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.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/Fl_Screen_Driver.H b/src/Fl_Screen_Driver.H
index 8ae19a816..511f892d2 100644
--- a/src/Fl_Screen_Driver.H
+++ b/src/Fl_Screen_Driver.H
@@ -150,8 +150,10 @@ public:
    A platform may also use its read_win_rectangle() implementation to capture
    window decorations (e.g., title bar). In that case, it is called by
    Fl_XXX_Window_Driver::capture_titlebar_and_borders().
+   
+   win is the window to capture from, or NULL to capture from the current offscreen
    */
-  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h) {return NULL;}
+  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h, Fl_Window *win) {return NULL;}
   static void write_image_inside(Fl_RGB_Image *to, Fl_RGB_Image *from, int to_x, int to_y);
   static Fl_RGB_Image *traverse_to_gl_subwindows(Fl_Group *g, int x, int y, int w, int h,
                                                  Fl_RGB_Image *full_img);