CN102520849B - Electronic brush writing method and system - Google Patents

Abstract

The invention discloses an electronic brush writing method, which includes the following steps: S1 calculating the distance of two adjacent touch points according to touch point coordinates on a touch track transmitted by a touch device; S2 obtaining touch points with a preset threshold value as a separation distance if the distance is smaller than the preset threshold value; inserting interpolate points between two adjacent touch points if the distance is larger than the preset threshold value; and S3 drawing preset stroke shapes according to points on the touch track to generate handwriting, and drawing current stroke shapes according to stroke shape angles of the current stroke shapes obtained by pushing the touch device at the turning of the touch track or calculated according to the proceeding angle of the handwriting. The electronic brush writing method achieves electronic brush handwriting with high simulation degree and strong sense of reality generated on a handheld device with low computing power.

Description

Electronic brush pen Writing method and system

Technical field

The present invention relates to the computer graphics disposal technology field, particularly a kind of electronic brush pen Writing method and system.

Background technology

China's Writing brush calligraphy is an ancient and deep art, is shining jewel in Chinese nation's art treasure-house, and it is accompanied by the development of Chinese civilization and develops.In today of computing machine high speed development, people wish to make calligraphy to grow with each passing hour, and merge mutually with modern science and technology, and how the writing effect that simulates writing brush true to nature is the direction of a lot of experts and scholars' researchs on computers.In numerous correlative study work, the main method of simulation brush writing person's handwriting is to adopt hardware to obtain the input data, come these data are carried out correcting process by software algorithm, to realize the effect of brush writing, reach the purpose of the true writing brush action of simulation, as adopt light transmitting fiber to simulate the brush writing skill of handstand, catch data such as catch position, pressure by adding sensor at writing brush, and these data-switching are become each parameter of writing brush, then by a series of software correction algorithm, revise the person's handwriting shape, the writing effect of simulation person's handwriting.In these implementation methods, need be exclusively used in the hardware device of writing of writing brush person's handwriting, the equipment cost height, simultaneously, " carrying by making commentaries on classics " in the process of wieling the pen can't be embodied, in the brush writing operational process if do not carry by participation, the calligraphy lines will be frank and outspoken, stiff stiff, the lines quality is just very poor, even does not reach calligraphy art requirement at least.

In the prior art, the track of wieling the pen is to streak the track that stays at device screen by felt pen, when felt pen when device screen moves, equipment can be notified the position of the current felt pen of corresponding process software in the mode of touch event, pressure, time, information such as slope, because the CPU processing power of equipment and the mechanism of event notice, cause the interval of equipment notice touch event also unbalanced, when the travelling speed of felt pen is very slow, touch event can be very frequent, can cause person's handwriting to be drawn at same region overlapping like this, the waste cpu resource, and, because the user writing process has shake, if the movement of each pixel is drawn, then the person's handwriting of Xing Chenging has a lot of folds, and is unsmooth; And when the felt pen motion was very fast, touch event then can seldom can cause person's handwriting discontinuous like this.In turnover or the bending place of stroke, do not change if draw the angle of the form of a stroke or a combination of strokes this moment, the person's handwriting in stroke turnover or bending place will differ greatly with real writing brush stroke so, and the simulation degree that makes electronic brush pen write is not high, lacks the sense of reality.And occur projection at the turning easily, therefore, need to consider to increase based on the physical mechanics model, the form of a stroke or a combination of strokes can be changed.According to the research to existing writing brush emulation mode and achievement, generally the simulation that the writing brush form of a stroke or a combination of strokes is changed is all carried out based on three dimensions, has with circular cone form of a stroke or a combination of strokes simulation nib, the distortion of each hair of research that has, what have is divided into many bunches with the pen hair, studies the center framework distortion of each bunch.Aspect the mechanics algorithm, utilize the spring force amount to calculate, also have by energy minimization and calculate, all need to carry out careful analysis and a large amount of integral operationes to stressed.Distortion by three dimensions simulation nib, on the sense of reality effect of simulation writing brush, to get well much than two-dimensional approach, but three-dimensional simulation needs a large amount of computings, for the PC of routine, all can not satisfy the needs of its smooth operation, said nothing of for the lower handheld device of arithmetic capability, therefore, though the three dimensional constitution simulation is more true to nature, expressive force is stronger, but availability is not high for handheld device.

As known from the above, it is not high to carry out generating when electronic brush pen is write simulation degree in the lower handheld device of arithmetic capability, and the writing brush person's handwriting of strong sense of reality is problem demanding prompt solution.

Summary of the invention

(1) technical matters that will solve

The technical problem to be solved in the present invention is: it is higher how to generate simulation degree in the lower handheld device of arithmetic capability, the electronic brush pen written handwriting of strong sense of reality.

(2) technical scheme

For solving the problems of the technologies described above, the invention provides a kind of electronic brush pen Writing method, may further comprise the steps:

S1: according to the distance of coordinate Calculation adjacent two touch points in touch point on the touch track of touch apparatus transmission;

S2: if described distance less than predetermined threshold, is that spacing is obtained the touch point by described predetermined threshold then; If described distance greater than described predetermined threshold, is then inserted interpolation point between adjacent two touch points;

S3: the form of a stroke or a combination of strokes that sets in advance according to the point-rendering on the described touch track to be to generate person's handwriting, and the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes that obtains by touch apparatus at the turning of touch track or calculate according to the travel angle of person's handwriting is drawn the current form of a stroke or a combination of strokes.

