IGUIScrollBar.cpp

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/* Copyright (C) 2009 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
IGUIScrollBar
*/

#include "precompiled.h"
#include "GUI.h"
#include "maths/MathUtil.h"
#include "ps/CLogger.h"

//-------------------------------------------------------------------
//  IGUIScrollBar
//-------------------------------------------------------------------
IGUIScrollBar::IGUIScrollBar() : m_pStyle(NULL), m_pGUI(NULL),
                                 m_X(300.f), m_Y(300.f),
                                 m_ScrollRange(1.f), m_ScrollSpace(0.f), // MaxPos: not 0, due to division.
                                 m_Length(200.f), m_Width(20.f), 
                                 m_BarSize(0.f), m_Pos(0.f),
                                 m_UseEdgeButtons(true),
                                 m_ButtonPlusPressed(false),
                                 m_ButtonMinusPressed(false),
                                 m_ButtonPlusHovered(false),
                                 m_ButtonMinusHovered(false),
                                 m_BarHovered(false),
                                 m_BarPressed(false)
{
}

IGUIScrollBar::~IGUIScrollBar()
{
}

void IGUIScrollBar::SetupBarSize()
{
    float min = GetStyle()->m_MinimumBarSize;
    float max = GetStyle()->m_MaximumBarSize;
    float length = m_Length;

    // Check for edge buttons
    if (m_UseEdgeButtons)
        length -= GetStyle()->m_Width * 2.f;

    // Check min and max are valid
    if (min > length)
    {
        LOGWARNING(L"Minimum scrollbar size of %g is larger than the total scrollbar size of %g", min, length);
        min = 0.f;
    }
    if (max < min)
        max = length;

    // Clamp size to not exceed a minimum or maximum.
    m_BarSize = clamp(length * std::min((float)m_ScrollSpace / (float)m_ScrollRange, 1.f), min, max);
}

const SGUIScrollBarStyle *IGUIScrollBar::GetStyle() const
{
    if (!m_pHostObject)
        return NULL;

    return m_pHostObject->GetScrollBarStyle(m_ScrollBarStyle);
}

CGUI *IGUIScrollBar::GetGUI() const 
{ 
    if (!m_pHostObject)
        return NULL;

    return m_pHostObject->GetGUI(); 
}

void IGUIScrollBar::UpdatePosBoundaries()
{
    if (m_Pos < 0.f ||
        m_ScrollRange < m_ScrollSpace) // <= scrolling not applicable
        m_Pos = 0.f;
    else
    if (m_Pos > GetMaxPos())
        m_Pos = GetMaxPos();
}

void IGUIScrollBar::HandleMessage(SGUIMessage &Message)
{
    switch (Message.type)
    {
    case GUIM_MOUSE_MOTION:
        {
            // TODO Gee: Optimizations needed!

            CPos mouse = m_pHostObject->GetMousePos();

            // If bar is being dragged
            if (m_BarPressed)
            {
                SetPosFromMousePos(mouse);
                UpdatePosBoundaries();
            }

            // check if components are being hovered
            m_BarHovered = GetBarRect().PointInside(mouse);
            m_ButtonMinusHovered = HoveringButtonMinus(mouse);
            m_ButtonPlusHovered =  HoveringButtonPlus(mouse);

            if (!m_ButtonMinusHovered)
                m_ButtonMinusPressed = false;

            if (!m_ButtonPlusHovered)
                m_ButtonPlusPressed = false;
        } break;

    case GUIM_MOUSE_PRESS_LEFT:
        {
            if (!m_pHostObject)
                break;

            CPos mouse = m_pHostObject->GetMousePos();

            // if bar is pressed
            if (GetBarRect().PointInside(mouse))
            {
                m_BarPressed = true;
                m_BarPressedAtPos = mouse;
                m_PosWhenPressed = m_Pos;
            }
            else
            // if button-minus is pressed
            if (m_ButtonMinusHovered)
            {
                m_ButtonMinusPressed = true;
                ScrollMinus();
            }
            else
            // if button-plus is pressed
            if (m_ButtonPlusHovered)
            {
                m_ButtonPlusPressed = true;
                ScrollPlus();
            }
            else
            // Pressing the background of the bar, to scroll
            //  notice the if-sentence alone does not admit that,
            //  it must be after the above if/elses
            {
                if (GetOuterRect().PointInside(mouse))
                {
                    // Scroll plus or minus a lot, this might change, it doesn't
                    //  have to be fancy though.
                    if (mouse.y < GetBarRect().top)
                        ScrollMinusPlenty();
                    else
                        ScrollPlusPlenty();

                    // Simulate mouse movement to see if bar now is hovered
                    SGUIMessage msg(GUIM_MOUSE_MOTION);
                    HandleMessage(msg);
                }
            }
        } break;

    case GUIM_MOUSE_RELEASE_LEFT:
        m_ButtonMinusPressed = false;
        m_ButtonPlusPressed = false;
        break;

    default:
        break;
    }
}