2020-08-16

import numpyas np

import matplotlib.pyplotas plt

def BresenhamLine(img,x1, y1, x2,  y2):

pointList = []

y_neg =False

    dx = x2 - x1

if (dx <0):#向左走，就将起点终点调换

        temp = x2

x2 = x1

x1 = temp

temp = y2

y2 = y1

y1 = temp

dx = x2 - x1# 重新计算dx

    dy = y2 - y1

if (dy <0):# 向下走，就将计算出来的y加个负号

        y_neg=True

        dy=-dy

x = x1

y = y1#从起点开始

    if(dx==0):#打竖画线,向左走换了(x1,y1),(x2,y2),向下走没有换，注意

        y=min(y1,y2)

y_end=max(y1,y2)

while(y<=y_end):

img[x, y] =1

            y+=1

            pointList.append([x, y])

return img,pointList

elif(dy==0):#打横画线

        while (x <= x2):

img[x, y] =1

            x+=1

            pointList.append([x, y])

return img,pointList

else:

k = dy /(1.0*dx)#斜率

    if (abs(k) <=1):#画横斜线，|斜率|<=1

        sign_k =True  # 斜率标记

        xend = x2

else:#| 斜率|>1

        sign_k =False# 等会关于y=x对称,计算|斜率|<=1的值,画|斜率|>1的画

        #先打横了来算，画的时候才对称

        xend = x1+dy

temp=dy

dy=dx

dx=temp

k = dy / (1.0*dx)# 斜率

    p =2 * dy - dx#P0 = 2*dy - dx

    v =2 * dy

u = p - dx#Pk+1 = Pk + 2*dy - 2*dx,u 表示2*dy - 2*dx

############开始画线###################3

    b=y1-x1

while ( x <= xend):

if (sign_k ==True):#画横斜线，|斜率|<=1

            if(y_neg==True):#向下走，画横线,只需要关于y=y0上下翻转就好了

                #SetPixel(hDC, x, y, color);

                img[x, 2*y1-y] =1#(x,-y)

                pointList.append([x, y])

else:#向上走，画横线,最正常了

                img[x, y] =1#(x,y)

                pointList.append([x, y])

else :#画竖斜线，|斜率|>1

#SetPixel(hDC, y, x, color);

            if (y_neg ==True):#画竖斜线，又向下走，要先关于y=kx+b对称，之后再关于y=y0上下翻转

                # SetPixel(hDC, x, y, color);

                img[y-b,  2*y1-(x+b)] =1#（y,-x）

                pointList.append([x, y])

else:#向上走，画竖斜线，关于y=kx+b对称

                img[y-b, x+b] =1#（y,x）

                pointList.append([x, y])

if (p>0):

y+=1

            p = p + u

#cout << "1 ";

        else:

p = p + v

#//cout << "0 ";

        x+=1

    return img,pointList

if __name__ =='__main__':

img = np.full([100,100],np.nan)

# plt.imshow(img)

# plt.show()

    line = []

count =0

    for iin range(img.shape[0]):

for jin range(img.shape[1]):

if np.sqrt((i-50)**2+(j-50)**2)<50 and np.sqrt((i-50)**2+(j-50)**2)>48  and img[i,j]!=1:

img,pointList = BresenhamLine(img, i, j, 50, 50)

line.append(pointList)

for iin range(img.shape[0]):

for jin range(img.shape[1]):

if np.sqrt((i-50)**2+(j-50)**2)<50 and img[i,j]!=1:

img,pointList = BresenhamLine(img, i, j, 50, 50)

line.append(pointList)

print(len(line))

plt.imshow(img)

plt.show()