screen_region_trigger.py

"""
屏幕区域定时监控 + Windows BitBlt 截图
支持 PNG / JPEG 两种输出格式
自动查找并监控名为"相机"的窗口
"""

import ctypes
import ctypes.wintypes
import datetime
import os
import time

import mss.tools
from PIL import Image, ImageChops

# ──────────────────────────────────────────────
#  ① 配置区域（按需修改）
# ──────────────────────────────────────────────
POLL_INTERVAL     = 2.0        # 扫描间隔（秒）
DIFF_THRESHOLD    = 3.0       # 差异阈值：超过此值视为"有变化"（%），正确的像素变化率
SAVE_DIR          = r"E:\iflow\screen_cap\screenshots"

SAVE_FORMAT       = "PNG"      # 截图格式：PNG（无损）或 JPEG（有损压缩）
JPEG_QUALITY      = 85         # SAVE_FORMAT=JPEG 时生效，1-100，越高越清晰/文件越大

TARGET_WINDOW_TITLE = "相机"    # 要监控的窗口名称

# 节流配置
MIN_SAVE_INTERVAL = 5.0        # 两次截图之间的最小时间间隔（秒），避免频繁截图
# ──────────────────────────────────────────────

os.makedirs(SAVE_DIR, exist_ok=True)


# ── Windows API 结构体（BitBlt 全屏截图）────────────────
class BITMAPINFOHEADER(ctypes.Structure):
    _fields_ = [
        ("biSize",          ctypes.wintypes.DWORD),
        ("biWidth",         ctypes.wintypes.LONG),
        ("biHeight",        ctypes.wintypes.LONG),
        ("biPlanes",        ctypes.wintypes.WORD),
        ("biBitCount",      ctypes.wintypes.WORD),
        ("biCompression",   ctypes.wintypes.DWORD),
        ("biSizeImage",     ctypes.wintypes.DWORD),
        ("biXPelsPerMeter", ctypes.wintypes.LONG),
        ("biYPelsPerMeter", ctypes.wintypes.LONG),
        ("biClrUsed",       ctypes.wintypes.DWORD),
        ("biClrImportant",  ctypes.wintypes.DWORD),
    ]

class BITMAPINFO(ctypes.Structure):
    _fields_ = [
        ("bmiHeader", BITMAPINFOHEADER),
        ("bmiColors", ctypes.c_ubyte * 4),
    ]

gdi32   = ctypes.WinDLL("gdi32",   use_last_error=True)
user32  = ctypes.WinDLL("user32",  use_last_error=True)
kernel32= ctypes.WinDLL("kernel32",use_last_error=True)

# ── 窗口查找函数 ──────────────────────────────────────
def find_window_by_title(title: str):
    """根据窗口标题查找窗口句柄"""
    return user32.FindWindowW(None, title)

def get_window_rect(hwnd):
    """获取窗口的位置和大小"""
    class RECT(ctypes.Structure):
        _fields_ = [
            ("left", ctypes.wintypes.LONG),
            ("top", ctypes.wintypes.LONG),
            ("right", ctypes.wintypes.LONG),
            ("bottom", ctypes.wintypes.LONG),
        ]
    
    rect = RECT()
    if user32.GetWindowRect(hwnd, ctypes.byref(rect)):
        return {
            "left": rect.left,
            "top": rect.top,
            "width": rect.right - rect.left,
            "height": rect.bottom - rect.top
        }
    return None

def get_client_rect(hwnd):
    """获取窗口客户区的位置和大小（不含标题栏）"""
    class RECT(ctypes.Structure):
        _fields_ = [
            ("left", ctypes.wintypes.LONG),
            ("top", ctypes.wintypes.LONG),
            ("right", ctypes.wintypes.LONG),
            ("bottom", ctypes.wintypes.LONG),
        ]
    
    rect = RECT()
    if user32.GetClientRect(hwnd, ctypes.byref(rect)):
        # 获取客户区相对于屏幕的坐标
        client_left = ctypes.wintypes.LONG(0)
        client_top = ctypes.wintypes.LONG(0)
        user32.ClientToScreen(hwnd, ctypes.byref(client_left), ctypes.byref(client_top))
        return {
            "left": client_left.value,
            "top": client_top.value,
            "width": rect.right - rect.left,
            "height": rect.bottom - rect.top
        }
    return None

def find_camera_window():
    """查找相机窗口并返回其区域信息和窗口句柄"""
    print(f"[screen_region_trigger] 正在查找窗口: '{TARGET_WINDOW_TITLE}'...")
    
