对任意一张图片，我们可以用代码给它加点雪花特效，做成动图。
原图：
加特效后：
首先我们需要雪花的图片，比如下面这张（其实这张有点不太真实，不过无妨，我只是拿它来做演示）。
做图像分割后我们就得到了16张雪花的图片（其实一张也足够）：
用pickle模块将它们保存到本地，以供后续调用。
万事俱备，下面我们来给原图加上雪花。主要代码如下：
代码语言：javascript复制"""
Created on Sat Dec 15 10:15:18 2019
@author: wangsp
"""
import numpy as np
from matplotlib import pyplot as plt
import cv2
import pickle
import imageio
from random import randint,normalvariate
def create_gif(frames, gif_name,duration=0.3,reverse=False):
if reverse: frames.sort(reverse=True)
imageio.mimsave(gif_name,frames,"GIF",duration=duration)
return frames
BG = plt.imread("plum.jpg")#加载背景图
H,W,C = BG.shape
frame = BG.astype(np.uint16)
frames = []
class Snow:
def __init__(self,type_,x0,y0,speed0,scale):
self.scale = scale
#type_ : from 1 to 16
self.data = self.get_snow(type_)
self.x = x0
self.y = y0
self.speed = speed0
def get_snow(self, type_):
with open("snow%d.data"%type_,"rb") as f:
data = pickle.load(f)
#缩小一点
self.h,self.w = data.shape
data = cv2.resize(data,(int(self.h*self.scale),int(self.w*self.scale)))
self.h,self.w = data.shape
snow = np.zeros((self.h,self.w,3),dtype = np.uint8)
snow[data==1] = np.array([255,255,255])
return snow
def update(self): #动画效果
global frames, frame
c = self.w%2 #compensation, 偶数0， 奇数1
#restore
if self.y < self.h:
frame[0:self.y, self.x-int(self.w/2):self.x int(self.w/2) c] = BG[0:self.y,self.x-int(self.w/2):self.x int(self.w/2) c]
elif self.y < H:
frame[self.y-self.h:self.y, self.x-int(self.w/2):self.x int(self.w/2) c]= BG[self.y-self.h:self.y,self.x-int(self.w/2):self.x int(self.w/2) c]
elif self.y < H self.h:
frame[self.y-self.h:, self.x-int(self.w/2):self.x int(self.w/2) c] = BG[self.y-self.h:,self.x-int(self.w/2):self.x int(self.w/2) c]
else:
pass
self.x = 0
self.y = self.speed
if self.y < self.h:
frame[0:self.y, self.x-int(self.w/2):self.x int(self.w/2) c] = self.data[self.h-self.y:,:]
elif self.y < H:
frame[self.y-self.h:self.y, self.x-int(self.w/2):self.x int(self.w/2) c] = self.data
elif self.y < H self.h:
frame[self.y-self.h:, self.x-int(self.w/2):self.x int(self.w/2) c] = self.data[:H-(self.y-self.h),:]
else:
self.y = 0
frame[frame>255] = 255
n_snows = randint(100,120) # include both ends
snows = []
for i in range(n_snows):
type_ = randint(1,16) #include both ends
x0 = randint(10,W-10)
y0 = randint(0,H)
speed = int(normalvariate(3,0.5))
scale = normalvariate(0.02,0.005)
snow = Snow(type_,x0, y0, speed,scale)
snows.append(snow)
n_frames = 30 #因为公众号只能穿5M以下的图，所以帧数弄少一点
for n in range(n_frames):
for i in range(n_snows):
snows[i].update()
frames.append(frame.astype(np.uint8))
create_gif(frames,"snow_plum_5M.gif",0.01) #创建GIF至此 ，我们可以给小倩下场雪：
效果略显粗糙，有时间的话会再做优化。
