通过 Python + Python Imaging Library (PIL) 生成简单函数图像

 

# !/usr/bin/env python
# coding=utf-8

# -------------------------------------------------------------------------------
#  名 称：简单函数绘制类
#  版 本：V0.1
#  作 者：mapig (http://mapig.cnblogs.com QQ:33221979)
#  功 能：生成简单函数图像 
#  创 建：2009-05-18
#  备 注：需要 Python Imaging Library (PIL)
# -------------------------------------------------------------------------------

import  math
import  Image
import  ImageDraw

class  DrawFun():
     # 画布像素尺寸
    width   =   512
    height  =   512
     # X取值范围
    min     =   - 10
    max     =   10
     # X的步长值
    step    =   1
     # X单位值像素
    unit    =   1
     # 画板对象
    canvas  =  None
     # 画笔对象
    draw    =  None
     # 画布中心值偏移值
    ctrx  =  0
    ctry  =  0
    
     def   __init__ (self, width, height, min, max, step, unit):
        
        self.width   =  width
        self.height  =  height
        self.min     =  min
        self.max     =  max
        self.step    =  step
        self.unit    =  unit
         # 创建画板对象
        self.canvas  =  Image.new( " RGB " , [self.width, self.height],( 255 , 255 , 255 ))
         # 创建画笔对象
        self.draw    =  ImageDraw.Draw(self.canvas)
         # 获取画布中心点
        self.ctrx  =  math.floor(self.width / 2 )
        self.ctry  =  math.floor(self.height / 2 )
         # 绘制中心轴线
        self.draw.line([(0,self.ctry),(self.width,self.ctry)],  fill  = (0,0,0))
        self.draw.line([(self.ctrx,0),(self.ctrx,self.height)], fill  = (0,0,0))
         # 显示单元格数 左右对称计算
        viewx  =  int(math.floor((self.width / self.unit   +   1 ) / 2 ))
        viewy  =  int(math.floor((self.height / self.unit  +   1 ) / 2 ))
         # 绘制单元格
         for  x  in  range( 1 ,viewx + 1 ):
            offsetx  =  x  *  self.unit
            self.draw.line([(self.ctrx  +  offsetx,0),(self.ctrx  +  offsetx,self.height)], fill  = ( 200 , 200 , 200 ))
            self.draw.line([(self.ctrx  -  offsetx,0),(self.ctrx  -  offsetx,self.height)], fill  = ( 200 , 200 , 200 ))
         for  y  in  range( 1 ,viewy + 1 ):
            offsety  =  y  *  self.unit
            self.draw.line([(0,self.ctry  +  offsety),(self.width,self.ctry  +  offsety)],  fill  = ( 200 , 200 , 200 ))
            self.draw.line([(0,self.ctry  -  offsety),(self.width,self.ctry  -  offsety)],  fill  = ( 200 , 200 , 200 ))
        
     def  paint(self, fun, color):
        
         # 结果点集
        aryPoint  =  []
         # 转换为1为步长
        min  =  int(math.floor(self.min / self.step))
        max  =  int(math.floor(self.max / self.step))
         for  i  in  range(min, max):
             # 实际函数值
            x  =  i  *  self.step
            y  =  fun(x)
             # 笛卡尔坐标系到屏幕坐标系
             # 比例变换
            x  =  x  *  self.unit
            y  =  y  *  self.unit
             # 坐标变换
            curX  =  self.ctrx  +  x
            curY  =  self.ctry  -  y
             # 保存坐标到数组
            aryPoint.append((curX,curY))   
         # 绘制函数         
        self.draw.point(aryPoint,fill  =  color)   
    
     # 显示图片    
     def  show(self):
         # 显示图片
        self.canvas.show()
     # 保存到JPG
     def  saveToJPG(self, path):
        self.canvas.save(path, " JPEG " )
     # 保存到PNG
     def  saveToPNG(self, path):
        self.canvas.save(path, " PNG " )


def  sin(x):
     return  math.sin(x)
def  cos(x):
     return  math.cos(x)
def  tan(x):
     return  math.tan(x)

  
if   __name__   ==   " __main__ " :
    
     # DrawFun("画布宽度","画布高度","x最小值","x最大值","x步长值","x单位值像素大小")
    drawfun  =  DrawFun( 512 ,  512 ,  - 10 ,  10 ,  0.001 ,  50 )

     # DrawFun.paint(f(x)函数，RGB颜色)
    drawfun.paint(sin,( 255 ,0,0))
    drawfun.paint(cos,(0, 255 ,0))
    drawfun.paint(tan,(0,0, 255 ))
    
     # 显示函数图像
    drawfun.show()
    
     # 保存到图片
    drawfun.saveToJPG( " demo.jpg " )
    drawfun.saveToPNG( " demo.png " )

 

生成效果