Wherein, the process of insertion interpolation point is as follows among the described step S2:

S2.1: be that the Bezier track is calculated at the reference mark with the touch point;

S2.2: calculate interpolation point according to following formula:

$\mathrm{insertCount}=\frac{\mathrm{dis}\tan \mathrm{ce}}{\mathrm{width}}\×\mathrm{number}\_\mathrm{per}\_\mathrm{shape}$

Wherein, insertCount is point-to-point transmission interpolation point number, distance is along any the distance before it of distance on the Bezier trajectory direction nearest touch point of interpolation part, the number of the point that the width of last form of a stroke or a combination of strokes that width partly draws for interpolation, number_per_shape need be drawn for each form of a stroke or a combination of strokes;

S2.3: whether judge insertCount less than 1, if less than 1, then increase the length of the Bezier of interpolation, jump to step S2.2, otherwise execution in step S2.4;

S2.4: the interpolation step-length stepLength=distance/insertCount that calculates interpolation point;

S2.5: be that the part of above-mentioned distance is inserted a point by described step-length length on described Bezier track;

S2.6: repeated execution of steps S2.2～S2.5, to the last a touch point.

Wherein, the mode of calculating the Bezier track among the described step S2.1 is: be the reference mark with the more preceding of current point, and the more preceding mid-point computation Bezier track from the first two point of current point to current point and current point.

Wherein, when the Bezier of interpolation arrives the mid point of last touch point last with it, touch point, to the straight path of the mid point of its touch point last with it, carry out linear interpolation by described step S2.2～step S2.6 in described last touch point.

Wherein, among the described step S3, the mode that touch apparatus obtains the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes is: the touch-screen of touch apparatus detects the angle of felt pen projection line and screen X-axis on screen plane, is the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes with described angle.

Wherein, among the described step S3, when the situation of a pen or Hui Feng appearred in person's handwriting, form of a stroke or a combination of strokes angle was described travel angle, otherwise is calculated as follows the form of a stroke or a combination of strokes angle A ngle that obtains the current form of a stroke or a combination of strokes:

Angle＝Angle _prev+Angle _diff×TrunRatio

$\mathrm{TrunRatio}=\frac{1}{\mathrm{VEER}\&times;{{\mathrm{<figure-callout\; id="2"\; label="P\; prev"\; filenames="HDA0000113303890000032.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{prev}}}^2}$

Wherein, TrunRatio is the ratio of angular setting, and VEER is for counting P on default turnover or the bending place person's handwriting _PrevBe more preceding force value, Angle _PrevBe more preceding form of a stroke or a combination of strokes angle, the Angle of locating _DiffDifferential seat angle for the travel angle of current point and more preceding person's handwriting.

Wherein, among the step S3 when drawing the described form of a stroke or a combination of strokes, also comprise the distortion to the described form of a stroke or a combination of strokes, be specially: if reach default deformation condition, then as follows the described form of a stroke or a combination of strokes is out of shape: according to the mass spring model that designs in advance described particle is carried out iterated integral with the particle on the axis of symmetry of the described form of a stroke or a combination of strokes, obtain the coordinate of described distortion back particle; Coordinate according to the coordinate Calculation form of a stroke or a combination of strokes edge of particle after the distortion; According to the form of a stroke or a combination of strokes after the form of a stroke or a combination of strokes edge coordinate drafting distortion, described default deformation condition is: at the turning person's handwriting place except a pen and Hui Feng, form of a stroke or a combination of strokes width is greater than the higher value of distance between default minimum form of a stroke or a combination of strokes width value and the shortest particle, and form of a stroke or a combination of strokes angle and travel angle differ at 60 °～90 °.

Wherein, be form of a stroke or a combination of strokes skeleton with the axis of symmetry that is out of shape the preceding form of a stroke or a combination of strokes, the account form of pen shape is as follows:

On the axis of symmetry, near an end of nib, calculate the point at form of a stroke or a combination of strokes edge as follows:

$R=\sqrt{2\&times;l\&times;\mathrm{rs}-{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000113303890000032.png"\; state="\{\{state\}\}">l</figure-callout>}}^2}$

Wherein, R is the distance of form of a stroke or a combination of strokes marginal point to the axis of symmetry, l be along the axis of symmetry from nib to the distance of current point, rs is the little radius of a circle near nib, the center of circle of described roundlet is near the point of nib one end on the axis of symmetry;

On the axis of symmetry, near an end of penholder, calculate the point at form of a stroke or a combination of strokes edge as follows:

$R=\sqrt{{\mathrm{rs}}^2-{(l--h-\mathrm{rb})}^2}$

Wherein, rb is the big radius of a circle near penholder, and the center of circle of described great circle is the point of close penholder one end on the axis of symmetry, and h is the distance between the great circle center of circle and the roundlet center of circle;

Be on a section of h in the corresponding length of the axis of symmetry, calculate the point at form of a stroke or a combination of strokes edge as follows:

$R=\frac{(\mathrm{rb}-\mathrm{rs})\&times;(l-\mathrm{rs})}{h}+\mathrm{rs};$

Be that the reference mark adopts Bezier to connect described marginal point with described marginal point, big radius of circle:

rb=W×pressure

Determine little radius of circle and the h of nib direction according to following formula:

rs=rb×k×pressure

h=H×pressure

Wherein, H represents the most a large sum of line length of presetting, and k is the shape scale parameter, and value is 0～1 floating number, and pressure is the force value of touch screen induction, and this value is for quantizing to 0～1 floating number, and W is for default the most a large sum of wide.

