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

3 files changed, 10 insertions, 10 deletions

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);