    hwnd = find_window_by_title(TARGET_WINDOW_TITLE)
    if hwnd == 0:
        print(f"[screen_region_trigger] 未找到窗口: '{TARGET_WINDOW_TITLE}'")
        return None
    
    # 获取窗口在屏幕上的位置
    window_rect = get_window_rect(hwnd)
    if not window_rect:
        print(f"[screen_region_trigger] 无法获取窗口位置")
        return None
    
    # 处理全屏/高DPI情况下的负数坐标问题
    window_left = max(0, window_rect["left"])
    window_top = max(0, window_rect["top"])
    
    # 获取客户区（不含标题栏）
    client_rect = get_client_rect(hwnd)
    if client_rect and client_rect["width"] > 0 and client_rect["height"] > 0:
        # 客户区坐标需要加上窗口位置转换为屏幕坐标
        screen_left = window_left + client_rect["left"]
        screen_top = window_top + client_rect["top"]
        
        # 确保坐标不为负数
        screen_left = max(0, screen_left)
        screen_top = max(0, screen_top)
        
        print(f"[screen_region_trigger] 找到窗口客户区: left={screen_left}, top={screen_top}, w={client_rect['width']}, h={client_rect['height']}")
        return {
            "hwnd": hwnd,
            "left": screen_left,
            "top": screen_top,
            "width": client_rect["width"],
            "height": client_rect["height"]
        }
    
    # 如果客户区获取失败，使用整个窗口
    if window_rect["width"] > 0 and window_rect["height"] > 0:
        print(f"[screen_region_trigger] 找到窗口: left={window_left}, top={window_top}, w={window_rect['width']}, h={window_rect['height']}")
        return {
            "hwnd": hwnd,
            "left": window_left,
            "top": window_top,
            "width": window_rect["width"],
            "height": window_rect["height"]
        }
    
    return None


def windows_screenshot(left: int, top: int, width: int, height: int, save_path: str):
    """BitBlt 截取指定区域，以 PNG 或 JPEG 保存。"""
    hdc_screen = user32.GetDC(0)
    hdc_mem    = gdi32.CreateCompatibleDC(hdc_screen)
    hbmp       = gdi32.CreateCompatibleBitmap(hdc_screen, width, height)
    gdi32.SelectObject(hdc_mem, hbmp)

    if not gdi32.BitBlt(hdc_mem, 0, 0, width, height,
                        hdc_screen, left, top, 0x00CC0020):
        raise ctypes.WinError(ctypes.get_last_error())

    bmi = BITMAPINFO()
    bmi.bmiHeader.biSize        = ctypes.sizeof(BITMAPINFOHEADER)
    bmi.bmiHeader.biWidth       = width
    bmi.bmiHeader.biHeight      = -height      # top-down DIB
    bmi.bmiHeader.biPlanes      = 1
    bmi.bmiHeader.biBitCount    = 24
    bmi.bmiHeader.biCompression = 0

    buf = ctypes.create_string_buffer(width * height * 3)
    gdi32.GetDIBits(hdc_mem, hbmp, 0, height, buf, ctypes.byref(bmi), 0)

    img = Image.frombytes("RGB", (width, height), buf.raw, "raw", "BGR")

    if SAVE_FORMAT == "JPEG":
        img.save(save_path, "JPEG", quality=JPEG_QUALITY)
    else:
        img.save(save_path, "PNG")

    gdi32.DeleteObject(hbmp)
    gdi32.DeleteDC(hdc_mem)
    user32.ReleaseDC(0, hdc_screen)
    return save_path


def windows_screenshot_to_image(left: int, top: int, width: int, height: int) -> Image.Image:
    """BitBlt 截取指定区域，返回 PIL Image 对象"""
    hdc_screen = user32.GetDC(0)
    hdc_mem    = gdi32.CreateCompatibleDC(hdc_screen)
    hbmp       = gdi32.CreateCompatibleBitmap(hdc_screen, width, height)
    gdi32.SelectObject(hdc_mem, hbmp)

    if not gdi32.BitBlt(hdc_mem, 0, 0, width, height,
                        hdc_screen, left, top, 0x00CC0020):
        raise ctypes.WinError(ctypes.get_last_error())

    bmi = BITMAPINFO()
    bmi.bmiHeader.biSize        = ctypes.sizeof(BITMAPINFOHEADER)
    bmi.bmiHeader.biWidth       = width
    bmi.bmiHeader.biHeight      = -height      # top-down DIB
    bmi.bmiHeader.biPlanes      = 1
    bmi.bmiHeader.biBitCount    = 24
    bmi.bmiHeader.biCompression = 0

