542 lines
13 KiB
Go
542 lines
13 KiB
Go
package win32
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// 取景框：屏幕上的一个红框，常驻显示当前框选区域。
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//
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// 三个关键点：
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// 1. 用 WS_EX_LAYERED 分层窗口自己画，框外像素 alpha=0，既不遮挡下方内容，
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// 也不需要 Fyne 的透明窗口支持（OpenGL 窗口改颜色键并不可靠）；
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// 2. WS_EX_TRANSPARENT + WM_NCHITTEST 返回 HTTRANSPARENT，鼠标事件直接穿透，
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// 不会挡住底下的点击；
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// 3. SetWindowDisplayAffinity(WDA_EXCLUDEFROMCAPTURE) 让它不出现在截屏和录屏
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// 画面里，包括本程序自己抓屏用的 GDI BitBlt（Windows 10 2004+）。
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import (
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"fmt"
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"os"
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"sync"
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"syscall"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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const (
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frameWNDClass = "ViewsAgentFrameWnd"
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wsExLayered = 0x00080000
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wsExTransparent = 0x00000020
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wsExToolWindow = 0x00000080
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wsExNoActivate = 0x08000000
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wsPopup = 0x80000000
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swShowNoActivate = 4
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ulwAlpha = 0x02
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acSrcOver = 0x00
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acSrcAlpha = 0x01
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biRgb = 0x00
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dibRgbColors = 0x00
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// wdaExcludeFromCapture 让窗口从截屏/录屏里消失（Windows 10 2004+）。
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wdaExcludeFromCapture = 0x11
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wdaNone = 0x00
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wmDestroy = 0x0002
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wmEraseBkgnd = 0x0014
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wmNCHitTest = 0x0084
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wmFrameRedraw = 0x8001 // WM_APP + 1
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// htTransparent 让鼠标事件穿透到下层窗口。
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htTransparent = ^uintptr(0)
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)
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var (
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gdi32 = windows.NewLazySystemDLL("gdi32.dll")
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procCreateCompatibleDC = gdi32.NewProc("CreateCompatibleDC")
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procCreateDIBSection = gdi32.NewProc("CreateDIBSection")
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procSelectObject = gdi32.NewProc("SelectObject")
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procDeleteObject = gdi32.NewProc("DeleteObject")
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procDeleteDC = gdi32.NewProc("DeleteDC")
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procGetDC = user32.NewProc("GetDC")
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procReleaseDC = user32.NewProc("ReleaseDC")
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procCreateWindowExW = user32.NewProc("CreateWindowExW")
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procRegisterClassExW = user32.NewProc("RegisterClassExW")
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procDefWindowProcW = user32.NewProc("DefWindowProcW")
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procTranslateMessage = user32.NewProc("TranslateMessage")
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procDispatchMessageW = user32.NewProc("DispatchMessageW")
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procPostMessageW = user32.NewProc("PostMessageW")
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procDestroyWindow = user32.NewProc("DestroyWindow")
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procShowWindow = user32.NewProc("ShowWindow")
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procUpdateLayered = user32.NewProc("UpdateLayeredWindow")
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procSetDisplayAffinity = user32.NewProc("SetWindowDisplayAffinity")
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procGetDisplayAffinity = user32.NewProc("GetWindowDisplayAffinity")
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procIsWindowVisible = user32.NewProc("IsWindowVisible")
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)
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type bitmapInfoHeader struct {
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Size uint32
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Width int32
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Height int32
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Planes uint16
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BitCount uint16
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Compression uint32
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SizeImage uint32
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XPelsPerMeter int32
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YPelsPerMeter int32
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ClrUsed uint32
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ClrImportant uint32
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}
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type bitmapInfo struct {
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Header bitmapInfoHeader
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Colors [1]uint32
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}
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type blendFunction struct {
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BlendOp byte
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BlendFlags byte
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SourceConstantAlpha byte
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AlphaFormat byte
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}
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type winPoint struct {
