Use canvas to draw the besell curve and canvas to draw the besell Curve
This article mainly introduces how to use canvas to draw the bésel curve, including the fansel curve twice and three times. It is very detailed and recommended to a small partner.
1. Quadratic besell Curve
QuadraticCurveTo (cpx, cpy, x, y) // cpx, cpy indicates the coordinate of the control point, and x, y indicates the coordinate of the end point;
The mathematical formula is as follows:
The path of the bizz curve is defined by function B of the given point P0, P1, and P2 (T) Tracking:
Code example:
The Code is as follows:
<! DOCTYPE html>
<Html>
<Head>
<Meta charset = "UTF-8">
<Title> canvas line </title>
<Meta name = "Keywords" content = "">
<Meta name = "author" content = "@ my_programmer">
<Style type = "text/css">
Body, h1 {margin: 0 ;}
Canvas {margin: 20px ;}
</Style>
</Head>
<Body onload = "draw ()">
<H1> quadratic besell curve <Canvas id = "canvas" width = 200 height = 200 style = "border: 1px solid # ccc;"> </canvas>
<Script>
Function draw (){
Var canvas = document. getElementById ('canvas ');
Var context = canvas. getContext ('2d ');
// Draw the start point, control point, and end point
Context. beginPath ();
Context. moveTo (20,170 );
Context. lineTo (130,40 );
Context. lineTo (180,150 );
Context. stroke (); </p> <p> // draws the besell curve twice.
Context. beginPath ();
Context. moveTo (20,170 );
Context. quadraticCurveTo (180,150 );
Context. strokeStyle = "red ";
Context. stroke ();
}
</Script>
</Body>
</Html>
Code effect:
2. Cubic besell Curve
BezierCurveTo (cp1x, cp1y, cp2x, cp2y, x, y) // cp1x, cp1y indicates the coordinates of the first control point, cp2x, cp2y indicates the coordinates of the second control point, x, y indicates the coordinates of the end point;
The mathematical formula is as follows:
P0, P1, P2, and P3 point on a plane or in a three-dimensional space, a cubic Beitz curve is defined. The curve starts from P0 to P1 and starts from P2 to P3. It generally does not pass through P1 or P2; these two points only provide direction information there. The spacing between P0 and P1 determines the "length" of the curve toward P2 before it is switched to P3 ".
Code example:
The Code is as follows:
<! DOCTYPE html>
<Html>
<Head>
<Meta charset = "UTF-8">
<Title> canvas line </title>
<Meta name = "Keywords" content = "">
<Meta name = "Description" content = "">
<Style type = "text/css">
Body, h1 {margin: 0 ;}
Canvas {margin: 20px ;}
</Style>
</Head>
<Body onload = "draw ()">
<H1> cubic besell curve <Canvas id = "canvas" width = 200 height = 200 style = "border: 1px solid # ccc;"> </canvas>
<Script>
Function draw (){
Var canvas = document. getElementById ('canvas ');
Var context = canvas. getContext ('2d ');
// Draw the start point, control point, and end point
Context. beginPath ();
Context. moveTo (25,175 );
Context. lineTo (60, 80 );
Context. lineTo (150,30 );
Context. lineTo (170,150 );
Context. stroke (); </p> <p> // draw the besell curve three times.
Context. beginPath ();
Context. moveTo (25,175 );
Context. bezierCurveTo (60, 80, 170,150 );
Context. strokeStyle = "red ";
Context. stroke ();
}
</Script>
</Body>
</Html>
Code:
Is it cool... HTML5 + canvas is really a fun and addictive.
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