diff --git a/makefile.lst b/makefile.lst
index 98d00610b..e08f2724e 100644
--- a/makefile.lst
+++ b/makefile.lst
@@ -510,9 +510,11 @@ VACA_SOURCES =					\
 	$(VACA_DIR)/src/Application.cpp		\
 	$(VACA_DIR)/src/Component.cpp		\
 	$(VACA_DIR)/src/Debug.cpp		\
+	$(VACA_DIR)/src/Event.cpp		\
 	$(VACA_DIR)/src/Exception.cpp		\
 	$(VACA_DIR)/src/Mutex.cpp		\
 	$(VACA_DIR)/src/Point.cpp		\
+	$(VACA_DIR)/src/PreferredSizeEvent.cpp	\
 	$(VACA_DIR)/src/Property.cpp		\
 	$(VACA_DIR)/src/Rect.cpp		\
 	$(VACA_DIR)/src/Referenceable.cpp	\
diff --git a/src/commands/cmd_palette_editor.cpp b/src/commands/cmd_palette_editor.cpp
index 30c506ee6..8b629749d 100644
--- a/src/commands/cmd_palette_editor.cpp
+++ b/src/commands/cmd_palette_editor.cpp
@@ -25,6 +25,7 @@
 #include <vector>
 
 #include "Vaca/Bind.h"
+#include "Vaca/Size.h"
 #include "jinete/jinete.h"
 
 #include "app.h"
@@ -50,6 +51,8 @@
 #include "sprite_wrappers.h"
 #include "ui_context.h"
 
+using Vaca::Size;
+
 static Frame* window = NULL;
 static int redraw_timer_id = -1;
 static bool redraw_all = false;
@@ -997,20 +1000,20 @@ static bool select_hsv_hook(JWidget widget, void *data)
 
 static bool expand_button_select_hook(JWidget widget, void *data)
 {
-  int req_w, req_h;
+  Size reqSize;
 
   if (more_options->isVisible()) {
     set_config_bool("PaletteEditor", "ShowMoreOptions", false);
     more_options->setVisible(false);
 
     // Get the required size of the "More options" panel
-    jwidget_request_size(more_options, &req_w, &req_h);
-    req_h += 4;
+    reqSize = more_options->getPreferredSize();
+    reqSize.h += 4;
 
     // Remove the space occupied by the "More options" panel
     {
       JRect rect = jrect_new(window->rc->x1, window->rc->y1,
-			     window->rc->x2, window->rc->y2 - req_h);
+			     window->rc->x2, window->rc->y2 - reqSize.h);
       window->move_window(rect);
       jrect_free(rect);
     }
@@ -1020,12 +1023,12 @@ static bool expand_button_select_hook(JWidget widget, void *data)
     more_options->setVisible(true);
 
     // Get the required size of the whole window
-    jwidget_request_size(window, &req_w, &req_h);
+    reqSize = window->getPreferredSize();
 
     // Add space for the "more_options" panel
-    if (jrect_h(window->rc) < req_h) {
+    if (jrect_h(window->rc) < reqSize.h) {
       JRect rect = jrect_new(window->rc->x1, window->rc->y1,
-			     window->rc->x2, window->rc->y1 + req_h);
+			     window->rc->x2, window->rc->y1 + reqSize.h);
 
       // Show the expanded area inside the screen
       if (rect->y2 > JI_SCREEN_H)
diff --git a/src/jinete/jbox.cpp b/src/jinete/jbox.cpp
index bd699415d..810a0f308 100644
--- a/src/jinete/jbox.cpp
+++ b/src/jinete/jbox.cpp
@@ -38,6 +38,7 @@
 #include "jinete/jrect.h"
 #include "jinete/jwidget.h"
 #include "jinete/jtheme.h"
+#include "Vaca/Size.h"
 
 static bool box_msg_proc(JWidget widget, JMessage msg);
 static void box_request_size(JWidget widget, int *w, int *h);
@@ -80,11 +81,11 @@ static void box_request_size(JWidget widget, int *w, int *h)
 #define GET_CHILD_SIZE(w, h)			\
   {						\
     if (widget->getAlign() & JI_HOMOGENEOUS)	\
-      *w = MAX(*w, req_##w);			\
+      *w = MAX(*w, reqSize.w);			\
     else					\
-      *w += req_##w;				\
+      *w += reqSize.w;				\
 						\
-    *h = MAX(*h, req_##h);			\
+    *h = MAX(*h, reqSize.h);			\
   }
 
 #define FINAL_SIZE(w)					\
@@ -96,7 +97,6 @@ static void box_request_size(JWidget widget, int *w, int *h)
   }
 
   int nvis_children;
-  int req_w, req_h;
   JWidget child;
   JLink link;
 
@@ -115,7 +115,7 @@ static void box_request_size(JWidget widget, int *w, int *h)
     if (child->flags & JI_HIDDEN)
       continue;
 
-    jwidget_request_size(child, &req_w, &req_h);
+    Size reqSize = child->getPreferredSize();
 
     if (widget->getAlign() & JI_HORIZONTAL) {
       GET_CHILD_SIZE(w, h);
@@ -151,7 +151,7 @@ static void box_set_position(JWidget widget, JRect rect)
 	extra = width / nvis_children;					\
       }									\
       else if (nexpand_children > 0) {					\
-	width = jrect_##w(widget->rc) - req_##w;			\
+	width = jrect_##w(widget->rc) - reqSize.w;			\
 	extra = width / nexpand_children;				\
       }									\
       else {								\
@@ -179,9 +179,9 @@ static void box_set_position(JWidget widget, JRect rect)
 	    width -= extra;						\
 	  }								\
 	  else {							\
-	    jwidget_request_size(child, &req_w, &req_h);		\
+	    reqSize = child->getPreferredSize();			\
 									\
-	    child_width = req_##w;					\
+	    child_width = reqSize.w;					\
 									\
 	    if (jwidget_is_expansive(child)) {				\
 	      if (nexpand_children == 1)				\
@@ -213,7 +213,6 @@ static void box_set_position(JWidget widget, JRect rect)
   JWidget child;
   int nvis_children = 0;
   int nexpand_children = 0;
-  int req_w, req_h;
   int child_width;
   JLink link;
   int width;
@@ -232,7 +231,7 @@ static void box_set_position(JWidget widget, JRect rect)
     }
   }
 
-  jwidget_request_size(widget, &req_w, &req_h);
+  Size reqSize = widget->getPreferredSize();
 
   if (widget->getAlign() & JI_HORIZONTAL) {
     FIXUP(x, y, w, h, l, t, r, b);
diff --git a/src/jinete/jcombobox.cpp b/src/jinete/jcombobox.cpp
index e7dc0ad68..274e6c986 100644
--- a/src/jinete/jcombobox.cpp
+++ b/src/jinete/jcombobox.cpp
@@ -34,6 +34,8 @@
 #include <allegro.h>
 
