Add one argument to Fl_Screen_Driver::read_win_rectangle()

The new argument gives the window to be captured, or NULL to indicate capture
from the current offscreen.
Calling this function becomes easier because less dependent on global variables.

3 files changed, 15 insertions, 20 deletions

diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.H b/src/drivers/X11/Fl_X11_Screen_Driver.H
index b348dfc3e..7b14d4375 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.H
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.H
@@ -95,7 +95,7 @@ public:
   virtual int compose(int &del);
   virtual void compose_reset();
   virtual int text_display_can_leak();
-  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h);
+  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h, Fl_Window *win);
   virtual int get_mouse(int &x, int &y);
   virtual void enable_im();
   virtual void disable_im();
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.cxx b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
index 43482bb1a..ed703f78d 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
@@ -745,7 +745,7 @@ extern "C" {
   }
 }
 
-Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int h)
+Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int h, Fl_Window *win)
 {
   XImage	*image;		// Captured image
   int		i, maxindex;	// Looping vars
@@ -772,12 +772,14 @@ Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int
   int allow_outside = w < 0;    // negative w allows negative X or Y, that is, window frame
   if (w < 0) w = - w;
   
-  float s = allow_outside ? Fl::screen_driver()->scale(Fl_Window::current()->screen_num()) : Fl_Surface_Device::surface()->driver()->scale();
+  Window xid = (win && !allow_outside ? fl_xid(win) : fl_window);
+
+  float s = allow_outside ? Fl::screen_driver()->scale(win->screen_num()) : Fl_Surface_Device::surface()->driver()->scale();
   int ws = w * s, hs = h * s, Xs = X*s, Ys = Y*s;
   
 #  ifdef __sgi
   if (XReadDisplayQueryExtension(fl_display, &i, &i)) {
-    image = XReadDisplay(fl_display, fl_window, Xs, Ys, ws, hs, 0, NULL);
+    image = XReadDisplay(fl_display, xid, Xs, Ys, ws, hs, 0, NULL);
   } else
 #  else
     image = 0;
@@ -788,11 +790,8 @@ Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int
     int dx, dy, sx, sy, sw, sh;
     Window child_win;
     
-    Fl_Window *win;
-    if (allow_outside) win = Fl_Window::current();
-    else win = fl_find(fl_window);
     if (win) {
-      XTranslateCoordinates(fl_display, fl_window,
+      XTranslateCoordinates(fl_display, xid,
                             RootWindow(fl_display, fl_screen), Xs, Ys, &dx, &dy, &child_win);
       // screen dimensions
       Fl::screen_xywh(sx, sy, sw, sh, Fl_Window_Driver::driver(win)->screen_num());
@@ -811,7 +810,7 @@ Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int
       // however, if the window is obscured etc. the function will still fail. Make sure we
       // catch the error and continue, otherwise an exception will be thrown.
       XErrorHandler old_handler = XSetErrorHandler(xgetimageerrhandler);
-      image = XGetImage(fl_display, fl_window, Xs, Ys, ws, hs, AllPlanes, ZPixmap);
+      image = XGetImage(fl_display, xid, Xs, Ys, ws, hs, AllPlanes, ZPixmap);
       XSetErrorHandler(old_handler);
     } else {
       // image is crossing borders, determine visible region
@@ -831,7 +830,7 @@ Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int
       }
       
       XErrorHandler old_handler = XSetErrorHandler(xgetimageerrhandler);
-      XImage *subimg = XGetSubImage(fl_display, fl_window, Xs + noffx, Ys + noffy,
+      XImage *subimg = XGetSubImage(fl_display, xid, Xs + noffx, Ys + noffy,
                                     nw, nh, AllPlanes, ZPixmap, image, noffx, noffy);
       XSetErrorHandler(old_handler);
       if (!subimg) {
diff --git a/src/drivers/X11/Fl_X11_Window_Driver.cxx b/src/drivers/X11/Fl_X11_Window_Driver.cxx
index e2ed5d073..1de2e5297 100644
--- a/src/drivers/X11/Fl_X11_Window_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Window_Driver.cxx
@@ -392,16 +392,14 @@ void Fl_X11_Window_Driver::free_icons() {
  
  This function exploits a feature of Fl_X11_Screen_Driver::read_win_rectangle() which,
  when called with negative 3rd argument, captures the window decoration.
- Other requirements to capture the window decoration:
- - fl_window is the parent window of the top window
- - Fl_Window::current() is the top window
+ Other requirement to capture the window decoration:
+   fl_window is the parent window of the top window
  */
 void Fl_X11_Window_Driver::capture_titlebar_and_borders(Fl_RGB_Image*& top, Fl_RGB_Image*& left, Fl_RGB_Image*& bottom, Fl_RGB_Image*& right)
 {
   top = left = bottom = right = NULL;
   if (pWindow->decorated_h() == h()) return;
   Window from = fl_window;
-  Fl_Window *oldcurrent = Fl_Window::current();
   Window root, parent, *children, child_win, xid = fl_xid(pWindow);
   unsigned n = 0;
   int do_it;
@@ -414,25 +412,23 @@ void Fl_X11_Window_Driver::capture_titlebar_and_borders(Fl_RGB_Image*& top, Fl_R
   float s = Fl::screen_driver()->scale(screen_num());
   htop /= s; wsides /= s;
   fl_window = parent;
-  current(pWindow);
   if (htop) {
-    top = Fl::screen_driver()->read_win_rectangle(0, 0, - (w() + 2 * wsides), htop);
+    top = Fl::screen_driver()->read_win_rectangle(0, 0, - (w() + 2 * wsides), htop, pWindow);
     if (top) top->scale(w() + 2 * wsides, htop, 0, 1);
   }
   if (wsides) {
-    left = Fl::screen_driver()->read_win_rectangle(0, htop, -wsides, h());
+    left = Fl::screen_driver()->read_win_rectangle(0, htop, -wsides, h(), pWindow);
     if (left) {
       left->scale(wsides, h(), 0, 1);
     }
-    right = Fl::screen_driver()->read_win_rectangle(w() + wsides, htop, -wsides, h());
+    right = Fl::screen_driver()->read_win_rectangle(w() + wsides, htop, -wsides, h(), pWindow);
     if (right) {
       right->scale(wsides, h(), 0, 1);
     }
-    bottom = Fl::screen_driver()->read_win_rectangle(0, htop + h(), -(w() + 2*wsides), hbottom);
+    bottom = Fl::screen_driver()->read_win_rectangle(0, htop + h(), -(w() + 2*wsides), hbottom, pWindow);
     if (bottom) {
       bottom->scale(w() + 2*wsides, wsides, 0, 1);
     }  }
-  current(oldcurrent);
   fl_window = from;
 }