Question

我在使用Python的CS项目时遇到了问题，每当我认为我已经接近解决问题时，它就无法工作。

我的老师问我们的是显示实际窗口（不在shell中）中点附近的线的中点坐标。到目前为止，这是我的代码：

win = GraphWin("Exercise 8 Page 119", 400,400)
for i in range(1):
    p1 = win.getMouse()
    p1.draw(win)
    p1.setFill("black")
    p2 = win.getMouse()
    p2.draw(win)
    p2.setFill("black")
    line = Line(Point(p1.getX(),p1.getY()), Point(p2.getX(), p2.getY()))
    line.draw(win)

    # midpoint
    midpoint = line.getCenter()
    midpoint.draw(win)
    midpoint.setFill("cyan")


    import math
    # midpoint math
    yMid = p2.getY()+p1.getY()/2
    xMid = p2.getX()+p1.getX()/2
   # midpoint text
    midpointLabel = Text(Point(xMid+0.5, yMid+0.5), "midpoint is: " + "(" + str(xMid) + "," + str(yMid) + ")")
    midpointLabel.draw(win)

每当我测试它时，中点会随机出现，或者根本无法看到它。我似乎无法每次都将坐标放在接近实际中点的位置。这些是教师的确切词语＆＃34;该程序将标记中点，略微偏离线中点的实际位置。＆＃34;

请帮帮我！谢谢！

Answer 1

我说问题是一个简单的数学错误：

yMid = p2.getY()+p1.getY()/2
xMid = p2.getX()+p1.getX()/2

应该是：

yMid = (p2.getY() + p1.getY()) / 2
xMid = (p2.getX() + p1.getX()) / 2

完整代码：

from graphics import *

win = GraphWin("Exercise 8 Page 119", 400, 400)

p1 = win.getMouse()
p1.setFill("black")
p1.draw(win)

p2 = win.getMouse()
p2.setFill("black")
p2.draw(win)

line = Line(p1, p2)
line.draw(win)

# midpoint
midpoint = line.getCenter()
midpoint.setFill("cyan")
midpoint.draw(win)

# midpoint math
yMid = (p2.getY() + p1.getY()) / 2
xMid = (p2.getX() + p1.getX()) / 2
# midpoint text
midpointLabel = Text(Point(xMid + 0.5, yMid + 0.5), "midpoint is: ({}, {})".format(xMid, yMid))
midpointLabel.draw(win)

win.getMouse()
win.close()

尝试通过用户输入标记图形中的点

1 个答案: