RGB888颜色码与十六位（RGB565）颜色码的转换

    最近弄了个ARDUINO开发板玩，发现RGB565的颜色代码转换很不习惯，查了不少资料，发现在我们的计算机中图像是以RGB888格式显示图像的，24位图每个像素保存了32bit的数据，即RGB888+Alpha，Alpha就是半透明填充字节。

  但是在很多单板机里面是使用RGB565显示图像的，网上很多调色板工具和程序都是用RGB888格式，很少有RGB565的。

  因此，自己弄了个简单的RGB565和RGB888颜色代码转换的工具。

基本原理：

一.RGB888->RGB565

方法只要提取相应单色高位即可(R5 G6 B5)，但会导致低位的缺失，影响精度，而且无法恢复。

二.RGB565->RGB888

方法只要补充相应单色低位即可(R3 G2 B3)。在图像转换中会使用一些算法来补充，这里不涉及图像转换，仅颜色码的转换。

RGB888用unsigned int 32位字节存储

0

0

0

0

0

0

0

0

R7

R6

R5

R4

R3

R2

R1

R0

G7

G6

G5

G4

G3

G2

G1

G0

B7

B6

B5

B4

B3

B2

B1

B0

RGB565用unsigned short 16位字节存储

R7

R6

R5

R4

R3

G7

G6

G5

G4

G3

G2

B7

B6

B5

B4

B3

程序实现：

基本的tkinter使用，python 3.7

核心程序就是通过位移取得RGB565的R,G,B三色值。简单的使用Label显示色块，三个颜色的滑块可以自由拉动。

#!/usr/bin/env python
# -*- coding: UTF-8 -*-

from tkinter import *
import re

window = Tk()
window.title("RGB888 转换 RGB565")
window.geometry('450x300+300+250')

def scalecommand(color):
    
    #print(s1.get(),s2.get(),s3.get())
    b=s3.get()
    g=s2.get()
    r=s1.get()

    R = r & 0xF8
    G = g & 0xFc
    B = b & 0xF8

    rgb565 = (R << 8) | (G << 3) | (B >> 3)

    
    rgb888 = (r << 16) | (g << 8) | b
    
    rgb888_text = 'RGB888: '+ "#%06x"%rgb888
    rgb888_Label.configure(text=rgb888_text)
    
    rgb565_text = 'RGB565: '+ "%#06x" %rgb565
    rgb565_Label.configure(text=rgb565_text)
    
    #print("%#08X"%rgb)
    info_Label.configure(bg="#%06x" %rgb888)
    
    

def HexToDec(value):
  try:
    return int(value, 16)
  except ValueError:
    return "Invalid Hexadecimal Value"


def buttonClick1():
    # RGB888 转 RGB565
    
    try:
        c888 = int(rgb1_Entry.get(),16)         #字符转16进制整数
    except ValueError:
        print( "Invalid Hexadecimal Value")
        return
    
    rgb2_Entry.delete(0,END)
    
    if c888 == None :
        return
    else:
        
        b = (c888 & 0xFF)                 #转换RB 取得rgb颜色B
        g = int((c888 & 0xFF00) >> 8)         #转换G 取得rgb颜色G
        r = int((c888 & 0xFF0000) >>16)     #转换R 取得rgb颜色R
        R = r & 0xF8                        #取得RGB565的5位R
        G = g & 0xFc                        #取得RGB565的5位G
        B = b & 0xF8                        #取得RGB565的5位B

        rgb565 = (R << 8) | (G << 3) | (B >> 3)        

        #print("%#06x" %rgb565)               
        
        #设置滑块位置
        s1.set(r)               
        s2.set(g)
        s3.set(b)

