ES-DE/es-core/src/components/ScrollIndicatorComponent.h

//  SPDX-License-Identifier: MIT
//
//  EmulationStation Desktop Edition
//  ScrollIndicatorComponent.h
//
//  Visually indicates whether a menu can be scrolled (up, up/down or down).
//

#ifndef ES_CORE_COMPONENTS_SCROLL_INDICATOR_COMPONENT_H
#define ES_CORE_COMPONENTS_SCROLL_INDICATOR_COMPONENT_H

#define FADE_IN_TIME 90.0f

#include "GuiComponent.h"
#include "animations/LambdaAnimation.h"
#include "components/ComponentList.h"

class ScrollIndicatorComponent : public GuiComponent
{
public:
    ScrollIndicatorComponent(std::shared_ptr<ComponentList> componentList,
                             std::shared_ptr<ImageComponent> scrollUp,
                             std::shared_ptr<ImageComponent> scrollDown)
        : mPreviousScrollState {ComponentList::SCROLL_NONE}
    {
        assert(componentList != nullptr && scrollUp != nullptr && scrollDown != nullptr);

        scrollUp->setImage(":/graphics/scroll_up.svg");
        scrollDown->setImage(":/graphics/scroll_down.svg");

        scrollUp->setColorShift(mMenuColorScrollIndicators);
        scrollDown->setColorShift(mMenuColorScrollIndicators);

        scrollUp->setOpacity(0.0f);
        scrollDown->setOpacity(0.0f);

        componentList.get()->setScrollIndicatorChangedCallback(
            [this, scrollUp, scrollDown](ComponentList::ScrollIndicator state,
                                         bool singleRowScroll) {
                float fadeTime {FADE_IN_TIME};

                bool upFadeIn = false;
                bool upFadeOut = false;
                bool downFadeIn = false;
                bool downFadeOut = false;

                scrollUp->finishAnimation(0);
                scrollDown->finishAnimation(0);

                if (state == ComponentList::SCROLL_UP &&
                    mPreviousScrollState == ComponentList::SCROLL_NONE) {
                    scrollUp->setOpacity(1.0f);
                }
                else if (state == ComponentList::SCROLL_UP &&
                         mPreviousScrollState == ComponentList::SCROLL_UP_DOWN) {
                    downFadeOut = true;
                }
                else if (state == ComponentList::SCROLL_UP &&
                         mPreviousScrollState == ComponentList::SCROLL_DOWN) {
                    upFadeIn = true;
                    fadeTime *= 2.0f;
                    scrollDown->setOpacity(0.0f);
                }
                else if (state == ComponentList::SCROLL_UP_DOWN &&
                         mPreviousScrollState == ComponentList::SCROLL_NONE) {
                    scrollUp->setOpacity(1.0f);
                    scrollDown->setOpacity(1.0f);
                }
                else if (state == ComponentList::SCROLL_UP_DOWN &&
                         mPreviousScrollState == ComponentList::SCROLL_DOWN) {
                    upFadeIn = true;
                }
                else if (state == ComponentList::SCROLL_UP_DOWN &&
                         mPreviousScrollState == ComponentList::SCROLL_UP) {
                    downFadeIn = true;
                }
                else if (state == ComponentList::SCROLL_DOWN &&
                         mPreviousScrollState == ComponentList::SCROLL_NONE) {
                    scrollDown->setOpacity(1.0f);
                }
                else if (state == ComponentList::SCROLL_DOWN &&
                         mPreviousScrollState == ComponentList::SCROLL_UP_DOWN) {
                    upFadeOut = true;
                }
                else if (state == ComponentList::SCROLL_DOWN &&
                         mPreviousScrollState == ComponentList::SCROLL_UP) {
                    downFadeIn = true;
                    fadeTime *= 2.0f;
                    scrollUp->setOpacity(0.0f);
                }

                // If jumping more than one row using the shoulder or trigger buttons, then
                // don't fade the indicators.
                if (!singleRowScroll)
                    fadeTime = 0.0f;

                if (upFadeIn) {
                    auto upFadeInFunc = [scrollUp](float t) {
                        scrollUp->setOpacity(glm::mix(0.0f, 1.0f, t));
                    };
                    scrollUp->setAnimation(
                        new LambdaAnimation(upFadeInFunc, static_cast<int>(fadeTime)), 0, nullptr,
                        false);
                }

                if (upFadeOut) {
                    auto upFadeOutFunc = [scrollUp](float t) {
                        scrollUp->setOpacity(glm::mix(0.0f, 1.0f, t));
                    };
                    scrollUp->setAnimation(
                        new LambdaAnimation(upFadeOutFunc, static_cast<int>(fadeTime)), 0, nullptr,
                        true);
                }

                if (downFadeIn) {
                    auto downFadeInFunc = [scrollDown](float t) {
                        scrollDown->setOpacity(glm::mix(0.0f, 1.0f, t));
                    };
                    scrollDown->setAnimation(
                        new LambdaAnimation(downFadeInFunc, static_cast<int>(fadeTime)), 0, nullptr,
                        false);
                }

                if (downFadeOut) {
                    auto downFadeOutFunc = [scrollDown](float t) {
                        scrollDown->setOpacity(glm::mix(0.0f, 1.0f, t));
                    };
                    scrollDown->setAnimation(
                        new LambdaAnimation(downFadeOutFunc, static_cast<int>(fadeTime)), 0,
                        nullptr, true);
                }

                mPreviousScrollState = state;
            });
    }

private:
    ComponentList::ScrollIndicator mPreviousScrollState;
};

#endif // ES_CORE_COMPONENTS_SCROLL_INDICATOR_COMPONENT_H