    buf = ctypes.create_string_buffer(width * height * 3)
    gdi32.GetDIBits(hdc_mem, hbmp, 0, height, buf, ctypes.byref(bmi), 0)

    img = Image.frombytes("RGB", (width, height), buf.raw, "raw", "BGR")

    gdi32.DeleteObject(hbmp)
    gdi32.DeleteDC(hdc_mem)
    user32.ReleaseDC(0, hdc_screen)
    return img


def bring_window_to_front(hwnd):
    """将窗口带到前台"""
    user32.SetForegroundWindow(hwnd)
    # 等待窗口置顶
    time.sleep(0.1)


def window_screenshot(hwnd, width: int, height: int, save_path: str):
    """使用 PrintWindow 直接截取窗口内容（即使窗口被遮挡也能截取）"""
    # 获取窗口DC
    hdc_window = user32.GetDC(hwnd)
    hdc_mem    = gdi32.CreateCompatibleDC(hdc_window)
    hbmp       = gdi32.CreateCompatibleBitmap(hdc_window, width, height)
    gdi32.SelectObject(hdc_mem, hbmp)

    # 使用 PrintWindow API 截取窗口
    # PW_CLIENTONLY = 0x00000001 表示只截取客户区
    if not user32.PrintWindow(hwnd, hdc_mem, 0):
        raise ctypes.WinError(ctypes.get_last_error())

    bmi = BITMAPINFO()
    bmi.bmiHeader.biSize        = ctypes.sizeof(BITMAPINFOHEADER)
    bmi.bmiHeader.biWidth       = width
    bmi.bmiHeader.biHeight      = -height      # top-down DIB
    bmi.bmiHeader.biPlanes      = 1
    bmi.bmiHeader.biBitCount    = 24
    bmi.bmiHeader.biCompression = 0

    buf = ctypes.create_string_buffer(width * height * 3)
    gdi32.GetDIBits(hdc_mem, hbmp, 0, height, buf, ctypes.byref(bmi), 0)

    img = Image.frombytes("RGB", (width, height), buf.raw, "raw", "BGR")

    if SAVE_FORMAT == "JPEG":
        img.save(save_path, "JPEG", quality=JPEG_QUALITY)
    else:
        img.save(save_path, "PNG")

    gdi32.DeleteObject(hbmp)
    gdi32.DeleteDC(hdc_mem)
    user32.ReleaseDC(hwnd, hdc_window)
    return save_path


def window_screenshot_to_image(hwnd, width: int, height: int) -> Image.Image:
    """使用 PrintWindow 截取窗口内容，返回 PIL Image 对象"""
    # 获取窗口DC
    hdc_window = user32.GetDC(hwnd)
    hdc_mem    = gdi32.CreateCompatibleDC(hdc_window)
    hbmp       = gdi32.CreateCompatibleBitmap(hdc_window, width, height)
    gdi32.SelectObject(hdc_mem, hbmp)

    # 使用 PrintWindow API 截取窗口
    # PW_CLIENTONLY = 0x00000001 表示只截取客户区
    if not user32.PrintWindow(hwnd, hdc_mem, 0):
        raise ctypes.WinError(ctypes.get_last_error())

    bmi = BITMAPINFO()
    bmi.bmiHeader.biSize        = ctypes.sizeof(BITMAPINFOHEADER)
    bmi.bmiHeader.biWidth       = width
    bmi.bmiHeader.biHeight      = -height      # top-down DIB
    bmi.bmiHeader.biPlanes      = 1
    bmi.bmiHeader.biBitCount    = 24
    bmi.bmiHeader.biCompression = 0

    buf = ctypes.create_string_buffer(width * height * 3)
    gdi32.GetDIBits(hdc_mem, hbmp, 0, height, buf, ctypes.byref(bmi), 0)

    img = Image.frombytes("RGB", (width, height), buf.raw, "raw", "BGR")

    gdi32.DeleteObject(hbmp)
    gdi32.DeleteDC(hdc_mem)
    user32.ReleaseDC(hwnd, hdc_window)
    return img


# ── 帧差计算（mss 快速采集）────────────────────────────
def capture_region_array(sct, region) -> Image.Image:
    shot = sct.grab(region)
    return Image.frombytes("RGB", shot.size, shot.rgb)


def diff_percent(img_a: Image.Image, img_b: Image.Image, thresh: int = 5) -> float:
    """计算两张图片的差异百分比（正确的像素级变化率）"""
    # 确保图片尺寸一致
    if img_a.size != img_b.size:
        return 100.0
    
