HoverButton
HoverButton is an image button whose normal, hover and disabled appearance all
come from one image: three pictures of the same size, side by side.
HoverButton close = new HoverButton("THEME/72x24_close.png", () -> closeWindow());
The image is the button
The control reads the image's dimensions at build time, divides the width by three, and sizes itself to one of them - so a 72x24 image is a 24x24 button showing its left third, its middle third on hover, and its right third when disabled. Getting that wrong is reported: an image whose width is not a multiple of three, or whose parts are far from square, is logged as an error.
| Method | What it does |
|---|---|
new HoverButton(rurl) / (rurl, click) |
the image, and optionally the handler |
setSrc(String) |
a different image; rebuilds the button |
setDisabled(boolean) / setDisabledBecause(String) |
off, with the reason as tooltip |
The url is an ordinary web resource path, with THEME/ in front of it meaning
"from the current theme's directory".
When to use it
This is the button of the framework's own furniture: the back and close buttons
of AppPageTitleBar and the expander of ExpandHeader are all HoverButtons,
and their images live in the theme.
For anything else, prefer SmallImgButton: it
takes an IIconRef, so it works with font icons, needs no image to be drawn in
three states, and scales with the page rather than with a bitmap.