 #include "jinete/jinete.h"
+#include "Vaca/Size.h"
+#include "Vaca/PreferredSizeEvent.h"
 
 struct ComboBox::Item
 {
@@ -267,47 +269,16 @@ bool ComboBox::onProcessMessage(JMessage msg)
       closeListBox();
       break;
 
-    case JM_REQSIZE: {
-      int w, h;
-
-      msg->reqsize.w = 0;
-      msg->reqsize.h = 0;
-
-      jwidget_request_size(m_entry, &w, &h);
-
-      // Get the text-length of every item and put in 'w' the maximum value
-      std::vector<Item*>::iterator it, end = m_items.end();
-      for (it = m_items.begin(); it != end; ++it) {
-	int item_w =
-	  2*jguiscale()+
-	  text_length(this->getFont(), (*it)->text.c_str())+
-	  10*jguiscale();
-
-	w = MAX(w, item_w);
-      }
-
-      msg->reqsize.w += w;
-      msg->reqsize.h += h;
-
-      jwidget_request_size(m_button, &w, &h);
-      msg->reqsize.w += w;
-      msg->reqsize.h = MAX(msg->reqsize.h, h);
-
-      return true;
-    }
-
     case JM_SETPOS: {
       JRect cbox = jrect_new_copy(&msg->setpos.rect);
-      int w, h;
-
       jrect_copy(this->rc, cbox);
 
-      /* button */
-      jwidget_request_size(m_button, &w, &h);
-      cbox->x1 = msg->setpos.rect.x2 - w;
+      // Button
+      Size buttonSize = m_button->getPreferredSize();
+      cbox->x1 = msg->setpos.rect.x2 - buttonSize.w;
       jwidget_set_rect(m_button, cbox);
 
-      /* entry */
+      // Entry
       cbox->x2 = cbox->x1;
       cbox->x1 = msg->setpos.rect.x1;
       jwidget_set_rect(m_entry, cbox);
@@ -338,6 +309,31 @@ bool ComboBox::onProcessMessage(JMessage msg)
   return Widget::onProcessMessage(msg);
 }
 
+void ComboBox::onPreferredSize(PreferredSizeEvent& ev)
+{
+  Size reqSize(0, 0);
+  Size entrySize = m_entry->getPreferredSize();
+
+  // Get the text-length of every item and put in 'w' the maximum value
+  std::vector<Item*>::iterator it, end = m_items.end();
+  for (it = m_items.begin(); it != end; ++it) {
+    int item_w =
+      2*jguiscale()+
+      text_length(this->getFont(), (*it)->text.c_str())+
+      10*jguiscale();
+
+    reqSize.w = MAX(reqSize.w, item_w);
+  }
+
+  reqSize.w += entrySize.w;
+  reqSize.h += entrySize.h;
+
+  Size buttonSize = m_button->getPreferredSize();
+  reqSize.w += buttonSize.w;
+  reqSize.h = MAX(reqSize.h, buttonSize.h);
+  ev.setPreferredSize(reqSize);
+}
+
 static bool combobox_entry_msg_proc(JWidget widget, JMessage msg)
 {
   ComboBox* combobox = reinterpret_cast<ComboBox*>(widget->user_data[0]);
diff --git a/src/jinete/jcombobox.h b/src/jinete/jcombobox.h
index 52ed29447..85cee1da2 100644
--- a/src/jinete/jcombobox.h
+++ b/src/jinete/jcombobox.h
@@ -79,6 +79,7 @@ public:
 
 protected:
   bool onProcessMessage(JMessage msg);
+  void onPreferredSize(PreferredSizeEvent& ev);
 
 private:
   struct Item;
diff --git a/src/jinete/jgrid.cpp b/src/jinete/jgrid.cpp
index f8f39a329..31f28bece 100644
--- a/src/jinete/jgrid.cpp
+++ b/src/jinete/jgrid.cpp
@@ -41,6 +41,7 @@
 #include "jinete/jrect.h"
 #include "jinete/jwidget.h"
 #include "jinete/jtheme.h"
+#include "Vaca/Size.h"
 
 struct Cell
 {
@@ -214,7 +215,7 @@ static void grid_set_position(JWidget widget, JRect rect)
   Grid* grid = reinterpret_cast<Grid*>(jwidget_get_data(widget, JI_GRID));
   JRect cpos = jrect_new(0, 0, 0, 0);
   int pos_x, pos_y;
-  int req_w, req_h;
+  Size reqSize;
   int x, y, w, h;
   int col, row;
   int i, j;
@@ -251,30 +252,30 @@ static void grid_set_position(JWidget widget, JRect rect)
 	CALCULATE_CELL_SIZE(col, hspan, colstrip, w);
 	CALCULATE_CELL_SIZE(row, vspan, rowstrip, h);
 
-	jwidget_request_size(cell->child, &req_w, &req_h);
+	reqSize = cell->child->getPreferredSize();
 
 	if (cell->align & JI_LEFT) {
-	  w = req_w;
+	  w = reqSize.w;
 	}
 	else if (cell->align & JI_CENTER) {
-	  x += w/2 - req_w/2;
-	  w = req_w;
+	  x += w/2 - reqSize.w/2;
+	  w = reqSize.w;
 	}
 	else if (cell->align & JI_RIGHT) {
-	  x += w - req_w;
-	  w = req_w;
+	  x += w - reqSize.w;
+	  w = reqSize.w;
 	}
 
 	if (cell->align & JI_TOP) {
-	  h = req_h;
+	  h = reqSize.h;
 	}
 	else if (cell->align & JI_MIDDLE) {
-	  y += h/2 - req_h/2;
-	  h = req_h;
+	  y += h/2 - reqSize.h/2;
+	  h = reqSize.h;
 	}
 	else if (cell->align & JI_BOTTOM) {
-	  y += h - req_h;
-	  h = req_h;
+	  y += h - reqSize.h;
+	  h = reqSize.h;
 	}
 
 	jrect_replace(cpos, x, y, x+w, y+h);
@@ -299,7 +300,7 @@ static void grid_calculate_size(JWidget widget)
 {
   Grid* grid = reinterpret_cast<Grid*>(jwidget_get_data(widget, JI_GRID));
   int row, col, size;
-  int req_w, req_h;
+  Size reqSize;
   int i, expand;
   int expand_count;
   int last_expand;
@@ -320,15 +321,15 @@ static void grid_calculate_size(JWidget widget)
     for (p_row=0; p_row<grid->p_rows; ++p_row) {			\
       /* for each cell */						\
       cell = grid->cells[row]+col;					\
-      req_w = req_h = 0;						\
+      reqSize.w = reqSize.h = 0;					\
 									\
       if (cell->child != NULL) {					\
 	if (cell->parent == NULL) {					\
 	  /* if the widget isn't hidden then we can request its size */ \
 	  if (!(cell->child->flags & JI_HIDDEN)) {			\
-	    jwidget_request_size(cell->child, &req_w, &req_h);		\
-	    cell->w = req_w - (cell->hspan-1) * widget->child_spacing;	\
-	    cell->h = req_h - (cell->vspan-1) * widget->child_spacing;	\
+	    reqSize = cell->child->getPreferredSize();			\
+	    cell->w = reqSize.w - (cell->hspan-1) * widget->child_spacing;	\
+	    cell->h = reqSize.h - (cell->vspan-1) * widget->child_spacing;	\
 	    if ((cell->align & p_align) == p_align)			\
 	      ++expand_count;						\
 	  }								\
@@ -397,8 +398,8 @@ static void grid_calculate_size(JWidget widget)
     ++current_span;							\
   } while (more_span);
   
