Fix fl_read_image() under MacOS platform when GUI is rescaled.

This commit also simplifies the platform-dependent support of fl_read_image():
only Fl_XXX_Screen_Driver::read_win_rectangle() contains platform-specific
code to capture pixels from the current window or from an offscreen buffer.
Platform-independent function Fl_Screen_Driver::traverse_to_gl_subwindows()
captures subwindows that intersect with the area fl_read_image() targets.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12653 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

13 files changed, 113 insertions, 93 deletions

diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
index 12d93b9e8..077416823 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.H
@@ -4,7 +4,7 @@
 // Definition of Apple Cocoa Screen interface
 // for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2017 by Bill Spitzak and others.
+// Copyright 2010-2018 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -40,6 +40,7 @@
 
 class Fl_Window;
 class Fl_Input;
+class Fl_RGB_Image;
 
 class FL_EXPORT Fl_Cocoa_Screen_Driver : public Fl_Screen_Driver 
 {
@@ -87,7 +88,6 @@ public:
   int insertion_point_location(int *px, int *py, int *pheight);
   virtual int dnd(int use_selection);
   virtual int compose(int &del);
-  virtual uchar *read_image(uchar *p, int x, int y, int w, int h, int alpha);
   virtual int input_widget_handle_key(int key, unsigned mods, unsigned shift, Fl_Input *input);
   virtual int get_mouse(int &x, int &y);
   virtual void enable_im();
@@ -100,6 +100,7 @@ public:
   virtual APP_SCALING_CAPABILITY rescalable() { return SYSTEMWIDE_APP_SCALING; }
   virtual float scale(int n) {return scale_;}
   virtual void scale(int n, float f) { scale_ = f;}
+  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h);
   virtual int run_also_windowless();
   virtual int wait_also_windowless(double delay);
 private:
diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
index 213995126..d46879932 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
@@ -256,70 +256,6 @@ int Fl_Cocoa_Screen_Driver::compose(int &del) {
   return 1;
 }
 
-uchar *                                       // O - Pixel buffer or NULL if failed
-Fl_Cocoa_Screen_Driver::read_image(uchar *p,	// I - Pixel buffer or NULL to allocate
-                                   int   x,		// I - Left position
-                                   int   y,		// I - Top position
-                                   int   w,		// I - Width of area to read
-                                   int   h,		// I - Height of area to read
-                                   int   alpha)// I - Alpha value for image (0 for none)
-{
-  uchar *base;
-  int rowBytes, delta;
-  float s = 1;
-  int ori_w = w, ori_h = h;
-  if (fl_window == NULL) { // reading from an offscreen buffer
-    CGContextRef src = (CGContextRef)Fl_Surface_Device::surface()->driver()->gc();  // get bitmap context
-    base = (uchar *)CGBitmapContextGetData(src);  // get data
-    if(!base) return NULL;
-    int sw = CGBitmapContextGetWidth(src);
-    int sh = CGBitmapContextGetHeight(src);
-    if( (sw - x < w) || (sh - y < h) )  return NULL;
-    rowBytes = CGBitmapContextGetBytesPerRow(src);
-    delta = CGBitmapContextGetBitsPerPixel(src)/8;
-    Fl_Image_Surface *imgs = (Fl_Image_Surface*)Fl_Surface_Device::surface();
-    int fltk_w, fltk_h;
-    imgs->printable_rect(&fltk_w, &fltk_h);
-    s = sw / float(fltk_w);
-    x *= s; y *= s; w *= s; h *= s;
-    if (x + w > sw) w = sw - x;
-    if (y + h > sh) h = sh - y;
-  }
-  else { // reading from current window
-    Fl_Cocoa_Window_Driver *d = Fl_Cocoa_Window_Driver::driver(Fl_Window::current());
-    base = d->bitmap_from_window_rect(x,y,w,h,&delta);
-    if (!base) return NULL;
-    rowBytes = delta*w;
-    x = y = 0;
-  }
-  // Allocate the image data array as needed...
-  int d = alpha ? 4 : 3;
-  if (!p) p = new uchar[w * h * d];
-  // Initialize the default colors/alpha in the whole image...
-  memset(p, alpha, w * h * d);
-  // Copy the image from the off-screen buffer to the memory buffer.
-  int idx, idy;	// Current X & Y in image
-  uchar *pdst, *psrc;
-  for (idy = y, pdst = p; idy < h + y; idy ++) {
-    for (idx = 0, psrc = base + idy * rowBytes + x * delta; idx < w; idx ++, psrc += delta, pdst += d) {
-      pdst[0] = psrc[0];  // R
-      pdst[1] = psrc[1];  // G
-      pdst[2] = psrc[2];  // B
-    }
-  }
-  if (fl_window != NULL) delete[] base;
-  if (s != 1) {
-    Fl_RGB_Image *rgb = new Fl_RGB_Image(p, w, h, alpha ? 4 : 3);
-    rgb->alloc_array = 1;
-    Fl_RGB_Image *rgb2 = (Fl_RGB_Image*)rgb->copy(ori_w, ori_h);
-    rgb2->alloc_array = 0;
-    delete rgb;
-    p = (uchar*)rgb2->array;
-    delete rgb2;
-  }
-  return p;
-}
-
 
