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Python利用自帶模塊實(shí)現(xiàn)屏幕像素高效操作

更新時(shí)間：2025年02月09日 11:03:47 作者：Jo喬戈里

這篇文章主要為大家詳細(xì)介紹了Python如何利用自帶模塊實(shí)現(xiàn)屏幕像素高效操作,文中的示例代碼講解詳,感興趣的小伙伴可以跟隨小編一起學(xué)習(xí)一下

1、獲取屏幕放縮比例

from ctypes import wintypes
import ctypes
 
 
HORZRES = 8
LOGPIXELSX = 118
 
 
def get_scale_factor() -> float:
    user32 = ctypes.windll.user32
    gdi32 = ctypes.windll.gdi32
 
    # 定義 HDC 和 UINT 類型
    HDC = wintypes.HDC
    UINT = wintypes.UINT
 
    # 定義 GetDC 和 GetDeviceCaps 的參數(shù)類型和返回類型
    user32.GetDC.argtypes = [wintypes.HWND]
    user32.GetDC.restype = HDC
 
    gdi32.GetDeviceCaps.argtypes = [HDC, UINT]
    gdi32.GetDeviceCaps.restype = wintypes.INT
 
    # 獲取設(shè)備上下文
    dc = user32.GetDC(None)
    widthScale = gdi32.GetDeviceCaps(dc, HORZRES)
    width = gdi32.GetDeviceCaps(dc, LOGPIXELSX)
    scale = width / widthScale
    return scale

2、獲取屏幕指定坐標(biāo)處像素顏色

import ctypes
from ctypes import wintypes
from typing import Sequence, Generator
 
 
user32 = ctypes.windll.user32
gdi32 = ctypes.windll.gdi32
 
# 定義類型
HWND = wintypes.HWND
HDC = wintypes.HDC
HBITMAP = wintypes.HBITMAP
 
 
class BITMAPINFOHEADER(ctypes.Structure):
    _fields_ = [
        ("biSize", wintypes.DWORD),
        ("biWidth", wintypes.LONG),
        ("biHeight", wintypes.LONG),
        ("biPlanes", wintypes.WORD),
        ("biBitCount", wintypes.WORD),
        ("biCompression", wintypes.DWORD),
        ("biSizeImage", wintypes.DWORD),
        ("biXPelsPerMeter", wintypes.LONG),
        ("biYPelsPerMeter", wintypes.LONG),
        ("biClrUsed", wintypes.DWORD),
        ("biClrImportant", wintypes.DWORD)
    ]
 
class BITMAPINFO(ctypes.Structure):
    _fields_ = [
        ("bmiHeader", BITMAPINFOHEADER),
        ("bmiColors", wintypes.DWORD * 3)
    ]
 
 
def get_pixel_color(coords: Sequence[tuple[int, int]], hwnd: HWND) -> Generator[tuple[int, int, int], None, None]:
    rect = wintypes.RECT()
    user32.GetClientRect(hwnd, ctypes.byref(rect))
    width = rect.right - rect.left
    height = rect.bottom - rect.top
 
    # 創(chuàng)建內(nèi)存設(shè)備上下文
    hdc_src = user32.GetDC(hwnd)
    hdc_dst = gdi32.CreateCompatibleDC(hdc_src)
    bmp = gdi32.CreateCompatibleBitmap(hdc_src, width, height)
    gdi32.SelectObject(hdc_dst, bmp)
 
    # 使用 BitBlt 復(fù)制窗口內(nèi)容到內(nèi)存設(shè)備上下文
    gdi32.BitBlt(hdc_dst, 0, 0, width, height, hdc_src, 0, 0, 0x00CC0020)  # SRCCOPY
 
    # 獲取位圖信息
    bmi = BITMAPINFO()
    bmi.bmiHeader.biSize = ctypes.sizeof(BITMAPINFOHEADER)
    bmi.bmiHeader.biWidth = width
    bmi.bmiHeader.biHeight = -height  # 負(fù)值表示自底向上
    bmi.bmiHeader.biPlanes = 1
    bmi.bmiHeader.biBitCount = 32
    bmi.bmiHeader.biCompression = 0
 
    # 創(chuàng)建緩沖區(qū)并獲取位圖數(shù)據(jù)
    buffer = ctypes.create_string_buffer(width * height * 4)
    gdi32.GetDIBits(hdc_dst, bmp, 0, height, buffer, ctypes.byref(bmi), 0)
 
    # 釋放資源
    gdi32.DeleteObject(bmp)
    gdi32.DeleteDC(hdc_dst)
    user32.ReleaseDC(hwnd, hdc_src)
 
    # 遍歷指定坐標(biāo)并返回像素顏色
    for x, y in coords:
        if 0 <= x < width and 0 <= y < height:
            offset = (y * width + x) * 4
            color = buffer[offset:offset + 4]
            yield color[2], color[1], color[0]  # BGR -> RGB
        else:
            yield (0, 0, 0)

3、一個(gè)簡(jiǎn)單的使用案例

from typing import Sequence, Generator, Tuple
from tkinter import ttk
import tkinter as tk
from ctypes import wintypes
import ctypes
import requests
from io import BytesIO
from PIL import Image, ImageTk
 
 
 
