dropdown.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD 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 General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "../stdafx.h"
#include "../window_gui.h"
#include "../string_func.h"
#include "../strings_func.h"
#include "../window_func.h"
#include "../zoom_func.h"
#include "../timer/timer.h"
#include "../timer/timer_window.h"
#include "dropdown_type.h"
 
#include "dropdown_widget.h"
 
#include "../safeguards.h"
 
 
static constexpr NWidgetPart _nested_dropdown_menu_widgets[] = {
  NWidget(NWID_HORIZONTAL),
    NWidget(WWT_PANEL, COLOUR_END, WID_DM_ITEMS), SetScrollbar(WID_DM_SCROLL), EndContainer(),
    NWidget(NWID_SELECTION, INVALID_COLOUR, WID_DM_SHOW_SCROLL),
      NWidget(NWID_VSCROLLBAR, COLOUR_END, WID_DM_SCROLL),
    EndContainer(),
  EndContainer(),
};
 
static WindowDesc _dropdown_desc(__FILE__, __LINE__,
  WDP_MANUAL, nullptr, 0, 0,
  WC_DROPDOWN_MENU, WC_NONE,
  WDF_NO_FOCUS,
  std::begin(_nested_dropdown_menu_widgets), std::end(_nested_dropdown_menu_widgets)
);
 
struct DropdownWindow : Window {
  WidgetID parent_button;       
  Rect wi_rect;                 
  const DropDownList list;      
  int selected_result;          
  byte click_delay = 0;         
  bool drag_mode = true;
  bool instant_close;           
  int scrolling = 0;            
  Point position;               
  Scrollbar *vscroll;
 
  Dimension items_dim; 
 
  DropdownWindow(Window *parent, DropDownList &&list, int selected, WidgetID button, const Rect wi_rect, bool instant_close, Colours wi_colour)
      : Window(&_dropdown_desc)
      , parent_button(button)
      , wi_rect(wi_rect)
      , list(std::move(list))
      , selected_result(selected)
      , instant_close(instant_close)
  {
    assert(!this->list.empty());
 
    this->parent = parent;
 
    this->CreateNestedTree();
 
    this->GetWidget<NWidgetCore>(WID_DM_ITEMS)->colour = wi_colour;
    this->GetWidget<NWidgetCore>(WID_DM_SCROLL)->colour = wi_colour;
    this->vscroll = this->GetScrollbar(WID_DM_SCROLL);
    this->UpdateSizeAndPosition();
 
    this->FinishInitNested(0);
    CLRBITS(this->flags, WF_WHITE_BORDER);
  }
 
  void Close([[maybe_unused]] int data = 0) override
  {
    /* Finish closing the dropdown, so it doesn't affect new window placement.
     * Also mark it dirty in case the callback deals with the screen. (e.g. screenshots). */
    this->Window::Close();
 
    Point pt = _cursor.pos;
    pt.x -= this->parent->left;
    pt.y -= this->parent->top;
    this->parent->OnDropdownClose(pt, this->parent_button, this->selected_result, this->instant_close);
 
    /* Set flag on parent widget to indicate that we have just closed. */
    NWidgetCore *nwc = this->parent->GetWidget<NWidgetCore>(this->parent_button);
    if (nwc != nullptr) SetBit(nwc->disp_flags, NDB_DROPDOWN_CLOSED);
  }
 
  void OnFocusLost(bool closing) override
  {
    if (!closing) {
      this->instant_close = false;
      this->Close();
    }
  }
 
  void FitAvailableHeight(Dimension &desired, const Dimension &list, uint available_height)
  {
    if (desired.height < available_height) return;
 
    /* If the dropdown doesn't fully fit, we a need a dropdown. */
    uint avg_height = list.height / (uint)this->list.size();
    uint rows = std::max((available_height - WidgetDimensions::scaled.dropdownlist.Vertical()) / avg_height, 1U);
 
    desired.width = std::max(list.width, desired.width - NWidgetScrollbar::GetVerticalDimension().width);
    desired.height = rows * avg_height + WidgetDimensions::scaled.dropdownlist.Vertical();
  }
 
  void UpdateSizeAndPosition()
  {
    Rect button_rect = this->wi_rect.Translate(this->parent->left, this->parent->top);
 