The invention provides a kind of electronic brush pen writing system, comprising:

The touch point computing module, the distance of adjacent two coordinate points of touch point coordinate Calculation on the touch track that is used for transmitting according to touch apparatus;

Interpolating module is used for if described distance less than predetermined threshold, is that spacing is obtained the touch point by described predetermined threshold then; If described distance greater than described predetermined threshold, is then inserted interpolation point between adjacent two touch points;

The person's handwriting generation module, the form of a stroke or a combination of strokes that is used for setting in advance according to the point-rendering on the described touch track to be to generate person's handwriting, and the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes that obtains by touch apparatus at the turning of touch track or calculate according to the travel angle of person's handwriting is drawn the current form of a stroke or a combination of strokes.

Wherein, this system also comprises:

Form of a stroke or a combination of strokes deformation module, if reach default deformation condition, be used for as follows the described form of a stroke or a combination of strokes being out of shape: according to the mass spring model that designs in advance described particle is carried out iterated integral with the particle on the axis of symmetry of the described form of a stroke or a combination of strokes, obtain the coordinate of described distortion back particle; Coordinate according to the coordinate Calculation form of a stroke or a combination of strokes edge of particle after the distortion; Draw the form of a stroke or a combination of strokes after the distortion according to form of a stroke or a combination of strokes edge coordinate, described default deformation condition is: at the turning person's handwriting place except a pen and Hui Feng, form of a stroke or a combination of strokes width is greater than the higher value of distance between the minimum form of a stroke or a combination of strokes width value of presetting and the shortest particle.

(3) beneficial effect

When the travelling speed of felt pen is very slow, reduce the number of touch point by method of the present invention, avoided person's handwriting to draw the fold that causes at same region overlapping, saved cpu resource simultaneously; And when felt pen motion is very fast, adopt method of interpolation to carry out interpolation, make that the writing brush person's handwriting of handwriting input is level and smooth, continuously; When the turnover of person's handwriting or turning point, the form of a stroke or a combination of strokes is carried out suitable angle control, and based on the form of a stroke or a combination of strokes deformation method of mass spring model, realize the distortion to writing brush form of a stroke or a combination of strokes smoothness, thereby improved person's handwriting that electronic brush pen writes in simulation degree and the sense of reality of stroke turnover or bending place.

Description of drawings

Fig. 1 is a kind of electronic brush pen Writing method process flow diagram of the embodiment of the invention;

Fig. 2 is the synoptic diagram that adopts the linear interpolation method when generating person's handwriting in the method for Fig. 1;

Fig. 3 is the form of a stroke or a combination of strokes synoptic diagram when not needing form of a stroke or a combination of strokes distortion when generating person's handwriting in the method for Fig. 1

Fig. 4 is the synoptic diagram that touch panel device obtains form of a stroke or a combination of strokes angle in the method for Fig. 1;

Fig. 5 is the form of a stroke or a combination of strokes model synoptic diagram (shape when not being out of shape) that adopts when needing form of a stroke or a combination of strokes distortion when generating person's handwriting in the method for Fig. 1;

The mass spring model synoptic diagram that Fig. 6 adopts when being form of a stroke or a combination of strokes distortion;

Form of a stroke or a combination of strokes distortion synoptic diagram when Fig. 7 is form of a stroke or a combination of strokes distortion.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used for explanation the present invention, but are not used for limiting the scope of the invention.

Step S101 is according to the distance of coordinate Calculation adjacent two coordinate points in touch point on the touch track of touch apparatus transmission.Touch apparatus can record the information such as position coordinates, pressure of felt pen when felt pen was write at the touch-screen of touch apparatus.Because felt pen moves, the position coordinates of felt pen forms a continuous movement locus, and touch apparatus can record some touch points according to the movement velocity of felt pen.Obtain behind these touch points according to the distance between the adjacent touch point of its coordinate Calculation.

Step S102: whether judging above-mentioned distance less than predetermined threshold, if less than this threshold value, then is the touch point that obtains of spacing by this threshold value.Because the CPU processing power of equipment and the mechanism of event notice, cause the interval of equipment notice touch event also unbalanced, when the travelling speed of felt pen was very slow, touch event can be very frequent, cause above-mentioned distance can cause person's handwriting to be drawn at same region overlapping like this less than predetermined threshold.Therefore for this situation, directly with the threshold value be spacing obtain the touch point avoided same region overlapping draw and also can guarantee the final person's handwriting that generates continuously, level and smooth, saved cpu resource simultaneously.When the travelling speed of felt pen is very fast, the touch event that touch apparatus CPU captures can be seldom, therefore the touch point also seldom, if go to draw the form of a stroke or a combination of strokes by these touch points, the person's handwriting of Sheng Chenging is with discontinuous so, for fear of the generation of this situation, the present invention inserts some interpolation points between adjacent two touch points.The method of interpolation is as follows:

Adopt the Bezier method of interpolation, can overcome in the linear interpolation has a significantly problem of turnover between two straight lines, the interpolation synoptic diagram as shown in Figure 2, interpolation procedure is as follows:

Step 1, be that the Bezier track is calculated at the reference mark with the touch point, in the present embodiment, the mode of calculating the Bezier track is: be the reference mark with the more preceding of current point, and the more preceding mid-point computation Bezier track from the first two point of current point to current point and current point.

Step 2, calculate interpolation point according to following formula:

$\mathrm{insertCount}=\frac{\mathrm{dis}\tan \mathrm{ce}}{\mathrm{width}}\&times;\mathrm{number}\_\mathrm{per}\_\mathrm{shape}$

Wherein, insertCount is point-to-point transmission interpolation point number, distance is along any the distance before it of distance on the Bezier trajectory direction nearest touch point of interpolation part, the number of the point that the width of last form of a stroke or a combination of strokes that width partly draws for interpolation, number_per_shape need be drawn for each form of a stroke or a combination of strokes.

