WIN32: fixed printing of window borders and title bar on Windows 10

by Fl_Paged_Device::print_window(). The GetWindowRect()
function gives inadequate results on Windows 10. DwmGetWindowAttributes()
from dwmapi.dll gives adequate results. This new function is dynamically
loaded at run-time, when dwmapi.dll is available.
On Windows XP, dwmapi.dll is not available.
On Windows 7, DwmGetWindowAttributes() returns with error, so GetWindowRect()
is used.
On Windows 10, DwmGetWindowAttributes() computes the correct window full rectangle.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10921 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 25 insertions, 2 deletions

diff --git a/src/Fl_win32.cxx b/src/Fl_win32.cxx
index 5823294a6..c14055336 100644
--- a/src/Fl_win32.cxx
+++ b/src/Fl_win32.cxx
@@ -104,6 +104,10 @@ typedef int (WINAPI* fl_wsk_select_f)(int, fd_set*, fd_set*, fd_set*, const stru
 typedef int (WINAPI* fl_wsk_fd_is_set_f)(SOCKET, fd_set *);
 
 static HMODULE s_wsock_mod = 0;
+static HMODULE dwmapi_dll = LoadLibrary("dwmapi.dll");
+typedef HRESULT (WINAPI* DwmGetWindowAttribute_type)(HWND hwnd, DWORD dwAttribute, PVOID pvAttribute, DWORD cbAttribute);
+static DwmGetWindowAttribute_type DwmGetWindowAttribute = 0;
+static const DWORD DWMA_EXTENDED_FRAME_BOUNDS = 9;
 static fl_wsk_select_f s_wsock_select = 0;
 static fl_wsk_fd_is_set_f fl_wsk_fd_is_set = 0;
 
@@ -1618,7 +1622,19 @@ static int fake_X_wm_style(const Fl_Window* w,int &X,int &Y, int &bt,int &bx, in
 }
 
 int Fl_X::fake_X_wm(const Fl_Window* w,int &X,int &Y, int &bt,int &bx, int &by) {
-  return fake_X_wm_style(w, X, Y, bt, bx, by, 0, 0, w->maxw, w->minw, w->maxh, w->minh, w->size_range_set);
+  int val = fake_X_wm_style(w, X, Y, bt, bx, by, 0, 0, w->maxw, w->minw, w->maxh, w->minh, w->size_range_set);
+  if (dwmapi_dll) {
+    RECT r;
+    if (!DwmGetWindowAttribute) DwmGetWindowAttribute = (DwmGetWindowAttribute_type)GetProcAddress(dwmapi_dll, "DwmGetWindowAttribute");
+    if (DwmGetWindowAttribute) {
+      if ( DwmGetWindowAttribute(fl_xid(w), DWMA_EXTENDED_FRAME_BOUNDS, &r, sizeof(RECT)) == S_OK ) {
+        bx = (r.right - r.left - w->w())/2;
+        by = bx;
+        bt = r.bottom - r.top - w->h() - 2*by;
+      }
+    }
+  }
+  return val;
 }
 
 ////////////////////////////////////////////////////////////////
@@ -2730,7 +2746,14 @@ void Fl_Paged_Device::print_window(Fl_Window *win, int x_offset, int y_offset)
   HDC save_gc = fl_gc;
   fl_gc = GetDC(NULL); // get the screen device context
   // capture the 4 window sides from screen
-  RECT r; GetWindowRect(fl_window, &r);
+  RECT r;
+  HRESULT res = S_OK + 1;
+  if (DwmGetWindowAttribute) {
+    res = DwmGetWindowAttribute(fl_window, DWMA_EXTENDED_FRAME_BOUNDS, &r, sizeof(RECT));
+  }
+  if (res != S_OK) {
+    GetWindowRect(fl_window, &r);
+  }
   Window save_win = fl_window;
   fl_window = NULL; // force use of read_win_rectangle() by fl_read_image()
   uchar *top_image = fl_read_image(NULL, r.left, r.top, ww, bt + by);