Padding.java

package com.github.czyzby.kiwi.util.gdx.scene2d;

import com.badlogic.gdx.scenes.scene2d.ui.Cell;
import com.badlogic.gdx.scenes.scene2d.ui.Table;

/** A simple helper class that holds informations about padding on each side of an object. Static methods can be used to
 * quickly set padding or spacing of a cell or a table using this class' object.
 *
 * When padding is set for a table, its cells will be separated from its borders by the given value. When padding is set
 * for a window, additionally to the table's padding effect, top padding will be a draggable area, allowing to move the
 * window.
 *
 * When padding is set for a cell, it will be separated from other cells and table's border by the given value. When
 * spacing is set for a cell, it will be separated by at least as many pixels from other cells as specified. If spacing
 * or padding with the same values is used on every cell in a table, padding will provide twice as big distances between
 * cells, since spacings can overlap.
 *
 * @author MJ */
public class Padding {
    /** Common padding sizes. */
    public static final Padding PAD_0 = of(0f), PAD_2 = of(2f), PAD_4 = of(4f), PAD_8 = of(8f);

    private final float top, left, bottom, right;

    /** @param padding will be set as padding for all directions. */
    public Padding(final float padding) {
        this(padding, padding, padding, padding);
    }

    /** @param horizontal will be set as left and right padding.
     * @param vertical will be set as top and bottom padding. */
    public Padding(final float horizontal, final float vertical) {
        this(vertical, horizontal, vertical, horizontal);
    }

    /** @param top top padding value.
     * @param left left padding value.
     * @param bottom bottom padding value.
     * @param right right padding value. */
    public Padding(final float top, final float left, final float bottom, final float right) {
        this.top = top;
        this.left = left;
        this.bottom = bottom;
        this.right = right;
    }

    /** @param padding will be set as padding for all directions. */
    public static Padding of(final float padding) {
        return new Padding(padding, padding, padding, padding);
    }

    /** @param horizontal will be set as left and right padding.
     * @param vertical will be set as top and bottom padding. */
    public static Padding of(final float horizontal, final float vertical) {
        return new Padding(vertical, horizontal, vertical, horizontal);
    }

    /** @param top top padding value.
     * @param left left padding value.
     * @param bottom bottom padding value.
     * @param right right padding value. */
    public static Padding of(final float top, final float left, final float bottom, final float right) {
        return new Padding(top, left, bottom, right);
    }

    /** @return top padding value. */
    public float getTop() {
        return top;
    }

    /** @return left padding value. */
    public float getLeft() {
        return left;
    }

    /** @return bottom padding value. */
    public float getBottom() {
        return bottom;
    }

    /** @return right padding value. */
    public float getRight() {
        return right;
    }

    /** @param padding will be added to the given padding.
     * @return new Padding object with summed pad values. */
    public Padding add(final Padding padding) {
        return new Padding(top + padding.getTop(), left + padding.getLeft(), bottom + padding.getBottom(),
                right + padding.getRight());
    }

    /** @param padding will be subtracted from the given padding.
     * @return new Padding object with subtracted pad values. */
    public Padding subtract(final Padding padding) {
        return new Padding(top - padding.getTop(), left - padding.getLeft(), bottom - padding.getBottom(),
                right - padding.getRight());
    }

    /** @return new Padding object with reversed pad values. */
    public Padding reverse() {
        return new Padding(-top, -left, -bottom, -right);
    }

    /** Allows to set Table's padding with the Padding object, which has be done externally, as it's not part of the
     * standard libGDX API.
     *
     * @param table will have the padding set according to the this object's data.
     * @return the given table for chaining. */
    public Table applyPadding(final Table table) {
        table.pad(top, left, bottom, right);
        return table;
    }

    /** Allows to set Cell's padding with the Padding object, which has be done externally, as it's not part of the
     * standard libGDX API.
     *
     * @param cell will have the padding set according to the this object's data.
     * @return the given cell for chaining. */
    public Cell<?> applyPadding(final Cell<?> cell) {
        cell.pad(top, left, bottom, right);
        return cell;
    }

    /** Allows to set Cell's spacing with the Padding object, which has be done externally, as it's not part of the
     * standard libGDX API. Padding holds 4 floats for each direction, so it's compatible with both padding and spacing
     * settings without any additional changes.
     *
     * @param cell will have the padding set according to the this object's data.
     * @return the given cell for chaining. */
    public Cell<?> applySpacing(final Cell<?> cell) {
        cell.space(top, left, bottom, right);
        return cell;
    }

    // Padding utilities:
    /** Allows to set Table's padding with the Padding object, which has be done externally, as it's not part of the
     * standard libGDX API.
     *
     * @param padding contains data of padding sizes.
     * @param table will have the padding set according to the given data.
     * @return the given table for chaining. */
    public static Table setPadding(final Padding padding, final Table table) {
        table.pad(padding.getTop(), padding.getLeft(), padding.getBottom(), padding.getRight());
        return table;
    }

    /** Allows to set Cell's padding with the Padding object, which has be done externally, as it's not part of the
     * standard libGDX API.
     *
     * @param padding contains data of padding sizes.
     * @param cell will have the padding set according to the given data.
     * @return the given cell for chaining. */
    public static Cell<?> setPadding(final Padding padding, final Cell<?> cell) {
        return cell.pad(padding.getTop(), padding.getLeft(), padding.getBottom(), padding.getRight());
    }

    /** Allows to set Cell's spacing with the Padding object, which has be done externally, as it's not part of the
     * standard libGDX API. Padding holds 4 floats for each direction, so it's compatible with both padding and spacing
     * settings without any additional changes.
     *
     * @param spacing contains data of spacing sizes.
     * @param cell will have the padding set according to the given data.
     * @return the given cell for chaining. */
    public static Cell<?> setSpacing(final Padding spacing, final Cell<?> cell) {
        return cell.space(spacing.getTop(), spacing.getLeft(), spacing.getBottom(), spacing.getRight());
    }
}