3 files changed, 10 insertions, 5 deletions
diff --git a/src/Fl_cocoa.mm b/src/Fl_cocoa.mm
index 814604f22..14ea72303 100644
--- a/src/Fl_cocoa.mm
+++ b/src/Fl_cocoa.mm
@@ -3351,6 +3351,7 @@ unsigned char *Fl_X::bitmap_from_window_rect(Fl_Window *win, int x, int y, int w
  */
 {
   NSBitmapImageRep *bitmap = rect_to_NSBitmapImageRep(win, x, y, w, h);
+  if (bitmap == nil) return NULL;
   *bytesPerPixel = [bitmap bitsPerPixel]/8;
   int bpp = (int)[bitmap bytesPerPlane];
   int bpr = (int)[bitmap bytesPerRow];
@@ -3388,6 +3389,7 @@ CGImageRef Fl_X::CGImage_from_window_rect(Fl_Window *win, int x, int y, int w, i
   else {
     int bpp;
     unsigned char *bitmap = bitmap_from_window_rect(win, x, y, w, h, &bpp);
+    if (!bitmap) return NULL;
     CGColorSpaceRef lut = CGColorSpaceCreateDeviceRGB();
     CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, bitmap, w*h*bpp, imgProviderReleaseData);
     img = CGImageCreate(w, h, 8, 8*bpp, w*bpp, lut,
diff --git a/src/fl_read_image_mac.cxx b/src/fl_read_image_mac.cxx
index 5dbd70781..a92684d1a 100644
--- a/src/fl_read_image_mac.cxx
+++ b/src/fl_read_image_mac.cxx
@@ -45,6 +45,7 @@ fl_read_image(uchar *p,		// I - Pixel buffer or NULL to allocate
     Fl_Window *window = Fl_Window::current();
     while(window->window()) window = window->window();
     base = Fl_X::bitmap_from_window_rect(window,x,y,w,h,&delta);
+    if (!base) return NULL;
     rowBytes = delta*w;
     x = y = 0;
     }
diff --git a/src/fl_scroll_area.cxx b/src/fl_scroll_area.cxx
index 7531f3d90..a8cba57c4 100644
--- a/src/fl_scroll_area.cxx
+++ b/src/fl_scroll_area.cxx
@@ -143,11 +143,13 @@ void fl_scroll(int X, int Y, int W, int H, int dx, int dy,
 
 #elif defined(__APPLE_QUARTZ__)
   CGImageRef img = Fl_X::CGImage_from_window_rect(Fl_Window::current(), src_x, src_y, src_w, src_h);
-  CGRect rect = { { dest_x, dest_y }, { src_w, src_h } };
-  Fl_X::q_begin_image(rect, 0, 0, src_w, src_h);
-  CGContextDrawImage(fl_gc, rect, img);
-  Fl_X::q_end_image();
-  CFRelease(img);
+  if (img) {
+    CGRect rect = { { dest_x, dest_y }, { src_w, src_h } };
+    Fl_X::q_begin_image(rect, 0, 0, src_w, src_h);
+    CGContextDrawImage(fl_gc, rect, img);
+    Fl_X::q_end_image();
+    CFRelease(img);
+    }
 #else
 # error unsupported platform
 #endif