-  CALCULATE_STRIPS(col, cols, row, rows, vspan, req_w, colstrip, JI_HORIZONTAL);
-  CALCULATE_STRIPS(row, rows, col, cols, hspan, req_h, rowstrip, JI_VERTICAL);
+  CALCULATE_STRIPS(col, cols, row, rows, vspan, reqSize.w, colstrip, JI_HORIZONTAL);
+  CALCULATE_STRIPS(row, rows, col, cols, hspan, reqSize.h, rowstrip, JI_VERTICAL);
   EXPAND_STRIPS(col, cols, row, rows, hspan, w, colstrip, grid_inc_col_size);
   EXPAND_STRIPS(row, rows, col, cols, vspan, h, rowstrip, grid_inc_row_size);
 
diff --git a/src/jinete/jlistbox.cpp b/src/jinete/jlistbox.cpp
index 4eee82b6d..eee0582bf 100644
--- a/src/jinete/jlistbox.cpp
+++ b/src/jinete/jlistbox.cpp
@@ -41,6 +41,7 @@
 #include "jinete/jtheme.h"
 #include "jinete/jview.h"
 #include "jinete/jwidget.h"
+#include "Vaca/Size.h"
 
 static bool listbox_msg_proc(JWidget widget, JMessage msg);
 static void listbox_request_size(JWidget widget, int *w, int *h);
@@ -326,16 +327,16 @@ static bool listbox_msg_proc(JWidget widget, JMessage msg)
 
 static void listbox_request_size(JWidget widget, int *w, int *h)
 {
-  int req_w, req_h;
+  Size reqSize;
   JLink link;
 
   *w = *h = 0;
 
   JI_LIST_FOR_EACH(widget->children, link) {
-    jwidget_request_size(reinterpret_cast<JWidget>(link->data), &req_w, &req_h);
+    reqSize = reinterpret_cast<Widget*>(link->data)->getPreferredSize();
 
-    *w = MAX(*w, req_w);
-    *h += req_h + ((link->next)? widget->child_spacing: 0);
+    *w = MAX(*w, reqSize.w);
+    *h += reqSize.h + ((link->next)? widget->child_spacing: 0);
   }
 
   *w += widget->border_width.l + widget->border_width.r;
@@ -344,7 +345,7 @@ static void listbox_request_size(JWidget widget, int *w, int *h)
 
 static void listbox_set_position(JWidget widget, JRect rect)
 {
-  int req_w, req_h;
+  Size reqSize;
   JWidget child;
   JRect cpos;
   JLink link;
@@ -355,9 +356,9 @@ static void listbox_set_position(JWidget widget, JRect rect)
   JI_LIST_FOR_EACH(widget->children, link) {
     child = (JWidget)link->data;
 
-    jwidget_request_size(child, &req_w, &req_h);
+    reqSize = child->getPreferredSize();
 
-    cpos->y2 = cpos->y1+req_h;
+    cpos->y2 = cpos->y1+reqSize.h;
     jwidget_set_rect(child, cpos);
 
     cpos->y1 += jrect_h(child->rc) + widget->child_spacing;
@@ -427,24 +428,24 @@ static bool listitem_msg_proc(JWidget widget, JMessage msg)
 
 static void listitem_request_size(JWidget widget, int *w, int *h)
 {
-  int max_w, max_h;
-  int req_w, req_h;
+  Size maxSize;
+  Size reqSize;
   JLink link;
 
   if (widget->hasText()) {
-    max_w = jwidget_get_text_length(widget);
-    max_h = jwidget_get_text_height(widget);
+    maxSize.w = jwidget_get_text_length(widget);
+    maxSize.h = jwidget_get_text_height(widget);
   }
   else
-    max_w = max_h = 0;
+    maxSize.w = maxSize.h = 0;
 
   JI_LIST_FOR_EACH(widget->children, link) {
-    jwidget_request_size(reinterpret_cast<JWidget>(link->data), &req_w, &req_h);
+    reqSize = reinterpret_cast<Widget*>(link->data)->getPreferredSize();
 
-    max_w = MAX(max_w, req_w);
-    max_h = MAX(max_h, req_h);
+    maxSize.w = MAX(maxSize.w, reqSize.w);
+    maxSize.h = MAX(maxSize.h, reqSize.h);
   }
 
-  *w = widget->border_width.l + max_w + widget->border_width.r;
-  *h = widget->border_width.t + max_h + widget->border_width.b;
+  *w = widget->border_width.l + maxSize.w + widget->border_width.r;
+  *h = widget->border_width.t + maxSize.h + widget->border_width.b;
 }
diff --git a/src/jinete/jmenu.cpp b/src/jinete/jmenu.cpp
index 03db6909c..609773b19 100644
--- a/src/jinete/jmenu.cpp
+++ b/src/jinete/jmenu.cpp
@@ -38,6 +38,7 @@
 
 #include "jinete/jinete.h"
 #include "jinete/jintern.h"
+#include "Vaca/Size.h"
 
 /**********************************************************************/
 /* Internal messages: to move between menus */
@@ -405,23 +406,23 @@ static bool menu_msg_proc(JWidget widget, JMessage msg)
 
 static void menu_request_size(JWidget widget, int *w, int *h)
 {
-  int req_w, req_h;
+  Size reqSize;
   JLink link;
 
   *w = *h = 0;
 
   JI_LIST_FOR_EACH(widget->children, link) {
-    jwidget_request_size((JWidget)link->data, &req_w, &req_h);
+    reqSize = ((Widget*)link->data)->getPreferredSize();
 
     if (widget->parent->type == JI_MENUBAR) {
-      *w += req_w + ((link->next != widget->children->end) ?
-		     widget->child_spacing: 0);
-      *h = MAX(*h, req_h);
+      *w += reqSize.w + ((link->next != widget->children->end) ?
+			 widget->child_spacing: 0);
+      *h = MAX(*h, reqSize.h);
     }
     else {
-      *w = MAX(*w, req_w);
-      *h += req_h + ((link->next != widget->children->end) ?
-		     widget->child_spacing: 0);
+      *w = MAX(*w, reqSize.w);
+      *h += reqSize.h + ((link->next != widget->children->end) ?
+			 widget->child_spacing: 0);
     }
   }
 