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X, Y int32
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}
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type winSize struct {
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Cx, Cy int32
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}
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type wndClassEx struct {
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Size uint32
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Style uint32
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WndProc uintptr
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ClsExtra int32
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WndExtra int32
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Instance windows.Handle
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Icon windows.Handle
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Cursor windows.Handle
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Background windows.Handle
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MenuName *uint16
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ClassName *uint16
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IconSmall windows.Handle
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}
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// Frame 是屏幕上的取景框。内部自带一条消息线程，
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// 窗口消息必须有人泵，否则窗口不会响应。
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type Frame struct {
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mu sync.Mutex
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hwnd syscall.Handle
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region Rect
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shown bool
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memDC syscall.Handle
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dib syscall.Handle
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oldBmp syscall.Handle
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bits unsafe.Pointer
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w, h int
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buf []uint32
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threadID uintptr
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lastULW uintptr
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lastErr uintptr
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ready chan error
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done chan struct{}
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}
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// frames 记录窗口句柄到 Frame 的映射，窗口过程里要用。
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var (
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framesMu sync.Mutex
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frames = map[syscall.Handle]*Frame{}
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)
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// NewFrame 创建一个取景框。此时还没有区域，调用 SetRegion 才会显示。
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func NewFrame() (*Frame, error) {
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f := &Frame{
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ready: make(chan error, 1),
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done: make(chan struct{}),
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}
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go f.loop()
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if err := <-f.ready; err != nil {
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return nil, err
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}
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return f, nil
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}
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// loop 在独立线程上建窗口并跑消息循环。
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func (f *Frame) loop() {
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className, err := windows.UTF16PtrFromString(frameWNDClass)
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if err != nil {
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f.ready <- err
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close(f.done)
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return
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}
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wc := wndClassEx{
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Size: uint32(unsafe.Sizeof(wndClassEx{})),
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Style: 0x0008, // CS_DBLCLKS 无所谓，主要是别带 CS_HREDRAW/CS_VREDRAW
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WndProc: windows.NewCallback(frameWndProc),
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ClassName: className,
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}
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if atom, _, _ := procRegisterClassExW.Call(uintptr(unsafe.Pointer(&wc))); atom == 0 {
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// 1410 = ERROR_CLASS_ALREADY_EXISTS，重复注册不算错。
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if code := lastErrorCode(); code != 1410 {
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err = fmt.Errorf("RegisterClassEx 失败: %w", syscall.Errno(code))
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f.ready <- err
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close(f.done)
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return
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}
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}
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style := uintptr(wsExLayered | wsExTransparent | wsExToolWindow | wsExNoActivate)
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hwnd, _, _ := procCreateWindowExW.Call(
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style,
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uintptr(unsafe.Pointer(className)),
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0,
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uintptr(wsPopup),
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0, 0, 1, 1,
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0, 0, 0, 0,
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)
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if hwnd == 0 {
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f.ready <- fmt.Errorf("CreateWindowEx 失败: %w", syscall.Errno(lastErrorCode()))
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close(f.done)
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return
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}
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f.mu.Lock()