As shown in Figure 2, P0, P1, P2, P3 are continuous several touch points, P3 is current point, and when the P3 touch event took place, person's handwriting is treated (namely to be interpolated into the IPL0 point) to the IPL0 position, at this moment, calculate IPL0 to the interpolation point between P2, according to the number number_per_shape of last demonstration form of a stroke or a combination of strokes width width with the point of each form of a stroke or a combination of strokes needs drafting of presetting, adopt above-mentioned formula to calculate IPL0 and P2 point-to-point transmission interpolation point number, wherein, distance is the length of curve from IPL0 to P2.

Whether step 3 judges insertCount less than 1, if less than 1, then increases the length of the Bezier of interpolation, jumps to step 2, otherwise execution in step 4.

Step 4, the interpolation step-length stepLength=distance/insertCount of calculating interpolation point.

Step 5 is point of part insertion of above-mentioned distance by described step-length length on described Bezier track.

Step 6, repeated execution of steps 2～step 5, to the last a touch point.(Bezier is always drawn the mid point from the first two point-rendering of current point to current more preceding and current point because the singularity of above-mentioned calculating Bezier track, therefore, always can not be processed between this mid point and the current point), in repetitive process, when the Bezier of interpolation arrives the mid point of last touch point last with it, touch point, in the end touch point to the straight path of the mid point of its touch point last with it set by step 2～step 6 carry out.

In above-mentioned two kinds of interpolation methods, width has lower limit 20 pixels and upper limit preset value 80 pixels, otherwise hour can cause very much the insertion point too many and influence performance as width, and too greatly then the insertion point is very few for width, and track is unsmooth.Change the density that parameter number_per_shape can change the form of a stroke or a combination of strokes, this value arranges that greatly then density is big, show that person's handwriting is smoothly tight, but can cause travelling speed slack-off, this value arranges little, and travelling speed improves, but may cause the person's handwriting out-of-flatness, even not continuous, according to experiment, preferably be set to 5 proper to 10.

Step S103, the form of a stroke or a combination of strokes that sets in advance according to the point-rendering on the touch track is to generate person's handwriting.Form of a stroke or a combination of strokes model as shown in Figure 3, the mode of specifically drawing is as follows:

The pressure of responding to according to default the most a large sum of wide W (value is 10～100 pixels) and current touch apparatus determines that the form of a stroke or a combination of strokes is along the big radius of circle of penholder direction:

d2＝W×pressure

When calculating interpolation point, if 2 * d2 is in the scope of 20～80 pixels, width ValueBe 2 * d2,2 * d2 was less than 20 o'clock, and width got 20,2 * d2 greater than 80 o'clock, and width gets 80.

Determine the little radius of circle of nib direction according to following formula:

d1＝d2×k×pressure

Draw respectively in the same side of two circles one with two circles tangent straight line all, forming the shape of sealing, form trapezoidal, trapezoidal height at two diameter of a circles and two tangent lines and be:

h＝H×pressure

Wherein, the default maximum form of a stroke or a combination of strokes length of H (value is 10～100 pixels) expression, k is the shape scale parameter, and value is 0～1 floating number, and pressure quantizes to 0～1 floating number.

The direction of traditional calligraphy technique requirement penholder will be towards the direction of wieling the pen, just along the capable pen in peak, but actual conditions many times are not this situation, unlikely do in strict accordance with this requirement in other words, such as when writing horizontal, pen often pauses downwards earlier, the capable pen in peak to the right then, turning to gradually along the capable pen in peak, suddenly penholder is become laterally behind the pen if pause, writing effect is bad, nor is easy to do again, therefore, the penholder direction of writing brush is different with the direction of wieling the pen under a lot of situations.In order to make in the turnover or the bending place that generate person's handwriting higher simulation degree and the sense of reality are arranged, need carry out angle control to the form of a stroke or a combination of strokes in turnover or bending place, concrete mode is as follows: when drawing person's handwriting to the turnover of stroke or bending place, and obtain the touch apparatus acquisition or the current form of a stroke or a combination of strokes that calculates according to the travel angle of person's handwriting form of a stroke or a combination of strokes angle.

If the touch-screen of touch apparatus supports the angle of inclination of felt pen to detect, then the calculating of form of a stroke or a combination of strokes angle can be according to tilt angle calculation, from the physical form of writing brush as can be seen, nib is reciprocal towards penholder always, therefore, just can calculate form of a stroke or a combination of strokes angle as long as know felt pen projection on screen plane, as shown in Figure 4, the angle of the felt pen that angle R provides for equipment projection and X-axis on the XY plane, the just form of a stroke or a combination of strokes angle at current some place, i.e. current form of a stroke or a combination of strokes angle.

Generally the slope of penholder equates with form of a stroke or a combination of strokes angle, but neither be absolute, considers following situation, when writing brush carried out capable of peak regulation or contrary peak, then the slope of penholder was different with form of a stroke or a combination of strokes angle, even on the contrary, therefore, also to take all factors into consideration to determine form of a stroke or a combination of strokes direction with a row direction.When row a direction and penholder angle of inclination difference during smaller or equal to 90 °, form of a stroke or a combination of strokes angle equals the projection line of penholder on writing plane and the angle of X-axis, and when a capable direction and angle of inclination difference during greater than 90 °, form of a stroke or a combination of strokes angle is opposite with the angle of inclination of penholder.

