of the vector graphic, there is a problem in that the ratio of processing to a useless tile area increases and drawing efficiency deteriorates.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a vector graphic drawing apparatus that operates at high speed while omitting processing for useless tile areas.

  The vector graphic drawing apparatus according to the present invention includes a curve dividing unit that divides a contour curve into a plurality of minute straight lines, a contour drawing unit that obtains information on intersections between straight lines and scan lines, and information obtained by the contour drawing unit , A pixel generation unit that reads out information stored in the contour buffer and generates pixels, an effective tile flag buffer that holds a flag indicating which tile area is valid in the processing direction of the tile area, The curve dividing unit, the contour drawing unit, and the pixel generation unit are controlled to perform processing in units of tile areas, and a control unit that determines which tile area is to be processed next with reference to the effective tile flag buffer. It is provided.

  The vector graphic drawing apparatus according to the present invention includes an effective tile flag buffer that holds a flag indicating which tile area is valid in the processing direction of the tile area, and which tile area is processed next with reference to the effective tile flag buffer. Therefore, it is possible to omit processing for useless tile areas and to perform high-speed drawing.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a vector graphic drawing apparatus according to Embodiment 1 of the present invention.
In the figure, a vector graphic drawing apparatus 10 includes a coordinate conversion unit 11, an input buffer 12, a curve dividing unit 13, a contour drawing unit 14, a contour buffer 15, an effective tile flag buffer 16, an auxiliary buffer 17, a pixel generation unit 18, and a control unit. 19 is provided.

  The coordinate conversion unit 11 is a processing unit that performs coordinate conversion processing on input vector data and converts the vector data into coordinates on the frame buffer 20. The input buffer 12 is a buffer that stores vector data output from the coordinate conversion unit 11. The curve dividing unit 13 is a processing unit that reads data stored in the input buffer 12 and divides the curve into minute line segments. The contour drawing unit 14 is a processing unit that performs rasterization processing on the straight line output from the curve dividing unit 13 to draw contour information and determine an effective tile area. The contour buffer 15 is a buffer that holds the contour information output from the contour drawing unit 14. The effective tile flag buffer 16 is a buffer that holds information on effective tile areas determined by the contour drawing unit 14. The auxiliary buffer 17 is a buffer that holds contour information for one vertical column of the contour buffer 15. The pixel generation unit 18 is a processing unit that generates pixels to be drawn with reference to the contour buffer 15 and the auxiliary buffer 17. The control unit 19 is a control unit that controls each processing unit. The frame buffer 20 is a buffer that holds an image of a drawing result.

  The vector graphic drawing apparatus 10 is realized by using a computer. The coordinate conversion unit 11, the curve dividing unit 13, the contour drawing unit 14, the pixel generation unit 18 and the control unit 19 include software corresponding to each process, It is composed of hardware such as a CPU and memory for executing software, or each is composed of dedicated hardware. The input buffer 12, contour buffer 15, and valid tile flag buffer 16 are temporary storage units provided on the memory, respectively.

  Since the outline font is considered to be a kind of vector graphic, it will be described as a vector graphic including the outline font. Furthermore, in the embodiment, the horizontal direction in the drawing area will be described as the processing direction of the tile area.

Next, the operation of the vector graphic drawing apparatus of the first embodiment will be described.
As an initial state of the vector graphic drawing apparatus 10, it is assumed that the input buffer 12 is empty and the contour buffer 15, valid tile flag buffer 16 and auxiliary buffer 17 are all initialized to an initial value “0”.
In order to simplify the drawing, it is assumed here that the contour buffer 15 has a capacity of 8 × 8 pixel tiles. The effective tile flag buffer 16 is a one-dimensional buffer having 1-bit information per tile area. The auxiliary buffer 17 is a buffer having a capacity corresponding to one vertical column of the contour buffer 15 as described above.

  When the vector graphic drawing apparatus 10 draws a vector graphic, first, an attribute such as the color of the graphic is designated from a host device (not shown), and vector data constituting the outline of the graphic is input. Alternatively, the vector graphic drawing apparatus 10 may read out vector data stored in an external memory (not shown). The vector data constituting the contour of the figure is composed of commands and XY coordinates, and the contour is defined by the vertices of straight lines, the vertices of curves, and control points as shown in FIG. In the following description, it is assumed that the origin of the XY coordinates exists at the upper left.