@@ -431,7 +432,7 @@ static void menu_request_size(JWidget widget, int *w, int *h)
 
 static void menu_set_position(JWidget widget, JRect rect)
 {
-  int req_w, req_h;
+  Size reqSize;
   JWidget child;
   JRect cpos;
   JLink link;
@@ -442,12 +443,12 @@ static void menu_set_position(JWidget widget, JRect rect)
   JI_LIST_FOR_EACH(widget->children, link) {
     child = (JWidget)link->data;
 
-    jwidget_request_size(child, &req_w, &req_h);
+    reqSize = child->getPreferredSize();
 
     if (widget->parent->type == JI_MENUBAR)
-      cpos->x2 = cpos->x1+req_w;
+      cpos->x2 = cpos->x1+reqSize.w;
     else
-      cpos->y2 = cpos->y1+req_h;
+      cpos->y2 = cpos->y1+reqSize.h;
 
     jwidget_set_rect(child, cpos);
 
@@ -780,8 +781,11 @@ static void menubox_request_size(JWidget widget, int *w, int *h)
 {
   JWidget menu = jmenubox_get_menu(widget);
 
-  if (menu)
-    jwidget_request_size(menu, w, h);
+  if (menu) {
+    Size reqSize = menu->getPreferredSize();
+    *w = reqSize.w;
+    *h = reqSize.h;
+  }
   else
     *w = *h = 0;
 
diff --git a/src/jinete/jpanel.cpp b/src/jinete/jpanel.cpp
index 89fc8348c..4279e2b37 100644
--- a/src/jinete/jpanel.cpp
+++ b/src/jinete/jpanel.cpp
@@ -37,6 +37,7 @@
 #include "jinete/jsystem.h"
 #include "jinete/jtheme.h"
 #include "jinete/jwidget.h"
+#include "Vaca/Size.h"
 
 typedef struct Panel
 {
@@ -227,8 +228,8 @@ static void panel_request_size(JWidget widget, int *w, int *h)
 {
 #define GET_CHILD_SIZE(w, h)			\
   do {						\
-    *w = MAX(*w, req_##w);			\
-    *h = MAX(*h, req_##h);			\
+    *w = MAX(*w, reqSize.w);			\
+    *h = MAX(*h, reqSize.h);			\
   } while(0)
 
 #define FINAL_SIZE(w)					\
@@ -238,7 +239,7 @@ static void panel_request_size(JWidget widget, int *w, int *h)
   } while(0)
 
   int nvis_children;
-  int req_w, req_h;
+  Size reqSize;
   JWidget child;
   JLink link;
 
@@ -257,7 +258,7 @@ static void panel_request_size(JWidget widget, int *w, int *h)
     if (child->flags & JI_HIDDEN)
       continue;
 
-    jwidget_request_size(child, &req_w, &req_h);
+    reqSize = child->getPreferredSize();
 
     if (widget->getAlign() & JI_HORIZONTAL)
       GET_CHILD_SIZE(w, h);
@@ -286,7 +287,7 @@ static void panel_set_position(JWidget widget, JRect rect)
     pos->y##1 = widget->rc->y##1;					\
     pos->x##2 = pos->x##1 + avail*panel->pos/100;			\
     /* TODO uncomment this to make a restricted panel */		\
-    /* pos->w = MID(req1_##w, pos->w, avail-req2_##w); */		\
+    /* pos->w = MID(reqSize1.w, pos->w, avail-reqSize2.w); */		\
     pos->y##2 = pos->y##1 + jrect_##h(widget->rc);			\
 									\
     jwidget_set_rect(child1, pos);					\
@@ -309,11 +310,8 @@ static void panel_set_position(JWidget widget, JRect rect)
   if (jlist_length(widget->children) == 2) {
     JWidget child1 = reinterpret_cast<JWidget>(jlist_first(widget->children)->data);
     JWidget child2 = reinterpret_cast<JWidget>(jlist_first(widget->children)->next->data);
-    int req1_w, req1_h;
-    int req2_w, req2_h;
-
-    jwidget_request_size(child1, &req1_w, &req1_h);
-    jwidget_request_size(child2, &req2_w, &req2_h);
+    //Size reqSize1 = child1->getPreferredSize();
+    //Size reqSize2 = child2->getPreferredSize();
 
     if (widget->getAlign() & JI_HORIZONTAL)
       FIXUP(x, y, w, h, l, t, r, b);
diff --git a/src/jinete/jpopup_window.cpp b/src/jinete/jpopup_window.cpp
index 555f00809..413c81a54 100644
--- a/src/jinete/jpopup_window.cpp
+++ b/src/jinete/jpopup_window.cpp
@@ -36,6 +36,8 @@
 
 #include "jinete/jinete.h"
 #include "jinete/jintern.h"
+#include "Vaca/Size.h"
+#include "Vaca/PreferredSizeEvent.h"
 
 PopupWindow::PopupWindow(const char* text, bool close_on_buttonpressed)
   : Frame(false, text)
@@ -104,37 +106,6 @@ bool PopupWindow::onProcessMessage(JMessage msg)
       }
       break;
 
-    case JM_REQSIZE: {
-      int w = 0, h = 0;
-
-      _ji_theme_textbox_draw(NULL, this, &w, &h, 0, 0);
-
-      msg->reqsize.w = w;
-      msg->reqsize.h = this->border_width.t + this->border_width.b;
-
-      if (!jlist_empty(this->children)) {
-	int max_w, max_h;
-	int req_w, req_h;
-	JWidget child;
-	JLink link;
-
-	max_w = max_h = 0;
-	JI_LIST_FOR_EACH(this->children, link) {
-	  child = (JWidget)link->data;
-
-	  jwidget_request_size(child, &req_w, &req_h);
-
-	  max_w = MAX(max_w, req_w);
-	  max_h = MAX(max_h, req_h);
-	}
-
-	msg->reqsize.w = MAX(msg->reqsize.w,
-			     this->border_width.l + max_w + this->border_width.r);
-	msg->reqsize.h += max_h;
-      }
-      return true;
-    }
-
     case JM_SIGNAL:
       if (msg->signal.num == JI_SIGNAL_INIT_THEME) {
 	int w = 0, h = 0;
@@ -216,3 +187,32 @@ bool PopupWindow::onProcessMessage(JMessage msg)
 
