JP2641790B2 - Vector raster converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a vector raster conversion apparatus used for image processing in a workstation, desktop publishing (DTP), or the like.

[Prior art]

Recently, the use of vector fonts in image processing in workstations and DTP has been increasing. The reason is that there is an advantage that the print quality is not degraded even when processing such as rotation, scaling, inclination, etc., and that it is not necessary to prepare a font for each size. In DTP, WYSIWYG (What You See Is What Y
ou Get) function, that is, the function of printing and obtaining the same thing displayed on the screen is emphasized, and in order to realize this, it is necessary to use a vector font even in the CRT. . The raster conversion of this vector font has conventionally been performed according to the procedure shown in FIG. That is, first, in step S31, parameters of the affine transformation such as the rotation angle, the tilt angle, the magnification, and the offset value from the coordinate origin are set, and then in step S32, the address of the memory in which the vector font is stored is set. . These set values are stored in a register or the like, and stored until a new value is set. After completing the setting, the process proceeds to step S33, and when the memory control unit is activated by an execution command, the memory control unit loads the vector of the stored address. Vector data is often differential data for data compression. The difference data is converted into absolute coordinates in step S34 before being subjected to the affine transformation. This is because if affine transformation is performed and then converted to absolute coordinates, there is accumulation of errors. The value converted into the absolute coordinates is subjected to affine transformation in step S35. The affine transformation is represented by the following equation, for example. X = (x · Mx + y · My · tanθ) · cosφ−y · My · sinφ + CPx Y = (x · Mx + y · My · tanθ) · sinφ−y · My · cosφ + CPx where Mx is the magnification in the x direction and My Is the magnification in the y direction,
θ is a tilt angle, φ is a rotation angle, and CPx and CPy are offset values. Next, the process proceeds to step S36, in which the coordinate values subjected to the affine transformation are raster-converted by the Bresenham algorithm or the like, and straight lines are drawn in the output buffer. Then, in a step S37, it is determined whether or not the output buffer becomes full. When the output buffer becomes full, the data in the output buffer is written to the external memory in a step S38. This operation is repeated until a one-character vector is drawn. When an outline for one character is drawn, the process proceeds from step S39 to step S40, and the inside of the outline is filled with a method such as a switching fill or a seed fill. I was

[Problems to be solved by the invention]

By the way, usually, vector fonts of one or two sizes are prepared, and if other sizes are required, they are often scaled and used.
Usually, 512 dots × 512 dots or 1024 dots × 1024
Often, a large character vector like a dot is used to reduce it. In such a case, the reduction often causes the vector to become a zero vector. It is not necessary to perform an affine transformation on a vector that becomes a zero vector due to such reduction, but in the above-described conventional raster conversion of a vector, an affine transformation is also performed on such a vector. The multiplication was performed 12 times and the addition was performed 6 times with respect to the coordinates of the start point and the end point, as shown in the above equation. Therefore, there is a disadvantage that the processing speed is slow. In particular, when many small characters are displayed on the screen, the number of characters is proportional to the area (the square of the character size), but the processing speed is determined by the vector length (the square of the character size). Since the large characters and the number of vectors are the same, a high processing speed is required. However, the processing speed becomes slow due to the unnecessary affine transformation as described above, which is a problem. SUMMARY OF THE INVENTION It is an object of the present invention to provide a vector raster conversion apparatus in which affine transformation is not performed on a vector that becomes a zero vector when reduced, thereby increasing the processing speed.

[Means for Solving the Problems]