  The input vector data is input to the coordinate conversion unit 11. The coordinate conversion unit 11 performs coordinate conversion processing on the coordinates of the vector data in accordance with a preset conversion matrix in order to perform enlargement / reduction, rotation, translation, etc. of characters, and the coordinates on the frame buffer 20 to be drawn And stored in the input buffer 12. At that time, the minimum value and the maximum value are stored for the X coordinate and the Y coordinate after the coordinate conversion.

  When all the vector data constituting one figure is stored in the input buffer 12, the coordinate conversion unit 11 stores the minimum and maximum values for the X coordinate and Y coordinate of the vector data constituting the figure as shown in FIG. (Xmin, Ymin, Xmax, Ymax) is stored. Here, as a result of the coordinate conversion, it is assumed that the figure has a size that spans six tile areas (size of the contour buffer 15) in the vertical and horizontal directions as shown in FIG.

  When all the vector data composing one graphic is stored in the input buffer 12, the control unit 19 instructs the curve dividing unit 13 to start processing. At that time, first, the control unit 19 performs a drawing in the region 1A in FIG. 3 so that the minimum coordinates (Xmin, Ymin) of the bounding box of the character and the origin of the contour buffer 15 correspond to each other. 13 is instructed. Further, the control unit 19 notifies the curve dividing unit 13 that the processing target area 1A is the first tile area in the horizontal direction.

When the control unit 19 gives an instruction to start processing, the curve dividing unit 13 sequentially reads vector data from the input buffer 12 and performs processing. Hereinafter, the operation of the curve dividing unit 13 will be described with reference to FIG.
The curve dividing unit 13 sets the value of Xmin from the X coordinate value of the vector data read from the input buffer 12 in order to make the coordinates (Xmin, Ymin) of the vector data correspond to the origin (0, 0) on the contour buffer 15. Similarly, the value of Ymin is subtracted from the value of the Y coordinate (FIG. 4-a).

  Next, it is determined whether or not the straight line or curve constituting the outline is completely outside the tile area to be processed, and if it is determined to be located outside, the straight line or curve is discarded and the subsequent Do not perform processing. However, since the processing target area 1A is the first tile area in the horizontal direction, control is performed so as to discard only the straight line or curve located outside the tile in the vertical direction. That is, the straight lines / curves whose Y coordinates of the vertices / control points defining the straight lines / curves are all less than 0 or 8 or more are discarded (FIG. 4B).

  Next, the curve dividing unit 13 divides the curve into minute straight lines. A method of dividing a curve into straight lines is well known and will not be described in detail, but a method of changing the number of divisions based on the curvature of the curve is desirable. If the input data is a straight line, no division is performed (FIG. 4-c).

Next, the curve dividing unit 13 determines again whether or not the straight line divided from the curve is completely outside the tile area to be processed. Discard the straight line or curve so that no further processing is performed. Here, similarly to the above, since the processing target area 1A is the first tile area in the horizontal direction, only the straight line located outside the tile in the vertical direction is discarded. Further, when the straight line straddles the upper side and the lower side of the tile area, the clipping process is performed (FIG. 4-d).
By performing the above processing, the curve dividing unit 13 outputs straight line data to the contour drawing unit 14.

The contour drawing unit 14 rasterizes the straight line input from the curve dividing unit 13, finds the intersection of the scan line and the straight line, and draws the contour buffer 15. At this time, if the line is an upward straight line, 1 is added to the value of the intersection coordinate in the contour buffer 15, and if the line is a downward straight line, drawing is performed so that 1 is subtracted from the value of the contour buffer. Further, when the coordinates of the intersection point exceed the tile area to be processed, writing is not performed.
In addition, since the processing target region 1A is the first tile region in the horizontal direction, the contour drawing unit 14 determines that the straight line having coordinates exceeding the processing target tile region is horizontal from the start point and end point coordinates. It is determined which tile region in the direction is covered, and the corresponding bit of the valid tile flag buffer 16 is set to “1”.
The curve dividing unit 13 and the contour drawing unit 14 perform the above processing by pipeline processing, and perform processing for all data of one figure stored in the input buffer 12.

