Fl_Scroll.cxx

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//
// "$Id: Fl_Scroll.cxx 7903 2010-11-28 21:06:39Z matt $"
//
// Scroll widget for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2010 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_Tiled_Image.H>
#include <FL/Fl_Scroll.H>
#include <FL/fl_draw.H>

void Fl_Scroll::clear() {
  // Note: the scrollbars are removed from the group before calling
  // Fl_Group::clear() to take advantage of the optimized widget removal
  // and deletion. Finally they are added to Fl_Scroll's group again. This
  // is MUCH faster than removing the widgets one by one (STR #2409).

  remove(scrollbar);
  remove(hscrollbar);
  Fl_Group::clear();
  add(hscrollbar);
  add(scrollbar);
}

void Fl_Scroll::fix_scrollbar_order() {
  Fl_Widget** a = (Fl_Widget**)array();
  if (a[children()-1] != &scrollbar) {
    int i,j; for (i = j = 0; j < children(); j++)
      if (a[j] != &hscrollbar && a[j] != &scrollbar) a[i++] = a[j];
    a[i++] = &hscrollbar;
    a[i++] = &scrollbar;
  }
}

// Draw widget's background and children within a specific clip region
//    So widget can just redraw damaged parts.
//
void Fl_Scroll::draw_clip(void* v,int X, int Y, int W, int H) {
  fl_push_clip(X,Y,W,H);
  Fl_Scroll* s = (Fl_Scroll*)v;
  // erase background as needed...
  switch (s->box()) {
    case FL_NO_BOX :
    case FL_UP_FRAME :
    case FL_DOWN_FRAME :
    case FL_THIN_UP_FRAME :
    case FL_THIN_DOWN_FRAME :
    case FL_ENGRAVED_FRAME :
    case FL_EMBOSSED_FRAME :
    case FL_BORDER_FRAME :
    case _FL_SHADOW_FRAME :
    case _FL_ROUNDED_FRAME :
    case _FL_OVAL_FRAME :
    case _FL_PLASTIC_UP_FRAME :
    case _FL_PLASTIC_DOWN_FRAME :
        if (s->parent() == (Fl_Group *)s->window() && Fl::scheme_bg_) {
          Fl::scheme_bg_->draw(X-(X%((Fl_Tiled_Image *)Fl::scheme_bg_)->image()->w()),
                               Y-(Y%((Fl_Tiled_Image *)Fl::scheme_bg_)->image()->h()),
                               W+((Fl_Tiled_Image *)Fl::scheme_bg_)->image()->w(),
                               H+((Fl_Tiled_Image *)Fl::scheme_bg_)->image()->h());
          break;
        }

    default :
        fl_color(s->color());
        fl_rectf(X,Y,W,H);
        break;
  }
  Fl_Widget*const* a = s->array();
  for (int i=s->children()-2; i--;) {
    Fl_Widget& o = **a++;
    s->draw_child(o);
    s->draw_outside_label(o);
  }
  fl_pop_clip();
}

void Fl_Scroll::recalc_scrollbars(ScrollInfo &si) {

  // inner box of widget (excluding scrollbars)
  si.innerbox_x = x()+Fl::box_dx(box());
  si.innerbox_y = y()+Fl::box_dy(box());
  si.innerbox_w = w()-Fl::box_dw(box());
  si.innerbox_h = h()-Fl::box_dh(box());

  // accumulate a bounding box for all the children
  si.child_l = si.innerbox_x;
  si.child_r = si.innerbox_x;
  si.child_b = si.innerbox_y;
  si.child_t = si.innerbox_y;
  int first = 1;
  Fl_Widget*const* a = array();
  for (int i=children()-2; i--;) {
    Fl_Widget* o = *a++;
    if ( first ) {
        first = 0;
        si.child_l = o->x();
        si.child_r = o->x()+o->w();
        si.child_b = o->y()+o->h();
        si.child_t = o->y();
    } else {
        if (o->x() < si.child_l) si.child_l = o->x();
        if (o->y() < si.child_t) si.child_t = o->y();
        if (o->x()+o->w() > si.child_r) si.child_r = o->x()+o->w();
        if (o->y()+o->h() > si.child_b) si.child_b = o->y()+o->h();
    }
  }