 int Fl_Cocoa_Screen_Driver::input_widget_handle_key(int key, unsigned mods, unsigned shift, Fl_Input *input)
 {
@@ -401,6 +337,67 @@ void Fl_Cocoa_Screen_Driver::offscreen_size(Fl_Offscreen off, int &width, int &h
   height = CGBitmapContextGetHeight(off);
 }
 
+Fl_RGB_Image *Fl_Cocoa_Screen_Driver::read_win_rectangle(int X, int Y, int w, int h)
+{
+  int bpp, bpr, depth = 4;
+  uchar *base, *p;
+  if (!fl_window) { // read from offscreen buffer
+    float s = 1;
+    CGContextRef src = (CGContextRef)Fl_Surface_Device::surface()->driver()->gc();  // get bitmap context
+    base = (uchar *)CGBitmapContextGetData(src);  // get data
+    if(!base) return NULL;
+    int sw = CGBitmapContextGetWidth(src);
+    int sh = CGBitmapContextGetHeight(src);
+    if( (sw - X < w) || (sh - Y < h) )  return NULL;
+    bpr = CGBitmapContextGetBytesPerRow(src);
+    bpp = CGBitmapContextGetBitsPerPixel(src)/8;
+    Fl_Image_Surface *imgs = (Fl_Image_Surface*)Fl_Surface_Device::surface();
+    int fltk_w, fltk_h;
+    imgs->printable_rect(&fltk_w, &fltk_h);
+    s = sw / float(fltk_w);
+    X *= s; Y *= s; w *= s; h *= s;
+    if (X + w > sw) w = sw - X;
+    if (Y + h > sh) h = sh - Y;
+    // Copy the image from the off-screen buffer to the memory buffer.
+    int idx, idy;  // Current X & Y in image
+    uchar *pdst, *psrc;
+    p = new uchar[w * h * depth];
+    for (idy = Y, pdst = p; idy < h + Y; idy ++) {
+      for (idx = 0, psrc = base + idy * bpr + X * bpp; idx < w; idx ++, psrc += bpp, pdst += depth) {
+        pdst[0] = psrc[0];  // R
+        pdst[1] = psrc[1];  // G
+        pdst[2] = psrc[2];  // B
+      }
+    }
+    bpr = 0;
+  } else { // read from window
+    Fl_Cocoa_Window_Driver *d = Fl_Cocoa_Window_Driver::driver(Fl_Window::current());
+    CGImageRef cgimg = d->CGImage_from_window_rect(X, Y, w, h);
+    if (!cgimg) {
+      return NULL;
+    }
+    w = CGImageGetWidth(cgimg);
+    h = CGImageGetHeight(cgimg);
+    Fl_Image_Surface *surf = new Fl_Image_Surface(w, h);
+    Fl_Surface_Device::push_current(surf);
+    ((Fl_Quartz_Graphics_Driver*)fl_graphics_driver)->draw_CGImage(cgimg, 0, 0, w, h, 0, 0, w, h);
+    CGContextRef gc = (CGContextRef)fl_graphics_driver->gc();
+    w = CGBitmapContextGetWidth(gc);
+    h = CGBitmapContextGetHeight(gc);
+    bpr = CGBitmapContextGetBytesPerRow(gc);
+    bpp = CGBitmapContextGetBitsPerPixel(gc)/8;
+    base = (uchar*)CGBitmapContextGetData(gc);
+    p = new uchar[bpr * h];
+    memcpy(p, base, bpr * h);
+    Fl_Surface_Device::pop_current();
+    delete surf;
+    CFRelease(cgimg);
+  }
+  Fl_RGB_Image *rgb = new Fl_RGB_Image(p, w, h, depth, bpr);
+  rgb->alloc_array = 1;
+  return rgb;
+}
+
 //
 // End of "$Id$".
 //
diff --git a/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H b/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H
index 08a8ce42c..ef64799c9 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H
+++ b/src/drivers/Cocoa/Fl_Cocoa_Window_Driver.H
@@ -88,7 +88,6 @@ public:
   CGRect* subRect() { return subRect_; } // getter
   void subRect(CGRect *r) { subRect_ = r; } // setter
   static void destroy(FLWindow*);
-  unsigned char *bitmap_from_window_rect(int x, int y, int w, int h, int *bytesPerPixel);
   CGImageRef CGImage_from_window_rect(int x, int y, int w, int h);
 