  5A and 5B are diagrams showing examples of the contour buffer 15 and the effective tile flag buffer 16 when the processing of the area 1A in FIG. 3 is finished. In FIG. 5B, in the effective tile flag buffer 16, the leftmost bit and the fifth bit from the left are “1”, which indicates that there are contour lines in the region 1B and the region 1F in FIG. ing.

  When the control unit 19 detects that the processes of the curve dividing unit 13 and the contour drawing unit 14 are finished, it instructs the pixel generation unit 18 to start the process next. At that time, the control unit 19 instructs the pixel generation unit 18 to associate the origin of the contour buffer 15 with the coordinates (Xmin, Ymin) on the frame buffer 20.

When instructed to start processing from the control unit 19, the pixel generation unit 18 refers to the contour buffer 15 and the auxiliary buffer 17 to generate pixels to be drawn. Hereinafter, the operation of the pixel generation unit 18 will be described with reference to FIGS.
The pixel generation unit 18 generates pixels by repeating pixel generation in the scan line direction by the vertical resolution of the contour buffer 15. Further, pixel generation in the scan line direction is performed by obtaining the number of times of intersection with the contour in each pixel.
The number of intersections with the contour in each pixel is obtained by adding the value of the corresponding position in the contour buffer 15 to the value of the number of intersections with the contour in the left pixel. Further, the initial value of the number of times of intersection with the contour is a value at a corresponding position in the auxiliary buffer 17. If the number of intersections with the contour in each pixel is other than 0, it is determined that the pixel needs to be drawn because it is inside the figure, and a pixel is generated.

  For example, in the example of the uppermost scan line (Y = 0), the initial value is a value read from the corresponding position of the auxiliary buffer 17, and is “0” here (FIG. 6A). When the values of the contour buffer 15 (see FIG. 5A) are sequentially added from the coordinates (0, 0), the pixels at the coordinates (2, 0), (3, 0), and (4, 0) are added. Since the number of intersections with the contour is “1”, the pixel generation unit 18 generates these pixels. Then, the number of intersections with the contour at the rightmost pixel is written back to the corresponding position in the auxiliary buffer 17.

  By repeating the above processing up to the scan line at the bottom (Y = 7), all the pixels that need to be drawn in the region of the contour buffer 15 are generated. The generated pixels are converted into coordinates on the frame buffer 20 by adding the Xmin value to the X coordinate value, and adding the Ymin value to the Y coordinate value, and the frame buffer has a preset drawing color. 20 is drawn.

  The pixel generation unit 18 performs the above processing by pipeline processing, and ends the operation when all the pixels that need to be drawn are drawn in the frame buffer 20. 6B is a diagram illustrating a result of pixel generation by the pixel generation unit 18 in the region 1A of FIG. Similarly, FIG. 6C is a diagram showing the contents of the auxiliary buffer 17 at the time when the operation of the pixel generation unit 18 is completed in the region 1A of FIG.

In the description of the pixel generation unit 18 described above, the contour buffer 15 is read pixel by pixel. However, the pixel generation processing may be performed by reading the contour buffer 15 for a plurality of pixels at a time. .
The contour buffer 15 needs to be initialized before the next tile area is processed. Therefore, initialization is performed when the pixel generation unit 18 reads the contour buffer 15. In order to be able to perform reading and initialization at the same time, it is desirable that the contour buffer 15 is composed of a two-port memory.

  When the drawing of the portion of the area 1A in FIG. 3 is completed by the above processing, the control unit 19 refers to the valid tile flag buffer 16 and determines which tile area is to be processed next. In this example, since the effective tile flag buffer 16 shows that there are contour lines in the region 1B and the region 1F in FIG. 3, the control unit 19 first determines that the processing is performed on the region 1B, and the curve dividing unit 13 again Instruct the start of processing. At that time, the control unit 19 instructs the curve dividing unit 13 to associate the upper left coordinates of the region 1B with the origin of the contour buffer 15 in order to draw the portion of the region 1B. That is, if the size of the contour buffer 15 is 8 × 8, an instruction is issued to associate the coordinates (Xmin + 8, Ymin) of the vector data with the origin of the contour buffer 15. Also, the control unit 19 notifies that the processing target area 1B is not the first tile area in the horizontal direction. Further, the control unit 19 clears the bit corresponding to the area 1B of the valid tile flag buffer 16 to “0”.