In order to achieve the above object, the present invention performs affine transformation of vector data created based on image data,
In a vector raster conversion device that performs raster conversion based on the vector data obtained as a result and performs straight line drawing, when the vector after the affine conversion is a zero vector, the starting point of the vector before the affine conversion is determined. The absolute value of the difference between the X coordinate and the X coordinate of the end point △ Xn, the Y coordinate of the start point of the vector before the affine transformation, and the Y of the end point
Storage means capable of storing a plurality of sets (n = 1, 2, 3,...) Of the absolute value △ Yn of the difference from the coordinates, and the difference between the X coordinate of the start point and the X coordinate of the end point of the vector before affine transformation The absolute value △ X and the absolute value △ Y of the difference between the Y coordinate of the start point and the Y coordinate of the end point of the vector are compared with the absolute value △ Xn and the absolute value △ Yn stored in the storage means, respectively. Means of comparison;
In response to the comparison result by the comparing means, the absolute value △ X and the absolute value △ Y of the vector before the affine transformation
Is in the relationship of △ X ≦ △ Xn and △ Y ≦ △ Yn with at least one set of the absolute value △ Xn and the absolute value △ Yn stored in the storage means, Of the vector before the affine transformation, the absolute value △ X and the absolute value △ Y of the vector before the affine transformation are performed.
△ Xn and △ Y ≦ in both sets of the absolute value 格納 Xn and the absolute value △ Yn stored in the storage means.
If there is no relationship of ΔYn, affine transformation means for affine transformation of the vector before the affine transformation, decision means for deciding whether the vector after affine transformation is a zero vector, and receiving the decision result of the decision means When the vector after the affine transformation is a zero vector, the absolute value △ X and the absolute value △ Y of the vector before the affine transformation are stored in the storage means. If at least one of the absolute values △ Yn has a relationship of △ X ≧ △ Xn and △ Y ≧ △ Yn, the absolute value △ Xn and the absolute value △ stored in the storage means having the relationship Yn is updated with the absolute value △ X and the absolute value △ Y of the vector before the affine transformation, while the absolute value △ X of the vector before the affine transformation is updated.
If the absolute value △ Y is not in the relationship of △ X ≧ △ Xn and △ Y ≧ △ Yn with any set of the absolute value △ Xn and the absolute value △ Yn stored in the storage means, the affine A control unit for newly storing the absolute value △ X and the absolute value △ Y of the vector before conversion in the storage unit.

[Action]

In the above configuration, 構成 Xn and △ Yn are not stored in the storage means in the initial state. In this state, △ X
Since △ Xn and △ Y ≦ Yn are not satisfied, affine transformation of the vector is performed. The vector after the affine transformation When becomes zero vector is stored in the storage means that affine transformation before the vector △ X and △ Y respectively as △ X ₁ and △ Y _1. Next, △ X and △ Y of the vector to be affine-transformed are represented by △ X ₁ and △, respectively.
Compare with Y ₁ . Then, if the comparison result △ X ≦ △ X ₁ and △ Y ≦ △ Y _1, since the vector becomes naturally zero vector also affine transformation, skips the affine transformation process. On the other hand, the comparison result △ X ≦ △ X ₁ and △ Y
≦ △ Y ₁ unless performing affine transformation. Then, if the vector after the affine transformation is not a zero vector, the process proceeds to the next process. On the other hand, a vector is zero vector after the affine transformation, the △ X and △ Y newly respectively if said comparison result is △ X ≧ △ X ₁ and △ Y ≧ △ Y a ₁ △ X ₁ and △ Y ₁ And On the other hand, the vector after the affine transformation is zero vector, the comparison result is △ X ≧ △ X ₁ and △ Y ≧ △
Otherwise Y _2, is stored in the storage means thereof △ X and △ Y respectively as △ X ₂ and △ Y _2. Then, for the vector to be affine-transformed next, its △ X
And △ Y are △ X1 and △ Y1, △ X2 and △ Y2, respectively.
And performs the same processing as above. In general, when △ Xn, △ Yn (n = 1, 2,..., N) are stored in the storage unit, △ X and △ Y are respectively converted into the affine transformation vectors. Compare with N sets of △ Xn and △ Yn. If the vector before the affine transformation has a relationship of △ X ≦ △ Xn and △ Y ≦ △ Yn with any of the vectors stored in the storage unit, the affine transformation of the vector before the affine transformation is performed. Without performing, the vector before the affine transformation is set to {X ≦ {Xn to {
If there is no relationship of Y ≦ Yn, the affine transformation of the vector before the affine transformation is performed. When the vector after the affine transformation is a zero vector, the vector before the affine transformation is in a relationship of △ X ≧ △ Xn and △ Y ≧ △ Yn with any of the vectors stored in the storage means. For example, while the vectors △ Xn and △ Yn having the relation are updated with △ X and △ Y, respectively, the vector before the affine transformation is △ X ≧ △ Xn with any of the vectors stored in the storage means. If there is no relation of △ Y ≧ △ Yn, △ X and △ Y are stored in the storage means as △ XN + 1 and △ YN + 1, respectively. As described above, before the affine transformation, it is determined whether the vector after the affine transformation becomes a zero vector, and when the vector becomes the zero vector, the affine transformation is not performed, so that the processing speed is increased.