For the equipment of not supporting that the felt pen slope detects, the calculating of form of a stroke or a combination of strokes angle can only be calculated by the travel angle of person's handwriting.The travel angle of person's handwriting is current point and the line that descends any and the angle of X-axis on the person's handwriting, and this person's handwriting is straight line person's handwriting or curve person's handwriting.If during the curve person's handwriting, preferably, travel angle is the tangent line of the fooled preceding point of curve person's handwriting and the angle of X-axis.Simply introduce the interpolation method of person's handwriting curve below.

In most cases, form of a stroke or a combination of strokes angle equates with travel angle.Therefore with travel angle as form of a stroke or a combination of strokes angle.The capable pen in suitable peak is the basic demand of the technique of writing, and travel angle is form of a stroke or a combination of strokes angle during therefore along cutting edge of a knife or a sword.

When person's handwriting appearance turnover or bending, form of a stroke or a combination of strokes angle just is travel angle if a pen or time cutting edge of a knife or a sword situation take place then.

Judge whether current point is a pen, pressure ratio of (term of " more preceding " or " current point " and so on refers to touch point or the interpolation point on the person's handwriting when generating person's handwriting herein) and current point is less than predetermined threshold value if person's handwriting is gone forward a bit, as 0.7, and current point pressure is greater than preset pressure value, as 0.65, then think a pen take place, the time form of a stroke or a combination of strokes angle consistent with the travel angle of person's handwriting.

Judge whether current point is Hui Feng, if current point and more preceding differential seat angle are greater than preset angles threshold value (as: 170 °) on the person's handwriting, think then Hui Feng takes place that form of a stroke or a combination of strokes angle is consistent with the travel angle of person's handwriting when returning cutting edge of a knife or a sword.Otherwise can calculate form of a stroke or a combination of strokes angle A ngle according to the following procedure:

Angle＝Angle _prev+Angle _diff×TrunRatio

$\mathrm{TrunRatio}=\frac{1}{\mathrm{VEER}\&times;{{\mathrm{<figure-callout\; id="2"\; label="P\; prev"\; filenames="HDA0000113303890000032.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{prev}}}^2}$

Wherein, TrunRatio is the ratio of angular setting, and VEER is for counting P on default turnover or the turning point person's handwriting _PrevBe more preceding force value, Angle _PrevBe more preceding form of a stroke or a combination of strokes angle, the Angle of locating _DiffDifferential seat angle for the travel angle of current point and more preceding person's handwriting.

After transferring or the bending place, get access to form of a stroke or a combination of strokes angle, person's handwriting draws the current form of a stroke or a combination of strokes according to this form of a stroke or a combination of strokes angle.

After the form of a stroke or a combination of strokes being carried out angle control, at the turning of person's handwriting the higher sense of reality is arranged, but because the form of a stroke or a combination of strokes is single and not variation, be not inconsistent with writing brush softness, flexible and changeable characteristic, occur projection at the turning easily, therefore, need to consider to increase based on the physical mechanics model, the form of a stroke or a combination of strokes can be changed, so that the person's handwriting that generates has the higher sense of reality.

Have only more qualified turnings just need improve writing effect by distortion, therefore remedying the deficiency of graphical model, whether need the sign that be out of shape, when carrying out the processing of a touch point if being provided with, need at first to judge whether distortion, condition and the process of judgement are as follows:

If a pen does not then need distortion, because a pen should turn at once, the effect of plane deformation is bad;

Then do not need distortion if go back to the peak, because Hui Feng is out of shape at vertical plane, based on the very difficult simulation of the deformation technology on plane;

Do not need distortion if form of a stroke or a combination of strokes width is too little, because width too small deformation does not have effect, the waste cpu resource, the width value that herein compares, two parameter controls are arranged, one is the minimum form of a stroke or a combination of strokes width value of presetting, another one is distance between the particle of lacking most, two particle distances of close nib just, then there is not spring to participate in calculating less than this distance, can not calculate deflection, form of a stroke or a combination of strokes width will with bigger comparing in these two parameters, and the form of a stroke or a combination of strokes angle at turning and travel angle differ at 60 °～90 °.

If current point and more preceding deflection angle in default threshold values then need distortion, otherwise do not need, angle threshold values herein can rule of thumb be determined with experimental result.

If as follows the described form of a stroke or a combination of strokes is out of shape when reaching above-mentioned deformation condition:

According to the mass spring model that designs in advance described particle is carried out iterated integral with the particle on the axis of symmetry of the form of a stroke or a combination of strokes, obtain the coordinate of described distortion back particle.

In the present embodiment, the design of particle on the form of a stroke or a combination of strokes axis of symmetry just can be determined whole shape as long as consider the distortion of the axis of symmetry of the form of a stroke or a combination of strokes as shown in Figure 5.On the determining of particle, selects a kind of not equidistant mode, this mode can better be simulated softer and the fact of case that a root is harder of nib, and namely the particle on the axis of symmetry is intensive relatively near the nib place, and is sparse relatively at close penholder place.Each particle identical in quality, the selection of distance is determined according to following formula between particle:

$\mathrm{Li}=\mathrm{Ls}\&times;{\left(\frac{i}{N-1}\right)}^2$

Wherein, Li is the distance of i particle and last particle, and i is the total length of the form of a stroke or a combination of strokes since 0, Ls, i be current be which point, be default particle sum since 0, N.