When the control unit 19 gives an instruction to start processing, the curve dividing unit 13 sequentially reads vector data from the input buffer 12 again and performs processing. FIG. 7 is a diagram for explaining the operation of the curve dividing unit 13 at this time.
The curve dividing unit 13 uses the X-coordinate value of the vector data read from the input buffer 12 (Xmin + 8) in order to make the coordinates (Xmin + 8, Ymin) of the vector data correspond to the origin (0, 0) on the contour buffer 15. Similarly, the Ymin value is subtracted from the Y coordinate value (FIG. 7A).

Next, it is determined whether or not the straight line or curve constituting the outline is completely outside the tile area to be processed, and if it is determined to be located outside, the straight line or curve is discarded and the subsequent Do not perform processing. At this time, since the processing target area 1B is not the first tile area in the horizontal direction, unlike the processing of FIG. 4, all the straight lines / curves located outside the target tile area are discarded (FIG. 7B).
Next, the curve is divided into minute straight lines (FIG. 7C), and for the straight lines divided from the curve, it is determined again whether the straight line is completely outside the tile area to be processed. If it is determined that it is located at the position, the straight line or curve is discarded and the subsequent processing is not performed. Here, similarly to the above-described processing before the division, the processing target region 1B is not the first tile region in the horizontal direction, and therefore all straight lines located outside the tile region are discarded. Further, when the straight line extends over the four sides of the tile area, the clip process is performed (FIG. 7D).
By performing the above processing, the curve dividing unit 13 outputs straight line data to the contour drawing unit 14.

  The contour drawing unit 14 rasterizes the straight line input from the curve dividing unit 13 in the same manner as the processing of the region 1A described above, obtains the intersection of the scan line and the straight line, and draws it in the contour buffer 15. At this time, the contour drawing unit 14 does not write to the effective tile flag buffer 16, unlike the region 1A, because the processing target region 1B is not the first tile region in the horizontal direction. Only drawing to 15 is performed. FIG. 8 is a diagram illustrating an example of the contour buffer 15 when the processing of the contour drawing unit 14 in the region 1B of FIG. 3 is finished.

  When the control unit 19 detects that the processes in the curve dividing unit 13 and the contour drawing unit 14 are finished, the control unit 19 instructs the pixel generation unit 18 to start the process next. At that time, the control unit 19 instructs the pixel generation unit 18 to associate the origin of the contour buffer 15 with the coordinates (Xmin + 8, Ymin) on the frame buffer.

  When instructed to start processing from the control unit 19, the pixel generation unit 18 refers to the contour buffer 15 and the auxiliary buffer 17 to generate pixels to be drawn. The processing in the pixel generation unit 18 is the same as the processing in the region 1A described above except that the value added to the X coordinate of the generated pixel is (Xmin + 8). At this time, as shown in FIG. 9A, the auxiliary buffer 17 at the start of processing stores the value of the number of intersections with the contour in the rightmost pixel of the previous region, that is, the region 1A in FIG. By using this value as an initial value, it is possible to accurately generate pixels without causing pixel omission between tile areas. FIG. 9B is a diagram illustrating a result of pixel generation by the pixel generation unit 18 in the region 1B of FIG. Similarly, FIG. 9C is a diagram showing the contents of the auxiliary buffer 17 at the time when the operation of the pixel generation unit 18 is completed in the region 1B of FIG.

