source/gui/IGUIScrollBar.cpp

   1 /* Copyright (C) 2021 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "precompiled.h"
  19
  20 #include "IGUIScrollBar.h"
  21
  22 #include "gui/CGUI.h"
  23 #include "gui/SGUIMessage.h"
  24 #include "gui/ObjectBases/IGUIScrollBarOwner.h"
  25 #include "maths/MathUtil.h"
  26
  27 IGUIScrollBar::IGUIScrollBar(CGUI& pGUI)
  28         : m_pGUI(pGUI),
  29          m_pStyle(nullptr),
  30          m_X(300.f), m_Y(300.f),
  31          m_ScrollRange(1.f), m_ScrollSpace(0.f), // MaxPos: not 0, due to division.
  32          m_Length(200.f), m_Width(20.f),
  33          m_BarSize(0.f), m_Pos(0.f),
  34          m_ButtonPlusPressed(false),
  35          m_ButtonMinusPressed(false),
  36          m_ButtonPlusHovered(false),
  37          m_ButtonMinusHovered(false),
  38          m_BarHovered(false),
  39          m_BarPressed(false)
  40 {
  41 }
  42
  43 IGUIScrollBar::~IGUIScrollBar()
  44 {
  45 }
  46
  47 void IGUIScrollBar::SetupBarSize()
  48 {
  49         if (!GetStyle())
  50                 return;
  51
  52         float min = GetStyle()->m_MinimumBarSize;
  53         float max = GetStyle()->m_MaximumBarSize;
  54         float length = m_Length;
  55
  56         // Check for edge buttons
  57         if (GetStyle()->m_UseEdgeButtons)
  58                 length -= GetStyle()->m_Width * 2.f;
  59
  60         // Check min and max are valid
  61         if (min > length)
  62                 min = 0.f;
  63         if (max < min)
  64                 max = length;
  65
  66         // Clamp size to not exceed a minimum or maximum.
  67         m_BarSize = Clamp(length * std::min(m_ScrollSpace / m_ScrollRange, 1.f), min, max);
  68 }
  69
  70 const SGUIScrollBarStyle* IGUIScrollBar::GetStyle() const
  71 {
  72         if (!m_pHostObject)
  73                 return nullptr;
  74
  75         return m_pHostObject->GetScrollBarStyle(m_ScrollBarStyle);
  76 }
  77
  78 void IGUIScrollBar::UpdatePosBoundaries()
  79 {
  80         if (m_Pos < 0.f ||
  81                 m_ScrollRange < m_ScrollSpace) // <= scrolling not applicable
  82                 m_Pos = 0.f;
  83         else if (m_Pos > GetMaxPos())
  84                 m_Pos = GetMaxPos();
  85 }
  86
  87 void IGUIScrollBar::HandleMessage(SGUIMessage& Message)
  88 {
  89         switch (Message.type)
  90         {
  91         case GUIM_MOUSE_MOTION:
  92         {
  93                 // TODO Gee: Optimizations needed!
  94
  95                 const CVector2D& mouse = m_pGUI.GetMousePos();
  96
  97                 // If bar is being dragged
  98                 if (m_BarPressed)
  99                 {
 100                         SetPosFromMousePos(mouse);
 101                         UpdatePosBoundaries();
 102                 }
 103
 104                 // check if components are being hovered
 105                 m_BarHovered = GetBarRect().PointInside(mouse);
 106                 m_ButtonMinusHovered = HoveringButtonMinus(mouse);
 107                 m_ButtonPlusHovered =  HoveringButtonPlus(mouse);
 108
 109                 if (!m_ButtonMinusHovered)
 110                         m_ButtonMinusPressed = false;
 111
 112                 if (!m_ButtonPlusHovered)
 113                         m_ButtonPlusPressed = false;
 114                 break;
 115         }
 116
 117         case GUIM_MOUSE_PRESS_LEFT:
 118         {
 119                 if (!m_pHostObject)
 120                         break;
 121
 122                 const CVector2D& mouse = m_pGUI.GetMousePos();
 123
 124                 // if bar is pressed
 125                 if (GetBarRect().PointInside(mouse))
 126                 {
 127                         m_BarPressed = true;
 128                         m_BarPressedAtPos = mouse;
 129                         m_PosWhenPressed = m_Pos;
 130                 }
 131                 // if button-minus is pressed
 132                 else if (m_ButtonMinusHovered)
 133                 {
 134                         m_ButtonMinusPressed = true;
 135                         ScrollMinus();
 136                 }
 137                 // if button-plus is pressed
 138                 else if (m_ButtonPlusHovered)
 139                 {
 140                         m_ButtonPlusPressed = true;
 141                         ScrollPlus();
 142                 }
 143                 // Pressing the background of the bar, to scroll
 144                 //  notice the if-sentence alone does not admit that,
 145                 //  it must be after the above if/elses
 146                 else
 147                 {
 148                         if (GetOuterRect().PointInside(mouse))
 149                         {
 150                                 // Scroll plus or minus a lot, this might change, it doesn't
 151                                 //  have to be fancy though.
 152                                 if (mouse.Y < GetBarRect().top)
 153                                         ScrollMinusPlenty();
 154                                 else
 155                                         ScrollPlusPlenty();
 156                                 // Simulate mouse movement to see if bar now is hovered
 157                                 SGUIMessage msg(GUIM_MOUSE_MOTION);
 158                                 HandleMessage(msg);
 159                         }
 160                 }
 161                 break;
 162         }
 163
 164         case GUIM_MOUSE_RELEASE_LEFT:
 165                 m_ButtonMinusPressed = false;
 166                 m_ButtonPlusPressed = false;
 167                 break;
 168
 169         case GUIM_MOUSE_WHEEL_UP:
 170         {
 171                 ScrollMinus();
 172                 // Since the scroll was changed, let's simulate a mouse movement
 173                 //  to check if scrollbar now is hovered
 174                 SGUIMessage msg(GUIM_MOUSE_MOTION);
 175                 HandleMessage(msg);
 176                 break;
 177         }
 178
 179         case GUIM_MOUSE_WHEEL_DOWN:
 180         {
 181                 ScrollPlus();
 182                 // Since the scroll was changed, let's simulate a mouse movement
 183                 //  to check if scrollbar now is hovered
 184                 SGUIMessage msg(GUIM_MOUSE_MOTION);
 185                 HandleMessage(msg);
 186                 break;
 187         }
 188
 189         default:
 190                 break;
 191         }
 192 }