   // --- window data
diff --git a/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx b/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx
index 573bca696..453a5f600 100644
--- a/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx
+++ b/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx
@@ -92,7 +92,7 @@ void Fl_GDI_Image_Surface_Driver::untranslate() {
 
 Fl_RGB_Image* Fl_GDI_Image_Surface_Driver::image()
 {
-  Fl_RGB_Image *image = Fl::screen_driver()->read_win_rectangle(NULL, 0, 0, width, height, 0);
+  Fl_RGB_Image *image = Fl::screen_driver()->read_win_rectangle( 0, 0, width, height);
   return image;
 }
 
diff --git a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H
index 60a261e94..b23817d46 100644
--- a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H
+++ b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H
@@ -184,6 +184,8 @@ protected:
 #else
   void descriptor_init(const char* name, Fl_Fontsize Size, Fl_Quartz_Font_Descriptor *d);
 #endif
+  virtual bool overlay_rect_unscaled() {return false; }
+  virtual void overlay_rect(int x, int y, int w , int h);
 };
 
 class Fl_Quartz_Printer_Graphics_Driver : public Fl_Quartz_Graphics_Driver {
diff --git a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver_rect.cxx b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver_rect.cxx
index 3a83b94d6..8153f4e78 100644
--- a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver_rect.cxx
+++ b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver_rect.cxx
@@ -173,6 +173,30 @@ void Fl_Quartz_Graphics_Driver::loop(int x, int y, int x1, int y1, int x2, int y
   if (quartz_line_width_ > 1.5f) CGContextSetShouldAntialias(gc_, false);
 }
 
+// returns y of horizontal line corresponding to pixels of current window
+// read by Fl_Cocoa_Screen_Driver::read_win_rectangle(  -,  y, -, 1)
+// when GUI is scaled by s
+static float overlay_y(int y, float s, int H) {
+  int a, b, c;
+  a = int(H*s) - (y+1)*s; // in Cocoa units from window bottom
+  c = (s > 1 ? s : 1); // height of pixels read in Cocoa units
+  b = H*s - (a+c); // top of read image from window top in Cocoa units
+  return b/s; // top of read image from window top in FLTK units
+}
+
+void Fl_Quartz_Graphics_Driver::overlay_rect(int x, int y, int w , int h) {
+  float s = scale();
+  CGContextSetLineWidth(gc_, 0.01);
+  int H = Fl_Window::current()->h();
+  CGContextMoveToPoint(gc_, x, overlay_y(y, s, H));
+  CGContextAddLineToPoint(gc_, x+w-1, overlay_y(y, s, H));
+  CGContextAddLineToPoint(gc_, x+w-1, overlay_y(y+h-1, s, H));
+  CGContextAddLineToPoint(gc_, x, overlay_y(y+h-1, s, H));
+  CGContextClosePath(gc_);
+  CGContextStrokePath(gc_);
+  CGContextSetLineWidth(gc_, quartz_line_width_);
+}
+
 void Fl_Quartz_Graphics_Driver::polygon(int x, int y, int x1, int y1, int x2, int y2) {
   CGContextSetShouldAntialias(gc_, true);
   CGContextMoveToPoint(gc_, x, y);
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
index e28fb791a..b5d238ba9 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
+++ b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.H
@@ -4,7 +4,7 @@
 // Definition of MSWindows Win32/64 Screen interface
 // for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2016 by Bill Spitzak and others.
+// Copyright 2010-2018 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -79,8 +79,8 @@ public:
   virtual void remove_timeout(Fl_Timeout_Handler cb, void *argp);
   virtual int dnd(int unused);
   virtual int compose(int &del);
-  virtual Fl_RGB_Image *read_win_rectangle(uchar *p, int X, int Y, int w, int h, int alpha);
-  Fl_RGB_Image *read_win_rectangle_unscaled(uchar *p, int X, int Y, int w, int h, int alpha);
+  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h);
+  Fl_RGB_Image *read_win_rectangle_unscaled(int X, int Y, int w, int h);
   virtual int get_mouse(int &x, int &y);
   virtual void enable_im();
   virtual void disable_im();
diff --git a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
index 9373d345d..f44fa7a3c 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
+++ b/src/drivers/WinAPI/Fl_WinAPI_Screen_Driver.cxx
@@ -496,24 +496,21 @@ int Fl_WinAPI_Screen_Driver::compose(int &del) {
 