  When the drawing of the portion of the region 1B in FIG. 3 is completed by the above processing, the control unit 19 refers to the valid tile flag buffer 16 and determines which tile region is to be processed next. In this example, since the effective tile flag buffer 16 shows that an outline exists in the area 1F in FIG. 3, the control unit 19 determines that the area 1F will be processed next, and the curve dividing unit 13 performs the process again. Instruct the start. At that time, the control unit 19 instructs the curve dividing unit 13 to associate the upper left coordinates of the region 1F with the origin of the contour buffer 15 in order to draw a portion of the region 1F. That is, an instruction is issued so that (Xmin + 40, Ymin) corresponds to the origin of the contour buffer 15. In addition, the control unit 19 notifies that the processing target area 1F is not the first tile area in the horizontal direction. In addition, the control unit 19 clears the bit corresponding to the area 1F of the valid tile flag buffer to “0”.

  Drawing in the area 1F is the above-described area 1A except that the value to be subtracted from the coordinates of the vector data by the curve dividing unit 13 and the value to be added to the coordinates of the pixel generated by the pixel generating unit 18 are (Xmin + 40, Ymin). , 1B.

  When the drawing of the area 1F in FIG. 3 is completed by the above processing, the control unit 19 refers to the valid tile flag buffer 16 and determines that there is no more tile area to be processed in the horizontal direction, and then draws the area 2A. In order to perform the above, the curve dividing unit 13 is instructed to associate the upper left coordinates of the region 2A with the origin of the contour buffer 15. That is, an instruction is issued so that (Xmin, Ymin + 8) and the origin of the contour buffer 15 correspond to each other. In addition, the control unit 19 notifies that the processing target area 2A is the first tile area in the horizontal direction.

Drawing in the region 2A is processing for the region 1A except that the value to be subtracted from the coordinates of the vector data by the curve dividing unit 13 and the value to be added to the coordinates of the pixel generated by the pixel generating unit 18 are (Xmin, Ymin + 8). Therefore, detailed description thereof is omitted here.
When the drawing in the area 2A is completed, the control unit 19 refers to the valid tile flag buffer 16 to determine a valid tile in the horizontal direction and instructs the drawing process again. In the example of FIG. 3, the drawing process is performed in the order of the area 2B, the area 2E, and the area 2F.
Similarly, when processing the first tile area in the horizontal direction, the outline drawing unit 14 determines the tile area where the outline exists and writes it in the effective tile flag buffer 16. Only processes tile areas where outlines exist.

FIG. 10 is a diagram illustrating the processing of the curve dividing unit 13 in the region 5A of FIG. FIG. 11 is a diagram showing an example of the contour buffer 15 (FIG. 11-a) and the effective tile flag buffer 16 (FIG. 11-b) when the processing of the contour drawing unit 14 in the region 5A of FIG. 3 is completed. is there.
After the processing of the area 5A is completed, the control unit 19 refers to the effective tile flag buffer (FIG. 11B) and instructs the drawing process for the area 5B and the area 5E.
FIG. 12A shows the state of the frame buffer at the time when drawing in the area 5B is completed. When drawing is next performed in the area 5E in this state, the areas 5C and 5D that should originally be drawn are not drawn. Therefore, when the pixel generation unit 18 generates a pixel, when the process is performed on a tile area located in the lateral direction away from the tile area that was previously processed, the value of the auxiliary buffer 17 is other than “0”. For the scan line, pixels are generated so as to fill the tile area where the processing is omitted. Thereby, when the processing of the region 5E is completed, the drawing of the region 5C and the region 5D is also completed (FIG. 12B).

  Thereafter, the same processing is performed, and when the processing of the tile region in the horizontal row including the maximum value (Ymax) of the Y coordinate is completed, the control unit 19 determines that the drawing of the vector graphic is completed and holds it in the input buffer 12 The input data being discarded is discarded, and the vector graphic drawing apparatus 10 ends the operation.

  As described above, when processing the first tile area in the horizontal direction, it is determined which tile area needs to be processed in the horizontal direction at the same time, and the result is retained. By performing the contour processing only for the tile region where the contour line exists with reference to the flag during the processing, it is possible to omit the processing for the useless tile region and operate at high speed as shown in FIG.

  In the above description, the curve dividing unit 13 and the contour drawing unit 14 and the pixel generating unit 18 are described to operate alternately. However, the contour buffer 15 is configured as a double buffer, and the example of FIG. Then, while the pixel generation unit 18 is processing the region 1A, the curve dividing unit 13 and the contour drawing unit 14 perform the processing of the region 1B. The units 18 can be operated in parallel.