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f.hwnd = syscall.Handle(hwnd)
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f.threadID, _, _ = procGetCurrentThreadID.Call()
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f.mu.Unlock()
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framesMu.Lock()
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frames[syscall.Handle(hwnd)] = f
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framesMu.Unlock()
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// 关键：让窗口从截屏/录屏里排除出去。
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// 开发自检时可用 VIEWSAGENT_FRAME_NO_EXCLUDE=1 临时关掉，方便截图核对。
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if os.Getenv("VIEWSAGENT_FRAME_NO_EXCLUDE") == "" {
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procSetDisplayAffinity.Call(hwnd, wdaExcludeFromCapture)
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}
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// 准备离屏绘图用的 DC。
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hdcScreen, _, _ := procGetDC.Call(0)
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if hdcScreen != 0 {
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memDC, _, _ := procCreateCompatibleDC.Call(hdcScreen)
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f.mu.Lock()
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f.memDC = syscall.Handle(memDC)
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f.mu.Unlock()
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procReleaseDC.Call(0, hdcScreen)
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}
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f.ready <- nil
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var msg msg
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for {
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r, _, _ := procGetMessageW.Call(uintptr(unsafe.Pointer(&msg)), 0, 0, 0)
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if int32(r) <= 0 {
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break
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}
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procTranslateMessage.Call(uintptr(unsafe.Pointer(&msg)))
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procDispatchMessageW.Call(uintptr(unsafe.Pointer(&msg)))
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}
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close(f.done)
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}
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// SetRegion 把取景框移到指定区域并重画。区域无效时隐藏。
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func (f *Frame) SetRegion(r Rect) {
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f.mu.Lock()
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f.region = r
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f.shown = r.Width() > 0 && r.Height() > 0
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hwnd := f.hwnd
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f.mu.Unlock()
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if hwnd == 0 {
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return
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}
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if r.Width() <= 0 || r.Height() <= 0 {
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procShowWindow.Call(uintptr(hwnd), 0) // SW_HIDE
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return
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}
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procShowWindow.Call(uintptr(hwnd), swShowNoActivate)
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procPostMessageW.Call(uintptr(hwnd), wmFrameRedraw, 0, 0)
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}
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// Hide 隐藏取景框。
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func (f *Frame) Hide() {
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f.mu.Lock()
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f.shown = false
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hwnd := f.hwnd
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f.mu.Unlock()
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if hwnd != 0 {
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procShowWindow.Call(uintptr(hwnd), 0)
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}
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}
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// SetCaptureExclusion 开关某个窗口的"不出现在截屏/录屏里"。
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// 关掉之后窗口会被录进去，只用于自检和调试。
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func SetCaptureExclusion(hwnd syscall.Handle, on bool) {
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if hwnd == 0 {
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return
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}
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affinity := uintptr(wdaExcludeFromCapture)
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if !on {
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affinity = wdaNone
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}
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procSetDisplayAffinity.Call(uintptr(hwnd), affinity)
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}
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// SetCaptureExclusion 开关"不出现在截屏/录屏里"。
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// 关掉之后取景框会被录进去，只用于自检和调试。
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func (f *Frame) SetCaptureExclusion(on bool) {
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f.mu.Lock()
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hwnd := f.hwnd
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f.mu.Unlock()
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SetCaptureExclusion(hwnd, on)
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}
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// FindFrameWindow 按窗口类找到取景框窗口，给外部工具（如自检脚本）用。
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func FindFrameWindow() (syscall.Handle, error) {
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return FindWindowByClass(frameWNDClass)
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}
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// IsWindowVisible 返回窗口是否可见。
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func IsWindowVisible(hwnd syscall.Handle) bool {
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r, _, _ := procIsWindowVisible.Call(uintptr(hwnd))
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return r != 0
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}
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// DisplayAffinity 返回窗口的截屏亲和性设置。