        #显示RGB888和RGB565颜色码
        info_Label.configure(bg="#%06x" %c888)      
        rgb888_text = 'RGB888: '+ "#%06x"%c888
        rgb888_Label.configure(text=rgb888_text)
        rgb565_text = 'RGB565: '+ "%#06x" %rgb565
        rgb565_Label.configure(text=rgb565_text)



def buttonClick2():
    # RGB565 转 RGB888
    rgb1_Entry.delete(0,END)
    
    try:
        c565 = int(rgb2_Entry.get(),16)
    except ValueError:
        print( "Invalid Hexadecimal Value")
        return
    
    if c565 == None :
        return
    else:
        b = (c565 & 0x001F)                 #转换R 
        g = int((c565 & 0x07E0))           #转换G 
        r = int((c565 & 0xF800))          #转换B
        R = r >> 8
        G = g >> 3
        B = b << 3

        rgb888 = (R << 16) | (G << 8) | B        

        #print("%#06x" %rgb888)
        
        s1.set(R)
        s2.set(G)
        s3.set(B)
        info_Label.configure(bg="#%06x" %rgb888)
        rgb888_text = 'RGB888: '+ "#%06x"%rgb888
        rgb888_Label.configure(text=rgb888_text)
        rgb565_text = 'RGB565: '+ "%#06x" %c565
        rgb565_Label.configure(text=rgb565_text)
    

Rgb1_Label = Label(window, text="RGB888 代码：",height = 2,fg='#191970')
Rgb1_Label.place( x =20, y = 25 , anchor=NW)

R1_Label = Label(window, text="#",height = 2,fg='#191970')
R1_Label.place( x =20, y = 50 , anchor=NW)
rgb1_Entry = Entry(window,width=10)
rgb1_Entry.place( x =40, y = 60 , anchor=NW)

Rgb2_Label = Label(window, text="RGB565 代码：",height = 2,fg='#191970')
Rgb2_Label.place( x =20, y = 85 , anchor=NW)

R2_Label = Label(window, text="0x",height = 2,fg='#191970')
R2_Label.place( x =20, y = 110 , anchor=NW)
rgb2_Entry = Entry(window,width=10)
rgb2_Entry.place( x =40, y = 120 , anchor=NW)


button1 = Button(window,text="转换", bg='#8FBC8F',command=buttonClick1)    #转换按键
button1.place( x =160, y = 40 , anchor=NW)

button2 = Button(window,text="转换", bg='#8FBC8F',command=buttonClick2)    #转换按键
button2.place( x =160, y = 110 , anchor=NW)

info_Label = Label(window, text="",height = 10,width=20)        #色块
info_Label.configure(bg='#FFFFFF')
info_Label.place( x =280, y = 20 , anchor=NW)

R_Label = Label(window, text="R",height = 1,width=1)       
R_Label.place( x =20, y = 170 , anchor=NW)
s1 = Scale(window,  from_=0, to=255, orient=HORIZONTAL,
             length=200, showvalue=1, tickinterval=0, resolution=1, command=scalecommand)     #滑块R
s1.place( x =40, y = 150 , anchor=NW)

G_Label = Label(window, text="G",height = 1,width=1)       
G_Label.place( x =20, y = 210 , anchor=NW)
s2 = Scale(window,  from_=0, to=255, orient=HORIZONTAL,
             length=200, showvalue=1, tickinterval=0, resolution=1, command=scalecommand)   #滑块G
s2.place( x =40, y = 190 , anchor=NW)

B_Label = Label(window, text="B",height = 1,width=1)        
B_Label.place( x =20, y = 250 , anchor=NW)
s3 =  Scale(window, from_=0, to=255, orient=HORIZONTAL,
             length=200, showvalue=1, tickinterval=0, resolution=1, command=scalecommand)   #滑块B
s3.place( x =40, y = 230 , anchor=NW)

rgb888_Label = Label(window, text="RGB888:",height = 1,width=18 , fg = 'blue',anchor="w")
rgb888_Label.place( x =280, y = 210 )

rgb565_Label = Label(window, text="RGB565:",height = 1,width=18 , fg = 'blue',anchor="w")  
rgb565_Label.place( x =280, y = 250 ) 


window.mainloop()