Add static void Fl_Surface_Device::push_current(Fl_Surface_Device *new_current) and pop_current() to set/unset the current drawing surface.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12140 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_Device.H

@@ -40,24 +40,24 @@ class Fl_Widget;
 
  A drawing surface other than the computer's display, is typically used as follows:
  <ol><li> Create \c surface, an object from a particular Fl_Surface_Device derived class (e.g., Fl_Copy_Surface, Fl_Printer).
- <li> Memorize what is the current drawing surface with <tt> Fl_Surface_Device *old_current = Fl_Surface_Device::surface();</tt>
- <li> Call \c surface->set_current(); to redirect all graphics requests to \c surface which becomes the new
+ <li> Call \c Fl_Surface_Device::push_current(surface); to redirect all graphics requests to \c surface which becomes the new
  current drawing surface (not necessary with class Fl_Printer because it is done by Fl_Printer::start_job()).
- <li> At this point any of the \ref fl_drawings (e.g., fl_rect()) or the \ref fl_attributes or \ref drawing_images functions
- (e.g., fl_draw_image(), Fl_Image::draw()) operates on the new current drawing surface.
+ <li> At this point all of the \ref fl_drawings (e.g., fl_rect()) or the \ref fl_attributes or \ref drawing_images functions
+ (e.g., fl_draw_image(), Fl_Image::draw()) operate on the new current drawing surface.
  Certain drawing surfaces allow additional ways to draw to them (e.g., Fl_Printer::print_widget(), Fl_Image_Surface::draw()).
  <li> After all drawing requests have been performed, redirect graphics requests back to their previous destination
- with \c old_current->set_current();.
+ with \c Fl_Surface_Device::pop_current();.
  <li> Delete \c surface.
  </ol>
+ For back-compatibility, it is also possible to use the Fl_Surface_Device::set_current() member function
+ to change the current drawing surface, once to the new surface, once to the previous one.
  */
 class FL_EXPORT Fl_Surface_Device {
   /** The graphics driver in use by this surface. */
   Fl_Graphics_Driver *pGraphicsDriver;
-  static Fl_Surface_Device *surface_; // the surface that currently receives graphics output
+  static Fl_Surface_Device *surface_; // the surface that currently receives graphics requests
   static Fl_Surface_Device *default_surface(); // create surface if none exists yet
-  static Fl_Surface_Device *pre_surface_;
-  // Some drawing surfaces (e.g., Fl_XXX_Image_Surface_Driver) need to re-implement this.
+  // 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:
@@ -70,12 +70,14 @@ public:
   /** \brief Returns the graphics driver of this drawing surface. */
   inline Fl_Graphics_Driver *driver() {return pGraphicsDriver; };
   /** The current drawing surface.
-   In other words, the Fl_Surface_Device object that currently receives all graphics output */
+   In other words, the Fl_Surface_Device object that currently receives all graphics requests */
   static inline Fl_Surface_Device *surface() {
     return surface_ ? surface_ : default_surface();
   };
   /** \brief The destructor. */
   virtual ~Fl_Surface_Device();
+  static void push_current(Fl_Surface_Device *new_current);
+  static Fl_Surface_Device *pop_current();
 };
 
 /**

examples/shapedwindow.cxx

@@ -76,8 +76,7 @@ Fl_RGB_Image* prepare_shape(int w)
 {
   // draw a white circle with a hole in it on black background
   Fl_Image_Surface *surf = new Fl_Image_Surface(w, w);
-  Fl_Surface_Device* current = Fl_Surface_Device::surface();
-  surf->set_current();
+  Fl_Surface_Device::push_current(surf);
   fl_color(FL_BLACK);
   fl_rectf(-1, -1, w+2, w+2);
   fl_color(FL_WHITE);
@@ -86,7 +85,7 @@ Fl_RGB_Image* prepare_shape(int w)
   fl_pie(0.7*w,w/2,w/4,w/4,0,360);
   Fl_RGB_Image* img = surf->image();
   delete surf;
-  current->set_current();
+  Fl_Surface_Device::pop_current();
   return img; // return white image on black background
 }
 

src/Fl_Device.cxx

@@ -42,23 +42,18 @@
       |
       +- Fl_..._Graphics_Driver: platform specific graphics driver
 