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func DisplayAffinity(hwnd syscall.Handle) uint32 {
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var v uint32
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r, _, _ := procGetDisplayAffinity.Call(uintptr(hwnd), uintptr(unsafe.Pointer(&v)))
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if r == 0 {
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return 0
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}
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return v
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}
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// Debug 返回取景框的内部状态，用于自检排障。
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func (f *Frame) Debug() string {
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f.mu.Lock()
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defer f.mu.Unlock()
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red := 0
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if f.bits != nil && len(f.buf) > 0 {
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for _, v := range unsafe.Slice((*uint32)(f.bits), len(f.buf)) {
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if v == 0xFFFF0000 {
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red++
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}
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}
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}
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return fmt.Sprintf("w=%d h=%d memDC=%v dib=%v bits=%v buf=%d 红像素=%d 区域=%+v ULW=%v err=%d",
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f.w, f.h, f.memDC != 0, f.dib != 0, f.bits != nil, len(f.buf), red, f.region, f.lastULW, f.lastErr)
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}
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// FrameDebug 返回取景框的内部状态，用于自检排障。
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func FrameDebug(hwnd syscall.Handle) string {
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framesMu.Lock()
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f := frames[hwnd]
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framesMu.Unlock()
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if f == nil {
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return "找不到取景框实例"
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}
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f.mu.Lock()
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defer f.mu.Unlock()
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red := 0
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if f.bits != nil && len(f.buf) > 0 {
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for _, v := range unsafe.Slice((*uint32)(f.bits), len(f.buf)) {
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if v == 0xFFFF0000 {
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red++
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}
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}
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}
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return fmt.Sprintf("w=%d h=%d memDC=%v dib=%v bits=%v buf=%d 红像素=%d",
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f.w, f.h, f.memDC != 0, f.dib != 0, f.bits != nil, len(f.buf), red)
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}
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// Close 销毁取景框。
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func (f *Frame) Close() {
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f.mu.Lock()
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hwnd := f.hwnd
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threadID := f.threadID
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f.hwnd = 0
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memDC := f.memDC
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dib := f.dib
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oldBmp := f.oldBmp
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f.memDC, f.dib, f.oldBmp = 0, 0, 0
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f.mu.Unlock()
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if hwnd != 0 {
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framesMu.Lock()
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delete(frames, syscall.Handle(hwnd))
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framesMu.Unlock()
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procDestroyWindow.Call(uintptr(hwnd))
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// 让消息循环退出，否则这条线程会一直挂着。
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if threadID != 0 {
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procPostThreadMessageW.Call(threadID, wmQuit, 0, 0)
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}
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}
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if memDC != 0 {
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if oldBmp != 0 {
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procSelectObject.Call(uintptr(memDC), uintptr(oldBmp))
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}
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if dib != 0 {
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procDeleteObject.Call(uintptr(dib))
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}
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procDeleteDC.Call(uintptr(memDC))
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}
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}
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// redraw 重新绘制取景框（运行在窗口自己的线程上）。
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func (f *Frame) redraw() {
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f.mu.Lock()
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r := f.region
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memDC := f.memDC
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hwnd := f.hwnd
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f.mu.Unlock()
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w, h := r.Width(), r.Height()
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if w <= 0 || h <= 0 || memDC == 0 || hwnd == 0 {
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return
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}
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f.ensureBitmap(w, h)
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// 画框：四边实心红条，中间留空（全透明）。
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const thickness = 2
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red := uint32(0xFFFF0000) // DIB 是 BGRA 顺序，A=255 R=255 G=0 B=0
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for i := range f.buf {