   return Frame::onProcessMessage(msg);
 }
+
+void PopupWindow::onPreferredSize(PreferredSizeEvent& ev)
+{
+  Size resultSize(0, 0);
+
+  _ji_theme_textbox_draw(NULL, this, &resultSize.w, &resultSize.h, 0, 0);
+  resultSize.h = this->border_width.t + this->border_width.b;
+
+  if (!jlist_empty(this->children)) {
+    Size maxSize(0, 0);
+    Size reqSize;
+    JWidget child;
+    JLink link;
+
+    JI_LIST_FOR_EACH(this->children, link) {
+      child = (JWidget)link->data;
+
+      reqSize = child->getPreferredSize();
+
+      maxSize.w = MAX(maxSize.w, reqSize.w);
+      maxSize.h = MAX(maxSize.h, reqSize.h);
+    }
+
+    resultSize.w = MAX(resultSize.w, this->border_width.l + maxSize.w + this->border_width.r);
+    resultSize.h += maxSize.h;
+  }
+
+  ev.setPreferredSize(resultSize);
+}
diff --git a/src/jinete/jpopup_window.h b/src/jinete/jpopup_window.h
index abf52c389..1e6f1cfd1 100644
--- a/src/jinete/jpopup_window.h
+++ b/src/jinete/jpopup_window.h
@@ -48,6 +48,7 @@ public:
 
 protected:
   bool onProcessMessage(JMessage msg);
+  void onPreferredSize(PreferredSizeEvent& ev);
 };
 
 #endif
diff --git a/src/jinete/jsep.cpp b/src/jinete/jsep.cpp
index 79d88f567..7043c0893 100644
--- a/src/jinete/jsep.cpp
+++ b/src/jinete/jsep.cpp
@@ -36,6 +36,7 @@
 #include "jinete/jrect.h"
 #include "jinete/jtheme.h"
 #include "jinete/jwidget.h"
+#include "Vaca/Size.h"
 
 static bool separator_msg_proc(JWidget widget, JMessage msg);
 
@@ -56,25 +57,24 @@ static bool separator_msg_proc(JWidget widget, JMessage msg)
   switch (msg->type) {
 
     case JM_REQSIZE: {
-      int max_w, max_h;
-      int req_w, req_h;
+      Size maxSize(0, 0);
+      Size reqSize;
       JWidget child;
       JLink link;
 
-      max_w = max_h = 0;
       JI_LIST_FOR_EACH(widget->children, link) {
 	child = (JWidget)link->data;
 
-	jwidget_request_size(child, &req_w, &req_h);
-	max_w = MAX(max_w, req_w);
-	max_h = MAX(max_h, req_h);
+	reqSize = child->getPreferredSize();
+	maxSize.w = MAX(maxSize.w, reqSize.w);
+	maxSize.h = MAX(maxSize.h, reqSize.h);
       }
 
       if (widget->hasText())
-	max_w = MAX(max_w, jwidget_get_text_length(widget));
+	maxSize.w = MAX(maxSize.w, jwidget_get_text_length(widget));
 
-      msg->reqsize.w = widget->border_width.l + max_w + widget->border_width.r;
-      msg->reqsize.h = widget->border_width.t + max_h + widget->border_width.b;
+      msg->reqsize.w = widget->border_width.l + maxSize.w + widget->border_width.r;
+      msg->reqsize.h = widget->border_width.t + maxSize.h + widget->border_width.b;
       return true;
     }
 
diff --git a/src/jinete/jtooltips.cpp b/src/jinete/jtooltips.cpp
index 6210e5543..dd354f73f 100644
--- a/src/jinete/jtooltips.cpp
+++ b/src/jinete/jtooltips.cpp
@@ -23,6 +23,8 @@
 
 #include "jinete/jinete.h"
 #include "jinete/jintern.h"
+#include "Vaca/Size.h"
+#include "Vaca/PreferredSizeEvent.h"
 
 typedef struct TipData
 {
@@ -210,37 +212,6 @@ bool TipWindow::onProcessMessage(JMessage msg)
       }
       break;
 
-    case JM_REQSIZE: {
-      int w = 0, h = 0;
-
-      _ji_theme_textbox_draw(NULL, this, &w, &h, 0, 0);
-
-      msg->reqsize.w = w;
-      msg->reqsize.h = this->border_width.t + this->border_width.b;
-
-      if (!jlist_empty(this->children)) {
-	int max_w, max_h;
-	int req_w, req_h;
-	JWidget child;
-	JLink link;
-
-	max_w = max_h = 0;
-	JI_LIST_FOR_EACH(this->children, link) {
-	  child = (JWidget)link->data;
-
-	  jwidget_request_size(child, &req_w, &req_h);
-
-	  max_w = MAX(max_w, req_w);
-	  max_h = MAX(max_h, req_h);
-	}
-
-	msg->reqsize.w = MAX(msg->reqsize.w,
-			     this->border_width.l + max_w + this->border_width.r);
-	msg->reqsize.h += max_h;
-      }
-      return true;
-    }
-
     case JM_SIGNAL:
       if (msg->signal.num == JI_SIGNAL_INIT_THEME) {
 	int w = 0, h = 0;
@@ -325,3 +296,32 @@ bool TipWindow::onProcessMessage(JMessage msg)
 
   return Frame::onProcessMessage(msg);
 }
+
+void TipWindow::onPreferredSize(PreferredSizeEvent& ev)
+{
+  Size resultSize(0, 0);
+
+  _ji_theme_textbox_draw(NULL, this, &resultSize.w, &resultSize.h, 0, 0);
+  resultSize.h = this->border_width.t + this->border_width.b;
+
+  if (!jlist_empty(this->children)) {
+    Size maxSize(0, 0);
+    Size reqSize;
+    JWidget child;
+    JLink link;
+
+    JI_LIST_FOR_EACH(this->children, link) {
+      child = (JWidget)link->data;
+
+      reqSize = child->getPreferredSize();
+
+      maxSize.w = MAX(maxSize.w, reqSize.w);
+      maxSize.h = MAX(maxSize.h, reqSize.h);
+    }
+
+    resultSize.w = MAX(resultSize.w, this->border_width.l + maxSize.w + this->border_width.r);
+    resultSize.h += maxSize.h;
+  }
+
+  ev.setPreferredSize(resultSize);
+}
diff --git a/src/jinete/jtooltips.h b/src/jinete/jtooltips.h
index b6b42daba..ff3983c8e 100644
--- a/src/jinete/jtooltips.h
+++ b/src/jinete/jtooltips.h
@@ -49,6 +49,7 @@ public:
 
 protected:
   bool onProcessMessage(JMessage msg);
+  void onPreferredSize(PreferredSizeEvent& ev);
 };
 
 void jwidget_add_tooltip_text(Widget* widget, const char *text);
diff --git a/src/jinete/jview.cpp b/src/jinete/jview.cpp
index 49e4283ae..55cd931db 100644
--- a/src/jinete/jview.cpp
+++ b/src/jinete/jview.cpp
@@ -40,6 +40,7 @@
 #include "jinete/jtheme.h"
 #include "jinete/jview.h"
 #include "jinete/jwidget.h"
+#include "Vaca/Size.h"
 