-TODO:
-  Window Device to handle creation of surfaces and manage events
-  System Device to handle file system acces, standard dialogs, etc.
-
 */
 
-Fl_Surface_Device *Fl_Surface_Device::pre_surface_ = NULL;
-
-/** \brief Make this surface the current drawing surface.
- This surface will receive all future graphics requests. */
+/** Make this surface the current drawing surface.
+ This surface will receive all future graphics requests. 
+ \p Starting from FLTK 1.4.0, another convenient API to set/unset the current drawing surface
+ is Fl_Surface_Device::push_current( ) / Fl_Surface_Device::pop_current().*/
 void Fl_Surface_Device::set_current(void)
 {
-  if (pre_surface_) pre_surface_->end_current_();
+  if (surface_) surface_->end_current_();
   fl_graphics_driver = pGraphicsDriver;
   surface_ = this;
   pGraphicsDriver->global_gc();
-  pre_surface_ = this;
 }
 
 Fl_Surface_Device* Fl_Surface_Device::surface_; // the current target surface of graphics operations
@@ -66,7 +61,7 @@ Fl_Surface_Device* Fl_Surface_Device::surface_; // the current target surface of
 
 Fl_Surface_Device::~Fl_Surface_Device()
 {
-  if (pre_surface_ == this) pre_surface_ = NULL;
+  if (surface_ == this) surface_ = NULL;
 }
 
 
@@ -88,6 +83,31 @@ Fl_Surface_Device *Fl_Surface_Device::default_surface()
   return Fl_Display_Device::display_device();
 }
 
+static int surface_stack_height = 0;
+static Fl_Surface_Device *surface_stack[16];
+
+/** Pushes \p new_current on top of the stack of current drawing surfaces, and makes it current.
+ \p new_current will receive all future graphics requests.
+ \version 1.4.0 */
+void Fl_Surface_Device::push_current(Fl_Surface_Device *new_current)
+{
+  if (surface_stack_height < sizeof(surface_stack)/sizeof(void*)) {
+    surface_stack[surface_stack_height++] = surface();
+  } else {
+    fprintf(stderr, "FLTK Fl_Surface_Device::push_current Stack overflow error\n");
+  }
+  new_current->set_current();
+}
+
+/** Removes the top element from the current drawing surface stack, and makes the new top element current.
+ \return A pointer to the new current drawing surface. 
+ \version 1.4.0 */
+Fl_Surface_Device *Fl_Surface_Device::pop_current()
+{
+  if (surface_stack_height > 0) surface_stack[--surface_stack_height]->set_current();
+  return surface_;
+}
+
 //
 // End of "$Id$".
 //

src/Fl_Gl_Window.cxx

@@ -359,8 +359,7 @@ void Fl_Gl_Window::draw_overlay() {}
 */
 void Fl_Gl_Window::draw() {
 #ifdef FL_CFG_GFX_OPENGL
-  Fl_Surface_Device *prev_device = Fl_Surface_Device::surface();
-  Fl_OpenGL_Display_Device::display_device()->set_current();
+  Fl_Surface_Device::push_current( Fl_OpenGL_Display_Device::display_device() );
   glPushAttrib(GL_ENABLE_BIT);
   glDisable(GL_DEPTH_TEST);
   glPushMatrix();
@@ -375,7 +374,7 @@ void Fl_Gl_Window::draw() {
 
   glPopMatrix();
   glPushAttrib(GL_ENABLE_BIT);
-  prev_device->set_current();
+  Fl_Surface_Device::pop_current();
 #else
   Fl::fatal("Fl_Gl_Window::draw() *must* be overriden. Please refer to the documentation.");
 #endif