  In addition, the pixel generation unit 18 performs drawing if the number of intersections with the contour in each pixel is other than 0, but the process of drawing when the number of intersections is other than 0 (non-zero rule) and the number of intersections. The processing (even-odd rule) of drawing when the number is an odd number may be switched.

  The contour buffer 15 has a resolution of subpixels such as 4 × 4, for example, the contour drawing unit 14 generates contour information in units of subpixels and writes the information to the contour buffer 15, and the pixel generation unit 18 in units of subpixels. Generate a subpixel to be drawn, calculate the density of the pixel to be drawn from the ratio of effective subpixels for each pixel, and perform anti-aliasing processing by blending with the pixels already drawn You may make it draw.

  As described above, according to the vector graphic drawing apparatus of the first embodiment, in the vector graphic drawing apparatus that draws a vector graphic whose outline is defined by a mathematical expression in a drawing area divided by a plurality of tile areas, the contour curve Is divided into a plurality of minute straight lines, a contour drawing unit that obtains information on the intersection of a straight line and a scan line, a contour buffer that holds information obtained by the contour drawing unit, and a contour buffer A pixel generation unit that reads out information to generate pixels, an effective tile flag buffer that holds a flag indicating which tile region is valid in the processing direction of the tile region, a curve division unit, a contour drawing unit, and a pixel generation unit, A control unit that controls processing to be performed in units of tile areas and determines which tile area is to be processed next with reference to the valid tile flag buffer Because with a, it is possible to omit the processing for unnecessary tile area, it is possible to perform high-speed drawing.

  Further, according to the vector graphic drawing apparatus of the first embodiment, when performing processing on the tile area at the processing start end in the processing direction of the tile area, the contour drawing unit processes which tile area for the tile area to be processed from now on. The result is stored in the valid tile flag buffer, and when the next tile area is processed, the control unit processes only the valid tile area with reference to the valid tile flag buffer. By performing control so as to perform the above, it is possible to easily determine a useless tile area and to realize a high-speed operation.

  Further, according to the vector graphic drawing apparatus of the first embodiment, the curve dividing unit clips only in a direction perpendicular to the processing direction of the tile area when processing the tile area at the processing start end in the processing direction of the tile area. When processing the next and subsequent tile areas, the clipping process is performed on the top, bottom, left, and right of the tile area, so that each tile area can be processed accurately, and high-speed and accurate drawing can be performed. It can be carried out.

  In addition, according to the vector graphic drawing apparatus of the first embodiment, the pixel generation unit has the auxiliary buffer that holds the pixel values for one column of the tile area in the direction perpendicular to the processing direction of the tile area. Sometimes, the number of intersections with the contour of the first pixel in the processing direction of the processed tile area is stored as a value in the auxiliary buffer, and the value of the auxiliary buffer is used as the initial value of the number of intersections with the outline when processing the next tile area. Since it did in this way, the pixel generation process of each tile area | region can be performed correctly.

  Further, according to the vector graphic drawing apparatus of the first embodiment, the pixel generation unit includes a tile area that is not a processing target between the processing target tile areas and refers to the value of the auxiliary buffer. When pixel generation is necessary, pixel generation is performed including a portion of a tile area that is not a processing target, so that even if there is a tile area that is not processed, rendering can be performed reliably.