In order to reach the distortion of simulating the writing brush form of a stroke or a combination of strokes at two-dimensional space better, adopt the mass spring model to realize form of a stroke or a combination of strokes distortion in the present embodiment, mass spring is theoretical realizes that simple, speed is the most fast with respect to other similar algorithms, therefore is adapted at the distortion of the two-dimensional space simulation writing brush form of a stroke or a combination of strokes.As shown in Figure 6, the spring between particle is divided into two kinds, and a kind of is extension spring, connects two adjacent particles (i and i+1 particle); Another kind is flexural spring, connects i particle and i+2 particle.

The suffered power of axis of symmetry model is mainly the elastic force of spring and the resistance that produces with paper friction etc., be the skeleton of the form of a stroke or a combination of strokes with the axis of symmetry, the suffered spring force of each particle comprises on the skeleton, is connected elastic deformation power and the spring damping power of spring with each, is respectively calculated as follows:

Spring deformation power:

Fk＝ks×(ls-distance1)

Wherein, Fk is elastic force, and ks is the elasticity coefficient (parameter preset) that is connected spring with particle, and ls is the raw footage (parameter preset) of spring, and distance1 is the length when front spring, the i.e. coordinate distance of both ends of the spring point.

Spring damping power:

$\mathrm{Fd}=\mathrm{Kd}\&times;\left(\frac{(V1x-V2x)\&times;\mathrm{dx}+(V1y-V2y)\&times;\mathrm{dy}}{\mathrm{dis}\tan \mathrm{cel}}\right)$

Wherein, Fd is spring damping power, Kd is the ratio of damping (parameter preset) with spring, V1x is the speed of particle on directions X of spring one end, and V2x is the speed of particle on directions X of the spring other end, and dx is the distance on directions X between the two ends particle of spring, V1y is the speed of particle on Y-direction of spring one end, V2y is the speed of particle on Y-direction of the spring other end, and dy is the distance on Y-direction between the two ends particle of spring, and distance1 is the length when front spring.

The form of a stroke or a combination of strokes also can be subjected to the motion that resistance stops writing brush in motion process, the viscous force of the friction force of these resistances such as writing brush and paper, pen hair and paper China ink, mao between viscous force etc., these power unifications are called resistance, its computing method are:

Fr＝Kr×Vm/M

Wherein, Fr represents resistance, and Kr is ratio of damping (parameter preset), and Vm is particle movement speed (for the resultant velocity of X and Y-direction), and M is point mass (parameter preset).

The mass spring algorithm need be used integral algorithm and calculate particle and take stable status to, contrasted following several integral algorithm: show integral algorithm, implicit expression integral algorithm, Runge-Kutta integration algorithm, Verlet integral algorithm, consider from computing velocity and stable aspect, the preferred Verlet integral method that adopts, formula is as follows:

$r(t+\mathrm{\&Delta;t})\&cong;2r\left(t\right)-r(t-\mathrm{\&Delta;t})+\frac{f\left(t\right)}{M}{\mathrm{\&Delta;<figure-callout\; id="2"\; label="t"\; filenames="HDA0000113303890000032.png"\; state="\{\{state\}\}">t</figure-callout>}}^2$

R (t) is the t coordinate of particle constantly, can arrange to begin distortion and be t constantly, and Δ t is time increment, f (t) be particle suffered with joint efforts, i.e. suffered spring power Fk, spring damping power Fd and resistance Fr in writing process.M is point mass.Can derive particle velocity Vm and time relation:

$v\left(t\right)=\frac{r(t+\mathrm{\&Delta;t})-r(t-\mathrm{\&Delta;t})}{2\mathrm{\&Delta;t}}+O\left({\mathrm{\&Delta;t}}^2\right).$

Particle on the spring model is divided into point of fixity and moving point, as previously mentioned, pressure parameter according to current contact can calculate current form of a stroke or a combination of strokes length, on form of a stroke or a combination of strokes model, the most advanced and sophisticated particle that covers to one section axis of symmetry in the form of a stroke or a combination of strokes great circle center of circle is moving point, expression can crushed element, and the particle that the form of a stroke or a combination of strokes great circle center of circle covers to one section axis of symmetry of form of a stroke or a combination of strokes end is point of fixity.Deformation calculation process is: when the form of a stroke or a combination of strokes a bit moves at current in the past, point of fixity directly moves to current some correspondence position, because the point of fixity shift position that links to each other with first moving point, cause the distance (distance1) between these two points to change, distance1 constantly changes in iterative process.According to spring basic mechanical theory, spring length changes and can produce corresponding power, according to Mechanics Calculation described below, moving point can produce corresponding to stressed velocity variations, thereby moving point produces displacement, and the displacement of first moving point can affect second moving point that links to each other with first moving point to be subjected to displacement again, arrives last moving point and so forth and produces change in displacement, iterative process that Here it is adopts above-mentioned Verlet integral method to carry out iteration in the present embodiment.Because the acting force between the moving point is mutual, can an iteration just can not reach stable, therefore need repeatedly iterative process, finally the movement velocity of each moving point is close to 0, and model tends towards stability, and stops iteration, has just finished the distortion of this form of a stroke or a combination of strokes and has calculated.

For the ease of adopting above-mentioned mass spring model to calculate, the original shape of the form of a stroke or a combination of strokes when deformation stage as shown in Figure 5, the mode of calculating the form of a stroke or a combination of strokes is as follows:

On the axis of symmetry, near an end of nib, calculate the point at form of a stroke or a combination of strokes edge as follows:

$R=\sqrt{2\&times;l\&times;\mathrm{rs}-{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000113303890000032.png"\; state="\{\{state\}\}">l</figure-callout>}}^2}$

Wherein, R is the distance of form of a stroke or a combination of strokes marginal point to the axis of symmetry, l be along the axis of symmetry from nib to the distance of current point, rs is the little radius of a circle near nib, the center of circle of described roundlet is near the point of nib one end, as O on the axis of symmetry ₁The point;

On the axis of symmetry, near an end of penholder, calculate the point at form of a stroke or a combination of strokes edge as follows:

$R=\sqrt{{\mathrm{rs}}^2-{(l--h-\mathrm{rb})}^2}$

Wherein, rb is the big radius of a circle near penholder, and the center of circle of described great circle is the point of close penholder one end on the axis of symmetry, as O ₂Point, h are the distance between the great circle center of circle and the roundlet center of circle, and great circle and little radius of a circle are that preset value is to guarantee to draw out the form of a stroke or a combination of strokes shown in Figure 5.

