Python uses DDA algorithm and midpoint Bresenham algorithm to draw straight line

Title: "Python uses DDA algorithm and midpoint Bresenham algorithm to draw straight line"
date:2018-06-11t19:28:02+08:00
Tags: ["Graphic science"]
Categories: ["Python"]

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#!/usr/bin/env python# Coding=utf-8 fromPylabImport * fromMatplotlib.tickerImportMultiplelocatorImportMatplotlib.patches asPatches'''1. Input line ends Point x0,y0 xn,yn2. Calculate initial value delta_x, delta_y,k=delta_y/delta_x,d=0, X=x0,y=y03. Plot point x, y4. D Update to D+k, if d>0.5, then x, y update to X+1,y+1,d=d-1, otherwise x, y update to X+1,y5. Repeat 3,4 until the line is finished'''defInit (ax, width):# Set the length widthAx.axis ([0, Width,0, Width])# Set the position of the main tick label, the format of the label textMajorlocator=Multiplelocator (1) Minorlocator=Multiplelocator (0.5) Ax.xaxis.set_major_locator (Majorlocator) ax.yaxis.set_major_locator (majorlocator)# Ax.xaxis.set_minor_locator (minorlocator)    # Ax.yaxis.set_minor_locator (minorlocator)Ax.grid (True)# Grid of x axes using main scaledefAdd_pixel (x, y, Ax, c): X= round(x) Y= round(y)ifC== 1: Ax.add_patch (patches. Rectangle ((x- 0.5Y- 0.5),1,1, color=' B ')) Ax.plot (x, Y,' R. ')Else: Ax.add_patch (patches. Rectangle ((x- 0.5Y- 0.5),1,1)) Ax.plot (x, Y,' Y. ')if __name__ == ' __main__ ':# Splits a line of strings and converts them into numbersX0, y0, x1, y1, Width= Map(int,input("Enter the two points of the line and the side length of the canvas:"). Split (' '))ifX0>X1:x0,x1=X1,x0 y0,y1=Y1,y0 Ax=Subplot (121, Aspect=' equal ', title=' modified Bresenham ')# Improved BresenhamAx.plot ([x0, X1], [y0, Y1],'-K ') BX=Subplot (122, Aspect=' equal ', title=' DDA ')# DDABx.plot ([x0, X1], [y0, Y1],'-K ')# Graphical InitializationInit (ax, width) init (bx, width) delta_x=X1-X0 delta_y=Y1-Y0 D= 0    ifDelta_x== 0: K= 999999999    Else: K=Delta_y/Delta_x x= round(x0) Y= round(y0)'''DDA algorithm    '''    ifK> -1  andK< 1:# X Maximum Displacement         while True:ifX>X1: BreakAdd_pixel (x, y, BX,1) x=X+1Y=Y+KelifK>= 1:# Y Maximum Displacement         while True:ifY>Y1: BreakAdd_pixel (x, y, BX,1) y=Y+1X=X+1/KElse: while True:ifY<Y1: BreakAdd_pixel (x, y, BX,1) y=Y-1X=X-1/K'''range of K1. (0,1) x is maximum displacement, y positive increase2. (1,+inf) Y is the maximum displacement, x positive increase3. (0,-1) x is maximum displacement, Y negative increase4. ( -1,-inf) Y is the maximum displacement and y decreases. X Positive Increase    '''X=X0 y=Y0ifK> 1: while True:ifY>Y1: BreakAdd_pixel (x, y, Ax,0) y=Y+ 1D=D+ 1 /KifD> 0.5: X=X+ 1D=D- 1    elifK> 0: while True:ifX>X1: BreakAdd_pixel (x, y, Ax,0) x=X+ 1D=D+KifD> 0.5: Y=Y+ 1D=D- 1    elifK> -1: while True:ifX>X1: BreakAdd_pixel (x, y, Ax,0) x=X+ 1D=D-KifD> 0.5: Y=Y- 1D=D- 1    Else: while True:ifY<Y1: BreakAdd_pixel (x, y, Ax,0) y=Y- 1D=D- 1 /KifD> 0.5: X=X+ 1D=D- 1Show ()

Python uses DDA algorithm and midpoint Bresenham algorithm to draw straight line