Add method to flash a given window

Author: MHendricks

casement/enums.py

@@ -0,0 +1,22 @@
+from enum import Enum
+
+
+class FlashTimes(Enum):
+    """Windows flags for casement.utils.flashWindow().
+
+    https://docs.microsoft.com/en-us/windows/desktop/api/winuser/ns-winuser-flashwinfo
+    """
+
+    "'Stop flashing. The system restores the window to its original state.'"
+    FLASHW_STOP = 0
+    "Flash the window caption."
+    FLASHW_CAPTION = 0x00000001
+    "Flash the taskbar button."
+    FLASHW_TRAY = 0x00000002
+    """Flash both the window caption and taskbar button. This is equivalent
+    to setting the ``FLASHW_CAPTION | FLASHW_TRAY flags``."""
+    FLASHW_ALL = 0x00000003
+    "Flash continuously, until the ``FLASHW_STOP`` flag is set."
+    FLASHW_TIMER = 0x00000004
+    "Flash continuously until the window comes to the foreground."
+    FLASHW_TIMERNOFG = 0x0000000C

casement/utils.py

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+import ctypes
+from .enums import FlashTimes
+
+
+def flash_window(hwnd, dw_flags=None, count=1, timeout=0):
+    """Flashes the application depending on the os.
+
+    On Windows this calls FlashWindowEx. See
+    https://msdn.microsoft.com/en-us/library/ms679348(v=vs.85).aspx for documentation.
+
+    Args:
+        hwnd (int or None): Flash this hwnd id.
+        dw_flags (casement.enums.FlashTimes): A enum value used to control the
+            flashing behavior. See
+            https://msdn.microsoft.com/en-us/library/ms679348(v=vs.85).aspx for more
+            details. Defaults to FLASHW_TIMERNOFG.
+        count (int): The number of times to flash the window. Defaults to 1.
+        timeout (int): The rate at which the window is to be flashed in
+            milliseconds. if zero is passed, the default cursor blink rate is used.
+    """
+
+    if dw_flags is None:
+        dw_flags = FlashTimes.FLASHW_TIMERNOFG
+
+    ctypes.windll.user32.FlashWindow(hwnd, int(dw_flags.value), count, timeout)