Be on a section of h in the corresponding length of the axis of symmetry, calculate the point at form of a stroke or a combination of strokes edge as follows:

$R=\frac{(\mathrm{rb}-\mathrm{rs})\&times;(l-\mathrm{rs})}{h}+\mathrm{rs};$

Be that the reference mark adopts Bezier to connect described marginal point with the marginal point.Big radius of circle d2, roundlet radius d1 and the h of the form of a stroke or a combination of strokes determine that mode is identical among great circle radius r b, roundlet radius r s and h and Fig. 3.

The axis of symmetry is the skeleton line of the form of a stroke or a combination of strokes, and the particle in the mass spring model is the point on the skeleton line, adopts above-mentioned deformation method, and deformation effect as shown in Figure 7.In addition, if begun distortion, and the result who judges previously is not for needing distortion, then need to check on the skeleton particle whether point-blank, if then distortion finishes, otherwise continue distortion, that is to say that distortion stops to see whether skeleton has moved is straight line.

After the framework deformation, press the coordinate that above-mentioned form of a stroke or a combination of strokes computing formula is calculated the point at form of a stroke or a combination of strokes edge, and according to the form of a stroke or a combination of strokes after the form of a stroke or a combination of strokes edge coordinate drafting distortion.

The present invention also provides a kind of electronic brush pen writing system, comprising:

The touch point computing module, the distance of adjacent two coordinate points of touch point coordinate Calculation on the touch track that is used for transmitting according to touch apparatus;

Interpolating module is used for if described distance less than predetermined threshold, then is the touch point that obtains of spacing by described predetermined threshold; If described distance greater than described predetermined threshold, is then inserted interpolation point between adjacent two touch points;

The person's handwriting generation module, the form of a stroke or a combination of strokes that is used for setting in advance according to the point-rendering on the described touch track to be to generate person's handwriting, and the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes that obtains by touch apparatus at the turning of touch track or calculate according to the travel angle of person's handwriting is drawn the current form of a stroke or a combination of strokes.

Preferably, this system also comprises:

Form of a stroke or a combination of strokes deformation module, if reach default deformation condition, be used for as follows the described form of a stroke or a combination of strokes being out of shape: according to the mass spring model that designs in advance described particle is carried out iterated integral with the particle on the axis of symmetry of the described form of a stroke or a combination of strokes, obtain the coordinate of described distortion back particle; Coordinate according to the coordinate Calculation form of a stroke or a combination of strokes edge of particle after the distortion; Draw the form of a stroke or a combination of strokes after the distortion according to form of a stroke or a combination of strokes edge coordinate, described default deformation condition is: at the turning person's handwriting place except a pen and Hui Feng, form of a stroke or a combination of strokes width is greater than the higher value of distance between the minimum form of a stroke or a combination of strokes width value of presetting and the shortest particle.

Above embodiment only is used for explanation the present invention; and be not limitation of the present invention; the those of ordinary skill in relevant technologies field; under the situation that does not break away from the spirit and scope of the present invention; can also make a variety of changes and modification; therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (10)

1. an electronic brush pen Writing method is characterized in that, may further comprise the steps:

S1: according to the distance of coordinate Calculation adjacent two touch points in touch point on the touch track of touch apparatus transmission;

S2: if described distance less than predetermined threshold, is that spacing is obtained the touch point by described predetermined threshold then; If described distance greater than described predetermined threshold, is then inserted interpolation point between adjacent two touch points;

S3: the form of a stroke or a combination of strokes that sets in advance according to the point-rendering on the described touch track to be to generate person's handwriting, and the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes that obtains by touch apparatus at the turning of touch track or calculate according to the travel angle of person's handwriting is drawn the current form of a stroke or a combination of strokes.

2. electronic brush pen Writing method as claimed in claim 1 is characterized in that, the process of inserting interpolation point among the described step S2 is as follows:

S2.1: be that the Bezier track is calculated at the reference mark with the touch point;

S2.2: calculate interpolation point according to following formula:

Wherein, insertCount is point-to-point transmission interpolation point number, distance is along any the distance before it of distance on the Bezier trajectory direction nearest touch point of interpolation part, the number of the point that the width of last form of a stroke or a combination of strokes that width partly draws for interpolation, number_per_shape need be drawn for each form of a stroke or a combination of strokes;

S2.3: whether judge insertCount less than 1, if less than 1, then increase the length of the Bezier of interpolation, jump to step S2.2, otherwise execution in step S2.4;

S2.4: the interpolation step-length stepLength=distance/insertCount that calculates interpolation point;

S2.5: be that the part of above-mentioned distance is inserted a point by described step-length length on described Bezier track;

S2.6: repeated execution of steps S2.2～S2.5, to the last a touch point.

3. electronic brush pen Writing method as claimed in claim 2, it is characterized in that, the mode of calculating the Bezier track among the described step S2.1 is: be the reference mark with the more preceding of current point, and the more preceding mid-point computation Bezier track from the first two point of current point to current point and current point.

