Summary

Add convenience methods for creating simple Backgrounds and Borders.

Problem

Creating simple Backgrounds and Borders is cumbersome as they require a verbose constructor invocation compared to what is requested from the user.

Solution

Add convenience factory methods for the simple cases.

Specification

Added to Background:

/**
 * A convenience factory method for creating a {@code Background} with a single {@code Paint}.
 *
 * @implSpec
 * This call is equivalent to {@link BackgroundFill#BackgroundFill(Paint, CornerRadii, Insets)
 * new Background(new BackgroundFill(fill, null, null));}.
 * @param fill the fill of the background. If {@code null}, {@code Color.TRANSPARENT} will be used.
 * @return a new background of the given fill
 * @since 18
 */
public static Background fill(Paint fill) {
    return new Background(new BackgroundFill(fill, null, null));
}

Added to Border:

/**
 * A convenience factory method for creating a solid {@code Border} with a single {@code Paint}.
 *
 * @implSpec
 * This call is equivalent to {@link BorderStroke#BorderStroke(Paint, BorderStrokeStyle, CornerRadii, BorderWidths)
 * new Border(new BorderStroke(stroke, BorderStrokeStyle.SOLID, null, null));}.
 * @param stroke the stroke of the border (for all sides). If {@code null}, {@code Color.BLACK} will be used.
 * @return a new border of the given stroke
 * @since 18
 */
public static Border stroke(Paint stroke) {
    return new Border(new BorderStroke(stroke, BorderStrokeStyle.SOLID, null, null));
}