add option to capture all monitors on Windows

Tests/test_imagegrab.py

@@ -8,7 +8,11 @@ try:
 
     class TestImageGrab(PillowTestCase):
         def test_grab(self):
-            for im in [ImageGrab.grab(), ImageGrab.grab(include_layered_windows=True)]:
+            for im in [
+                ImageGrab.grab(),
+                ImageGrab.grab(include_layered_windows=True),
+                ImageGrab.grab(multimonitor=True),
+            ]:
                 self.assert_image(im, im.mode, im.size)
 
         def test_grabclipboard(self):

docs/reference/ImageGrab.rst

@@ -11,7 +11,7 @@ or the clipboard to a PIL image memory.
 
 .. versionadded:: 1.1.3
 
-.. py:function:: PIL.ImageGrab.grab(bbox=None, include_layered_windows=False)
+.. py:function:: PIL.ImageGrab.grab(bbox=None, include_layered_windows=False, multimonitor=False)
 
     Take a snapshot of the screen. The pixels inside the bounding box are
     returned as an "RGB" image on Windows or "RGBA" on macOS.
@@ -21,6 +21,7 @@ or the clipboard to a PIL image memory.
 
     :param bbox: What region to copy. Default is the entire screen.
     :param include_layered_windows: Includes layered windows. Windows OS only.
+    :param multimonitor: Capture all monitors. Windows OS only.
     :return: An image
 
 .. py:function:: PIL.ImageGrab.grabclipboard()

src/PIL/ImageGrab.py

@@ -29,7 +29,7 @@ else:
     raise ImportError("ImageGrab is macOS and Windows only")
 
 
-def grab(bbox=None, include_layered_windows=False):
+def grab(bbox=None, include_layered_windows=False, multimonitor=False):
     if sys.platform == "darwin":
         fh, filepath = tempfile.mkstemp(".png")
         os.close(fh)
@@ -37,8 +37,10 @@ def grab(bbox=None, include_layered_windows=False):
         im = Image.open(filepath)
         im.load()
         os.unlink(filepath)
+        if bbox:
+            im = im.crop(bbox)
     else:
-        size, data = grabber(include_layered_windows)
+        offset, size, data = grabber(include_layered_windows, multimonitor)
         im = Image.frombytes(
             "RGB",
             size,
@@ -49,8 +51,10 @@ def grab(bbox=None, include_layered_windows=False):
             (size[0] * 3 + 3) & -4,
             -1,
         )
-    if bbox:
-        im = im.crop(bbox)
+        if bbox:
+            x0, y0 = offset
+            left, top, right, bottom = bbox
+            im = im.crop((left - x0, top - y0, right - x0, bottom - y0))
     return im
 
 

src/display.c

@@ -322,15 +322,15 @@ PyImaging_DisplayModeWin32(PyObject* self, PyObject* args)
 PyObject*
 PyImaging_GrabScreenWin32(PyObject* self, PyObject* args)
 {
-    int width, height;
-    int includeLayeredWindows = 0;
+    int x = 0, y = 0, width, height;
+    int includeLayeredWindows = 0, multimonitor = 0;
     HBITMAP bitmap;
     BITMAPCOREHEADER core;
     HDC screen, screen_copy;
     DWORD rop;
     PyObject* buffer;
 
-    if (!PyArg_ParseTuple(args, "|i", &includeLayeredWindows))
+    if (!PyArg_ParseTuple(args, "|ii", &includeLayeredWindows, &multimonitor))
         return NULL;
 
     /* step 1: create a memory DC large enough to hold the
@@ -339,8 +339,15 @@ PyImaging_GrabScreenWin32(PyObject* self, PyObject* args)
     screen = CreateDC("DISPLAY", NULL, NULL, NULL);
     screen_copy = CreateCompatibleDC(screen);
 
-    width = GetDeviceCaps(screen, HORZRES);
-    height = GetDeviceCaps(screen, VERTRES);
+    if (multimonitor) {
+        x = GetSystemMetrics(SM_XVIRTUALSCREEN);
+        y = GetSystemMetrics(SM_YVIRTUALSCREEN);
+        width = GetSystemMetrics(SM_CXVIRTUALSCREEN);
+        height = GetSystemMetrics(SM_CYVIRTUALSCREEN);
+    } else {
+        width = GetSystemMetrics(SM_CXSCREEN);
+        height = GetSystemMetrics(SM_CYSCREEN);
+    }
 
     bitmap = CreateCompatibleBitmap(screen, width, height);
     if (!bitmap)
@@ -354,7 +361,7 @@ PyImaging_GrabScreenWin32(PyObject* self, PyObject* args)
     rop = SRCCOPY;
     if (includeLayeredWindows)
         rop |= CAPTUREBLT;
-    if (!BitBlt(screen_copy, 0, 0, width, height, screen, 0, 0, rop))
+    if (!BitBlt(screen_copy, 0, 0, width, height, screen, x, y, rop))
         goto error;
 
     /* step 3: extract bits from bitmap */
@@ -376,7 +383,7 @@ PyImaging_GrabScreenWin32(PyObject* self, PyObject* args)
     DeleteDC(screen_copy);
     DeleteDC(screen);
 
-    return Py_BuildValue("(ii)N", width, height, buffer);
+    return Py_BuildValue("(ii)(ii)N", x, y, width, height, buffer);
 
 error:
     PyErr_SetString(PyExc_IOError, "screen grab failed");