4. electronic brush pen Writing method as claimed in claim 3, it is characterized in that, when the Bezier of interpolation arrives the mid point of last touch point last with it, touch point, to the straight path of the mid point of its touch point last with it, carry out linear interpolation by described step S2.2～step S2.6 in described last touch point.

5. electronic brush pen Writing method as claimed in claim 1, it is characterized in that, among the described step S3, the mode that touch apparatus obtains the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes is: the touch-screen of touch apparatus detects the angle of felt pen projection line and screen X-axis on screen plane, is the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes with described angle.

6. electronic brush pen Writing method as claimed in claim 1 is characterized in that, among the described step S3, when the situation of a pen or Hui Feng appearred in person's handwriting, form of a stroke or a combination of strokes angle was described travel angle, otherwise is calculated as follows the form of a stroke or a combination of strokes angle A ngle that obtains the current form of a stroke or a combination of strokes:

Angle=?Angle _prev+?Angle _diff×TrunRatio

Wherein, TrunRatio is the ratio of angular setting, and VEER is for counting P on default turnover or the bending place person's handwriting _PrevBe more preceding force value, Angle _PrevBe more preceding form of a stroke or a combination of strokes angle, the Angle of locating _DiffDifferential seat angle for the travel angle of current point and more preceding person's handwriting.

7. as each described electronic brush pen Writing method in the claim 1～6, it is characterized in that, among the step S3 when drawing the described form of a stroke or a combination of strokes, also comprise the distortion to the described form of a stroke or a combination of strokes, be specially: if reach default deformation condition, then as follows the described form of a stroke or a combination of strokes is out of shape: according to the mass spring model that designs in advance described particle is carried out iterated integral with the particle on the axis of symmetry of the described form of a stroke or a combination of strokes, obtain the coordinate of described distortion back particle; Coordinate according to the coordinate Calculation form of a stroke or a combination of strokes edge of particle after the distortion; According to the form of a stroke or a combination of strokes after the form of a stroke or a combination of strokes edge coordinate drafting distortion, described default deformation condition is: at the turning person's handwriting place except a pen and Hui Feng, form of a stroke or a combination of strokes width is greater than the higher value of distance between default minimum form of a stroke or a combination of strokes width value and the shortest particle, and form of a stroke or a combination of strokes angle and travel angle differ at 60 °～90 °.

8. electronic brush pen Writing method as claimed in claim 7 is characterized in that, is form of a stroke or a combination of strokes skeleton with the axis of symmetry that is out of shape the preceding form of a stroke or a combination of strokes, and the account form of pen shape is as follows:

On the axis of symmetry, near an end of nib, calculate the point at form of a stroke or a combination of strokes edge as follows:

Wherein, R is the distance of form of a stroke or a combination of strokes marginal point to the axis of symmetry, l be along the axis of symmetry from nib to the distance of current point, rs is the little radius of a circle near nib, the center of circle of described roundlet is near the point of nib one end on the axis of symmetry;

On the axis of symmetry, near an end of penholder, calculate the point at form of a stroke or a combination of strokes edge as follows:

Wherein, rb is the big radius of a circle near penholder, and the center of circle of described great circle is the point of close penholder one end on the axis of symmetry, and h is the distance between the great circle center of circle and the roundlet center of circle;

Be on a section of h in the corresponding length of the axis of symmetry, calculate the point at form of a stroke or a combination of strokes edge as follows:

Be that the reference mark adopts Bezier to connect described marginal point with described marginal point, big radius of circle:

rb=W×pressure

Determine little radius of circle and the h of nib direction according to following formula:

rs=rb×k×pressure

h=H×pressure

Wherein, H represents the most a large sum of line length of presetting, and k is the shape scale parameter, and value is 0～1 floating number, and pressure is the force value of touch screen induction, and this value is for quantizing to 0～1 floating number, and W is for default the most a large sum of wide.

9. an electronic brush pen writing system is characterized in that, comprising:

The touch point computing module, the distance of adjacent two coordinate points of touch point coordinate Calculation on the touch track that is used for transmitting according to touch apparatus;

Interpolating module is used for if described distance less than predetermined threshold, is that spacing is obtained the touch point by described predetermined threshold then; If described distance greater than described predetermined threshold, is then inserted interpolation point between adjacent two touch points;

The person's handwriting generation module, the form of a stroke or a combination of strokes that is used for setting in advance according to the point-rendering on the described touch track to be to generate person's handwriting, and the form of a stroke or a combination of strokes angle of the current form of a stroke or a combination of strokes that obtains by touch apparatus at the turning of touch track or calculate according to the travel angle of person's handwriting is drawn the current form of a stroke or a combination of strokes.

10. electronic brush pen writing system as claimed in claim 9 is characterized in that, also comprises:

Form of a stroke or a combination of strokes deformation module, if reach default deformation condition, be used for as follows the described form of a stroke or a combination of strokes being out of shape: according to the mass spring model that designs in advance described particle is carried out iterated integral with the particle on the axis of symmetry of the described form of a stroke or a combination of strokes, obtain the coordinate of described distortion back particle; Coordinate according to the coordinate Calculation form of a stroke or a combination of strokes edge of particle after the distortion; Draw the form of a stroke or a combination of strokes after the distortion according to form of a stroke or a combination of strokes edge coordinate, described default deformation condition is: at the turning person's handwriting place except a pen and Hui Feng, form of a stroke or a combination of strokes width is greater than the higher value of distance between the minimum form of a stroke or a combination of strokes width value of presetting and the shortest particle.

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