  // Turn the scrollbars on and off as necessary.
  // See if children would fit if we had no scrollbars...
  {
    int X = si.innerbox_x;
    int Y = si.innerbox_y;
    int W = si.innerbox_w;
    int H = si.innerbox_h;

    si.scrollsize = scrollbar_size_ ? scrollbar_size_ : Fl::scrollbar_size();
    si.vneeded = 0;
    si.hneeded = 0;
    if (type() & VERTICAL) {
      if ((type() & ALWAYS_ON) || si.child_t < Y || si.child_b > Y+H) {
        si.vneeded = 1;
        W -= si.scrollsize;
        if (scrollbar.align() & FL_ALIGN_LEFT) X += si.scrollsize;
      }
    }
    if (type() & HORIZONTAL) {
      if ((type() & ALWAYS_ON) || si.child_l < X || si.child_r > X+W) {
        si.hneeded = 1;
        H -= si.scrollsize;
        if (scrollbar.align() & FL_ALIGN_TOP) Y += si.scrollsize;
        // recheck vertical since we added a horizontal scrollbar
        if (!si.vneeded && (type() & VERTICAL)) {
          if ((type() & ALWAYS_ON) || si.child_t < Y || si.child_b > Y+H) {
            si.vneeded = 1;
            W -= si.scrollsize;
            if (scrollbar.align() & FL_ALIGN_LEFT) X += si.scrollsize;
          }
        }
      }
    }
    si.innerchild_x = X;
    si.innerchild_y = Y;
    si.innerchild_w = W;
    si.innerchild_h = H;
  }

  // calculate hor scrollbar position
  si.hscroll_x = si.innerchild_x;
  si.hscroll_y = (scrollbar.align() & FL_ALIGN_TOP) 
                     ? si.innerbox_y
                     : si.innerbox_y + si.innerbox_h - si.scrollsize;
  si.hscroll_w = si.innerchild_w;
  si.hscroll_h = si.scrollsize;

  // calculate ver scrollbar position
  si.vscroll_x = (scrollbar.align() & FL_ALIGN_LEFT)
                     ? si.innerbox_x
                     : si.innerbox_x + si.innerbox_w - si.scrollsize;
  si.vscroll_y = si.innerchild_y;
  si.vscroll_w = si.scrollsize;
  si.vscroll_h = si.innerchild_h;

  // calculate h/v scrollbar values (pos/size/first/total)
  si.hpos = si.innerchild_x - si.child_l;
  si.hsize = si.innerchild_w;
  si.hfirst = 0;
  si.htotal = si.child_r - si.child_l;
  if ( si.hpos < 0 ) { si.htotal += (-si.hpos); si.hfirst = si.hpos; }

  si.vpos = si.innerchild_y - si.child_t;
  si.vsize = si.innerchild_h;
  si.vfirst = 0;
  si.vtotal = si.child_b - si.child_t;
  if ( si.vpos < 0 ) { si.vtotal += (-si.vpos); si.vfirst = si.vpos; }

//  printf("DEBUG --- ScrollInfo ---\n");
//  printf("DEBUG        scrollsize: %d\n", si.scrollsize);
//  printf("DEBUG  hneeded, vneeded: %d %d\n", si.hneeded, si.vneeded);
//  printf("DEBUG     innerbox xywh: %d %d %d %d\n", si.innerbox_x,   si.innerbox_y,   si.innerbox_w,   si.innerbox_h);
//  printf("DEBUG   innerchild xywh: %d %d %d %d\n", si.innerchild_x, si.innerchild_y, si.innerchild_w, si.innerchild_h);
//  printf("DEBUG        child lrbt: %d %d %d %d\n", si.child_l, si.child_r, si.child_b, si.child_t);
//  printf("DEBUG      hscroll xywh: %d %d %d %d\n", si.hscroll_x, si.hscroll_y, si.hscroll_w, si.hscroll_h);
//  printf("DEBUG      vscroll xywh: %d %d %d %d\n", si.vscroll_x, si.vscroll_y, si.vscroll_w, si.vscroll_h);
//  printf("DEBUG  horz scroll vals: %d %d %d %d\n", si.hpos, si.hsize, si.hfirst, si.htotal);
//  printf("DEBUG  vert scroll vals: %d %d %d %d\n", si.vpos, si.vsize, si.vfirst, si.vtotal);
//  printf("DEBUG \n");
}