  In addition, according to the vector graphic drawing apparatus of the first embodiment, the contour buffer is configured with a resolution in units of subpixels, and the pixel generation unit generates a pixel to be drawn from the ratio of effective subpixels when generating the pixels. Since the density is calculated and the anti-aliased figure is drawn by blending with the already drawn pixels, the anti-aliased figure can be drawn easily and at high speed. it can.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the vector figure drawing apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows an example of the vector figure of the vector figure drawing apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the relationship between the vector figure of the vector figure drawing apparatus by Embodiment 1 of this invention, and a tile area | region. It is explanatory drawing which shows operation | movement of the curve division part of the vector figure drawing apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the state of the outline buffer and effective tile flag buffer when the process of area | region 1A of the vector graphics drawing apparatus by Embodiment 1 of this invention is complete | finished. It is explanatory drawing which shows the state before pixel drawing of the result of pixel generation in the area | region 1A of the vector graphics drawing apparatus by Embodiment 1 of this invention, and after drawing of an auxiliary buffer. It is explanatory drawing which shows operation | movement of the curve division part of the area | region 1B of the vector figure drawing apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the state of the outline buffer when the process of the outline drawing part of the area | region 1B of the vector figure drawing apparatus by Embodiment 1 of this invention is finished. It is explanatory drawing which shows the state before the drawing of the pixel generation in the area | region 1B of the vector graphics drawing apparatus by Embodiment 1 of this invention, and the drawing of an auxiliary buffer, and after drawing. It is explanatory drawing which shows operation | movement of the curve division part of the area | region 5A of the vector figure drawing apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the state of the outline buffer and effective tile flag buffer when the process of area | region 5A of the vector graphics drawing apparatus by Embodiment 1 of this invention is complete | finished. It is explanatory drawing which shows a pixel production | generation when there exists a tile area | region which does not process between the vector figure drawing apparatuses by Embodiment 1 of this invention. It is explanatory drawing which shows the tile area | region which can be omitted by the process of the vector graphic drawing apparatus by Embodiment 1 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Vector figure drawing apparatus, 13 Curve division | segmentation part, 14 Outline drawing part, 15 Outline buffer, 16 Effective tile flag buffer, 17 Auxiliary buffer, 18 Pixel generation part, 19 Control part.

Claims (6)

In a vector graphic drawing apparatus that draws a vector graphic whose contour is defined by a mathematical expression in a drawing area divided by a plurality of tile areas,
A curve dividing unit for dividing the contour curve into a plurality of minute straight lines;
An outline drawing unit for obtaining information of an intersection of the straight line and the scan line;
A contour buffer for holding information obtained by the contour drawing unit;
A pixel generation unit that reads out information held in the contour buffer and generates pixels;
An effective tile flag buffer that holds a flag indicating which tile area is valid in the processing direction of the tile area;
The curve dividing unit, the contour drawing unit, and the pixel generation unit are controlled to perform processing in units of tile regions, and determine which tile region is to be processed next with reference to the effective tile flag buffer. A vector graphic drawing apparatus comprising a control unit for performing The contour drawing unit determines which tile area needs to be processed for the tile area to be processed when processing the tile area at the processing start end in the processing direction of the tile area, and obtains the result as an effective tile flag buffer. To hold
2. The vector graphic drawing apparatus according to claim 1, wherein when the processing of the next tile area is performed, the control unit performs control so that only the effective tile area is processed with reference to the effective tile flag buffer. .   When performing processing on the tile area at the processing start end in the processing direction of the tile area, the curve dividing unit performs clip processing only in a direction perpendicular to the processing direction of the tile area, and when processing on the subsequent tile areas 3. The vector graphic drawing apparatus according to claim 1, wherein clip processing is performed on the top, bottom, left and right of the tile area. An auxiliary buffer that holds pixel values for one column of the tile area in a direction perpendicular to the processing direction of the tile area;
The pixel generation unit stores the number of intersections with the contour of the first pixel in the processing direction of the processed tile area in the auxiliary buffer during the pixel generation process as the value, and stores the value of the auxiliary buffer in the next tile area processing. The vector graphic drawing apparatus according to any one of claims 1 to 3, wherein the vector graphic drawing apparatus is used as an initial value of the number of times of intersection with a contour.   When there is a tile area not to be processed between the tile areas to be processed and the pixel generation needs to be generated by referring to the value of the auxiliary buffer, the pixel generation unit does not set the process target 5. The vector graphic drawing apparatus according to claim 4, wherein pixel generation is performed including a tile area portion. The contour buffer consists of subpixel resolution,
When generating a pixel, the pixel generation unit calculates the density of the pixel to be drawn from the ratio of effective sub-pixels, and performs anti-aliasing processing by blending with the pixels already drawn The vector graphic drawing apparatus according to claim 1, wherein the vector graphic drawing apparatus draws.

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