src/Fl_Image_Surface.cxx

@@ -146,21 +146,13 @@ void fl_delete_offscreen(Fl_Offscreen ctx) {
   }
 }
 
-static Fl_Surface_Device* stack_surface[16];
-static unsigned stack_height = 0;
-
 /**  Send all subsequent drawing commands to this offscreen buffer.
    \param ctx     the offscreen buffer.
    */
 void fl_begin_offscreen(Fl_Offscreen ctx) {
   for (int i = 0; i < count_offscreens; i++) {
     if (offscreen_api_surface[i] && offscreen_api_surface[i]->offscreen() == ctx) {
-      if (stack_height < sizeof(stack_surface)/sizeof(void*)) {
-        stack_surface[stack_height++] = Fl_Surface_Device::surface();
-      } else {
-        fprintf(stderr, "FLTK fl_begin_offscreen Stack overflow error\n");
-      }
-      offscreen_api_surface[i]->set_current();
+      Fl_Surface_Device::push_current(offscreen_api_surface[i]);
       return;
     }
   }
@@ -169,9 +161,7 @@ void fl_begin_offscreen(Fl_Offscreen ctx) {
 /** Quit sending drawing commands to the current offscreen buffer.
    */
 void fl_end_offscreen() {
-  if (stack_height > 0) {
-    stack_surface[--stack_height]->set_current();
-  }
+  Fl_Surface_Device::pop_current();
 }
 
 /** @} */

src/Fl_win32.cxx

@@ -2392,9 +2392,8 @@ void Fl_WinAPI_Window_Driver::capture_titlebar_and_borders(Fl_Shared_Image*& top
   float scaling = 1;
   RECT r = border_width_title_bar_height(wsides, hbottom, bt, &scaling);
   int htop = bt + hbottom;
-  Fl_Surface_Device *previous = Fl_Surface_Device::surface();
   Window save_win = fl_window;
-  Fl_Display_Device::display_device()->set_current();
+  Fl_Surface_Device::push_current( Fl_Display_Device::display_device() );
   pWindow->show();
   Fl::check();
   void* save_gc = fl_graphics_driver->gc();
@@ -2417,7 +2416,7 @@ void Fl_WinAPI_Window_Driver::capture_titlebar_and_borders(Fl_Shared_Image*& top
   ReleaseDC(NULL, (HDC)fl_graphics_driver->gc());
   fl_window = save_win;
   fl_graphics_driver->gc(save_gc);
-  previous->set_current();
+  Fl_Surface_Device::pop_current();
 }
 
 

src/drivers/Quartz/Fl_Quartz_Graphics_Driver_image.cxx

@@ -251,12 +251,11 @@ static void pmProviderRelease (void *ctxt, const void *data, size_t size) {
 }
 
 fl_uintptr_t Fl_Quartz_Graphics_Driver::cache(Fl_Pixmap *img, int w, int h, const char *const*data) {
-  Fl_Surface_Device *old = Fl_Surface_Device::surface();
   Fl_Image_Surface *surf = new Fl_Image_Surface(w, h);
-  surf->set_current();
+  Fl_Surface_Device::push_current(surf);
   fl_draw_pixmap(data, 0, 0, FL_BLACK);
   CGContextRef src = surf->get_offscreen_before_delete();
-  old->set_current();
+  Fl_Surface_Device::pop_current();
   delete surf;
   void *cgdata = CGBitmapContextGetData(src);
   int sw = CGBitmapContextGetWidth(src);

src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx

@@ -29,7 +29,6 @@ class Fl_Quartz_Image_Surface_Driver : public Fl_Image_Surface_Driver {
   friend class Fl_Image_Surface;
   virtual void end_current_();
 public:
-  Fl_Surface_Device *previous;
   Window pre_window;
   Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res);
   ~Fl_Quartz_Image_Surface_Driver();
@@ -47,7 +46,6 @@ Fl_Image_Surface_Driver *Fl_Image_Surface_Driver::newImageSurfaceDriver(int w, i
 