    # 转换为灰度图比较（避免RGB通道重复计算问题）
    gray_a = img_a.convert("L")
    gray_b = img_b.convert("L")
    
    # 计算绝对差值
    diff = ImageChops.difference(gray_a, gray_b)
    
    # 统计变化像素数
    total_pixels = img_a.width * img_a.height
    changed_pixels = sum(1 for pixel in diff.getdata() if pixel > thresh)
    
    return (changed_pixels / total_pixels) * 100


# ── 主循环 ────────────────────────────────────────────
def main():
    sct = mss.MSS()
    
    fmt_display = "JPEG" if SAVE_FORMAT == "JPEG" else "PNG"
    print(f"[screen_region_trigger] 扫描间隔: {POLL_INTERVAL}s  |  变化阈值: {DIFF_THRESHOLD}%")
    print(f"[screen_region_trigger] 截图格式: {fmt_display}  |  保存目录: {SAVE_DIR}")
    print("[screen_region_trigger] 按 Ctrl+C 停止\n")

    # 持续查找相机窗口
    reg = None
    while reg is None:
        reg = find_camera_window()
        if reg is None:
            print(f"[screen_region_trigger] 等待 {POLL_INTERVAL} 秒后重试...")
            time.sleep(POLL_INTERVAL)
    
    reg["mon"] = 1  # 添加显示器编号
    
    print(f"[screen_region_trigger] 开始监控窗口区域: left={reg['left']}, top={reg['top']}, "
          f"w={reg['width']}, h={reg['height']}\n")

    shot_count = 0
    last_save_time = 0  # 上次保存时间
    oldscr = None  # 上次保存的图片，初始为 None

    while True:
        # 检查窗口是否仍然存在
        current_reg = find_camera_window()
        if current_reg is None:
            print(f"[screen_region_trigger] 窗口已关闭或移动，重新查找...")
            reg = None
            while reg is None:
                reg = find_camera_window()
                if reg is None:
                    print(f"[screen_region_trigger] 等待 {POLL_INTERVAL} 秒后重试...")
                    time.sleep(POLL_INTERVAL)
            reg["mon"] = 1
            print(f"[screen_region_trigger] 重新找到窗口: left={reg['left']}, top={reg['top']}, "
                  f"w={reg['width']}, h={reg['height']}")
            # 重置 oldscr
            oldscr = None
            continue
        
        time.sleep(POLL_INTERVAL)
        
        # 使用屏幕截图（BitBlt）进行比较，确保获取实际显示内容
        # 先将窗口置顶以确保截取到正确内容
        if "hwnd" in reg and reg["hwnd"]:
            bring_window_to_front(reg["hwnd"])
        
        curr_img = windows_screenshot_to_image(
            reg["left"], reg["top"], reg["width"], reg["height"]
        )

        current_time = time.time()
        
        # 如果是首次截图，直接保存；否则比较与上次保存的图片差异
        should_save = False
        diff = 0.0
        
        if oldscr is None:
            # 首次截图，直接保存
            should_save = True
        else:
            # 比较当前截图与 oldscr 的差异
            diff = diff_percent(oldscr, curr_img)
            # 如果差异超过阈值且满足时间间隔，则保存截图
            if diff > DIFF_THRESHOLD:
                should_save = True
        
        if should_save:
            if oldscr is None or current_time - last_save_time >= MIN_SAVE_INTERVAL:
                now  = datetime.datetime.now().strftime("%Y%m%d_%H%M%S")
                ext  = "jpg" if SAVE_FORMAT == "JPEG" else "png"
                fname = os.path.join(SAVE_DIR, f"trigger_{now}_{shot_count:04d}.{ext}")

                # 使用屏幕截图（BitBlt）保存，确保获取实际显示内容
                try:
                    # 先将窗口置顶
                    if "hwnd" in reg and reg["hwnd"]:
                        bring_window_to_front(reg["hwnd"])
                    
                    windows_screenshot(
                        reg["left"], reg["top"], reg["width"], reg["height"], fname
                    )
                except Exception as e:
                    print(f"[错误] 保存图片失败: {e}")
                    fname = None

                if fname:
                    shot_count += 1
                    last_save_time = current_time
                    # 更新 oldscr 为屏幕截图，确保下次比较一致
                    oldscr = windows_screenshot_to_image(
                        reg["left"], reg["top"], reg["width"], reg["height"]
                    )
                    print(f"[截屏] {fname}  (diff={diff:.1f}%)")
            else:
                print(f"[提示] 检测到变化 ({diff:.1f}%)，但距离上次截图不足 {MIN_SAVE_INTERVAL} 秒，跳过")


if __name__ == "__main__":
    main()