SliderBlock.java

package nl.utwente.viskell.ui.components;

import java.util.Locale;
import java.util.Map;
import java.util.Optional;

import com.google.common.collect.ImmutableMap;
import javafx.event.Event;
import javafx.fxml.FXML;
import javafx.scene.control.Slider;
import javafx.scene.input.TouchEvent;
import nl.utwente.viskell.ui.ToplevelPane;
import nl.utwente.viskell.ui.serialize.Bundleable;

/**
 * An extension of ValueBlock.
 * The value of this Block can be changed by dragging a slider.
 */
public class SliderBlock extends ValueBlock  implements Bundleable {
    @FXML protected Slider slider;
    
    /** Whether this slider represent an integral value. */
    public final boolean isIntegral;
    
    /** The value as of the latest finished modification. */
    private double baseValue;

    /**
     * Constructs a new SliderBlock
     * @param pane The parent pane this Block resides on.
     * @param isIntegral wWhether this slider represent an integral value.
     */
    public SliderBlock(ToplevelPane pane, boolean isIntegral) {
        super("SliderBlock", pane, pane.getEnvInstance().buildType(isIntegral ? "Num a => a" : "Fractional a => a"));

        this.isIntegral = isIntegral;
        this.baseValue = 0;
        this.slider.setValue(0);
        this.updateValue();

        slider.getStyleClass().add("inactive");
        slider.setOnMousePressed(e -> slider.getStyleClass().removeAll("inactive"));
        slider.setOnMouseReleased(e -> slider.getStyleClass().add("inactive"));
        slider.setOnTouchPressed(e -> slider.getStyleClass().removeAll("inactive"));
        slider.setOnTouchReleased(e -> slider.getStyleClass().add("inactive"));

        slider.valueProperty().addListener(ev -> this.updateValue());
        slider.valueChangingProperty().addListener(ev -> this.toggleSliding());
        
        slider.addEventHandler(TouchEvent.TOUCH_MOVED, Event::consume);
    }

    @Override
    protected ImmutableMap<String, Object> toBundleFragment() {
        return ImmutableMap.of(
                "isIntegral", isIntegral,
                "value", getValue());
    }

    public static SliderBlock fromBundleFragment(ToplevelPane pane, Map<String,Object> bundleFragment) {
        boolean isIntegral = (Boolean)bundleFragment.get("isIntegral");
        SliderBlock sliderBlock = new SliderBlock(pane, isIntegral);
        sliderBlock.setValue((String)bundleFragment.get("value"));
        return sliderBlock;
    }

    private double computeCurrentValue() {
        double offset = this.slider.getValue();
        if (this.isIntegral) {
            return Math.rint(this.baseValue + Math.signum(offset) * 4 * Math.expm1(Math.abs(offset) * 4));
        }
        else {
            return this.baseValue + Math.signum(offset) * Math.expm1(Math.abs(offset) * 5);
        }
    }
    
    private void updateValue() {
        if (this.isIntegral) {
            setValue("" + Math.round(this.computeCurrentValue()));
        } else {
            setValue(String.format(Locale.US, "%.5f", this.computeCurrentValue()));
        }
        this.initiateConnectionChanges();
    }
    
    private void toggleSliding() {
        if (!slider.isValueChanging()) {
            // on finish reset slider and use new base value
            this.baseValue = this.computeCurrentValue();
            this.slider.setValue(0.0);
        }
    }
    
    public void resetSlider() {
        this.baseValue = 0;
        this.slider.setValue(0);
        this.updateValue();
    }
    
    @Override
    public Optional<Block> getNewCopy() {
        SliderBlock block = new SliderBlock(this.getToplevel(), this.isIntegral);
        block.slider.setValue(this.slider.getValue());
        return Optional.of(block);
    }
    
}