Package limn.graphics

Interface Icon

All Known Implementing Classes:
BitmapIcon, SvgIcon
public interface Icon
A themeable, resolution-independent glyph, conceptually distinct from an Image, which is just a fixed grid of RGBA pixels for display. An icon knows how to produce the right bitmap for a given device-pixel size and theme brightness, and whether that bitmap is a single-color mask (recolored with the theme) or a finished, pre-colored picture.

This split is why components take an Icon (buttons, labels, tabs, field adornments) while style-free image widgets take a raw Image: an icon adapts to DPI and theme, a picture does not.

Built-in implementations:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static enum 
    Icon.Mirroring
    Whether an icon turns around when the interface does.

  • Method Summary

    Modifier and Type
    Method
    Description
    Image
    image(int pixelSize, boolean dark)
    The bitmap best suited to a pixelSize×pixelSize box measured in device pixels, for the given theme brightness.
    default void
    paint(Canvas canvas, float x, float y, float size, Color tint, boolean dark)
    Paints this icon into a size×size logical box at (x, y): it requests a bitmap at the exact device resolution (size × Canvas.contentScale()) so the result is crisp, then applies tint when tintable (otherwise draws the picture untouched).
    default void
    paint(Canvas canvas, float x, float y, float size, Color tint, boolean dark, boolean mirrored)
    Paints this icon, flipped horizontally about its own box when mirrored.
    default boolean
    tintable()
    Whether image(int, boolean) returns a single-color mask to be recolored with the theme (true: SVG, grayscale/mono PNG), or a finished picture to draw as-is (false: pre-colored light/dark variants).

  • Method Details

    • image

      Image image(int pixelSize, boolean dark)
      The bitmap best suited to a pixelSize×pixelSize box measured in device pixels, for the given theme brightness. Vector icons rasterize at exactly this size (so they stay sharp on HiDPI and at any zoom); bitmap icons pick their nearest available variant.

      Answers on the calling thread, and has no asynchronous form on purpose: paint(limn.graphics.Canvas, float, float, float, limn.graphics.Color, boolean) calls it from inside a frame, and a paint that asked for a bitmap has to be given one before it can finish. An implementation whose bitmap is expensive to produce carries the warm-up on its own type instead, where the caller can run it ahead of the frame; SvgIcon.imageAsync(int) is the one that does.

      Parameters:
      pixelSize - target extent in physical pixels (≥ 1)
      dark - whether the active theme is dark (selects light/dark variants)

    • tintable

      default boolean tintable()
      Whether image(int, boolean) returns a single-color mask to be recolored with the theme (true: SVG, grayscale/mono PNG), or a finished picture to draw as-is (false: pre-colored light/dark variants). Governs whether paint(limn.graphics.Canvas, float, float, float, limn.graphics.Color, boolean) applies its tint.

    • paint

      default void paint(Canvas canvas, float x, float y, float size, Color tint, boolean dark)
      Paints this icon into a size×size logical box at (x, y): it requests a bitmap at the exact device resolution (size × Canvas.contentScale()) so the result is crisp, then applies tint when tintable (otherwise draws the picture untouched). This is the one idiom every component uses to draw an icon.

    • paint

      default void paint(Canvas canvas, float x, float y, float size, Color tint, boolean dark, boolean mirrored)
      Paints this icon, flipped horizontally about its own box when mirrored.

      The flip is a negative x scale about the destination rect, and it is the one legal negative scale in this toolkit: it acts on a single image, never on a tree. Mirroring a layout is a placement decision taken by the widget that owns the coordinate, and a transform at any root would turn correctly shaped text into a mirror image, flip every picture and every video frame, and put an inverse transform on the hot path of every hit test.

      A caller passes mirrored as mirroring == Mirroring.IN_RTL && widget.layoutDirection() == RTL: the flag says what the icon means and the axis says which way the interface reads, and neither alone is the answer.

      Parameters:
      mirrored - whether to flip; false is exactly paint(Canvas, float, float, float, Color, boolean)