Skip to content

ui::PointerEvent

Header: winui/core/Input.hpp.

One mouse / touch / pen event, in window-client DIPs, as delivered to Element::handle_pointer() and Window::handle_pointer().

A pen or a finger arrives as mouse events. device says which it was and, for a pen, the event carries its pressure, tilt and buttons. A press-and-release pair is what a control counts as a click.

Example: 

// In an element of your own: a press and a release inside the bounds is a click.
class ToggleControl : public ui::Element
{
protected:
    bool pointer_override(const ui::PointerEvent& e) override
    {
        if (e.action == ui::PointerAction::Down && e.button == ui::PointerButton::Left)
        {
            pressed_ = true;
            return true;
        }
        if (e.action == ui::PointerAction::Up && pressed_)
        {
            pressed_ = false;
            if (bounds().contains(e.position))
            {
                toggle();
            }
            return true;
        }
        return false;
    }

    // The wheel arrives through wheel_override(); return true when the element scrolled.
    bool wheel_override(const ui::PointerEvent& e) override
    {
        offset_ += e.wheel_delta; // positive scrolls down
        return true;
    }

private:
    void toggle();

    bool  pressed_ = false;
    float offset_  = 0.0f;
};

Field Type Default
position Point Pointer position in window-client DIPs (the same space as Element::bounds()).
button PointerButton PointerButton::None The button pressed or released; None for Move, Leave and Wheel.
action PointerAction PointerAction::Move What happened; defaults to a plain move.
wheel_delta float 0.0f Valid only for PointerAction::Wheel: the scroll amount in DIPs. Positive scrolls down, so the content moves up, as with a non-inverted wheel. One notch of a standard mouse wheel is a few dozen DIPs. Code that constructs an event converts the platform's wheel units to DIPs first.
modifiers ModifierKeys The modifier keys held at the time of this event. TextBox extends its selection on Shift+click, and Ctrl+wheel zooms where a plain wheel turn scrolls.
click_count int 1 Valid only for PointerAction::Down: 1 for a plain click, 2/3 for a double-/triple-click. Clicks count as one sequence while they fall within the system's double-click time and distance. TextBox selects a word on a double-click and everything on a triple-click.
horizontal_wheel bool false Valid only for PointerAction::Wheel: the turn came from a horizontal wheel or a sideways touchpad swipe, and wheel_delta is positive toward the right. A vertical wheel with Shift held stays a vertical turn here. A scroller decides itself whether Shift redirects it.
device PointerDeviceType PointerDeviceType::Mouse The device behind the event. A pen's tip and a finger press, move and release as the left button.
pressure float 0.5f How hard the pen or finger presses, 0..1. 0.5 when the device does not say, which is always the case for the mouse, so pressure-sensitive drawing comes out even.
tilt_x float 0.0f A pen's tilt along x in degrees, -90..90, positive toward the right; 0 for any other device.
tilt_y float 0.0f A pen's tilt along y in degrees, -90..90, positive toward the user; 0 for any other device.
eraser bool false A pen is erasing: its eraser end is down (the pen is turned over), or its eraser button is held. False for any other device.
barrel_button bool false A pen's barrel button is held. With the default pen settings the system turns a press with it held into a right-click, so it shows up mostly on hover moves.