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f.buf[i] = 0
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}
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fillRect(f.buf, w, h, 0, 0, w, thickness, red)
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fillRect(f.buf, w, h, 0, h-thickness, w, h, red)
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fillRect(f.buf, w, h, 0, 0, thickness, h, red)
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fillRect(f.buf, w, h, w-thickness, 0, w, h, red)
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copy(unsafe.Slice((*uint32)(f.bits), len(f.buf)), f.buf)
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hdcScreen, _, _ := procGetDC.Call(0)
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if hdcScreen == 0 {
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return
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}
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defer procReleaseDC.Call(0, hdcScreen)
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blend := blendFunction{BlendOp: acSrcOver, SourceConstantAlpha: 255, AlphaFormat: acSrcAlpha}
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dst := winPoint{X: int32(r.Left), Y: int32(r.Top)}
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size := winSize{Cx: int32(w), Cy: int32(h)}
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src := winPoint{}
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ok, _, _ := procUpdateLayered.Call(
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uintptr(hwnd),
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hdcScreen,
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uintptr(unsafe.Pointer(&dst)),
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uintptr(unsafe.Pointer(&size)),
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uintptr(memDC),
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uintptr(unsafe.Pointer(&src)),
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0,
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uintptr(unsafe.Pointer(&blend)),
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ulwAlpha,
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)
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f.mu.Lock()
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f.lastULW = ok
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f.lastErr = lastErrorCode()
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f.mu.Unlock()
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// 保持在最上层，但不抢焦点。
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procSetWindowPos.Call(uintptr(hwnd), hwndTopMost, 0, 0, 0, 0, swpNoMove|swpNoSize|swpNoActivate)
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}
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// ensureBitmap 保证离屏位图尺寸与区域一致。
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func (f *Frame) ensureBitmap(w, h int) {
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f.mu.Lock()
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defer f.mu.Unlock()
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if f.dib != 0 && f.w == w && f.h == h {
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return
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}
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if f.dib != 0 {
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procSelectObject.Call(uintptr(f.memDC), uintptr(f.oldBmp))
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procDeleteObject.Call(uintptr(f.dib))
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f.dib = 0
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f.bits = nil
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}
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bmi := bitmapInfo{}
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bmi.Header.Size = uint32(unsafe.Sizeof(bitmapInfoHeader{}))
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bmi.Header.Width = int32(w)
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bmi.Header.Height = -int32(h) // 负数表示自上而下
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bmi.Header.Planes = 1
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bmi.Header.BitCount = 32
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bmi.Header.Compression = biRgb
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var bits unsafe.Pointer
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dib, _, _ := procCreateDIBSection.Call(
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uintptr(f.memDC),
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uintptr(unsafe.Pointer(&bmi)),
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dibRgbColors,
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uintptr(unsafe.Pointer(&bits)),
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0, 0,
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)
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if dib == 0 {
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return
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}
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old, _, _ := procSelectObject.Call(uintptr(f.memDC), dib)
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f.dib = syscall.Handle(dib)
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f.oldBmp = syscall.Handle(old)
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f.bits = bits
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f.w, f.h = w, h
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f.buf = make([]uint32, w*h)
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}
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|
||
// fillRect 在像素缓冲里填一块矩形。
|
||
func fillRect(buf []uint32, w, h, x0, y0, x1, y1 int, color uint32) {
|
||
if x0 < 0 {
|
||
x0 = 0
|
||
}
|
||
if y0 < 0 {
|
||
y0 = 0
|
||
}
|
||
if x1 > w {
|
||
x1 = w
|
||
}
|
||
if y1 > h {
|
||
y1 = h
|
||
}
|
||
for y := y0; y < y1; y++ {
|
||
row := y * w
|
||
for x := x0; x < x1; x++ {
|
||
buf[row+x] = color
|
||
}
|
||
}
|
||
}
|
||
|
||
// frameWndProc 是取景框的窗口过程。
|
||
func frameWndProc(hwnd uintptr, msg uint32, wparam, lparam uintptr) uintptr {
|
||
switch msg {
|
||
case wmNCHitTest:
|
||
// 鼠标穿透：让下层窗口收到点击。
|
||
return htTransparent
|
||
case wmEraseBkgnd:
|
||
// 不擦背景：整个窗口由分层位图定义。
|
||
return 1
|
||
case wmFrameRedraw:
|
||
framesMu.Lock()
|
||
f := frames[syscall.Handle(hwnd)]
|
||
framesMu.Unlock()
|
||
if f != nil {
|
||
f.redraw()
|
||
}
|
||
return 0
|
||
case wmDestroy:
|
||
return 0
|
||
}
|
||
r, _, _ := procDefWindowProcW.Call(hwnd, uintptr(msg), wparam, lparam)
|
||
return r
|
||
}
|
||
|
||
// lastErrorCode 取最近一次 Win32 调用的错误码。
|
||
func lastErrorCode() uintptr {
|
||
if err, ok := windows.GetLastError().(syscall.Errno); ok {
|
||
return uintptr(err)
|
||
}
|
||
return 0
|
||
}
|