[gimp] plug-ins: put the initial foreground window back after a screenshot.

[Jehan Pagès <jehanp src gnome org>]

commit 382d6c8ad5b66719cc906501e0d3f92c7b55feef
Author: Jehan <jehan girinstud io>
Date:   Tue May 15 23:32:55 2018 +0200

    plug-ins: put the initial foreground window back after a screenshot.
    
    This was lost in commit 966843564d. It's not a big deal since this code
    path would only happen when the capture using magnification API fails,
    yet we may as well make it perfect.
    Also taking the opportunity to change the return type to gboolean for
    the various capture functions (though it is technically the same,
    semantically we were returning success boolean).
    And removing a comment which had been duplicated and left at a the wrong
    place.

 plug-ins/screenshot/screenshot-win32.c |   57 ++++++++++++++++---------------
 1 files changed, 29 insertions(+), 28 deletions(-)
---
diff --git a/plug-ins/screenshot/screenshot-win32.c b/plug-ins/screenshot/screenshot-win32.c
index 201926a..b02cfe7 100644
--- a/plug-ins/screenshot/screenshot-win32.c
+++ b/plug-ins/screenshot/screenshot-win32.c
@@ -85,22 +85,22 @@ static gint32    *image_id;
 static void sendBMPToGimp                      (HBITMAP         hBMP,
                                                 HDC             hDC,
                                                 RECT            rect);
-static void doWindowCapture                    (void);
-static int  doCapture                          (HWND            selectedHwnd);
-static BOOL isWindowIsAboveCaptureRegion       (HWND            hwndWindow,
-                                                RECT            rectCapture);
-static int  doCaptureMagnificationAPI          (HWND            selectedHwnd,
-                                                RECT            rect);
-static void doCaptureMagnificationAPI_callback (HWND            hwnd,
-                                                void           *srcdata,
-                                                MAGIMAGEHEADER  srcheader,
-                                                void           *destdata,
-                                                MAGIMAGEHEADER  destheader,
-                                                RECT            unclipped,
-                                                RECT            clipped,
-                                                HRGN            dirty);
-static int  doCaptureBitBlt                    (HWND            selectedHwnd,
-                                                RECT            rect);
+static void     doWindowCapture                    (void);
+static gboolean doCapture                          (HWND            selectedHwnd);
+static BOOL     isWindowIsAboveCaptureRegion       (HWND            hwndWindow,
+                                                    RECT            rectCapture);
+static gboolean doCaptureMagnificationAPI          (HWND            selectedHwnd,
+                                                    RECT            rect);
+static void     doCaptureMagnificationAPI_callback (HWND            hwnd,
+                                                    void           *srcdata,
+                                                    MAGIMAGEHEADER  srcheader,
+                                                    void           *destdata,
+                                                    MAGIMAGEHEADER  destheader,
+                                                    RECT            unclipped,
+                                                    RECT            clipped,
+                                                    HRGN            dirty);
+static gboolean doCaptureBitBlt                    (HWND            selectedHwnd,
+                                                    RECT            rect);
 
 BOOL CALLBACK dialogProc (HWND, UINT, WPARAM, LPARAM);
 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
@@ -478,7 +478,7 @@ primDoWindowCapture (HDC  hdcWindow,
  * handle to be captured or the NULL value
  * to specify the root window.
  */
-static int
+static gboolean
 doCapture (HWND selectedHwnd)
 {
   RECT rect;
@@ -499,22 +499,23 @@ doCapture (HWND selectedHwnd)
       *  This will solve the bug https://bugzilla.gnome.org/show_bug.cgi?id=793722/
       */
 
-      if (!doCaptureMagnificationAPI (selectedHwnd, rect))
+      if (! doCaptureMagnificationAPI (selectedHwnd, rect))
         {
           /* If for some reason this capture method failed then
           *  capture the window with the normal method:
           */
+          HWND     previousHwnd = GetForegroundWindow ();
+          gboolean success;
 
-          /* Get the device context for the whole screen
-          * even if we just want to capture a window.
-          * this will allow to capture applications that
-          * don't render to their main window's device
-          * context (e.g. browsers).
-          */
           SetForegroundWindow (selectedHwnd);
           BringWindowToTop (selectedHwnd);
 
-          return doCaptureBitBlt (selectedHwnd, rect);
+          success = doCaptureBitBlt (selectedHwnd, rect);
+
+          if (previousHwnd)
+            SetForegroundWindow (previousHwnd);
+
+          return success;
         }
 
       return TRUE;
@@ -535,15 +536,15 @@ doCapture (HWND selectedHwnd)
   return FALSE; /* we should never get here... */
 }
 
-static int
+static gboolean
 doCaptureBitBlt (HWND selectedHwnd,
                  RECT rect)
 {
 
   HDC     hdcSrc;
   HDC     hdcCompat;
-  HWND    oldForeground;
   HBITMAP hbm;
+
   /* Get the device context for the whole screen
    * even if we just want to capture a window.
    * this will allow to capture applications that
@@ -651,7 +652,7 @@ doCaptureMagnificationAPI_MonitorEnumProc (HMONITOR hMonitor,
   return TRUE;
 }
 
-static BOOL
+static gboolean
 doCaptureMagnificationAPI (HWND selectedHwnd,
                            RECT rect)
 {