RGB888转换为RGB565原理及工具

1.原理
首先RGB的范围是0-255，包括RGB三个值。

第一步将R,G,B三个值分别转化为八位二进制数，这里以GREEN为例子。
GREEN R:0 G:255 B:0
二进制：R00000000 11111111 00000000

565的意思就是RGB的位数，R取5位，G取六位，B取5位。其中要求取高位，舍低位。

00000 000 11111111 00000 00

其中非粗体的 0和1 舍去

得到0000011111100000
再转化为十六进制数0x7e0

2.工具

#!/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
    R = R >> 3
    G = G >> 2
    B = B >> 3
    rgb888_text = 'RGB888: '+ "#%06x"%rgb888
    rgb888_Label.configure(text=rgb888_text)
    
    rgb565_text = '565: '+ "%d " %R + "%d " %G + "%d" %B
    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6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="565:",height = 1,width=18 , fg = 'blue',anchor="w")  
rgb565_Label.place( x =280, y = 250 ) 
 
 
window.mainloop()
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转自 https://blog.csdn.net/wild_lee/article/details/122009234
修改了一下将RGB565的R G B 分别用十进制打出

一些常用的颜色
RGB888和RGB565颜色对照表

RGB颜色值与十六进制颜色码互转

RGB在线颜色生成调色板

色彩中间色/颜色中间值计算