    /* Get the dimensions required for the list. */
    Dimension list_dim = GetDropDownListDimension(this->list);
 
    /* Set up dimensions for the items widget. */
    Dimension widget_dim = list_dim;
    widget_dim.width += WidgetDimensions::scaled.dropdownlist.Horizontal();
    widget_dim.height += WidgetDimensions::scaled.dropdownlist.Vertical();
 
    /* Width should match at least the width of the parent widget. */
    widget_dim.width = std::max<uint>(widget_dim.width, button_rect.Width());
 
    /* Available height below (or above, if the dropdown is placed above the widget). */
    uint available_height_below = std::max(GetMainViewBottom() - button_rect.bottom - 1, 0);
    uint available_height_above = std::max(button_rect.top - 1 - GetMainViewTop(), 0);
 
    /* Is it better to place the dropdown above the widget? */
    if (widget_dim.height > available_height_below && available_height_above > available_height_below) {
      FitAvailableHeight(widget_dim, list_dim, available_height_above);
      this->position.y = button_rect.top - widget_dim.height;
    } else {
      FitAvailableHeight(widget_dim, list_dim, available_height_below);
      this->position.y = button_rect.bottom + 1;
    }
 
    this->position.x = (_current_text_dir == TD_RTL) ? button_rect.right + 1 - (int)widget_dim.width : button_rect.left;
 
    this->items_dim = widget_dim;
    this->GetWidget<NWidgetStacked>(WID_DM_SHOW_SCROLL)->SetDisplayedPlane(list_dim.height > widget_dim.height ? 0 : SZSP_NONE);
 
    /* Capacity is the average number of items visible */
    this->vscroll->SetCapacity((widget_dim.height - WidgetDimensions::scaled.dropdownlist.Vertical()) * this->list.size() / list_dim.height);
    this->vscroll->SetCount(this->list.size());
 
    /* If the dropdown is positioned above the parent widget, start selection at the bottom. */
    if (this->position.y < button_rect.top && list_dim.height > widget_dim.height) this->vscroll->UpdatePosition(INT_MAX);
  }
 
  void UpdateWidgetSize(WidgetID widget, Dimension *size, [[maybe_unused]] const Dimension &padding, [[maybe_unused]] Dimension *fill, [[maybe_unused]] Dimension *resize) override
  {
    if (widget == WID_DM_ITEMS) *size = this->items_dim;
  }
 
  Point OnInitialPosition([[maybe_unused]] int16_t sm_width, [[maybe_unused]] int16_t sm_height, [[maybe_unused]] int window_number) override
  {
    return this->position;
  }
 
  bool GetDropDownItem(int &value)
  {
    if (GetWidgetFromPos(this, _cursor.pos.x - this->left, _cursor.pos.y - this->top) < 0) return false;
 
    const Rect &r = this->GetWidget<NWidgetBase>(WID_DM_ITEMS)->GetCurrentRect().Shrink(WidgetDimensions::scaled.dropdownlist);
    int y     = _cursor.pos.y - this->top - r.top;
    int pos   = this->vscroll->GetPosition();
 
    for (const auto &item : this->list) {
      /* Skip items that are scrolled up */
      if (--pos >= 0) continue;
 
      int item_height = item->Height();
 
      if (y < item_height) {
        if (item->masked || !item->Selectable()) return false;
        value = item->result;
        return true;
      }
 
      y -= item_height;
    }
 
    return false;
  }
 
  void DrawWidget(const Rect &r, WidgetID widget) const override
  {
    if (widget != WID_DM_ITEMS) return;
 
    Colours colour = this->GetWidget<NWidgetCore>(widget)->colour;
 
    Rect ir = r.Shrink(WidgetDimensions::scaled.dropdownlist);
    int y = ir.top;
    int pos = this->vscroll->GetPosition();
    for (const auto &item : this->list) {
      int item_height = item->Height();
 