【Example】

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a host interface (host I / F), which includes a rotation angle, a tilt angle, a magnification, a top address of a vector font (VF), an offset value from a coordinate origin, and the like provided by the host. Is stored in the parameter register 2 and the command is decoded to the sequencer 7. Reference numeral 3 denotes an affine transformation unit, which includes a multiplier, an adder, a latch, a multiplexer, and the like, and performs affine transformation such as rotation and inclination of a vector based on the parameters stored in the parameter register 2. Reference numeral 4 denotes a vector raster converter, which includes a counter, a full adder, a selector, a multiplexer, a sequencer, a register, and the like. Based on the vector data affine-transformed by the affine converter 3, for example, a well-known Bresenham algorithm or the like is used. Straight line drawing is performed by the method. At that time, processing is performed to prevent errors from occurring in the filling of the inside of the figure represented by the straight line drawing (for example, the vertex processing of the figure when the filling is performed by the switching film random method). Reference numeral 5 denotes a DDA (Digital Differential Analyzer) buffer. The buffer 5 has, for example, 16
The buffer is a dot × 16 dot buffer, and the vector raster conversion unit 4 draws a straight line in the buffer 5.
Reference numeral 6 denotes a memory controller unit which, when the drawing data to the DDA buffer 5 overflows, stores the overflowed data in a frame buffer (FB).
Or writing to an external memory such as a work buffer (WB), or reading the VF from the memory where the VF is stored and writing it to the external memory. Reference numeral 7 denotes a sequencer for controlling the entire circuit. Reference numeral 8 denotes a register unit, which is an absolute value of the difference between the X coordinate of the start point and the X coordinate of the end point of the vector before the affine transformation when the vector after the affine transformation is the zero vector, and the Y coordinate of the start point And the end point Y
△ Y, which is the absolute value of the difference from the coordinates, is stored. Hereinafter, these △ X and △ Y are referred to as difference vector data. Note that the difference vector data stored in the register unit 8 is represented by △ Xn, △ Yn
(N = 1, 2,...) And are distinguished from the difference vector data △ X, △ Y of the newly affine-transformed vector. Reference numeral 9 denotes a magnitude comparison unit which compares the difference vector data of the newly affine-transformed vector with the difference vector data stored in the register unit 8 and outputs the comparison result to the sequencer unit 7. The sequencer 7 determines whether to perform affine transformation of the vector based on the comparison result, and rewrites or adds the difference vector data of the register 8. The various register units 10 store various data such as values of major axes and minor axes and evaluation functions in the Bresenham algorithm, values of absolute coordinates of vector data, and the like. The operation of the vector raster conversion device having the above configuration will be described with reference to the flowchart of FIG. First, in step S1, the affine transformation parameters described above are loaded into the parameter register 2. These values are stored in this register 2 because they do not change until at least one character is drawn. Next, in step S2, the head address of a memory (not shown) storing the vector font is loaded. This value is stored in a latched counter or the like of the sequencer unit 7, and is incremented each time the processing of the vector is completed for one character. Next, in step S3, the memory controller 6
Loads the vector font into external memory such as WB or FB. Vector fonts are written in differential data to reduce memory capacity. Next, the process proceeds to step S4, in which the loaded difference data is converted into absolute coordinates. This is necessary to prevent accumulation of errors. Next, the process proceeds from the affine transformation to the straight line drawing of the vector. At first, the register unit 8 stores {Xn and △
Yn is not stored. In this state, in step S5, since the magnitude comparison unit 9 does not determine that the vector before the affine transformation is △ X ≦ △ Xn and △ Y ≦ Yn, the affine transformation unit 3 determines in step S6 the affine transformation of the vector. Conversion is performed, and in step S7, the vector raster conversion unit 4