 
 
user32 = ctypes.windll.user32
gdi32 = ctypes.windll.gdi32
 
HWND = wintypes.HWND
HDC = wintypes.HDC
HBITMAP = wintypes.HBITMAP
 
 
class BITMAPINFOHEADER(ctypes.Structure):
    _fields_ = [
        ("biSize", wintypes.DWORD),
        ("biWidth", wintypes.LONG),
        ("biHeight", wintypes.LONG),
        ("biPlanes", wintypes.WORD),
        ("biBitCount", wintypes.WORD),
        ("biCompression", wintypes.DWORD),
        ("biSizeImage", wintypes.DWORD),
        ("biXPelsPerMeter", wintypes.LONG),
        ("biYPelsPerMeter", wintypes.LONG),
        ("biClrUsed", wintypes.DWORD),
        ("biClrImportant", wintypes.DWORD)
    ]
 
 
class BITMAPINFO(ctypes.Structure):
    _fields_ = [
        ("bmiHeader", BITMAPINFOHEADER),
        ("bmiColors", wintypes.DWORD * 3)
    ]
 
 
def get_pixel_color(coords: Sequence[Tuple[int, int]], hwnd: HWND) -> Generator[Tuple[int, int, int], None, None]:
    rect = wintypes.RECT()
    user32.GetClientRect(hwnd, ctypes.byref(rect))
    width = rect.right - rect.left
    height = rect.bottom - rect.top
 
    hdc_src = user32.GetDC(hwnd)
    hdc_dst = gdi32.CreateCompatibleDC(hdc_src)
    bmp = gdi32.CreateCompatibleBitmap(hdc_src, width, height)
    gdi32.SelectObject(hdc_dst, bmp)
 
    gdi32.BitBlt(hdc_dst, 0, 0, width, height, hdc_src, 0, 0, 0x00CC0020)  # SRCCOPY
 
    bmi = BITMAPINFO()
    bmi.bmiHeader.biSize = ctypes.sizeof(BITMAPINFOHEADER)
    bmi.bmiHeader.biWidth = width
    bmi.bmiHeader.biHeight = -height  # 負(fù)值表示自底向上
    bmi.bmiHeader.biPlanes = 1
    bmi.bmiHeader.biBitCount = 32
    bmi.bmiHeader.biCompression = 0
 
    buffer = ctypes.create_string_buffer(width * height * 4)
    gdi32.GetDIBits(hdc_dst, bmp, 0, height, buffer, ctypes.byref(bmi), 0)
 
    gdi32.DeleteObject(bmp)
    gdi32.DeleteDC(hdc_dst)
    user32.ReleaseDC(hwnd, hdc_src)
 
    for x, y in coords:
        print(x, y, width, height)
        if 0 <= x < width and 0 <= y < height:
            offset = (y * width + x) * 4
            color = buffer[offset:offset + 4]
            yield color[2], color[1], color[0]  # BGR -> RGB
        else:
            yield (0, 0, 0)
 
 
def get_window_handle(window):
    window_name = window._w
    if not window_name.startswith("."):
        window_name = "." + window_name
    
    hwnd = ctypes.windll.user32.FindWindowW(None, window.title())
    if not hwnd:
        raise ValueError("Cannot get the window handle.")
    return hwnd
 
def download_image(url):
    response = requests.get(url)
    if response.status_code == 200:
        return Image.open(BytesIO(response.content))
    else:
        raise Exception(f"Failed to download image: HTTP {response.status_code}")
 
def display_image_in_label(image):
    photo = ImageTk.PhotoImage(image)
    label = ttk.Label(root, image=photo)
    label.image = photo  # 保持對(duì) PhotoImage 的引用，防止被垃圾回收
    label.pack()
 
 
def show_color(event):
    hwnd = get_window_handle(root)
    x, y = event.x, event.y
    # 注意這里的坐標(biāo)是相對(duì)于窗口的坐標(biāo)，且傳入get_pixel_color的應(yīng)該是包含多個(gè)坐標(biāo)點(diǎn)的序列
    # 此外，為了高效獲取同一個(gè)畫面多個(gè)點(diǎn)的顏色，此處我使用了生成器進(jìn)行懶加載，因此獲取數(shù)據(jù)時(shí)請(qǐng)完整遍歷迭代器
    result = get_pixel_color([(x, y)], hwnd)
    colors = [i for i in result]
    print(f"{event.x, event.y}: {colors}")
 
 
if __name__ == "__main__":
    root = tk.Tk()
    width, height = 900, 500
    screenwidth = root.winfo_screenwidth()
    screenheight = root.winfo_screenheight()
    geometry = '%dx%d+%d+%d' % (width, height, (screenwidth - width) / 2, (screenheight - height) / 2)
    root.title("測(cè)試樣例")
    root.geometry(geometry)
    root.bind("<Motion>", show_color)
 
    image_url = "https://ts1.cn.mm.bing.net/th/id/R-C.475631ce281b88c3cd465761b37c5256?rik=ZFMiTYFwaPypTQ&riu=http%3a%2f%2fpic.ntimg.cn%2ffile%2f20180102%2f21532952_215949247000_2.jpg&ehk=9NnCJ9JG44zfdF2%2fr373s25s68H9vxLvyfMsKgEzAwc%3d&risl=&pid=ImgRaw&r=0"
    try:
        img = download_image(image_url)
        display_image_in_label(img)
    except Exception as e:
        print(f"Error: {e}")
        ttk.Label(root, text="Failed to load image.").pack()
 
    root.mainloop()

4、總結(jié)

上述方法比通常使用PIL的Image.ImageGrab方法要高效非常多，因?yàn)镮mage.ImageGrab是基于IO截屏操作的，頻繁的IO操作使單純進(jìn)行屏幕像素訪問十分低效。

而上述方法采用的是BitBlt。BitBlt 是一種高效的位圖操作方法，可以將窗口的內(nèi)容復(fù)制到內(nèi)存設(shè)備上下文中，然后通過 GetPixel 或直接訪問位圖數(shù)據(jù)來獲取像素顏色。就像素訪問而言其性能顯著強(qiáng)于前者。更多關(guān)于Window的API操作詳見官方文檔：

Windows GDI) (位圖函數(shù) - Win32 apps | Microsoft Learn

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