 
 Fl_Quartz_Image_Surface_Driver::Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res) : Fl_Image_Surface_Driver(w, h, high_res, 0) {
-  previous = 0;
   int W = high_res ? 2*w : w;
   int H = high_res ? 2*h : h;
   CGColorSpaceRef lut = CGColorSpaceCreateDeviceRGB();
@@ -77,7 +75,6 @@ Fl_Quartz_Image_Surface_Driver::~Fl_Quartz_Image_Surface_Driver() {
 
 void Fl_Quartz_Image_Surface_Driver::set_current() {
   pre_window = fl_window;
-  if (!previous) previous = Fl_Surface_Device::surface();
   driver()->gc(offscreen);
   fl_window = 0;
   Fl_Surface_Device::set_current();

src/drivers/X11/Fl_X11_Window_Driver.cxx

@@ -387,8 +387,7 @@ void Fl_X11_Window_Driver::capture_titlebar_and_borders(Fl_Shared_Image*& top, F
   top = left = bottom = right = NULL;
   if (pWindow->decorated_h() == h()) return;
   Window from = fl_window;
-  Fl_Surface_Device *previous = Fl_Surface_Device::surface();
-  Fl_Display_Device::display_device()->set_current();
+  Fl_Surface_Device::push_current( Fl_Display_Device::display_device() );
   pWindow->show();
   Fl::check();
   pWindow->make_current();
@@ -421,7 +420,7 @@ void Fl_X11_Window_Driver::capture_titlebar_and_borders(Fl_Shared_Image*& top, F
     }
   }
   fl_window = from;
-  previous->Fl_Surface_Device::set_current();
+  Fl_Surface_Device::pop_current();
 }
 
 

src/drivers/Xlib/Fl_Xlib_Copy_Surface_Driver.cxx

@@ -28,10 +28,10 @@
 
 class Fl_Xlib_Copy_Surface_Driver : public Fl_Copy_Surface_Driver {
   friend class Fl_Copy_Surface_Driver;
+  virtual void end_current_();
 protected:
   Fl_Offscreen xid;
   Window oldwindow;
-  Fl_Surface_Device *_ss;
   Fl_Xlib_Copy_Surface_Driver(int w, int h);
   ~Fl_Xlib_Copy_Surface_Driver();
   void set_current();
@@ -51,26 +51,22 @@ Fl_Copy_Surface_Driver *Fl_Copy_Surface_Driver::newCopySurfaceDriver(int w, int
 
 Fl_Xlib_Copy_Surface_Driver::Fl_Xlib_Copy_Surface_Driver(int w, int h) : Fl_Copy_Surface_Driver(w, h) {
   driver(new Fl_Translated_Xlib_Graphics_Driver());
-  Fl::first_window()->make_current();
-  oldwindow = fl_xid(Fl::first_window());
+  oldwindow = fl_window;
   xid = fl_create_offscreen(w,h);
-  _ss = NULL;
-  Fl_Surface_Device *present_surface = Fl_Surface_Device::surface();
-  Fl_Surface_Device::set_current();
-  fl_push_no_clip();
+  driver()->push_no_clip();
   fl_window = xid;
   driver()->color(FL_WHITE);
   driver()->rectf(0, 0, w, h);
-  present_surface->set_current();
   fl_window = oldwindow;
 }
 
 
 Fl_Xlib_Copy_Surface_Driver::~Fl_Xlib_Copy_Surface_Driver() {
-  fl_pop_clip();
+  driver()->pop_clip();
+  bool need_push = (Fl_Surface_Device::surface() != this);
+  if (need_push) Fl_Surface_Device::push_current(this);
   unsigned char *data = fl_read_image(NULL,0,0,width,height,0);
-  fl_window = oldwindow;
-  _ss->set_current();
+  if (need_push) Fl_Surface_Device::pop_current();
   Fl_X11_Screen_Driver::copy_image(data, width, height, 1);
   delete[] data;
   fl_delete_offscreen(xid);
@@ -79,11 +75,14 @@ Fl_Xlib_Copy_Surface_Driver::~Fl_Xlib_Copy_Surface_Driver() {
 
 
 void Fl_Xlib_Copy_Surface_Driver::set_current() {
+  oldwindow = fl_window;
   fl_window = xid;
-  if (!_ss) _ss = Fl_Surface_Device::surface();
   Fl_Surface_Device::set_current();
 }
 
