feat: refactor screenshot capture implementation and update UI reload labels

backend/utils/screenshot_windows.go

@@ -8,32 +8,18 @@ import (
 	"image/png"
 	"syscall"
 	"unsafe"
+
+	"github.com/kbinani/screenshot"
 )
 
 var (
-	user32   = syscall.NewLazyDLL("user32.dll")
-	gdi32    = syscall.NewLazyDLL("gdi32.dll")
-	dwmapi   = syscall.NewLazyDLL("dwmapi.dll")
+	user32 = syscall.NewLazyDLL("user32.dll")
+	dwmapi = syscall.NewLazyDLL("dwmapi.dll")
 
 	// user32 functions
-	getForegroundWindow  = user32.NewProc("GetForegroundWindow")
-	getWindowRect        = user32.NewProc("GetWindowRect")
-	getClientRect        = user32.NewProc("GetClientRect")
-	getDC                = user32.NewProc("GetDC")
-	releaseDC            = user32.NewProc("ReleaseDC")
-	findWindowW          = user32.NewProc("FindWindowW")
-	getWindowDC          = user32.NewProc("GetWindowDC")
-	printWindow          = user32.NewProc("PrintWindow")
-	clientToScreen       = user32.NewProc("ClientToScreen")
-
-	// gdi32 functions
-	createCompatibleDC     = gdi32.NewProc("CreateCompatibleDC")
-	createCompatibleBitmap = gdi32.NewProc("CreateCompatibleBitmap")
-	selectObject           = gdi32.NewProc("SelectObject")
-	bitBlt                 = gdi32.NewProc("BitBlt")
-	deleteDC               = gdi32.NewProc("DeleteDC")
-	deleteObject           = gdi32.NewProc("DeleteObject")
-	getDIBits              = gdi32.NewProc("GetDIBits")
+	getForegroundWindow = user32.NewProc("GetForegroundWindow")
+	getWindowRect       = user32.NewProc("GetWindowRect")
+	findWindowW         = user32.NewProc("FindWindowW")
 
 	// dwmapi functions
 	dwmGetWindowAttribute = dwmapi.NewProc("DwmGetWindowAttribute")
@@ -47,39 +33,7 @@ type RECT struct {
 	Bottom int32
 }
 
-// POINT structure for Windows API
-type POINT struct {
-	X int32
-	Y int32
-}
-
-// BITMAPINFOHEADER structure
-type BITMAPINFOHEADER struct {
-	BiSize          uint32
-	BiWidth         int32
-	BiHeight        int32
-	BiPlanes        uint16
-	BiBitCount      uint16
-	BiCompression   uint32
-	BiSizeImage     uint32
-	BiXPelsPerMeter int32
-	BiYPelsPerMeter int32
-	BiClrUsed       uint32
-	BiClrImportant  uint32
-}
-
-// BITMAPINFO structure
-type BITMAPINFO struct {
-	BmiHeader BITMAPINFOHEADER
-	BmiColors [1]uint32
-}
-
 const (
-	SRCCOPY             = 0x00CC0020
-	DIB_RGB_COLORS      = 0
-	BI_RGB              = 0
-	PW_CLIENTONLY       = 1
-	PW_RENDERFULLCONTENT = 2
 	DWMWA_EXTENDED_FRAME_BOUNDS = 9
 )
 
@@ -113,82 +67,10 @@ func CaptureWindowByHandle(hwnd uintptr) (*image.RGBA, error) {
 		return nil, fmt.Errorf("invalid window dimensions: %dx%d", width, height)
 	}
 
-	// Get window DC
-	hdcWindow, _, err := getWindowDC.Call(hwnd)
-	if hdcWindow == 0 {
-		return nil, fmt.Errorf("GetWindowDC failed: %v", err)
-	}
-	defer releaseDC.Call(hwnd, hdcWindow)
-
-	// Create compatible DC
-	hdcMem, _, err := createCompatibleDC.Call(hdcWindow)
-	if hdcMem == 0 {
-		return nil, fmt.Errorf("CreateCompatibleDC failed: %v", err)
-	}
-	defer deleteDC.Call(hdcMem)
-
-	// Create compatible bitmap
-	hBitmap, _, err := createCompatibleBitmap.Call(hdcWindow, uintptr(width), uintptr(height))
-	if hBitmap == 0 {
-		return nil, fmt.Errorf("CreateCompatibleBitmap failed: %v", err)
-	}
-	defer deleteObject.Call(hBitmap)
-
-	// Select bitmap into DC
-	oldBitmap, _, _ := selectObject.Call(hdcMem, hBitmap)
-	defer selectObject.Call(hdcMem, oldBitmap)
-
-	// Try PrintWindow first (works better with layered/composited windows)
-	ret, _, _ = printWindow.Call(hwnd, hdcMem, PW_RENDERFULLCONTENT)
-	if ret == 0 {
-		// Fallback to BitBlt
-		ret, _, err = bitBlt.Call(
-			hdcMem, 0, 0, uintptr(width), uintptr(height),
-			hdcWindow, 0, 0,
-			SRCCOPY,
-		)
-		if ret == 0 {
-			return nil, fmt.Errorf("BitBlt failed: %v", err)
-		}
-	}
-
-	// Prepare BITMAPINFO
-	bmi := BITMAPINFO{
-		BmiHeader: BITMAPINFOHEADER{
-			BiSize:        uint32(unsafe.Sizeof(BITMAPINFOHEADER{})),
-			BiWidth:       int32(width),
-			BiHeight:      -int32(height), // Negative for top-down DIB
-			BiPlanes:      1,
-			BiBitCount:    32,
-			BiCompression: BI_RGB,
-		},
-	}
-
-	// Allocate buffer for pixel data
-	pixelDataSize := width * height * 4
-	pixelData := make([]byte, pixelDataSize)
-
-	// Get the bitmap bits
-	ret, _, err = getDIBits.Call(
-		hdcMem,
-		hBitmap,
-		0,
-		uintptr(height),
-		uintptr(unsafe.Pointer(&pixelData[0])),
-		uintptr(unsafe.Pointer(&bmi)),
-		DIB_RGB_COLORS,
-	)
-	if ret == 0 {
-		return nil, fmt.Errorf("GetDIBits failed: %v", err)
-	}
-
-	// Convert BGRA to RGBA
-	img := image.NewRGBA(image.Rect(0, 0, width, height))
-	for i := 0; i < len(pixelData); i += 4 {
-		img.Pix[i+0] = pixelData[i+2] // R <- B
-		img.Pix[i+1] = pixelData[i+1] // G <- G
-		img.Pix[i+2] = pixelData[i+0] // B <- R
-		img.Pix[i+3] = pixelData[i+3] // A <- A
+	// Using kbinani/screenshot to capture the rectangle on screen
+	img, err := screenshot.CaptureRect(image.Rect(int(rect.Left), int(rect.Top), int(rect.Right), int(rect.Bottom)))
+	if err != nil {
+		return nil, fmt.Errorf("screenshot.CaptureRect failed: %v", err)
 	}
 
 	return img, nil