ES-DE/es-core/src/components/SliderComponent.cpp

//
//  SliderComponent.cpp
//
//  Slider to set value in a predefined range.
//

#include "components/SliderComponent.h"

#include "resources/Font.h"

#define MOVE_REPEAT_DELAY 500
#define MOVE_REPEAT_RATE 40

SliderComponent::SliderComponent(
        Window* window,
        float min,
        float max,
        float increment,
        const std::string& suffix)
        : GuiComponent(window),
        mMin(min),
        mMax(max),
        mSingleIncrement(increment),
        mMoveRate(0),
        mKnob(window),
        mSuffix(suffix)
{
    assert((min - max) != 0);

    // Some sane default value.
    mValue = (max + min) / 2;

    mKnob.setOrigin(0.5f, 0.5f);
    mKnob.setImage(":/graphics/slider_knob.svg");

    setSize(Renderer::getScreenWidth() * 0.15f, Font::get(FONT_SIZE_MEDIUM)->getLetterHeight());
}

bool SliderComponent::input(InputConfig* config, Input input)
{
    if (config->isMappedLike("left", input)) {
        if (input.value)
            setValue(mValue - mSingleIncrement);

        mMoveRate = input.value ? -mSingleIncrement : 0;
        mMoveAccumulator = -MOVE_REPEAT_DELAY;
        return true;
    }
    if (config->isMappedLike("right", input)) {
        if (input.value)
            setValue(mValue + mSingleIncrement);

        mMoveRate = input.value ? mSingleIncrement : 0;
        mMoveAccumulator = -MOVE_REPEAT_DELAY;
        return true;
    }

    return GuiComponent::input(config, input);
}

void SliderComponent::update(int deltaTime)
{
    if (mMoveRate != 0) {
        mMoveAccumulator += deltaTime;
        while (mMoveAccumulator >= MOVE_REPEAT_RATE) {
            setValue(mValue + mMoveRate);
            mMoveAccumulator -= MOVE_REPEAT_RATE;
        }
    }

    GuiComponent::update(deltaTime);
}

void SliderComponent::render(const Transform4x4f& parentTrans)
{
    Transform4x4f trans = parentTrans * getTransform();
    Renderer::setMatrix(trans);

    // Render suffix.
    if (mValueCache)
        mFont->renderTextCache(mValueCache.get());

    float width = mSize.x() - mKnob.getSize().x() -
            (mValueCache ? mValueCache->metrics.size.x() + 4 : 0);

    // Render line.
    const float lineWidth = 2;
    Renderer::drawRect(mKnob.getSize().x() / 2, mSize.y() / 2 -
            lineWidth / 2, width, lineWidth, 0x777777FF, 0x777777FF);

    // Render knob.
    mKnob.render(trans);

    GuiComponent::renderChildren(trans);
}

void SliderComponent::setValue(float value)
{
    mValue = value;
    if (mValue < mMin)
        mValue = mMin;
    else if (mValue > mMax)
        mValue = mMax;

    onValueChanged();
}

float SliderComponent::getValue()
{
    return mValue;
}

void SliderComponent::onSizeChanged()
{
    if (!mSuffix.empty())
        mFont = Font::get((int)(mSize.y()), FONT_PATH_LIGHT);

    onValueChanged();
}

void SliderComponent::onValueChanged()
{
    // Update suffix textcache.
    if (mFont) {
        std::stringstream ss;
        ss << std::fixed;
        ss.precision(0);
        ss << mValue;
        ss << mSuffix;
        const std::string val = ss.str();

        ss.str("");
        ss.clear();
        ss << std::fixed;
        ss.precision(0);
        ss << mMax;
        ss << mSuffix;
        const std::string max = ss.str();

        Vector2f textSize = mFont->sizeText(max);
        mValueCache = std::shared_ptr<TextCache>(mFont->buildTextCache(val, mSize.x() -
                textSize.x(), (mSize.y() - textSize.y()) / 2, 0x777777FF));
        mValueCache->metrics.size[0] = textSize.x(); // Fudge the width.
    }

    // Update knob position/size.
    mKnob.setResize(0, mSize.y() * 0.7f);
    float lineLength = mSize.x() - mKnob.getSize().x() -
            (mValueCache ? mValueCache->metrics.size.x() + 4 : 0);
    mKnob.setPosition((mValue / mMax) * lineLength +
            mKnob.getSize().x()/2, mSize.y() / 2);
}

std::vector<HelpPrompt> SliderComponent::getHelpPrompts()
{
    std::vector<HelpPrompt> prompts;
    prompts.push_back(HelpPrompt("left/right", "change value"));
    return prompts;
}