 
 Fl_RGB_Image *                                                  // O - image or NULL if failed
-Fl_WinAPI_Screen_Driver::read_win_rectangle(uchar *p,		// I - Pixel buffer or NULL to allocate
+Fl_WinAPI_Screen_Driver::read_win_rectangle(
                                             int   X,		// I - Left position
                                             int   Y,		// I - Top position
                                             int   w,		// I - Width of area to read
-                                            int   h,		// I - Height of area to read
-                                            int   alpha) 	// I - Alpha value for image (0 for none)
+                                            int   h)		// I - Height of area to read
 {
   float s = Fl_Surface_Device::surface()->driver()->scale();
-  return read_win_rectangle_unscaled(p, X*s, Y*s, w*s, h*s, alpha);
+  return read_win_rectangle_unscaled(X*s, Y*s, w*s, h*s);
 }
 
-Fl_RGB_Image *Fl_WinAPI_Screen_Driver::read_win_rectangle_unscaled(uchar *p, int X, int Y, int w, int h, int alpha)
+Fl_RGB_Image *Fl_WinAPI_Screen_Driver::read_win_rectangle_unscaled(int X, int Y, int w, int h)
 {
-  int	d;			// Depth of image
-  
-  // Allocate the image data array as needed...
-  d = alpha ? 4 : 3;
-  
+  int	d = 3;			// Depth of image
+  int alpha = 0; uchar *p = NULL;
+  // Allocate the image data array as needed...  
   const uchar *oldp = p;
   if (!p) p = new uchar[w * h * d];
   
diff --git a/src/drivers/X11/Fl_X11_Screen_Driver.H b/src/drivers/X11/Fl_X11_Screen_Driver.H
index 6ceca775c..78a0510a5 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.H
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.H
@@ -4,7 +4,7 @@
 // Definition of X11 Screen interface
 // for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2017 by Bill Spitzak and others.
+// Copyright 2010-2018 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -93,7 +93,7 @@ public:
   virtual int compose(int &del);
   virtual void compose_reset();
   virtual int text_display_can_leak();
-  virtual Fl_RGB_Image *read_win_rectangle(uchar *p, int X, int Y, int w, int h, int alpha);
+  virtual Fl_RGB_Image *read_win_rectangle(int X, int Y, int w, int h);
   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 6b253931d..7f6dc5528 100644
--- a/src/drivers/X11/Fl_X11_Screen_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Screen_Driver.cxx
@@ -750,7 +750,7 @@ extern "C" {
   }
 }
 
-Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(uchar *p, int X, int Y, int w, int h, int alpha)
+Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(int X, int Y, int w, int h)
 {
   XImage	*image;		// Captured image
   int		i, maxindex;	// Looping vars
@@ -862,14 +862,14 @@ Fl_RGB_Image *Fl_X11_Screen_Driver::read_win_rectangle(uchar *p, int X, int Y, i
   printf("map_entries      = %d\n", fl_visual->visual->map_entries);
 #endif // DEBUG
   
-  d = alpha ? 4 : 3;
-  
+  d = 3;
+  uchar *p = NULL;
   // Allocate the image data array as needed...
   const uchar *oldp = p;
   if (!p) p = new uchar[w * h * d];
   
