Question

我正在绘制一个椭圆并使用translate函数对其进行平移，该函数是手动定义的dx & dy

现在，我想在此数组中包含更多具有不同dx,dy值的图。

translation_points = 
[ (5, 6), (5, 7), (5, 8), (5, 9), (5, 10), (5, 11), (5, 12), (5, 13), (5, 14), (6, 5), (6, 6), (6, 7), (6, 8), (6, 9), (6, 10), (6, 11), (6, 12), (6, 13), (6, 14), (7, 5), (7, 6), (7, 7), (7, 8), (7, 9), (7, 10), (7, 11), (7, 12)]

我该怎么做？

import numpy as np
import matplotlib.pyplot as plt

def ellipse(x, y):
    value = (x*x) + (y*y)/3
    if (value >= 300):
        return 0
    else:
        return 1

def translate(x, y):
    DX = 5
    DY = 5
    return (x- DX, y - DY)    


def rotate(x, y):
    theta = np.radians(40)
    matrix = np.array([[np.cos(theta), -np.sin(theta)], [np.sin(theta), np.cos(theta)]])
    return np.dot(matrix, (x,y))

data = np.zeros((100,100))

for i in range(0, 100):
    for j in range(0, 100):
        (x, y) = translate(i,j)
        (x, y) = rotate(x, y)
        data[i,j] = ellipse(x, y)

plt.imshow(data, cmap="gray")
plt.show()

Answer 1

首先，修改您的translate()，添加新参数offset：

def translate(x, y, offset):
    (dx, dy) = offset
    return x - dx, y - dy

然后将2个for循环放入一个函数中，以便稍后我们可以调用它，该函数也应该接受参数offset。然后我们可以调用它来绘制每个偏移量。

def draw(offset):
    data = np.zeros((100, 100))
    for i in range(-100, 100):
        for j in range(-100, 100):
            (x, y) = translate(i, j, offset)
            (x, y) = rotate(x, y)
            data[i, j] = ellipse(x, y)
    plt.imshow(data, cmap="gray")

最后，创建一个循环，为translation_points中的每个偏移量绘制椭圆。在这里，我使用plt.subplot(4, 7, i+1)创建28个子图，每个子图是一个翻译的椭圆。如果您只想查看每个单独的图，则可以注释此行。

for i in range(len(translation_points)):
    plt.subplot(4, 7, i+1)
    draw(translation_points[i])

是的，我们做到了。

更多编辑：

由于我们使用imshow，因此将裁剪图。此外，坐标是完全错误的。因此，请先设置范围：

for i in range(-100, 100):
    for j in range(-100, 100):

然后给它一些默认的偏移量：

def translate(x, y, offset):
    (dx, dy) = offset
    return x - dx - 50, y - dy - 50

扩展图形，设置轴限制：在draw()中添加这些行

plt.xlim(-50, 50)
plt.ylim(-50, 50)
plt.imshow(data, cmap="cool", extent=[-data.shape[1]/2., data.shape[1]/2., -data.shape[0]/2., data.shape[0]/2.])

最后：

import numpy as np
import matplotlib.pyplot as plt

translation_points = [(5, 6), (5, 7), (5, 8), (5, 9), (5, 10), (5, 11),
                      (5, 12), (5, 13), (5, 14), (6, 5), (6, 6), (6, 7),
                      (6, 8), (6, 9), (6, 10), (6, 11), (6, 12), (6, 13),
                      (6, 14), (7, 5), (7, 6), (7, 7), (7, 8), (7, 9),
                      (7, 10), (7, 11), (7, 12)]


def ellipse(x, y):
    value = (x*x) + (y*y)/3
    if value >= 300:
        return 0
    else:
        return 1


def translate(x, y, offset):
    # dx = 5
    # dy = 5
    (dx, dy) = offset
    return x - dx - 50, y - dy - 50


def rotate(x, y):
    theta = np.radians(40)
    matrix = np.array([[np.cos(theta), -np.sin(theta)], [np.sin(theta), np.cos(theta)]])
    return np.dot(matrix, (x, y))


def draw(offset):
    data = np.zeros((100, 100))
    for i in range(-100, 100):
        for j in range(-100, 100):
            (x, y) = translate(i, j, offset)
            (x, y) = rotate(x, y)
            data[i, j] = ellipse(x, y)
    plt.xlim(-50, 50)
    plt.ylim(-50, 50)
    plt.imshow(data, cmap="gray",
               extent=[-data.shape[1]/2., data.shape[1]/2.,
                       -data.shape[0]/2., data.shape[0]/2.])


for i in range(len(translation_points)):
    plt.subplot(4, 7, i+1)
    draw(translation_points[i])

plt.show()

Answer 2

import numpy as np
import matplotlib.pyplot as plt
translation_points = [ (5, 6), (5, 7), (10,10), (20, 8), (5, 9), (12, 10), (40, 40), (50, 50),(20, 8)]
def ellipse(x, y):
    value = (x*x) + (y*y)/3
    if (value >= 300):
        return 0
    else:
        return 1

def translate(x, y,a,b):
    #print a,b
    DX = a
    DY = b
    return (x- DX, y - DY)    


def rotate(x, y):
    theta = np.radians(40)
    matrix = np.array([[np.cos(theta), -np.sin(theta)], [np.sin(theta), np.cos(theta)]])
    return np.dot(matrix, (x,y))

def create(tlpoints):
    a,b=tlpoints
    #print a,b
    data = np.zeros((100,100))

    for i in range(0, 100):
        for j in range(0, 100):
            (x, y) = translate(i,j,a,b)
            (x, y) = rotate(x, y)
            data[i,j] = ellipse(x, y)
    return data


ells=[create(translation_points[i]) for i in range(len(translation_points))]
fig=plt.figure(figsize=(10,10))
columns = 3
rows = len(translation_points)/columns
for i in range(1, columns*rows +1):
    fig.add_subplot(rows, columns, i)
    plt.imshow(ells[i-1],cmap='gray')
plt.show()

如何在数组中定义的不同中心上绘制椭圆

2 个答案:

更多编辑：