 #define BAR_SIZE widget->theme->scrollbar_size
 
@@ -353,9 +354,9 @@ static bool view_msg_proc(JWidget widget, JMessage msg)
     case JM_REQSIZE: {
       View* view = reinterpret_cast<View*>(jwidget_get_data(widget, JI_VIEW));
 
-      jwidget_request_size(view->viewport,
-			   &msg->reqsize.w,
-			   &msg->reqsize.h);
+      Size viewSize = view->viewport->getPreferredSize();
+      msg->reqsize.w = viewSize.w;
+      msg->reqsize.h = viewSize.h;
 
       msg->reqsize.w += widget->border_width.l + widget->border_width.r;
       msg->reqsize.h += widget->border_width.t + widget->border_width.b;
@@ -426,23 +427,23 @@ static bool viewport_msg_proc(JWidget widget, JMessage msg)
 
 static void viewport_needed_size(JWidget widget, int *w, int *h)
 {
-  int req_h, req_w;
+  Size reqSize;
   JLink link;
 
   *w = *h = 0;
 
   JI_LIST_FOR_EACH(widget->children, link) {
-    jwidget_request_size((JWidget)link->data, &req_w, &req_h);
+    reqSize = ((Widget*)link->data)->getPreferredSize();
 
-    *w = MAX(*w, req_w);
-    *h = MAX(*h, req_h);
+    *w = MAX(*w, reqSize.w);
+    *h = MAX(*h, reqSize.h);
   }
 }
 
 static void viewport_set_position(JWidget widget, JRect rect)
 {
   int scroll_x, scroll_y;
-  int req_h, req_w;
+  Size reqSize;
   JWidget child;
   JRect cpos;
   JLink link;
@@ -457,16 +458,15 @@ static void viewport_set_position(JWidget widget, JRect rect)
 
   JI_LIST_FOR_EACH(widget->children, link) {
     child = (JWidget)link->data;
+    reqSize = child->getPreferredSize();
 
-    jwidget_request_size(child, &req_w, &req_h);
+    cpos->x2 = cpos->x1 + MAX(reqSize.w, jrect_w(widget->rc)
+					 - widget->border_width.l
+					 - widget->border_width.r);
 
-    cpos->x2 = cpos->x1 + MAX(req_w, jrect_w(widget->rc)
-				     - widget->border_width.l
-				     - widget->border_width.r);
-
-    cpos->y2 = cpos->y1 + MAX(req_h, jrect_h(widget->rc)
-				     - widget->border_width.t
-				     - widget->border_width.b);
+    cpos->y2 = cpos->y1 + MAX(reqSize.h, jrect_h(widget->rc)
+					 - widget->border_width.t
+					 - widget->border_width.b);
 
     jwidget_set_rect(child, cpos);
   }
diff --git a/src/jinete/jwidget.cpp b/src/jinete/jwidget.cpp
index 037aa82ac..a50edf9df 100644
--- a/src/jinete/jwidget.cpp
+++ b/src/jinete/jwidget.cpp
@@ -49,6 +49,7 @@
 
 #include "jinete/jinete.h"
 #include "jinete/jintern.h"
+#include "Vaca/PreferredSizeEvent.h"
 
 int ji_register_widget_type()
 {
@@ -95,6 +96,8 @@ Widget::Widget(int type)
   this->user_data[1] = NULL;
   this->user_data[2] = NULL;
   this->user_data[3] = NULL;
+
+  m_preferredSize = NULL;
 }
 
 void jwidget_free(JWidget widget)
@@ -144,6 +147,9 @@ Widget::~Widget()
     jhook_free(reinterpret_cast<JHook>(link->data));
   jlist_free(this->hooks);
 
+  // Delete the preferred size
+  delete m_preferredSize;
+
   /* low level free */
   _ji_remove_widget(this);
 }
@@ -704,19 +710,6 @@ void Widget::setBounds(const Rect& rc)
   jwidget_set_rect(this, &jrc);
 }
 
-void jwidget_request_size(JWidget widget, int *w, int *h)
-{
-  JMessage msg;
-
-  assert_valid_widget(widget);
-
-  msg = jmessage_new(JM_REQSIZE);
-  jwidget_send_message(widget, msg);
-  *w = MID(widget->min_w, msg->reqsize.w, widget->max_w);
-  *h = MID(widget->min_h, msg->reqsize.h, widget->max_h);
-  jmessage_free(msg);
-}
-
 void jwidget_relayout(JWidget widget)
 {
   jwidget_set_rect(widget, widget->rc);
@@ -1308,6 +1301,76 @@ void Widget::closeWindow()
     frame->closeWindow(this);
 }
 
+// ===============================================================
+// SIZE & POSITION
+// ===============================================================
+
+/**
+   Returns the preferred size of the Widget.
+
+   It checks if the preferred size is static (it means when it was
+   set through #setPreferredSize before) or if it is dynamic (this is
+   the default and is when the #onPreferredSize is used to determined
+   the preferred size).
+
+   In another words, if you do not use #setPreferredSize to set a
+   <em>static preferred size</em> for the widget then #onPreferredSize
+   will be used to calculate it.
+
+   @see setPreferredSize, onPreferredSize, #getPreferredSize(const Size &)
+*/
+Size Widget::getPreferredSize()
+{
+  if (m_preferredSize != NULL)
+    return *m_preferredSize;
+  else {
+    PreferredSizeEvent ev(this, Size(0, 0));
+    onPreferredSize(ev);
+    return ev.getPreferredSize();
+  }
+}
+
+/**
+   Returns the preferred size trying to fit in the specified size.
+   Remember that if you use #setPreferredSize this routine will
+   return the static size which you specified manually.
+
+   @param fitIn
+       This can have both attributes (width and height) in
+       zero, which means that it'll behave same as #getPreferredSize().
+       If the width is great than zero the #onPreferredSize will try to
+       fit in that width (this is useful to fit @link Vaca::Label Label@endlink
+       or @link Vaca::Edit Edit@endlink controls in a specified width and
+       calculate the height it could occupy).
+
+   @see getPreferredSize
+*/
+Size Widget::getPreferredSize(const Size& fitIn)
+{
+  if (m_preferredSize != NULL)
+    return *m_preferredSize;
+  else {
+    PreferredSizeEvent ev(this, fitIn);
+    onPreferredSize(ev);
+    return ev.getPreferredSize();
+  }
+}
+
+/**
+   Sets a fixed preferred size specified by the user.
+   Widget::getPreferredSize() will return this value if it's setted.
+*/
+void Widget::setPreferredSize(const Size& fixedSize)
+{
+  delete m_preferredSize;
+  m_preferredSize = new Size(fixedSize);
+}
+
+void Widget::setPreferredSize(int fixedWidth, int fixedHeight)
+{
+  setPreferredSize(Size(fixedWidth, fixedHeight));
+}
+
 // ===============================================================
 // FOCUS & MOUSE
 // ===============================================================
@@ -1503,3 +1566,29 @@ bool Widget::onProcessMessage(JMessage msg)
 
