Android开发实现的几何图形工具类GeometryUtil完整实例

本文实例讲述了android开发实现的几何图形工具类geometryutil。分享给大家供大家参考，具体如下：

package com.android.imooc.goo;
import android.graphics.pointf;
/**
 * 几何图形工具
 */
public class geometryutil {
  /**
   * as meaning of method name. 获得两点之间的距离
   *
   * @param p0
   * @param p1
   * @return
   */
  public static float getdistancebetween2points(pointf p0, pointf p1) {
    float distance = (float) math.sqrt(math.pow(p0.y - p1.y, 2) + math.pow(p0.x - p1.x, 2));
    return distance;
  }
  /**
   * get middle point between p1 and p2. 获得两点连线的中点
   *
   * @param p1
   * @param p2
   * @return
   */
  public static pointf getmiddlepoint(pointf p1, pointf p2) {
    return new pointf((p1.x + p2.x) / 2.0f, (p1.y + p2.y) / 2.0f);
  }
  /**
   * get point between p1 and p2 by percent. 根据百分比获取两点之间的某个点坐标
   *
   * @param p1
   * @param p2
   * @param percent
   * @return
   */
  public static pointf getpointbypercent(pointf p1, pointf p2, float percent) {
    return new pointf(evaluatevalue(percent, p1.x, p2.x), evaluatevalue(percent, p1.y, p2.y));
  }
  /**
   * 根据分度值，计算从start到end中，fraction位置的值。fraction范围为0 -> 1
   *
   * @param fraction
   * @param start
   * @param end
   * @return
   */
  public static float evaluatevalue(float fraction, number start, number end) {
    return start.floatvalue() + (end.floatvalue() - start.floatvalue()) * fraction;
  }
  /**
   * get the point of intersection between circle and line. 获取
   * 通过指定圆心，斜率为linek的直线与圆的交点。
   *
   * @param pmiddle
   *      the circle center point.
   * @param radius
   *      the circle radius.
   * @param linek
   *      the slope of line which cross the pmiddle.
   * @return
   */
  public static pointf[] getintersectionpoints(pointf pmiddle, float radius, double linek) {
    pointf[] points = new pointf[2];
    float radian, xoffset = 0, yoffset = 0;
    if (linek != null) {
      radian = (float) math.atan(linek);
      xoffset = (float) (math.sin(radian) * radius);
      yoffset = (float) (math.cos(radian) * radius);
    } else {
      xoffset = radius;
      yoffset = 0;
    }
    points[0] = new pointf(pmiddle.x + xoffset, pmiddle.y - yoffset);
    points[1] = new pointf(pmiddle.x - xoffset, pmiddle.y + yoffset);
    return points;
  }
}

更多关于android相关内容感兴趣的读者可查看本站专题：《android图形与图像处理技巧总结》、《android开发入门与进阶教程》、《android调试技巧与常见问题解决方法汇总》、《android基本组件用法总结》、《android视图view技巧总结》、《android布局layout技巧总结》及《android控件用法总结》

希望本文所述对大家android程序设计有所帮助。