void Fl_Scroll::bbox(int& X, int& Y, int& W, int& H) {
  X = x()+Fl::box_dx(box());
  Y = y()+Fl::box_dy(box());
  W = w()-Fl::box_dw(box());
  H = h()-Fl::box_dh(box());
  if (scrollbar.visible()) {
    W -= scrollbar.w();
    if (scrollbar.align() & FL_ALIGN_LEFT) X += scrollbar.w();
  }
  if (hscrollbar.visible()) {
    H -= hscrollbar.h();
    if (scrollbar.align() & FL_ALIGN_TOP) Y += hscrollbar.h();
  }
}

void Fl_Scroll::draw() {
  fix_scrollbar_order();
  int X,Y,W,H; bbox(X,Y,W,H);

  uchar d = damage();

  if (d & FL_DAMAGE_ALL) { // full redraw
    draw_box(box(),x(),y(),w(),h(),color());
    draw_clip(this, X, Y, W, H);
  } else {
    if (d & FL_DAMAGE_SCROLL) {
      // scroll the contents:
      fl_scroll(X, Y, W, H, oldx-xposition_, oldy-yposition_, draw_clip, this);

      // Erase the background as needed...
      Fl_Widget*const* a = array();
      int L, R, T, B;
      L = 999999;
      R = 0;
      T = 999999;
      B = 0;
      for (int i=children()-2; i--; a++) {
        if ((*a)->x() < L) L = (*a)->x();
        if (((*a)->x() + (*a)->w()) > R) R = (*a)->x() + (*a)->w();
        if ((*a)->y() < T) T = (*a)->y();
        if (((*a)->y() + (*a)->h()) > B) B = (*a)->y() + (*a)->h();
      }
      if (L > X) draw_clip(this, X, Y, L - X, H);
      if (R < (X + W)) draw_clip(this, R, Y, X + W - R, H);
      if (T > Y) draw_clip(this, X, Y, W, T - Y);
      if (B < (Y + H)) draw_clip(this, X, B, W, Y + H - B);
    }
    if (d & FL_DAMAGE_CHILD) { // draw damaged children
      fl_push_clip(X, Y, W, H);
      Fl_Widget*const* a = array();
      for (int i=children()-2; i--;) update_child(**a++);
      fl_pop_clip();
    }
  }

  // Calculate where scrollbars should go, and draw them
  {
      ScrollInfo si;
      recalc_scrollbars(si);

      // Now that we know what's needed, make it so.
      if (si.vneeded && !scrollbar.visible()) {
        scrollbar.set_visible();
        d = FL_DAMAGE_ALL;
      }
      else if (!si.vneeded && scrollbar.visible()) {
        scrollbar.clear_visible();
        draw_clip(this, si.vscroll_x, si.vscroll_y, si.vscroll_w, si.vscroll_h);
        d = FL_DAMAGE_ALL;
      }
      if (si.hneeded && !hscrollbar.visible()) {
        hscrollbar.set_visible();
        d = FL_DAMAGE_ALL;
      }
      else if (!si.hneeded && hscrollbar.visible()) {
        hscrollbar.clear_visible();
        draw_clip(this, si.hscroll_x, si.hscroll_y, si.hscroll_w, si.hscroll_h);
        d = FL_DAMAGE_ALL;
      }
      else if ( hscrollbar.h() != si.scrollsize || scrollbar.w() != si.scrollsize ) {
         // scrollsize changed
         d = FL_DAMAGE_ALL;
      }

      scrollbar.resize(si.vscroll_x, si.vscroll_y, si.vscroll_w, si.vscroll_h);
      oldy = yposition_ = si.vpos;      // si.innerchild_y - si.child_t;
      scrollbar.value(si.vpos, si.vsize, si.vfirst, si.vtotal);

      hscrollbar.resize(si.hscroll_x, si.hscroll_y, si.hscroll_w, si.hscroll_h);
      oldx = xposition_ = si.hpos;      // si.innerchild_x - si.child_l;
      hscrollbar.value(si.hpos, si.hsize, si.hfirst, si.htotal);
  }