   return false;
 }
+
+// ===============================================================
+// EVENTS
+// ===============================================================
+
+/**
+   Calculates the preferred size for the widget.
+
+   The default implementation get the preferred size of the current
+   layout manager. Also, if there exists layout-free widgets inside
+   this parent (like a StatusBar), they preferred-sizes are
+   accumulated.
+
+   @see Layout#getPreferredSize,
+*/
+void Widget::onPreferredSize(PreferredSizeEvent& ev)
+{
+  JMessage msg = jmessage_new(JM_REQSIZE);
+  jwidget_send_message(this, msg);
+  Size sz(msg->reqsize.w, msg->reqsize.h);
+  sz.w = MID(this->min_w, sz.w, this->max_w);
+  sz.h = MID(this->min_h, sz.h, this->max_h);
+  jmessage_free(msg);
+
+  ev.setPreferredSize(sz);
+}
diff --git a/src/jinete/jwidget.h b/src/jinete/jwidget.h
index 821e7b48d..c6b0285b3 100644
--- a/src/jinete/jwidget.h
+++ b/src/jinete/jwidget.h
@@ -39,6 +39,8 @@
 #include "Vaca/Rect.h"
 #include "Vaca/Widget.h"
 
+namespace Vaca { class PreferredSizeEvent; }
+
 #ifndef NDEBUG
 #include "jinete/jintern.h"
 #define assert_valid_widget(widget) assert((widget) != NULL &&		\
@@ -48,6 +50,8 @@
 #endif
 
 using Vaca::Rect;
+using Vaca::Size;
+using Vaca::PreferredSizeEvent;
 
 struct FONT;
 struct BITMAP;
@@ -101,7 +105,6 @@ bool jwidget_has_child(JWidget widget, JWidget child);
 
 /* position and geometry */
 
-void jwidget_request_size(JWidget widget, int *w, int *h);
 void jwidget_relayout(JWidget widget);
 JRect jwidget_get_rect(JWidget widget);
 JRect jwidget_get_child_rect(JWidget widget);
@@ -292,6 +295,15 @@ public:
   bool sendMessage(JMessage msg);
   void closeWindow();
 
+  // ===============================================================
+  // SIZE & POSITION
+  // ===============================================================
+
+  Size getPreferredSize();
+  Size getPreferredSize(const Size& fitIn);
+  void setPreferredSize(const Size& fixedSize);
+  void setPreferredSize(int fixedWidth, int fixedHeight);
+
   // ===============================================================
   // FOCUS & MOUSE
   // ===============================================================
@@ -306,8 +318,21 @@ public:
   bool hasCapture();
 
 protected:
+
+  // ===============================================================
+  // MESSAGE PROCESSING
+  // ===============================================================
+
   virtual bool onProcessMessage(JMessage msg);
 
+  // ===============================================================
+  // EVENTS
+  // ===============================================================
+
+  virtual void onPreferredSize(PreferredSizeEvent& ev);
+
+private:
+  Size* m_preferredSize;
 };
 
 #endif
diff --git a/src/jinete/jwindow.cpp b/src/jinete/jwindow.cpp
index d7fee505d..bf97d648f 100644
--- a/src/jinete/jwindow.cpp
+++ b/src/jinete/jwindow.cpp
@@ -38,6 +38,8 @@
 
 #include "jinete/jinete.h"
 #include "jinete/jintern.h"
+#include "Vaca/Size.h"
+#include "Vaca/PreferredSizeEvent.h"
 
 enum {
   WINDOW_NONE = 0,
@@ -115,7 +117,7 @@ void Frame::set_wantfocus(bool state)
 
 void Frame::remap_window()
 {
-  int req_w, req_h;
+  Size reqSize;
   JRect rect;
 
   if (m_is_autoremap) {
@@ -123,11 +125,11 @@ void Frame::remap_window()
     this->setVisible(true);
   }
 
-  jwidget_request_size(this, &req_w, &req_h);
+  reqSize = this->getPreferredSize();
 
   rect = jrect_new(this->rc->x1, this->rc->y1,
-		   this->rc->x1+req_w,
-		   this->rc->y1+req_h);
+		   this->rc->x1+reqSize.w,
+		   this->rc->y1+reqSize.h);
   jwidget_set_rect(this, rect);
   jrect_free(rect);
 
@@ -242,10 +244,6 @@ bool Frame::onProcessMessage(JMessage msg)
 {
   switch (msg->type) {
 
-    case JM_REQSIZE:
-      this->window_request_size(&msg->reqsize.w, &msg->reqsize.h);
-      return true;
-
     case JM_SETPOS:
       this->window_set_position(&msg->setpos.rect);
       return true;
@@ -412,39 +410,38 @@ bool Frame::onProcessMessage(JMessage msg)
   return Widget::onProcessMessage(msg);
 }
 
-void Frame::window_request_size(int *w, int *h)
+void Frame::onPreferredSize(PreferredSizeEvent& ev)
 {
   JWidget manager = getManager();
 
   if (m_is_desktop) {
     JRect cpos = jwidget_get_child_rect(manager);
-    *w = jrect_w(cpos);
-    *h = jrect_h(cpos);
+    ev.setPreferredSize(jrect_w(cpos),
+			jrect_h(cpos));
     jrect_free(cpos);
   }
   else {
-    int max_w, max_h;
-    int req_w, req_h;
+    Size maxSize(0, 0);
+    Size reqSize;
     JWidget child;
     JLink link;
 
-    max_w = max_h = 0;
     JI_LIST_FOR_EACH(this->children, link) {
       child = (JWidget)link->data;
 
       if (!jwidget_is_decorative(child)) {
-	jwidget_request_size(child, &req_w, &req_h);
+	reqSize = child->getPreferredSize();
 
-	max_w = MAX(max_w, req_w);
-	max_h = MAX(max_h, req_h);
+	maxSize.w = MAX(maxSize.w, reqSize.w);
+	maxSize.h = MAX(maxSize.h, reqSize.h);
       }
     }
 
     if (this->hasText())
-      max_w = MAX(max_w, jwidget_get_text_length(this));
+      maxSize.w = MAX(maxSize.w, jwidget_get_text_length(this));
 
-    *w = this->border_width.l + max_w + this->border_width.r;
-    *h = this->border_width.t + max_h + this->border_width.b;
+    ev.setPreferredSize(this->border_width.l + maxSize.w + this->border_width.r,
+			this->border_width.t + maxSize.h + this->border_width.b);
   }
 }
 