+void Fl_Xlib_Copy_Surface_Driver::end_current_() {
+  fl_window = oldwindow;
+}
 
 void Fl_Xlib_Copy_Surface_Driver::translate(int x, int y) {
   ((Fl_Translated_Xlib_Graphics_Driver*)driver())->translate_all(x, y);

src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx

@@ -714,10 +714,9 @@ void Fl_Xlib_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, in
       depth |= FL_IMAGE_WITH_ALPHA;
     }
     if (surface) {
-      Fl_Surface_Device *old_surf = Fl_Surface_Device::surface();
-      surface->set_current();
+      Fl_Surface_Device::push_current(surface);
       fl_draw_image(img->array, 0, 0, img->w(), img->h(), depth, img->ld());
-      old_surf->set_current();
+      Fl_Surface_Device::pop_current();
       *Fl_Graphics_Driver::id(img) = surface->get_offscreen_before_delete();
       delete surface;
     }

src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx

@@ -29,7 +29,6 @@ class Fl_Xlib_Image_Surface_Driver : public Fl_Image_Surface_Driver {
   friend class Fl_Image_Surface;
   virtual void end_current_();
 public:
-  Fl_Surface_Device *previous;
   Window pre_window;
   int was_high;
   Fl_Xlib_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off);
@@ -46,7 +45,6 @@ Fl_Image_Surface_Driver *Fl_Image_Surface_Driver::newImageSurfaceDriver(int w, i
 }
 
 Fl_Xlib_Image_Surface_Driver::Fl_Xlib_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off) : Fl_Image_Surface_Driver(w, h, high_res, off) {
-  previous = 0;
   if (!off) {
     fl_open_display();
     offscreen = XCreatePixmap(fl_display, RootWindow(fl_display, fl_screen), w, h, fl_visual->depth);
@@ -61,7 +59,6 @@ Fl_Xlib_Image_Surface_Driver::~Fl_Xlib_Image_Surface_Driver() {
 
 void Fl_Xlib_Image_Surface_Driver::set_current() {
   pre_window = fl_window;
-  if (!previous) previous = Fl_Surface_Device::surface();
   Fl_Surface_Device::set_current();
   fl_window = offscreen;
   fl_push_no_clip();

test/device.cxx

@@ -570,7 +570,7 @@ void copy(Fl_Widget *, void *data) {
       decorated = 0;
     }
     rgb_surf = new Fl_Image_Surface(W, H, 1);
-    rgb_surf->set_current();
+    Fl_Surface_Device::push_current(rgb_surf);
     fl_color(FL_YELLOW);fl_rectf(0,0,W,H);
     if (decorated)
       rgb_surf->draw_decorated_window(target->as_window());
@@ -578,7 +578,7 @@ void copy(Fl_Widget *, void *data) {
       rgb_surf->draw(target);
     Fl_Image *img = rgb_surf->highres_image();
     delete rgb_surf;
-    Fl_Display_Device::display_device()->set_current();
+    Fl_Surface_Device::pop_current();
     if (img) {
       Fl_Window* g2 = new Fl_Window(img->w()+10, img->h()+10);
       g2->color(FL_YELLOW);
@@ -596,17 +596,17 @@ void copy(Fl_Widget *, void *data) {
     Fl_Copy_Surface *copy_surf;
     if (target->as_window() && !target->parent()) {
       copy_surf = new Fl_Copy_Surface(target->as_window()->decorated_w(), target->as_window()->decorated_h());
-      copy_surf->set_current();
+      Fl_Surface_Device::push_current(copy_surf);
       copy_surf->draw_decorated_window(target->as_window(), 0, 0);
     }
     else {
       copy_surf = new Fl_Copy_Surface(target->w()+10, target->h()+20);
-      copy_surf->set_current();
+      Fl_Surface_Device::push_current(copy_surf);
       fl_color(FL_YELLOW);fl_rectf(0,0,copy_surf->w(), copy_surf->h());
       copy_surf->draw(target, 5, 10);
     }
     delete copy_surf;
-    Fl_Display_Device::display_device()->set_current();  
+    Fl_Surface_Device::pop_current();
     }
   
   if (strcmp(operation, "Fl_Printer") == 0 || strcmp(operation, "Fl_PostScript_File_Device") == 0) {