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| Name | bezierTangent() |
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| Examples | 
noFill();
bezier(85, 20, 10, 10, 90, 90, 15, 80);
int steps = 6;
fill(255);
for (int i = 0; i <= steps; i++) {
float t = i / float(steps);
// Get the location of the point
float x = bezierPoint(85, 10, 90, 15, t);
float y = bezierPoint(20, 10, 90, 80, t);
// Get the tangent points
float tx = bezierTangent(85, 10, 90, 15, t);
float ty = bezierTangent(20, 10, 90, 80, t);
// Calculate an angle from the tangent points
float a = atan2(ty, tx);
a += PI;
stroke(255, 102, 0);
line(x, y, cos(a)*30 + x, sin(a)*30 + y);
// The following line of code makes a line
// inverse of the above line
//line(x, y, cos(a)*-30 + x, sin(a)*-30 + y);
stroke(0);
ellipse(x, y, 5, 5);
}
noFill();
bezier(85, 20, 10, 10, 90, 90, 15, 80);
stroke(255, 102, 0);
int steps = 16;
for (int i = 0; i <= steps; i++) {
float t = i / float(steps);
float x = bezierPoint(85, 10, 90, 15, t);
float y = bezierPoint(20, 10, 90, 80, t);
float tx = bezierTangent(85, 10, 90, 15, t);
float ty = bezierTangent(20, 10, 90, 80, t);
float a = atan2(ty, tx);
a -= HALF_PI;
line(x, y, cos(a)*8 + x, sin(a)*8 + y);
}
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| Description | Calculates the tangent of a point on a Bezier curve. There is a good definition of tangent on Wikipedia. | ||||||||||
| Syntax | bezierTangent(a, b, c, d, t) | ||||||||||
| Parameters |
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| Returns | float | ||||||||||
| Related | bezier() bezierVertex() curvePoint() |
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