@@ -546,10 +543,6 @@ int Frame::get_action(int x, int y)
 
 void Frame::limit_size(int *w, int *h)
 {
-  int req_w, req_h;
-
-  jwidget_request_size(this, &req_w, &req_h);
-
   *w = MAX(*w, this->border_width.l+this->border_width.r);
   *h = MAX(*h, this->border_width.t+this->border_width.b);
 }
diff --git a/src/jinete/jwindow.h b/src/jinete/jwindow.h
index 3d66636f7..b351d6c23 100644
--- a/src/jinete/jwindow.h
+++ b/src/jinete/jwindow.h
@@ -83,9 +83,9 @@ public:
 
 protected:
   bool onProcessMessage(JMessage msg);
+  void onPreferredSize(PreferredSizeEvent& ev);
 
 private:
-  void window_request_size(int* w, int* h);
   void window_set_position(JRect rect);
   int get_action(int x, int y);
   void limit_size(int* w, int* h);
diff --git a/third_party/vaca/include/Vaca/Event.h b/third_party/vaca/include/Vaca/Event.h
new file mode 100644
index 000000000..648a99a05
--- /dev/null
+++ b/third_party/vaca/include/Vaca/Event.h
@@ -0,0 +1,61 @@
+// Vaca - Visual Application Components Abstraction
+// Copyright (c) 2005-2010 David Capello
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// * Redistributions of source code must retain the above copyright
+//   notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in
+//   the documentation and/or other materials provided with the
+//   distribution.
+// * Neither the name of the author nor the names of its contributors
+//   may be used to endorse or promote products derived from this
+//   software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef VACA_EVENT_H
+#define VACA_EVENT_H
+
+#include "Vaca/base.h"
+
+namespace Vaca {
+
+/**
+   Base class for every kind of event.
+*/
+class VACA_DLL Event
+{
+  /**
+     The component which generates the event. It's specified in the
+     @link Event#Event(Component*) Event's constructor@endlink
+  */
+  Component* m_source;
+
+public:
+
+  Event(Component* source);
+  virtual ~Event();
+
+  Component* getSource();
+
+};
+
+} // namespace Vaca
+
+#endif // VACA_EVENT_H
diff --git a/third_party/vaca/include/Vaca/PreferredSizeEvent.h b/third_party/vaca/include/Vaca/PreferredSizeEvent.h
new file mode 100644
index 000000000..1766e241b
--- /dev/null
+++ b/third_party/vaca/include/Vaca/PreferredSizeEvent.h
@@ -0,0 +1,63 @@
+// Vaca - Visual Application Components Abstraction
+// Copyright (c) 2005-2010 David Capello
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// * Redistributions of source code must retain the above copyright
+//   notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in
+//   the documentation and/or other materials provided with the
+//   distribution.
+// * Neither the name of the author nor the names of its contributors
+//   may be used to endorse or promote products derived from this
+//   software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef VACA_PREFERREDSIZEEVENT_H
+#define VACA_PREFERREDSIZEEVENT_H
+
+#include "Vaca/base.h"
+#include "Vaca/Event.h"
+#include "Vaca/Size.h"
+
+namespace Vaca {
+
+class VACA_DLL PreferredSizeEvent : public Event
+{
+  Size m_fitIn;
+  Size m_preferredSize;
+
+public:
+
+  PreferredSizeEvent(Widget* source, const Size& fitIn);
+  virtual ~PreferredSizeEvent();
+
+  Size fitInSize() const;
+  int fitInWidth() const;
+  int fitInHeight() const;
+
+  Size getPreferredSize() const;
+  void setPreferredSize(const Size& preferredSize);
+  void setPreferredSize(int w, int h);
+
+};
+
+} // namespace Vaca
+
+#endif // VACA_PREFERREDSIZEEVENT_H
diff --git a/third_party/vaca/src/Event.cpp b/third_party/vaca/src/Event.cpp
new file mode 100644
index 000000000..56bf45b0d
--- /dev/null
+++ b/third_party/vaca/src/Event.cpp
@@ -0,0 +1,64 @@
+// Vaca - Visual Application Components Abstraction
+// Copyright (c) 2005-2010 David Capello
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// * Redistributions of source code must retain the above copyright
+//   notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in
+//   the documentation and/or other materials provided with the
+//   distribution.
+// * Neither the name of the author nor the names of its contributors
+//   may be used to endorse or promote products derived from this
+//   software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "Vaca/Event.h"
+
+using namespace Vaca;
+
+/**
+   Creates a new event specifying that it was generated
+   from the @a source component.
+
+   @param source
+     The component which generates the event.
+*/
+Event::Event(Component* source)
+  : m_source(source)
+{
+}
+
+/**
+   Destroys the event.
+*/
+Event::~Event()
+{
+}
+
+/**
+   Returns the event's source.
+
+   @return
+     The component which generates the event.
+*/
+Component* Event::getSource()
+{
+  return m_source;
+}
diff --git a/third_party/vaca/src/PreferredSizeEvent.cpp b/third_party/vaca/src/PreferredSizeEvent.cpp
new file mode 100644
index 000000000..b8ce705b5
--- /dev/null
+++ b/third_party/vaca/src/PreferredSizeEvent.cpp
@@ -0,0 +1,94 @@
+// Vaca - Visual Application Components Abstraction
+// Copyright (c) 2005-2010 David Capello
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+// * Redistributions of source code must retain the above copyright
+//   notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in
+//   the documentation and/or other materials provided with the
+//   distribution.
+// * Neither the name of the author nor the names of its contributors
+//   may be used to endorse or promote products derived from this
+//   software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "Vaca/PreferredSizeEvent.h"
+#include "Vaca/Widget.h"
+
+using namespace Vaca;
+
+/**
+   Event generated to calculate the preferred size of a widget.
+
+   @param source
+     The widget that want to know its preferred size.
+
+   @param fitIn
+     This could be Size(0, 0) that means calculate the preferred size
+     without restrictions. If its width or height is greater than 0,
+     you could try to fit your widget to that width or height.
+*/
+PreferredSizeEvent::PreferredSizeEvent(Widget* source, const Size& fitIn)
+  : Event(source)
+  , m_fitIn(fitIn)
+  , m_preferredSize(0, 0)
+{
+}
+
+/**
+   Destroys the PreferredSizeEvent.
+*/
+PreferredSizeEvent::~PreferredSizeEvent()
+{
+}
+
+Size PreferredSizeEvent::fitInSize() const
+{
+  return m_fitIn;
+}
+
+int PreferredSizeEvent::fitInWidth() const
+{
+  return m_fitIn.w;
+}
+
+int PreferredSizeEvent::fitInHeight() const
+{
+  return m_fitIn.h;
+}
+
+Size PreferredSizeEvent::getPreferredSize() const
+{
+  return m_preferredSize;
+}
+
+void PreferredSizeEvent::setPreferredSize(const Size& preferredSize)
+{
+  m_preferredSize = preferredSize;
+}
+
+/**
+   Sets the preferred size for the widget.
+*/
+void PreferredSizeEvent::setPreferredSize(int w, int h)
+{
+  m_preferredSize.w = w;
+  m_preferredSize.h = h;
+}