Java函数:输入两个坐标确定框图的位置,输入一个由n个坐标组成的折线图,给定坐标系上两点形成的框图,判断一随机折线图是从框图的哪边进哪边出或者是跟框图没有交集
时间: 2024-05-25 12:19:31 浏览: 3
public static String determinePosition(int x1, int y1, int x2, int y2, int[][] line) {
boolean intersectsTop = false;
boolean intersectsBottom = false;
boolean intersectsLeft = false;
boolean intersectsRight = false;
// Check if any segment of the line intersects with any side of the rectangle
for (int i = 0; i < line.length - 1; i++) {
int x3 = line[i][0];
int y3 = line[i][1];
int x4 = line[i+1][0];
int y4 = line[i+1][1];
// Check if the segment intersects with the top side
if (doSegmentsIntersect(x1, y1, x2, y1, x3, y3, x4, y4)) {
intersectsTop = true;
}
// Check if the segment intersects with the bottom side
if (doSegmentsIntersect(x1, y2, x2, y2, x3, y3, x4, y4)) {
intersectsBottom = true;
}
// Check if the segment intersects with the left side
if (doSegmentsIntersect(x1, y1, x1, y2, x3, y3, x4, y4)) {
intersectsLeft = true;
}
// Check if the segment intersects with the right side
if (doSegmentsIntersect(x2, y1, x2, y2, x3, y3, x4, y4)) {
intersectsRight = true;
}
}
// Determine which side(s) the line enters and exits from
if (intersectsTop && intersectsBottom && intersectsLeft && intersectsRight) {
return "Line intersects with all sides of the rectangle.";
} else if (intersectsTop && intersectsBottom && intersectsLeft) {
return "Line enters from left and exits from top and bottom.";
} else if (intersectsTop && intersectsBottom && intersectsRight) {
return "Line enters from right and exits from top and bottom.";
} else if (intersectsTop && intersectsLeft && intersectsRight) {
return "Line enters from top and exits from left and right.";
} else if (intersectsBottom && intersectsLeft && intersectsRight) {
return "Line enters from bottom and exits from left and right.";
} else if (intersectsTop && intersectsLeft) {
return "Line enters from top left corner and exits from left side.";
} else if (intersectsTop && intersectsRight) {
return "Line enters from top right corner and exits from right side.";
} else if (intersectsBottom && intersectsLeft) {
return "Line enters from bottom left corner and exits from left side.";
} else if (intersectsBottom && intersectsRight) {
return "Line enters from bottom right corner and exits from right side.";
} else {
return "Line does not intersect with any side of the rectangle.";
}
}
/**
* Checks if two line segments intersect.
*
* @param x1 X-coordinate of first endpoint of first segment
* @param y1 Y-coordinate of first endpoint of first segment
* @param x2 X-coordinate of second endpoint of first segment
* @param y2 Y-coordinate of second endpoint of first segment
* @param x3 X-coordinate of first endpoint of second segment
* @param y3 Y-coordinate of first endpoint of second segment
* @param x4 X-coordinate of second endpoint of second segment
* @param y4 Y-coordinate of second endpoint of second segment
* @return true if the segments intersect, false otherwise
*/
private static boolean doSegmentsIntersect(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4) {
int d1 = direction(x3, y3, x4, y4, x1, y1);
int d2 = direction(x3, y3, x4, y4, x2, y2);
int d3 = direction(x1, y1, x2, y2, x3, y3);
int d4 = direction(x1, y1, x2, y2, x4, y4);
if (((d1 > 0 && d2 < 0) || (d1 < 0 && d2 > 0)) && ((d3 > 0 && d4 < 0) || (d3 < 0 && d4 > 0))) {
return true;
} else if (d1 == 0 && onSegment(x3, y3, x4, y4, x1, y1)) {
return true;
} else if (d2 == 0 && onSegment(x3, y3, x4, y4, x2, y2)) {
return true;
} else if (d3 == 0 && onSegment(x1, y1, x2, y2, x3, y3)) {
return true;
} else if (d4 == 0 && onSegment(x1, y1, x2, y2, x4, y4)) {
return true;
} else {
return false;
}
}
/**
* Computes the direction of the turn between three points.
*
* @param x1 X-coordinate of first point
* @param y1 Y-coordinate of first point
* @param x2 X-coordinate of second point
* @param y2 Y-coordinate of second point
* @param x3 X-coordinate of third point
* @param y3 Y-coordinate of third point
* @return > 0 if the turn is to the left, < 0 if the turn is to the right, 0 if the points are collinear
*/
private static int direction(int x1, int y1, int x2, int y2, int x3, int y3) {
return (x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1);
}
/**
* Checks if a point is on a line segment.
*
* @param x1 X-coordinate of first endpoint of line segment
* @param y1 Y-coordinate of first endpoint of line segment
* @param x2 X-coordinate of second endpoint of line segment
* @param y2 Y-coordinate of second endpoint of line segment
* @param x X-coordinate of point
* @param y Y-coordinate of point
* @return true if the point is on the segment, false otherwise
*/
private static boolean onSegment(int x1, int y1, int x2, int y2, int x, int y) {
return Math.min(x1, x2) <= x && x <= Math.max(x1, x2) && Math.min(y1, y2) <= y && y <= Math.max(y1, y2);
}