Performs linear drawing of the affine-transformed vector in the DDA buffer 5. If the vector after the affine transformation is not a zero vector, the process returns to step S3 from steps S8 to S9 and S14. If the vector after the affine transformation becomes a zero vector, the process proceeds from step S8 to steps S11 and S12,
Stores the previous affine transformation vector △ X and △ Y respectively as △ X ₁ and △ Y ₁ in the register unit 8. Then, the process returns to step S3 via step S14, and converts the next vector data into absolute coordinates. The vector to be newly affine transformation at step S5 △ X and △ Y, respectively compared with the △ X ₁ and △ Y _1. The comparison result △ X ≦ △ X ₁ and △ Y ≦
If △ Y _1, since the vector becomes naturally zero vector also affine transformation, skip affine transformation processing returns from step S14 to step S3. Since the affine transformation takes 12 long multiplications and 6 additions as described in the conventional example, it takes a long processing time. By skipping this, the processing speed can be increased. In particular, when the number of characters in one screen is large, the character size is small, and naturally the number of zero vectors is large, which is very effective. In step S5, the comparison result △ X ≦ △ X ₁ and △
Performing Y ≦ △ Y ₁ Otherwise step S6 and subsequent steps. Then, in step S8, if the vector after the affine transformation is not a zero vector, the process proceeds to step S9, but if the vector after the affine transformation is a zero vector, the process proceeds to step S11. The comparison result in step S11 is △ X ≧ △ X ₁ and △ Y ≧
△ if Y ₁ proceeds to step S12 that △ X and △ Y newly respective △ and X ₁ and △ Y _1. On the other hand, the comparison result is △ X ≧ △ X ₁ and △ Y ≧ △ Y ₂ Otherwise, step
Proceeds to S13, and stores the △ X and △ Y to a different register respectively as △ X ₂ and △ Y ₂ and register storing the △ X ₁ and △ Y ₁ of the register unit 8. Then, for the vector to be affine-transformed next, its △ X and △ Y are respectively changed to △ 1 and △ Y
1. Perform the same processing as described above, comparing with △ X2 and △ Y2. Regarding the processing in steps S11, S12 and S13, for example, if △ X ₁ = 7, △ Y ₁ = 5, △ X = 10, △ Y = 8, then △ X
₁ and ΔY ₁ are rewritten to 10 and 8, respectively. Also X ₁
= 7, △ Y ₁ = 5, △ X = 8, △ Y = 3, then △ X ₂ = 8, △ Y ₂
= To store the new value of 3 △ X ₁ and △ Y ₁ to register a different register that store. Then, the next vector is compared with both values. In general, when △ Xn, △ Yn (n = 1, 2,..., N) are stored in the storage means, the △ X and △ Y of the vector to be affine-transformed △ Xn and △ Yn. If the vector before the affine transformation has a relationship of △ X ≦ △ Xn and △ Y ≦ △ Yn with any of the vectors stored in the register unit 8, the affine transformation of the vector before the affine transformation is performed. To skip. On the other hand, if none of the vectors before the affine transformation is in the relationship of △ X ≦ △ Xn and △ Y ≦ △ Yn, the affine transformation of the vector before the affine transformation is performed. I do. If the vector after the affine transformation is a zero vector, the relationship between the vector before the affine transformation and any of the vectors stored in the register unit 8 is △ X ≧ △ Xn and △ Y ≧ △ Yn. , The related vectors △ Xn and △ Yn are updated with the above △ X and △ Y, respectively, and the vector before the affine transformation is the same as the vector stored in the register unit.
If there is no relationship of X ≧ △ Xn and △ Y ≧ △ Yn, △ X and に Y are stored in the register unit 8 as △ XN + 1 and △ YN + 1, respectively. When the creation of the outline for one character is completed by the above-described processing, the process proceeds from step S14 to step S15, and the inside of the outline is filled. Step S9
When the DDA buffer 5 becomes full, the data in the DDA buffer 5 is written to the external memory. As described above, before the affine transformation, it is determined whether the vector after the affine transformation becomes a zero vector, and when the vector becomes the zero vector, the affine transformation is not performed. Can be. In the above-described embodiment, the case where the vector font is affine-transformed and the vector is drawn in a straight line has been described. Nor