  // draw the scrollbars:
  if (d & FL_DAMAGE_ALL) {
    draw_child(scrollbar);
    draw_child(hscrollbar);
    if (scrollbar.visible() && hscrollbar.visible()) {
      // fill in the little box in the corner
      fl_color(color());
      fl_rectf(scrollbar.x(), hscrollbar.y(), scrollbar.w(), hscrollbar.h());
    }
  } else {
    update_child(scrollbar);
    update_child(hscrollbar);
  }
}

void Fl_Scroll::resize(int X, int Y, int W, int H) {
  int dx = X-x(), dy = Y-y();
  int dw = W-w(), dh = H-h();
  Fl_Widget::resize(X,Y,W,H); // resize _before_ moving children around
  fix_scrollbar_order();
  // move all the children:
  Fl_Widget*const* a = array();
  for (int i=children()-2; i--;) {
    Fl_Widget* o = *a++;
    o->position(o->x()+dx, o->y()+dy);
  }
  if (dw==0 && dh==0) {
    char pad = ( scrollbar.visible() && hscrollbar.visible() );
    char al = ( (scrollbar.align() & FL_ALIGN_LEFT) != 0 );
    char at = ( (scrollbar.align() & FL_ALIGN_TOP)  !=0 );
    scrollbar.position(al?X:X+W-scrollbar.w(), (at&&pad)?Y+hscrollbar.h():Y);
    hscrollbar.position((al&&pad)?X+scrollbar.w():X, at?Y:Y+H-hscrollbar.h());
  } else {
    // FIXME recalculation of scrollbars needs to be moved out fo "draw()" (STR #1895)
    redraw(); // need full recalculation of scrollbars
  }
}

void Fl_Scroll::scroll_to(int X, int Y) {
  int dx = xposition_-X;
  int dy = yposition_-Y;
  if (!dx && !dy) return;
  xposition_ = X;
  yposition_ = Y;
  Fl_Widget*const* a = array();
  for (int i=children(); i--;) {
    Fl_Widget* o = *a++;
    if (o == &hscrollbar || o == &scrollbar) continue;
    o->position(o->x()+dx, o->y()+dy);
  }
  if (parent() == (Fl_Group *)window() && Fl::scheme_bg_) damage(FL_DAMAGE_ALL);
  else damage(FL_DAMAGE_SCROLL);
}

void Fl_Scroll::hscrollbar_cb(Fl_Widget* o, void*) {
  Fl_Scroll* s = (Fl_Scroll*)(o->parent());
  s->scroll_to(int(((Fl_Scrollbar*)o)->value()), s->yposition());
}

void Fl_Scroll::scrollbar_cb(Fl_Widget* o, void*) {
  Fl_Scroll* s = (Fl_Scroll*)(o->parent());
  s->scroll_to(s->xposition(), int(((Fl_Scrollbar*)o)->value()));
}
Fl_Scroll::Fl_Scroll(int X,int Y,int W,int H,const char* L)
  : Fl_Group(X,Y,W,H,L), 
    scrollbar(X+W-Fl::scrollbar_size(),Y,
              Fl::scrollbar_size(),H-Fl::scrollbar_size()),
    hscrollbar(X,Y+H-Fl::scrollbar_size(),
               W-Fl::scrollbar_size(),Fl::scrollbar_size()) {
  type(BOTH);
  xposition_ = oldx = 0;
  yposition_ = oldy = 0;
  scrollbar_size_ = 0;
  hscrollbar.type(FL_HORIZONTAL);
  hscrollbar.callback(hscrollbar_cb);
  scrollbar.callback(scrollbar_cb);
}

int Fl_Scroll::handle(int event) {
  fix_scrollbar_order();
  return Fl_Group::handle(event);
}

//
// End of "$Id: Fl_Scroll.cxx 7903 2010-11-28 21:06:39Z matt $".
//