      /* Skip items that are scrolled up */
      if (--pos >= 0) continue;
 
      if (y + item_height - 1 <= ir.bottom) {
        Rect full{ir.left, y, ir.right, y + item_height - 1};
 
        bool selected = (this->selected_result == item->result) && item->Selectable();
        if (selected) GfxFillRect(full, PC_BLACK);
 
        item->Draw(full, full.Shrink(WidgetDimensions::scaled.dropdowntext, RectPadding::zero), selected, colour);
      }
      y += item_height;
    }
  }
 
  void OnClick([[maybe_unused]] Point pt, WidgetID widget, [[maybe_unused]] int click_count) override
  {
    if (widget != WID_DM_ITEMS) return;
    int item;
    if (this->GetDropDownItem(item)) {
      this->click_delay = 4;
      this->selected_result = item;
      this->SetDirty();
    }
  }
 
  IntervalTimer<TimerWindow> scroll_interval = {std::chrono::milliseconds(30), [this](auto) {
    if (this->scrolling == 0) return;
 
    if (this->vscroll->UpdatePosition(this->scrolling)) this->SetDirty();
 
    this->scrolling = 0;
  }};
 
  void OnMouseLoop() override
  {
    if (this->click_delay != 0 && --this->click_delay == 0) {
      /* Close the dropdown, so it doesn't affect new window placement.
       * Also mark it dirty in case the callback deals with the screen. (e.g. screenshots). */
      this->Close();
      this->parent->OnDropdownSelect(this->parent_button, this->selected_result);
      return;
    }
 
    if (this->drag_mode) {
      int item;
 
      if (!_left_button_clicked) {
        this->drag_mode = false;
        if (!this->GetDropDownItem(item)) {
          if (this->instant_close) this->Close();
          return;
        }
        this->click_delay = 2;
      } else {
        if (_cursor.pos.y <= this->top + 2) {
          /* Cursor is above the list, set scroll up */
          this->scrolling = -1;
          return;
        } else if (_cursor.pos.y >= this->top + this->height - 2) {
          /* Cursor is below list, set scroll down */
          this->scrolling = 1;
          return;
        }
 
        if (!this->GetDropDownItem(item)) return;
      }
 
      if (this->selected_result != item) {
        this->selected_result = item;
        this->SetDirty();
      }
    }
  }
};
 
Dimension GetDropDownListDimension(const DropDownList &list)
{
  Dimension dim{};
  for (const auto &item : list) {
    dim.height += item->Height();
    dim.width = std::max(dim.width, item->Width());
  }
  dim.width += WidgetDimensions::scaled.dropdowntext.Horizontal();
  return dim;
}
 
void ShowDropDownListAt(Window *w, DropDownList &&list, int selected, WidgetID button, Rect wi_rect, Colours wi_colour, bool instant_close)
{
  CloseWindowByClass(WC_DROPDOWN_MENU);
  new DropdownWindow(w, std::move(list), selected, button, wi_rect, instant_close, wi_colour);
}
 
void ShowDropDownList(Window *w, DropDownList &&list, int selected, WidgetID button, uint width, bool instant_close)
{
  /* Our parent's button widget is used to determine where to place the drop
   * down list window. */
  NWidgetCore *nwi = w->GetWidget<NWidgetCore>(button);
  Rect wi_rect      = nwi->GetCurrentRect();
  Colours wi_colour = nwi->colour;
 
  if ((nwi->type & WWT_MASK) == NWID_BUTTON_DROPDOWN) {
    nwi->disp_flags |= ND_DROPDOWN_ACTIVE;
  } else {
    nwi->SetLowered(true);
  }
  nwi->SetDirty(w);
 
  if (width != 0) {
    if (_current_text_dir == TD_RTL) {
      wi_rect.left = wi_rect.right + 1 - ScaleGUITrad(width);
    } else {
      wi_rect.right = wi_rect.left + ScaleGUITrad(width) - 1;
    }
  }
 
  ShowDropDownListAt(w, std::move(list), selected, button, wi_rect, wi_colour, instant_close);
}
 
void ShowDropDownMenu(Window *w, const StringID *strings, int selected, WidgetID button, uint32_t disabled_mask, uint32_t hidden_mask, uint width)
{
  DropDownList list;
 
  for (uint i = 0; strings[i] != INVALID_STRING_ID; i++) {
    if (!HasBit(hidden_mask, i)) {
      list.push_back(std::make_unique<DropDownListStringItem>(strings[i], i, HasBit(disabled_mask, i)));
    }
  }
 
  if (!list.empty()) ShowDropDownList(w, std::move(list), selected, button, width);
}