fltk/src/Fl_Widget.cxx

//
// "$Id$"
//
// Base widget class for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2009 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems on the following page:
//
//     http://www.fltk.org/str.php
//

#include <FL/Fl.H>
#include <FL/Fl_Widget.H>
#include <FL/Fl_Group.H>
#include <FL/Fl_Tooltip.H>
#include <FL/fl_draw.H>
#include <stdlib.h>
#include "flstring.h"


////////////////////////////////////////////////////////////////
// for compatibility with Forms, all widgets without callbacks are
// inserted into a "queue" when they are activated, and the forms
// compatibility interaction functions (fl_do_events, etc.) will
// read one widget at a time from this queue and return it:

const int QUEUE_SIZE = 20;

static Fl_Widget *obj_queue[QUEUE_SIZE];
static int obj_head, obj_tail;

void Fl_Widget::default_callback(Fl_Widget *o, void * /*v*/) {
#if 0
  // This is necessary for strict forms compatibility but is confusing.
  // Use the parent's callback if this widget does not have one.
  for (Fl_Widget *p = o->parent(); p; p = p->parent())
    if (p->callback() != default_callback) {
      p->do_callback(o,v);
      return;
    }
#endif
  obj_queue[obj_head++] = o;
  if (obj_head >= QUEUE_SIZE) obj_head = 0;
  if (obj_head == obj_tail) {
    obj_tail++;
    if (obj_tail >= QUEUE_SIZE) obj_tail = 0;
  }
}
/**
    All Fl_Widgets that don't have a callback defined use a
    default callback that puts a pointer to the widget in this queue,
    and this method reads the oldest widget out of this queue.
*/
Fl_Widget *Fl::readqueue() {
  if (obj_tail==obj_head) return 0;
  Fl_Widget *o = obj_queue[obj_tail++];
  if (obj_tail >= QUEUE_SIZE) obj_tail = 0;
  return o;
}
/*
    This static internal function removes all pending callbacks for a
    specific widget from the default callback queue (Fl::readqueue()).
    It is only called from Fl_Widget's destructor if the widget
    doesn't have an own callback.
    Note: There's no need to have this in the Fl:: namespace.
*/
static void cleanup_readqueue(Fl_Widget *w) {

  if (obj_tail==obj_head) return;
  
  // Read the entire queue and copy over all valid entries.
  // The new head will be determined after the last copied entry.

  int old_head = obj_head;	// save newest entry
  int entry = obj_tail;		// oldest entry
  obj_head = obj_tail;		// new queue start
  for (;;) {
    Fl_Widget *o = obj_queue[entry++];
    if (entry >= QUEUE_SIZE) entry = 0;
    if (o != w) { // valid entry
      obj_queue[obj_head++] = o;
      if (obj_head >= QUEUE_SIZE) obj_head = 0;
    } // valid entry
    if (entry == old_head) break;
  }
  return;
}
////////////////////////////////////////////////////////////////

int Fl_Widget::handle(int) {
  return 0;
}

/** Default font size for widgets */
Fl_Fontsize FL_NORMAL_SIZE = 14;

Fl_Widget::Fl_Widget(int X, int Y, int W, int H, const char* L) {

  x_ = X; y_ = Y; w_ = W; h_ = H;

  label_.value	 = L;
  label_.image   = 0;
  label_.deimage = 0;
  label_.type	 = FL_NORMAL_LABEL;
  label_.font	 = FL_HELVETICA;
  label_.size	 = FL_NORMAL_SIZE;
  label_.color	 = FL_FOREGROUND_COLOR;
  tooltip_       = 0;
  callback_	 = default_callback;
  user_data_ 	 = 0;
  type_		 = 0;
  flags_	 = VISIBLE_FOCUS;
  damage_	 = 0;
  box_		 = FL_NO_BOX;
  color_	 = FL_GRAY;
  color2_	 = FL_GRAY;
  align_	 = FL_ALIGN_CENTER;
  when_		 = FL_WHEN_RELEASE;

  parent_ = 0;
  if (Fl_Group::current()) Fl_Group::current()->add(this);
}

void Fl_Widget::resize(int X, int Y, int W, int H) {
  x_ = X; y_ = Y; w_ = W; h_ = H;
}

// this is useful for parent widgets to call to resize children:
int Fl_Widget::damage_resize(int X, int Y, int W, int H) {
  if (x() == X && y() == Y && w() == W && h() == H) return 0;
  resize(X, Y, W, H);
  redraw();
  return 1;
}

int Fl_Widget::take_focus() {
  if (!takesevents()) return 0;
  if (!visible_focus()) return 0;
  if (!handle(FL_FOCUS)) return 0; // see if it wants it
  if (contains(Fl::focus())) return 1; // it called Fl::focus for us
  Fl::focus(this);
  return 1;
}

extern void fl_throw_focus(Fl_Widget*); // in Fl_x.cxx

/**
   Destroys the widget, taking care of throwing focus before if any.
   Destruction removes the widget from any parent group! And groups when
   destroyed destroy all their children. This is convenient and fast.
*/
Fl_Widget::~Fl_Widget() {
  Fl::clear_widget_pointer(this);
  if (flags() & COPIED_LABEL) free((void *)(label_.value));
  // remove from parent group
  if (parent_) parent_->remove(this);
#ifdef DEBUG_DELETE
  if (parent_) { // this should never happen
    printf("*** Fl_Widget: parent_->remove(this) failed [%p,%p]\n",parent_,this);
  }
#endif // DEBUG_DELETE
  parent_ = 0; // Don't throw focus to a parent widget.
  fl_throw_focus(this);
  // remove stale entries from default callback queue (Fl::readqueue())
  if (callback_ == default_callback) cleanup_readqueue(this);
}

