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listbox scroll into view

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This commit is contained in:
Jinhao 2018-02-11 17:53:07 +08:00
parent 2df5a506f5
commit cf536994cd
2 changed files with 98 additions and 12 deletions
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2
include/nana/stdc++.hpp
View File

@ -1,7 +1,7 @@
/**
* Standard Library for C++11/14/17
* Nana C++ Library(http://www.nanapro.org)
* Copyright(C) 2017 Jinhao(cnjinhao@hotmail.com)
* Copyright(C) 2018 Jinhao(cnjinhao@hotmail.com)
*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at

108
source/gui/widgets/listbox.cpp
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@ -725,6 +725,13 @@ namespace nana
std::size_t column_pos;
};
enum class view_action
{
auto_view,
top_view,
bottom_view,
};
class es_lister
{
public:
@ -980,7 +987,12 @@ namespace nana
return prstatus;
}
void scroll(const index_pair& abs_pos, bool to_bottom);
#if 0
void scroll(const index_pair& abs_pos, bool to_bottom); //deprecated
#endif
/// Scroll the selected item into the view
void scroll_into_view(const index_pair& abs_pos, view_action vw_act);
/// Append a new category with a specified name and return a pointer to it.
category_t* create_cat(native_string_type&& text)
@ -1681,7 +1693,7 @@ namespace nana
///<Selects an item besides the current selected item in the display.
/// we are moving in display, but the selection ocurre in abs position
void move_select(bool upwards=true, bool unselect_previous=true, bool trace_selected=false) noexcept;
void move_select(bool upwards=true, bool unselect_previous=true, bool into_view=false) noexcept;
struct pred_cancel
{
@ -2382,6 +2394,16 @@ namespace nana
max_font_px = (std::max)(as + ds, max_font_px);
}
if (0 == max_font_px)
{
graph.typeface(listbox_ptr->typeface());
unsigned as, ds, ileading;
graph.text_metrics(as, ds, ileading);
max_font_px = (std::max)(as + ds, max_font_px);
}
return max_font_px;
}
@ -2920,7 +2942,8 @@ namespace nana
std::vector<std::pair<index_type, inline_pane*>> panes_;
};
void es_lister::scroll(const index_pair& abs_pos, bool to_bottom)
#if 0
void es_lister::scroll(const index_pair& abs_pos, bool to_bottom) //deprecated
{
auto& cat = *get(abs_pos.cat);
@ -2964,6 +2987,63 @@ namespace nana
if(ess_->content_view->move_origin(origin - ess_->content_view->origin()))
ess_->content_view->sync(false);
}
#endif
void es_lister::scroll_into_view(const index_pair& abs_pos, view_action vw_act)
{
auto& cat = *get(abs_pos.cat);
if ((abs_pos.item != nana::npos) && (abs_pos.item >= cat.items.size()))
throw std::invalid_argument("listbox: invalid pos to scroll");
if (!cat.expand)
{
this->expand(abs_pos.cat, true);
ess_->calc_content_size();
}
else if (!ess_->auto_draw)
{
//force a update of content size and scrollbar status when auto_draw is false to make
//sure that the scroll function works fine.
ess_->calc_content_size();
}
auto origin = ess_->content_view->origin();
auto off = this->distance(this->first(), this->index_cast(abs_pos, false)) * ess_->item_height();
auto screen_px = ess_->content_view->view_area().height;
if (view_action::auto_view == vw_act)
{
if (static_cast<int>(off) < origin.y)
vw_act = view_action::top_view;
else if (static_cast<int>(off) >= static_cast<int>(origin.y + ess_->content_view->view_area().height))
vw_act = view_action::bottom_view;
else
return;
}
origin.y = 0;
if (view_action::bottom_view == vw_act)
{
off += ess_->item_height();
if (off >= screen_px)
origin.y = static_cast<int>(off - screen_px);
}
else
{
auto last_off = this->distance(this->first(), this->last()) * ess_->item_height();
if (last_off - off >= screen_px)
origin.y = static_cast<int>(off);
else if (last_off >= screen_px)
origin.y = static_cast<int>(last_off - screen_px);
}
if (ess_->content_view->move_origin(origin - ess_->content_view->origin()))
ess_->content_view->sync(false);
}
void es_lister::erase(const index_pair& pos)
{
@ -2983,7 +3063,7 @@ namespace nana
}
}
void es_lister::move_select(bool upwards, bool unselect_previous, bool /*trace_selected*/) noexcept
void es_lister::move_select(bool upwards, bool unselect_previous, bool into_view) noexcept
{
auto next_selected_dpl = index_cast_noexcpt(latest_selected_abs, false); //convert absolute position to display position
@ -3063,6 +3143,9 @@ namespace nana
}
else break;
}
if (into_view && !latest_selected_abs.empty())
this->scroll_into_view(latest_selected_abs, view_action::auto_view);
}
std::string es_lister::to_string(const export_options& exp_opt) const
@ -4469,7 +4552,7 @@ namespace nana
//Check if it scrolls in current screen window
//condition: top of target item is not less than top edge of content view and
//the bottom of target item is not greater than bottom edge of content view.
if ((screen_top + item_px <= logic_top) && (logic_top + item_px + item_px <= screen_bottom))
if ((screen_top + static_cast<int>(item_px) <= logic_top) && (logic_top + static_cast<int>(item_px) + static_cast<int>(item_px) <= screen_bottom))
{
int offset = (static_cast<int>(upward ? screen_top : screen_bottom - item_px) - logic_top) / static_cast<int>(item_px);
target_idx = list.advance(init_idx, offset);
@ -4561,8 +4644,11 @@ namespace nana
}
else
item_proxy::from_display(essence_, pos).select(true);
list.scroll_into_view(pos, view_action::auto_view);
}
}
}
break;
default:
@ -4658,7 +4744,7 @@ namespace nana
ess_->lister.get(pos_.cat)->expand = false;
if (!this->displayed())
ess_->lister.scroll(pos_, !(ess_->first_display() > this->to_display()));
ess_->lister.scroll_into_view(pos_, (ess_->first_display() > this->to_display() ? view_action::top_view : view_action::bottom_view));
}
ess_->update();
@ -4696,7 +4782,7 @@ namespace nana
ess_->lister.latest_selected_abs.set_both(npos);
if (scroll_view && (!this->displayed()))
ess_->lister.scroll(pos_, !(ess_->first_display() > this->to_display()));
ess_->lister.scroll_into_view(pos_, (ess_->first_display() > this->to_display() ? view_action::top_view : view_action::bottom_view));
ess_->update();
return *this;
@ -5364,13 +5450,13 @@ namespace nana
else
pos.item = ess.lister.size_item(cat_pos) ? 0 : ::nana::npos;
ess.lister.scroll(pos, to_bottom);
ess.update();
this->scroll(to_bottom, pos);
}
void listbox::scroll(bool to_bottom, const index_pair& abs_pos)
{
_m_ess().lister.scroll(abs_pos, to_bottom);
using view_action = drawerbase::listbox::view_action;
_m_ess().lister.scroll_into_view(abs_pos, (to_bottom ? view_action::bottom_view : view_action::top_view));
_m_ess().update();
}
@ -5742,7 +5828,7 @@ namespace nana
void listbox::move_select(bool upwards) ///<Selects an item besides the current selected item in the display.
{
_m_ess().lister.move_select(upwards);
_m_ess().lister.move_select(upwards, true, true);
_m_ess().update();
}