   // Initialize the default colors/alpha in the whole image...
-  memset(p, alpha, w * h * d);
+  memset(p, 0, w * h * d);
   
   // Check that we have valid mask/shift values...
   if (!image->red_mask && image->bits_per_pixel > 12) {
diff --git a/src/drivers/X11/Fl_X11_Window_Driver.cxx b/src/drivers/X11/Fl_X11_Window_Driver.cxx
index 5612ce4df..b89688b47 100644
--- a/src/drivers/X11/Fl_X11_Window_Driver.cxx
+++ b/src/drivers/X11/Fl_X11_Window_Driver.cxx
@@ -413,22 +413,22 @@ void Fl_X11_Window_Driver::capture_titlebar_and_borders(Fl_Shared_Image*& top, F
   htop /= s; wsides /= s;
   fl_window = parent;
   if (htop) {
-    r_top = Fl::screen_driver()->read_win_rectangle(NULL, 0, 0, - (w() + 2 * wsides), htop, 0);
+    r_top = Fl::screen_driver()->read_win_rectangle(0, 0, - (w() + 2 * wsides), htop);
     top = Fl_Shared_Image::get(r_top);
     top->scale(w() + 2 * wsides, htop, 0, 1);
   }
   if (wsides) {
-    r_left = Fl::screen_driver()->read_win_rectangle(NULL, 0, htop, -wsides, h(), 0);
+    r_left = Fl::screen_driver()->read_win_rectangle(0, htop, -wsides, h());
     if (r_left) {
       left =  Fl_Shared_Image::get(r_left);
       left->scale(wsides, h(), 0, 1);
     }
-    r_right = Fl::screen_driver()->read_win_rectangle(NULL, w() + wsides, htop, -wsides, h(), 0);
+    r_right = Fl::screen_driver()->read_win_rectangle(w() + wsides, htop, -wsides, h());
     if (r_right) {
       right = Fl_Shared_Image::get(r_right);
       right->scale(wsides, h(), 0, 1);
     }
-    r_bottom = Fl::screen_driver()->read_win_rectangle(NULL, 0, htop + h(), -(w() + 2*wsides), hbottom, 0);
+    r_bottom = Fl::screen_driver()->read_win_rectangle(0, htop + h(), -(w() + 2*wsides), hbottom);
     if (r_bottom) {
       bottom = Fl_Shared_Image::get(r_bottom);
       bottom->scale(w() + 2*wsides, wsides, 0, 1);
diff --git a/src/drivers/Xlib/Fl_Xlib_Copy_Surface_Driver.cxx b/src/drivers/Xlib/Fl_Xlib_Copy_Surface_Driver.cxx
index 73a69109b..74a5022f4 100644
--- a/src/drivers/Xlib/Fl_Xlib_Copy_Surface_Driver.cxx
+++ b/src/drivers/Xlib/Fl_Xlib_Copy_Surface_Driver.cxx
@@ -67,7 +67,7 @@ Fl_Xlib_Copy_Surface_Driver::~Fl_Xlib_Copy_Surface_Driver() {
   driver()->pop_clip();
   bool need_push = (Fl_Surface_Device::surface() != this);
   if (need_push) Fl_Surface_Device::push_current(this);
-  Fl_RGB_Image *rgb = Fl::screen_driver()->read_win_rectangle(NULL, 0, 0, width, height, 0);
+  Fl_RGB_Image *rgb = Fl::screen_driver()->read_win_rectangle(0, 0, width, height);
   if (need_push) Fl_Surface_Device::pop_current();
   Fl_X11_Screen_Driver::copy_image(rgb->array, rgb->w(), rgb->h(), 1);
   delete rgb;
diff --git a/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx b/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx
index 0d3383cc5..c5bcce9af 100644
--- a/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx
+++ b/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx
@@ -80,7 +80,7 @@ void Fl_Xlib_Image_Surface_Driver::untranslate() {
 
 Fl_RGB_Image* Fl_Xlib_Image_Surface_Driver::image()
 {
-  Fl_RGB_Image *image = Fl::screen_driver()->read_win_rectangle(NULL, 0, 0, width, height, 0);
+  Fl_RGB_Image *image = Fl::screen_driver()->read_win_rectangle(0, 0, width, height);
   return image;
 }