Call virtual member Fl_Surface_Device::end_current() when necessary

Rename member function Fl_Surface_Device::end_current_() to end_current(),
set it protected, and make it called by the destructor of all classes
derived from Fl_Surface_Device that re-implement end_current().
This way, end_current() runs equally if Fl_Surface_Device()::pop_current()
is called before or after the drawing surface is deleted.

FL/Fl_Device.H

@@ -70,10 +70,10 @@ class FL_EXPORT Fl_Surface_Device {
   Fl_Graphics_Driver *pGraphicsDriver;
   static Fl_Surface_Device *surface_; // the surface that currently receives graphics requests
   static Fl_Surface_Device *default_surface(); // create surface if none exists yet
+protected:
   /* Some drawing surfaces (e.g., Fl_XXX_Image_Surface_Driver) re-implement this.
    Gets called each time a surface ceases to be the current drawing surface. */
-  virtual void end_current_() {}
-protected:
+  virtual void end_current() {}
   /** Constructor that sets the graphics driver to use for the created surface. */
   Fl_Surface_Device(Fl_Graphics_Driver *graphics_driver) {pGraphicsDriver = graphics_driver; }
   /** Sets the graphics driver of this drawing surface. */

src/Fl_Device.cxx

@@ -63,7 +63,7 @@
  is Fl_Surface_Device::push_current( ) / Fl_Surface_Device::pop_current().*/
 void Fl_Surface_Device::set_current(void)
 {
-  if (surface_) surface_->end_current_();
+  if (surface_) surface_->end_current();
   fl_graphics_driver = pGraphicsDriver;
   surface_ = this;
   pGraphicsDriver->global_gc();

src/drivers/Android/Fl_Android_Graphics_Driver.H

@@ -58,7 +58,7 @@ private:
   virtual void draw_fixed(Fl_Pixmap * pxm,int XP, int YP, int WP, int HP, int cx, int cy) override;
   virtual void draw_fixed(Fl_Bitmap *bm, int XP, int YP, int WP, int HP, int cx, int cy) override;
   // some platforms may need to reimplement this
-  // This is called from the surface device, see: end_current_()
+  // This is called from the surface device, see: end_current()
   // super: virtual void set_current_();
 protected:
   /** Sets the current value of the scaling factor */

src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx

@@ -24,7 +24,7 @@
 #include <windows.h>
 
 class Fl_GDI_Image_Surface_Driver : public Fl_Image_Surface_Driver {
-  virtual void end_current_();
+  virtual void end_current();
 public:
   Window pre_window;
   int _savedc;
@@ -61,6 +61,7 @@ Fl_GDI_Image_Surface_Driver::Fl_GDI_Image_Surface_Driver(int w, int h, int high_
 
 Fl_GDI_Image_Surface_Driver::~Fl_GDI_Image_Surface_Driver() {
   if (offscreen && !external_offscreen) DeleteObject(offscreen);
+  if (is_current()) end_current();
   delete driver();
 }
 
@@ -93,7 +94,7 @@ Fl_RGB_Image* Fl_GDI_Image_Surface_Driver::image()
 }
 
 
-void Fl_GDI_Image_Surface_Driver::end_current_()
+void Fl_GDI_Image_Surface_Driver::end_current()
 {
   HDC gc = (HDC)driver()->gc();
   GetWindowOrgEx(gc, &origin);

src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx

@@ -27,7 +27,7 @@
 #include <ApplicationServices/ApplicationServices.h>
 
 class Fl_Quartz_Image_Surface_Driver : public Fl_Image_Surface_Driver {
-  virtual void end_current_();
+  virtual void end_current();
 public:
   Window pre_window;
   Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off);
@@ -89,6 +89,7 @@ Fl_Quartz_Image_Surface_Driver::~Fl_Quartz_Image_Surface_Driver() {
     CGContextRelease((CGContextRef)offscreen);
   }
   delete driver();
+  if (is_current()) end_current();
 }
 
 void Fl_Quartz_Image_Surface_Driver::set_current() {
@@ -124,7 +125,7 @@ Fl_RGB_Image* Fl_Quartz_Image_Surface_Driver::image()
   return image;
 }
 
-void Fl_Quartz_Image_Surface_Driver::end_current_()
+void Fl_Quartz_Image_Surface_Driver::end_current()
 {
   fl_window = pre_window;
 }

src/drivers/Xlib/Fl_Xlib_Copy_Surface_Driver.cxx

@@ -28,7 +28,7 @@
 
 class Fl_Xlib_Copy_Surface_Driver : public Fl_Copy_Surface_Driver {
   friend class Fl_Copy_Surface_Driver;
-  virtual void end_current_();
+  virtual void end_current();
 protected:
   Fl_Offscreen xid;
   Window oldwindow;
@@ -70,6 +70,7 @@ Fl_Xlib_Copy_Surface_Driver::~Fl_Xlib_Copy_Surface_Driver() {
   delete rgb;
   fl_delete_offscreen(xid);
   delete driver();
+  if (!need_push) end_current();
 }
 
 
@@ -79,7 +80,7 @@ void Fl_Xlib_Copy_Surface_Driver::set_current() {
   fl_window = xid;
 }
 
-void Fl_Xlib_Copy_Surface_Driver::end_current_() {
+void Fl_Xlib_Copy_Surface_Driver::end_current() {
   fl_window = oldwindow;
 }
 

src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx

@@ -21,7 +21,7 @@
 #include "../../Fl_Screen_Driver.H"
 
 class Fl_Xlib_Image_Surface_Driver : public Fl_Image_Surface_Driver {
-  virtual void end_current_();
+  virtual void end_current();
 public:
   Window pre_window;
   Fl_Xlib_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off);
@@ -55,6 +55,7 @@ Fl_Xlib_Image_Surface_Driver::Fl_Xlib_Image_Surface_Driver(int w, int h, int hig
 Fl_Xlib_Image_Surface_Driver::~Fl_Xlib_Image_Surface_Driver() {
   if (offscreen && !external_offscreen) XFreePixmap(fl_display, offscreen);
   delete driver();
+  if (is_current()) end_current();
 }
 
 void Fl_Xlib_Image_Surface_Driver::set_current() {
@@ -77,7 +78,7 @@ Fl_RGB_Image* Fl_Xlib_Image_Surface_Driver::image()
   return image;
 }
 
-void Fl_Xlib_Image_Surface_Driver::end_current_()
+void Fl_Xlib_Image_Surface_Driver::end_current()
 {
   fl_window = pre_window;
 }