button.hpp

/*
    KTech, Kaup's C++ 2D terminal game engine library.
    Copyright (C) 2023-2025 Ethan Kaufman (AKA Kaup)
 
    This file is part of KTech.
 
    KTech 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 3 of the License, or
    any later version.
 
    KTech 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 KTech. If not, see <https://www.gnu.org/licenses/>.
*/
 
#pragma once
 
#include "../ktech.hpp"
 
class Button : public KTech::Widget
{
public:
    std::function<void()> m_OnPress; 
 
    Button(KTech::Engine& engine,
        KTech::ID<KTech::UI> ui,
        std::function<void()> OnPress,
        const std::string& key = KTech::Keys::return_,
        KTech::Point position = KTech::Point(0, 0),
        const std::string& text = "Button",
        bool withFrame = false,
        KTech::RGBA unselected = KTech::RGBAColors::gray,
        KTech::RGBA selected = KTech::RGBAColors::white,
        KTech::RGBA down = KTech::RGBAColors::Widgets::buttonDownBlue)
        : Widget(engine, ui, position),
        m_OnPress(std::move(OnPress)),
        m_unselectedRGBA(unselected),
        m_selectedRGBA(selected),
        m_downRGBA(down),
        m_downInvocation(engine, [this]() -> bool { return RemovePressColor(); })
    {
        // Texture
        SetText(text, withFrame);
        // Input handlers
        m_callbackGroup.RegisterCallback(key, [this]() -> bool { return InsideOnPress(); });
    }
 
    void SetText(const std::string& text, bool withFrame)
    {
        KTech::RGBA tempColor;
        if (m_downInvocation.m_active) // The button is down as it is invoked to remove down color
        {
            tempColor = m_downRGBA;
        }
        else if (m_selected)
        {
            tempColor = m_selectedRGBA;
        }
        else
        {
            tempColor = m_unselectedRGBA;
        }
 
        if (withFrame)
        {
            m_textures.resize(TEXTURES_SIZE_FRAMED);
            m_textures[ti_topLeftCorner].Simple(KTech::UPoint(1, 1), KTech::CellA('#', tempColor), KTech::Point(0, 0));
            m_textures[ti_topRightCorner].Simple(KTech::UPoint(1, 1), KTech::CellA('#', tempColor), KTech::Point(1 + text.length(), 0));
            m_textures[ti_bottomLeftCorner].Simple(KTech::UPoint(1, 1), KTech::CellA('#', tempColor), KTech::Point(0, 2));
            m_textures[ti_bottomRightCorner].Simple(KTech::UPoint(1, 1), KTech::CellA('#', tempColor), KTech::Point(1 + text.length(), 2));
            m_textures[ti_topFrame].Simple(KTech::UPoint(text.length(), 1), KTech::CellA('-', tempColor), KTech::Point(1, 0));
            m_textures[ti_leftFrame].Simple(KTech::UPoint(1, 1), KTech::CellA('|', tempColor), KTech::Point(0, 1));
            m_textures[ti_bottomFrame].Simple(KTech::UPoint(text.length(), 1), KTech::CellA('-', tempColor), KTech::Point(1, 2));
            m_textures[ti_rightFrame].Simple(KTech::UPoint(1, 1), KTech::CellA('|', tempColor), KTech::Point(1 + text.length(), 1));
        }
        else
        {
            m_textures.resize(TEXTURES_SIZE_FRAMELESS);
        }
        // text
        m_textures[ti_text].Write({text}, tempColor, KTech::RGBAColors::transparent, KTech::Point(1, 1));
    }
 
private:
    enum TextureIndex : size_t
    {
        ti_text,
        TEXTURES_SIZE_FRAMELESS,
        ti_topLeftCorner = TEXTURES_SIZE_FRAMELESS,
        ti_topRightCorner,
        ti_bottomLeftCorner,
        ti_bottomRightCorner,
        ti_topFrame,
        ti_leftFrame,
        ti_bottomFrame,
        ti_rightFrame,
        TEXTURES_SIZE_FRAMED
    };
 
    KTech::RGBA m_unselectedRGBA, m_selectedRGBA, m_downRGBA;
    static constexpr size_t pressLength = 100;
    KTech::Time::Invocation m_downInvocation;
 
    void OnSelect() override
    {
        RenderSelected();
    }
 
    void OnDeselect() override
    {
        RenderUnselected();
    }
 
    void RenderSelected()
    {
        for (KTech::Texture& texture : m_textures)
        {
            texture.Transform([&](KTech::CellA& cell){ cell.f = m_selectedRGBA; });
        }
    }
 
    void RenderUnselected()
    {
        for (KTech::Texture& texture : m_textures)
        {
            texture.Transform([&](KTech::CellA& cell){ cell.f = m_unselectedRGBA; });
        }
    }
 
    auto RemovePressColor() -> bool
    {
        if (m_selected)
        {
            for (KTech::Texture& texture : m_textures)
            {
                texture.Transform([&](KTech::CellA& cell){ cell.f = m_selectedRGBA; });
            }
        }
        else
        {
            for (KTech::Texture& texture : m_textures)
            {
                texture.Transform([&](KTech::CellA& cell){ cell.f = m_unselectedRGBA; });
            }
        }
        return true;
    }
 
    auto InsideOnPress() -> bool
    {
        for (KTech::Texture& texture : m_textures)
        {
            texture.Transform([&](KTech::CellA& cell){ cell.f = m_downRGBA; });
        }
        m_downInvocation.Invoke(pressLength, KTech::Time::Measurement::milliseconds);
        if (m_OnPress)
        {
            m_OnPress();
        }
        return true;
    }
};