7 files changed, 48 insertions, 1 deletions
diff --git a/src/Fl_Graphics_Driver.cxx b/src/Fl_Graphics_Driver.cxx
index ab45bcf6e..0429eac0c 100644
--- a/src/Fl_Graphics_Driver.cxx
+++ b/src/Fl_Graphics_Driver.cxx
@@ -19,6 +19,7 @@
 #include <FL/Fl.H>
 #include "config_lib.h"
 #include <FL/Fl_Graphics_Driver.H>
+#include <FL/Fl_Screen_Driver.H>
 #include <FL/Fl_Image.H>
 #include <FL/fl_draw.H>
 
@@ -74,7 +75,22 @@ int Fl_Graphics_Driver::draw_scaled(Fl_Image *img, int X, int Y, int W, int H) {
 /** see fl_copy_offscreen() */
 void Fl_Graphics_Driver::copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy)
 {
-  // nothing to do, reimplement in driver if needed
+  // This platform-independent version is used when the current graphics driver is PostScript.
+  // It requires that pixmap has been created by fl_create_offscreen().
+  int px_width = w, px_height = h;
+  Fl::screen_driver()->offscreen_size(pixmap, px_width, px_height);
+  int px = srcx, py = srcy, pw = w, ph = h;
+  if (px < 0) {px = 0; pw += srcx; x -= srcx;}
+  if (py < 0) {py = 0; ph += srcy; y -= srcy;}
+  if (px + pw > px_width) {pw = px_width - px;}
+  if (py + ph > px_height) {ph = px_height - py;}
+  fl_begin_offscreen(pixmap);
+  uchar *img = fl_read_image(NULL, px, py, pw, ph, 0);
+  fl_end_offscreen();
+  if (img) {
+    fl_draw_image(img, x, y, pw, ph, 3, 0);
+    delete[] img;
+  }
 }
 
 /** see fl_set_spot() */
diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
index 29ae7570e..d825e6580 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
@@ -94,6 +94,8 @@ public:
   virtual void enable_im();
   virtual void disable_im();
   virtual void open_display();
+  // --- compute dimensions of an Fl_Offscreen
+  virtual void offscreen_size(Fl_Offscreen o, int &width, int &height);
 };
 
 
diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
index 71a64292d..8856f8cfe 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
@@ -400,6 +400,12 @@ int Fl_Cocoa_Screen_Driver::input_widget_handle_key(int key, unsigned mods, unsi
   return -1;
 }
 
+void Fl_Cocoa_Screen_Driver::offscreen_size(Fl_Offscreen off, int &width, int &height)
+{
+  width = CGBitmapContextGetWidth(off);
+  height = CGBitmapContextGetHeight(off);
+}
+
 //
 // End of "$Id$".
 //
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
index 80529138f..5c016ce73 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
+++ b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
@@ -77,6 +77,7 @@ public:
   virtual void enable_im();
   virtual void disable_im();
   virtual void open_display();
+  virtual void offscreen_size(Fl_Offscreen off, int &width, int &height);
 };
 
 
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
index 6c3e99dca..2b1f65e0a 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
+++ b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
@@ -638,6 +638,15 @@ float Fl_WinAPI_Screen_Driver::desktop_scaling_factor() {
   return scaling;
 }
 
+void Fl_WinAPI_Screen_Driver::offscreen_size(Fl_Offscreen off, int &width, int &height)
+{
+  BITMAP bitmap;
+  if ( GetObject(off, sizeof(BITMAP), &bitmap) ) {
+    width = bitmap.bmWidth;
+    height = bitmap.bmHeight;
+  }
+}
+
 //
 // End of "$Id$".
 //
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.H b/src/drivers/X11/Fl_X11_Screen_Driver.H
index 8f3638718..2be26a1ee 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.H
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.H
@@ -87,6 +87,8 @@ public:
   virtual void disable_im();
   virtual void open_display();
   virtual void close_display();
+  // --- compute dimensions of an Fl_Offscreen
+  virtual void offscreen_size(Fl_Offscreen o, int &width, int &height);
 };
 
 
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.cxx b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
index d28859949..7095ea948 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
@@ -1143,6 +1143,17 @@ Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(uchar *p, int X, int Y, i
   return rgb;
 }
 
+
+void Fl_X11_Screen_Driver::offscreen_size(Fl_Offscreen off, int &width, int &height)
+{
+  int px, py;
+  unsigned w, h, b, d;
+  Window root;
+  XGetGeometry(fl_display, off, &root, &px, &py, &w, &h, &b, &d);
+  width = (int)w;
+  height = (int)h;
+}
+
 //
 // End of "$Id$".
 //