Class UIScale


  • public class UIScale
    extends Object
    This class handles scaling in Swing UIs. It computes user scaling factor based on font size and provides methods to scale integer, float, Dimension and Insets. This class is look and feel independent.

    Two scaling modes are supported by FlatLaf for HiDPI displays:

    1) system scaling mode

    This mode is supported since Java 9 on all platforms and in some Java 8 VMs (e.g. Apple and JetBrains). The JRE determines the scale factor per-display and adds a scaling transformation to the graphics object. E.g. invokes java.awt.Graphics2D.scale( 1.5, 1.5 ) for 150%. So the JRE does the scaling itself. E.g. when you draw a 10px line, a 15px line is drawn on screen. The scale factor may be different for each connected display. The scale factor may change for a window when moving the window from one display to another one.

    2) user scaling mode

    This mode is mainly for Java 8 compatibility, but is also used on Linux or if the default font is changed. The user scale factor is computed based on the used font. The JRE does not scale anything. So we have to invoke scale(float) where necessary. There is only one user scale factor for all displays. The user scale factor may change if the active LaF, "defaultFont" or "Label.font" has changed. If system scaling mode is available the user scale factor is usually 1, but may be larger on Linux or if the default font is changed.
    • Constructor Detail

      • UIScale

        public UIScale()
    • Method Detail

      • addPropertyChangeListener

        public static void addPropertyChangeListener​(PropertyChangeListener listener)
      • removePropertyChangeListener

        public static void removePropertyChangeListener​(PropertyChangeListener listener)
      • isSystemScalingEnabled

        public static boolean isSystemScalingEnabled()
        Returns whether system scaling is enabled.
      • getSystemScaleFactor

        public static double getSystemScaleFactor​(Graphics2D g)
        Returns the system scale factor for the given graphics context.
      • getSystemScaleFactor

        public static double getSystemScaleFactor​(GraphicsConfiguration gc)
        Returns the system scale factor for the given graphics configuration.
      • computeFontScaleFactor

        public static float computeFontScaleFactor​(Font font)
        For internal use only.
        Since:
        2
      • applyCustomScaleFactor

        public static FontUIResource applyCustomScaleFactor​(FontUIResource font)
        Applies a custom scale factor given in system property "flatlaf.uiScale" to the given font.
      • getUserScaleFactor

        public static float getUserScaleFactor()
        Returns the user scale factor.
      • scale

        public static float scale​(float value)
        Multiplies the given value by the user scale factor.
      • scale

        public static int scale​(int value)
        Multiplies the given value by the user scale factor and rounds the result.
      • scale2

        public static int scale2​(int value)
        Similar as scale(int) but always "rounds down".

        For use in special cases. scale(int) is the preferred method.

      • unscale

        public static float unscale​(float value)
        Divides the given value by the user scale factor.
      • unscale

        public static int unscale​(int value)
        Divides the given value by the user scale factor and rounds the result.
      • scale

        public static Dimension scale​(Dimension dimension)
        Scales the given dimension with the user scale factor.

        If user scale factor is 1, then the given dimension is simply returned. Otherwise, a new instance of Dimension or DimensionUIResource is returned, depending on whether the passed dimension implements UIResource.

      • scale

        public static Insets scale​(Insets insets)
        Scales the given insets with the user scale factor.

        If user scale factor is 1, then the given insets is simply returned. Otherwise, a new instance of Insets or InsetsUIResource is returned, depending on whether the passed dimension implements UIResource.