As is apparent from the above description, in the vector raster conversion apparatus according to the present invention, the comparing means converts the difference vector data (△ X, △ Y) before affine transformation into the difference stored in the storage means. Compared with the vector data (△ Xn, △ Yn), the affine transformation means receives the comparison result by the comparison means, and the vector before the affine transformation is compared with one of the vectors stored in the storage means by △ X ≦ △ Xn and △ Y ≦ △ Yn
In the case of the relationship, the affine transformation of the vector before the affine transformation is not performed, and the vector before the affine transformation is △ X ≦ △ Xn and △ Y ≦ △ with any of the vectors stored in the storage unit. If the relationship is not Yn, the affine transformation of the vector before the affine transformation is performed, the determination unit determines whether the vector after the affine transformation is a zero vector, and the control unit receives the determination result of the determination unit. When the vector after the affine transformation is a zero vector, the vector before the affine transformation is set to {X ≧ △} with one of the vectors stored in the storage unit.
If Xn and △ Y ≧ △ Yn, the vectors に Xn and △ Yn in the relationship are updated with △ X and △ Y, respectively, while the vector before the affine transformation is stored in the storage means. △ X ≧ △
Xn and △ Y unless Xn and 関係 Y ≧ △ Yn
Is stored in the storage means, so that it is possible to omit the affine transformation of a vector which becomes a zero vector when the affine transformation is performed, thereby increasing the processing speed. Especially,
When displaying many characters in one screen, the character size is small and the number of zero vectors increases, which is very effective.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the circuit configuration of one embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the above embodiment,
FIG. 3 is a flowchart showing the operation of the conventional example. 1 ... host I / F, 2 ... parameter register, 3 ...
Affine conversion unit, 4 ... Vector raster conversion unit, 5 ... DD
A buffer, 6: memory controller, 7: sequencer, 8: register, 9: size comparison unit, 10
... various registers.

Claims (1)

(57) [Claims] 1. A vector raster conversion apparatus which performs affine transformation on vector data created based on image data, performs raster conversion based on the vector data obtained as a result, and performs straight line drawing. When the vector after the transformation is a zero vector, the absolute value △ Xn of the difference between the X coordinate of the starting point and the X coordinate of the ending point of the vector before the affine transformation and the Y coordinate and the ending point of the starting point of the vector before the affine transformation Storage means capable of storing a plurality of sets (n = 1, 2, 3,...) Of the absolute value △ Yn of the difference from the Y coordinate, and the difference between the X coordinate of the start point and the X coordinate of the end point of the vector before affine transformation And the absolute value ＹY of the difference between the Y coordinate of the start point and the Y coordinate of the end point of the vector are compared with the absolute value △ Xn and the absolute value △ Yn stored in the storage means, respectively. Means of comparison And the absolute value △ X and the absolute value △ Y of the vector before the affine transformation,
Is in the relationship of △ X ≦ △ Xn and △ Y ≦ △ Yn with at least one set of the absolute value △ Xn and the absolute value △ Yn stored in the storage means, Of the vector before the affine transformation, the absolute value △ X and the absolute value △ Y of the vector before the affine transformation are performed.
△ Xn and △ Y ≦ in both sets of the absolute value 格納 Xn and the absolute value △ Yn stored in the storage means.
If there is no relationship of ΔYn, affine transformation means for affine transformation of the vector before the affine transformation, decision means for determining whether the vector after the affine transformation is a zero vector, and receiving the decision result of the decision means When the vector after the affine transformation is a zero vector, the absolute value {X and the absolute value} of the vector before the affine transformation
Y is at least one set of the absolute value △ Xn and the absolute value △ Yn stored in the storage means and △ X ≧ △ Xn
And if there is a relationship of △ Y ≧ 絶 対 Yn, the absolute value △ Xn and the absolute value △ Yn stored in the storage means having the relationship are respectively converted into the absolute value △ X and the absolute value ベ ク ト ル X of the vector before the affine transformation. While updating with the absolute value △ Y, the absolute value △ X and the absolute value △ Y of the vector before the affine transformation are obtained by comparing the absolute value が Xn and the absolute value △ Yn stored in the storage means. △ X ≧ △ for both sets
A control means for newly storing the absolute value △ X and the absolute value △ Y of the vector before the affine transformation in the storage means if Xn and △ Y ≧ △ Yn are not satisfied. Vector raster converter.