pythagoras.f.Arc Maven / Gradle / Ivy
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A portable geometry library.
//
// Pythagoras - a collection of geometry classes
// http://github.com/samskivert/pythagoras
package pythagoras.f;
import java.io.Serializable;
/**
* Represents an arc defined by a framing rectangle, start angle, angular extend, and closure type.
*/
public class Arc extends AbstractArc implements Serializable
{
/** The x-coordinate of this arc's framing rectangle. */
public float x;
/** The y-coordinate of this arc's framing rectangle. */
public float y;
/** The width of this arc's framing rectangle. */
public float width;
/** The height of this arc's framing rectangle. */
public float height;
/** The starting angle of this arc. */
public float start;
/** The angular extent of this arc. */
public float extent;
/**
* Creates an open arc with frame (0x0+0+0) and zero angles.
*/
public Arc () {
this(OPEN);
}
/**
* Creates an arc of the specified type with frame (0x0+0+0) and zero angles.
*/
public Arc (int type) {
setArcType(type);
}
/**
* Creates an arc of the specified type with the specified framing rectangle, starting angle
* and angular extent.
*/
public Arc (float x, float y, float width, float height, float start, float extent, int type) {
setArc(x, y, width, height, start, extent, type);
}
/**
* Creates an arc of the specified type with the supplied framing rectangle, starting angle and
* angular extent.
*/
public Arc (IRectangle bounds, float start, float extent, int type) {
setArc(bounds.x(), bounds.y(), bounds.width(), bounds.height(),
start, extent, type);
}
@Override // from interface IArc
public int arcType () {
return type;
}
@Override // from interface IArc
public float x () {
return x;
}
@Override // from interface IArc
public float y () {
return y;
}
@Override // from interface IArc
public float width () {
return width;
}
@Override // from interface IArc
public float height () {
return height;
}
@Override // from interface IArc
public float angleStart () {
return start;
}
@Override // from interface IArc
public float angleExtent () {
return extent;
}
/**
* Sets the type of this arc to the specified value.
*/
public void setArcType (int type) {
if (type != OPEN && type != CHORD && type != PIE) {
throw new IllegalArgumentException("Invalid Arc type: " + type);
}
this.type = type;
}
/**
* Sets the starting angle of this arc to the specified value.
*/
public void setAngleStart (float start) {
this.start = start;
}
/**
* Sets the angular extent of this arc to the specified value.
*/
public void setAngleExtent (float extent) {
this.extent = extent;
}
/**
* Sets the location, size, angular extents, and closure type of this arc to the specified
* values.
*/
public void setArc (float x, float y, float width, float height,
float start, float extent, int type) {
setArcType(type);
this.x = x;
this.y = y;
this.width = width;
this.height = height;
this.start = start;
this.extent = extent;
}
/**
* Sets the location, size, angular extents, and closure type of this arc to the specified
* values.
*/
public void setArc (IPoint point, IDimension size, float start, float extent, int type) {
setArc(point.x(), point.y(), size.width(), size.height(), start, extent, type);
}
/**
* Sets the location, size, angular extents, and closure type of this arc to the specified
* values.
*/
public void setArc (IRectangle rect, float start, float extent, int type) {
setArc(rect.x(), rect.y(), rect.width(), rect.height(), start, extent, type);
}
/**
* Sets the location, size, angular extents, and closure type of this arc to the same values as
* the supplied arc.
*/
public void setArc (IArc arc) {
setArc(arc.x(), arc.y(), arc.width(), arc.height(), arc.angleStart(),
arc.angleExtent(), arc.arcType());
}
/**
* Sets the location, size, angular extents, and closure type of this arc based on the
* specified values.
*/
public void setArcByCenter (float x, float y, float radius,
float start, float extent, int type) {
setArc(x - radius, y - radius, radius * 2f, radius * 2f, start, extent, type);
}
/**
* Sets the location, size, angular extents, and closure type of this arc based on the
* specified values.
*/
public void setArcByTangent (IPoint p1, IPoint p2, IPoint p3, float radius) {
// use simple geometric calculations of arc center, radius and angles by tangents
float a1 = -FloatMath.atan2(p1.y() - p2.y(), p1.x() - p2.x());
float a2 = -FloatMath.atan2(p3.y() - p2.y(), p3.x() - p2.x());
float am = (a1 + a2) / 2f;
float ah = a1 - am;
float d = radius / Math.abs(FloatMath.sin(ah));
float x = p2.x() + d * FloatMath.cos(am);
float y = p2.y() - d * FloatMath.sin(am);
ah = ah >= 0f ? FloatMath.PI * 1.5f - ah : FloatMath.PI * 0.5f - ah;
a1 = normAngle(FloatMath.toDegrees(am - ah));
a2 = normAngle(FloatMath.toDegrees(am + ah));
float delta = a2 - a1;
if (delta <= 0f) {
delta += 360f;
}
setArcByCenter(x, y, radius, a1, delta, type);
}
/**
* Sets the starting angle of this arc to the angle defined by the supplied point relative to
* the center of this arc.
*/
public void setAngleStart (IPoint point) {
float angle = FloatMath.atan2(point.y() - centerY(), point.x() - centerX());
setAngleStart(normAngle(-FloatMath.toDegrees(angle)));
}
/**
* Sets the starting angle and angular extent of this arc using two sets of coordinates. The
* first set of coordinates is used to determine the angle of the starting point relative to
* the arc's center. The second set of coordinates is used to determine the angle of the end
* point relative to the arc's center. The arc will always be non-empty and extend
* counterclockwise from the first point around to the second point.
*/
public void setAngles (float x1, float y1, float x2, float y2) {
float cx = centerX();
float cy = centerY();
float a1 = normAngle(-FloatMath.toDegrees(FloatMath.atan2(y1 - cy, x1 - cx)));
float a2 = normAngle(-FloatMath.toDegrees(FloatMath.atan2(y2 - cy, x2 - cx)));
a2 -= a1;
if (a2 <= 0f) {
a2 += 360f;
}
setAngleStart(a1);
setAngleExtent(a2);
}
/**
* Sets the starting angle and angular extent of this arc using two sets of coordinates. The
* first set of coordinates is used to determine the angle of the starting point relative to
* the arc's center. The second set of coordinates is used to determine the angle of the end
* point relative to the arc's center. The arc will always be non-empty and extend
* counterclockwise from the first point around to the second point.
*/
public void setAngles (IPoint p1, IPoint p2) {
setAngles(p1.x(), p1.y(), p2.x(), p2.y());
}
@Override // from RectangularShape
public void setFrame (float x, float y, float width, float height) {
setArc(x, y, width, height, angleStart(), angleExtent(), type);
}
private int type;
}
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