diff options
| -rw-r--r-- | FL/Fl_Screen_Driver.H | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/FL/Fl_Screen_Driver.H b/FL/Fl_Screen_Driver.H index 57a8bfee0..762358412 100644 --- a/FL/Fl_Screen_Driver.H +++ b/FL/Fl_Screen_Driver.H @@ -123,6 +123,21 @@ public: #if defined(FL_PORTING) # pragma message "FL_PORTING: implement code to read RGB data from screen" #endif + /* Both member functions read_image() and read_win_rectangle() support + the public function fl_read_image() which captures pixel data either from + the current window or from an offscreen buffer. + + A platform re-implements either read_image() or read_win_rectangle(). + In the 1st case and for capture from a window, the returned pixel array + also contains data from any embedded sub-window. + In the 2nd case and for capture from a window, only data from the current + window is collected, and read_image()'s default implementation captures + pixels from any subwindow. + + 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(). + */ virtual uchar *read_image(uchar *p, int x, int y, int w, int h, int alpha); virtual Fl_RGB_Image *read_win_rectangle(uchar *p, int X, int Y, int w, int h, int alpha) {return NULL;} static void write_image_inside(Fl_RGB_Image *to, Fl_RGB_Image *from, int to_x, int to_y); |