Module crayon::input

Provides unified access to input devices across platforms.

Keyboard Inputs

To check whether the current platform provides keyboard input, call:

// Returns true if a keyboard is attached
input.has_keyboard_attached();

Nothing bad will happen if you call the keyboard functions even if has_keyboard_ attached returns false. To check the current state of specific keys:

// Checks if a key is currently held down.
input.is_key_down(KeyboardButton::A);

// Checks if a key has been pressed down during the last frame.
input.is_key_press(KeyboardButton::A);

// Checks if a key has been released during the last frame.
input.is_key_repeat(KeyboardButton::A);

A list of all key codes can be found in the KeyboardButton enumeration. Notes that the key code used here, are virtual keycode of physical keys, they don't necessarily represent what's actually printed on the key cap.

It's useful to get converted character input instead of raw key codes, to capture entered text in last frame, you can call:

// Gets captured text during the last frame.
input.text();

Mouse Inputs

Similar to keyboard device, to find out whether the host platform provides mouse input, call has_mouse_attached.

To check the state of the mouse buttons, use the following functions:

// Checks if a mouse button is held down.
input.is_mouse_down(MouseButton::Left);

// Checks if a mouse button has been pressed during last frame.
input.is_mouse_press(MouseButton::Left);

// Checks if a mouse button has been released during last frame.
input.is_mouse_release(MouseButton::Left);

A list of all mouse buttons can be found in the KeyboardButton enumeration. To get the current mouse position and the last frame's mouse movement in pixels:

// Gets the mouse position relative to the top-left hand corner of the window.
input.mouse_position();

// Gets mouse movement in pixels since last frame.
input.mouse_movement();

To get mouse wheel information:

// Gets the scroll movement of mouse in pixels, usually provided by mouse wheel.
input.mouse_scroll();

Mouse positions and movement are reported in pixel coordinates which makes it difficult to derive useful movement information out of it. It might changes in the future versions (dividing by the framebuffer resolution is a simple but very fuzzy workaround).

We also recognize some simple input patterns, like:

// Checks if a mouse button has been clicked during last frame.
input.mouse_position();

// Checks if a mouse button has been double clicked during last frame.
input.is_mouse_double_click();

TouchPad Inputs

The touch input functions provides access to basic touch- and multi-touch-input, and is currently only implemented on mobile platforms and not for notebook touchpads. You can get the touch informations by the finger index, which is ordered by the first touch time.

// Checks if the `n`th finger is touched during last frame.
input.is_finger_touched(n);

// Gets the position of the `n`th touched finger.
input.finger_position(n);

The touch support also addresses a few platform-agnostic gesture recognizers based on low-level touch inputs.

// Gets the tap gesture.
match input.finger_tap() {
    // A tap geture is detected during last frame.
    GestureTap::Action { position } => { ... },
    GestureTap::None => { ... },
}

// Gets the double tap gesture.
match input.finger_double_tap() {
    // A double tap geture is detected during last frame.
    GestureTap::Action { position } => { ... },
    GestureTap::None => { ... },
}

// Gets the panning gesture.
match input.finger_pan() {
    GesturePan::Start { start_position } => { ... },
    GesturePan::Move { start_position, position, movement } => { ... },
    GesturePan::End { start_position, position } => {... },
    GestureTap::None => { ... },
}

Others Inputs

Somethings that nice to have, but not implemented right now:

1. Device sensor inputs;
2. GamePad inputs;
3. More touch gesture like Pinching.

Structs

InputSetup	The setup parameters of all supported input devices.
InputSystem	The InputSystem struct are used to manage all the events and corresponding internal states.
InputSystemShared	The multi-thread friendly APIs of InputSystem.
KeyboardSetup	The setup parameters of keyboard device.
MouseSetup	The setup parameters of mouse device.
TouchPadSetup	The setup parameters of touch pad device.

Constants

MAX_TOUCHES

Maximum touches that would be tracked at sametime.