/** Draws a focus box for the widget at the given position and size */
void
Fl_Widget::draw_focus(Fl_Boxtype B, int X, int Y, int W, int H) const {
  if (!Fl::visible_focus()) return;
  switch (B) {
    case FL_DOWN_BOX:
    case FL_DOWN_FRAME:
    case FL_THIN_DOWN_BOX:
    case FL_THIN_DOWN_FRAME:
      X ++;
      Y ++;
    default:
      break;
  }

  fl_color(fl_contrast(FL_BLACK, color()));

#if defined(USE_X11) || defined(__APPLE_QUARTZ__)
  fl_line_style(FL_DOT);
  fl_rect(X + Fl::box_dx(B), Y + Fl::box_dy(B),
          W - Fl::box_dw(B) - 1, H - Fl::box_dh(B) - 1);
  fl_line_style(FL_SOLID);
#elif defined(WIN32) 
  // Windows 95/98/ME do not implement the dotted line style, so draw
  // every other pixel around the focus area...
  //
  // Also, QuickDraw (MacOS) does not support line styles specifically,
  // and the hack we use in fl_line_style() will not draw horizontal lines
  // on odd-numbered rows...
  int i, xx, yy;

  X += Fl::box_dx(B);
  Y += Fl::box_dy(B);
  W -= Fl::box_dw(B) + 2;
  H -= Fl::box_dh(B) + 2;

  for (xx = 0, i = 1; xx < W; xx ++, i ++) if (i & 1) fl_point(X + xx, Y);
  for (yy = 0; yy < H; yy ++, i ++) if (i & 1) fl_point(X + W, Y + yy);
  for (xx = W; xx > 0; xx --, i ++) if (i & 1) fl_point(X + xx, Y + H);
  for (yy = H; yy > 0; yy --, i ++) if (i & 1) fl_point(X, Y + yy);
#else
# error unsupported platform
#endif // WIN32
}


void Fl_Widget::activate() {
  if (!active()) {
    clear_flag(INACTIVE);
    if (active_r()) {
      redraw();
      redraw_label();
      handle(FL_ACTIVATE);
      if (inside(Fl::focus())) Fl::focus()->take_focus();
    }
  }
}

void Fl_Widget::deactivate() {
  if (active_r()) {
    set_flag(INACTIVE);
    redraw();
    redraw_label();
    handle(FL_DEACTIVATE);
    fl_throw_focus(this);
  } else {
    set_flag(INACTIVE);
  }
}

int Fl_Widget::active_r() const {
  for (const Fl_Widget* o = this; o; o = o->parent())
    if (!o->active()) return 0;
  return 1;
}

void Fl_Widget::show() {
  if (!visible()) {
    clear_flag(INVISIBLE);
    if (visible_r()) {
      redraw();
      redraw_label();
      handle(FL_SHOW);
      if (inside(Fl::focus())) Fl::focus()->take_focus();
    }
  }
}

void Fl_Widget::hide() {
  if (visible_r()) {
    set_flag(INVISIBLE);
    for (Fl_Widget *p = parent(); p; p = p->parent())
      if (p->box() || !p->parent()) {p->redraw(); break;}
    handle(FL_HIDE);
    fl_throw_focus(this);
  } else {
    set_flag(INVISIBLE);
  }
}

int Fl_Widget::visible_r() const {
  for (const Fl_Widget* o = this; o; o = o->parent())
    if (!o->visible()) return 0;
  return 1;
}

// return true if widget is inside (or equal to) this:
// Returns false for null widgets.
int Fl_Widget::contains(const Fl_Widget *o) const {
  for (; o; o = o->parent_) if (o == this) return 1;
  return 0;
}


void
Fl_Widget::label(const char *a) {
  if (flags() & COPIED_LABEL) {
    // reassigning a copied label remains the same copied label
    if (label_.value == a)
      return;
    free((void *)(label_.value));
    clear_flag(COPIED_LABEL);
  }
  label_.value=a;
  redraw_label();
}


void
Fl_Widget::copy_label(const char *a) {
  if (flags() & COPIED_LABEL) free((void *)(label_.value));
  if (a) {
    set_flag(COPIED_LABEL);
    label_.value=strdup(a);
  } else {
    clear_flag(COPIED_LABEL);
    label_.value=(char *)0;
  }
  redraw_label();
}

/** Calls the widget callback.

  Causes a widget to invoke its callback function with arbitrary arguments.

  \param[in] o call the callback with \p o as the widget argument
  \param[in] arg use \p arg as the user data argument
  \see callback()
*/
void
Fl_Widget::do_callback(Fl_Widget* o,void* arg) {
  Fl_Widget_Tracker wp(o);
  callback_(o,arg); 
  if (wp.deleted()) return;
  if (callback_ != default_callback) 
    clear_changed();
}

//
// End of "$Id$".
//