fltk 0.11.4

Rust bindings for the FLTK GUI library
Documentation

fltk-rs

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Rust bindings for the FLTK Graphical User Interface library.

The FLTK crate is a crossplatform lightweight gui library which can be statically linked to produce small, self-contained (no dependencies) and fast gui applications.

Here is a list of software using FLTK.

  • Link to the official FLTK repository.
  • Link to the official documentation.

Usage

Just add the following to your project's Cargo.toml file:

[dependencies]
fltk = "^0.11"

The library is automatically built and statically linked to your binary.

For faster builds with the cmake crate, you can try setting the NUM_JOBS environment variable, or you can enable ninja builds for the C++ source using the "use-ninja" feature.

An example hello world application:

use fltk::{app::*, window::*};

let app = App::default();
let mut wind = Window::new(100, 100, 400, 300, "Hello from rust");
wind.end();
wind.show();
app.run().unwrap();

Another example showing the basic callback functionality:

use fltk::{app::*, button::*, frame::*, window::*};

let app = App::default();
let mut wind = Window::new(100, 100, 400, 300, "Hello from rust");
let mut frame = Frame::new(0, 0, 400, 200, "");
let mut but = Button::new(160, 210, 80, 40, "Click me!");
wind.end();
wind.show();
but.set_callback(move || frame.set_label("Hello World!"));
app.run().unwrap();

Please check the examples directory for more examples. You will notice that all widgets are instantiated with a new() method, taking the x and y coordinates, the width and height of the widget, as well as a label which can be left blank if needed. Another way to initialize a widget is using the builder pattern: (The following buttons are equivalent)

let but1 = Button::new(10, 10, 80, 40, "Button 1");

let but2 = Button::default()
.with_pos(10, 10)
.with_size(80, 40)
.with_label("Button 2");

An example of a counter showing use of the builder pattern:

let app = app::App::default();
let mut wind = Window::default()
.with_size(160, 200)
.center_screen()
.with_label("Counter");
let mut frame = Frame::default()
.with_size(100, 40)
.center_of(&wind)
.with_label("0");
let mut but_inc = Button::default()
.size_of(&frame)
.above_of(&frame, 0)
.with_label("+");
let mut but_dec = Button::default()
.size_of(&frame)
.below_of(&frame, 0)
.with_label("-");
wind.make_resizable(true);
wind.end();
wind.show();
/* Event handling */

Events

Events can be handled using the set_callback method (as above) or the available fltk::app::set_callback() free function, which will handle the default trigger of each widget(like clicks for buttons):

/* previous hello world code */
but.set_callback(move || frame.set_label("Hello World!"));
app.run().unwrap();

Another way is to use message passing:

/* previous counter code */
let (s, r) = app::channel::<Message>();

but_inc.emit(s, Message::Increment);
but_dec.emit(s, Message::Decrement);

while app.wait() {
let label: i32 = frame.label().parse().unwrap();
match r.recv() {
Some(Message::Increment) => frame.set_label(&(label + 1).to_string()),
Some(Message::Decrement) => frame.set_label(&(label - 1).to_string()),
None => (),
}
}

For the remainder of the code, check the full example here: https://github.com/MoAlyousef/fltk-rs/blob/master/examples/counter2.rs

For custom event handling, the handle() method can be used:

some_widget.handle(move |ev: Event| {
match ev {
/* handle ev */
}
});

Handled or ignored events using the handle method should return true, unhandled events should return false. More examples are available in the examples directory.

Theming

FLTK offers 4 application themes (called schemes):

  • Base
  • Gtk
  • Gleam
  • Plastic

These can be set using the App::with_scheme() function.

let app = App::default().with_scheme(AppScheme::Gleam);

Themes of individual widgets can be optionally modified using the provided methods in the WidgetBase trait, such as set_color(), set_label_font(), set_frame() etc:

some_button.set_color(Color::Light1); //! You can use one of the provided colors in the fltk enums
some_button.set_color(Color::from_rgb(255, 0, 0)); //! Or you can specify a color by rgb or hex/u32 value
some_button.set_color(Color::from_u32(0xffebee));
some_button.set_frame(FrameType::RoundUpBox);
some_button.set_font(Font::TimesItalic);

Features

The following are the features offered by the crate:

  • use-ninja: If you have ninja build installed, it builds faster than make or VS
  • system-libpng: Uses the system libpng
  • system-libjpeg: Uses the system libjpeg
  • system-zlib: Uses the system zlib
  • fltk-bundled: Support for bundled versions of cfltk and fltk on selected platforms (requires curl and tar)
  • enable-glwindow: Support for drawing using OpenGL functions.

Dependencies

Rust (version > 1.38), CMake (version > 3.0), Git and a C++11 compiler need to be installed and in your PATH for a crossplatform build from source. This crate also offers a bundled form of fltk on selected platforms, this can be enabled using the fltk-bundled feature flag (which requires curl and tar to download and unpack the bundled libraries).

  • Windows: No dependencies.
  • MacOS: No dependencies.
  • Linux: X11 and OpenGL development headers need to be installed for development. The libraries themselves are available on linux distros with a graphical user interface.

For Debian-based GUI distributions, that means running:

$ sudo apt-get install libx11-dev libxext-dev libxft-dev libxinerama-dev libxcursor-dev libxrender-dev libxfixes-dev libpango1.0-dev libgl1-mesa-dev libglu1-mesa-dev

For RHEL-based GUI distributions, that means running:

$ sudo yum groupinstall "X Software Development" && yum install pango-devel libXinerama-devel

For Arch-based GUI distributions, that means running:

$ sudo pacman -S libx11 libxext libxft libxinerama libxcursor libxrender libxfixes pango cairo libgl mesa --needed

For Alpine linux:

$ apk add pango-dev fontconfig-dev libxinerama-dev libxfixes-dev libxcursor-dev

FAQ

please check the FAQ page for frequently asked questions, encountered issues, guides on deployment, and contribution.