tachyon::PointerDrag Struct Reference

One press on an element that may become a drag. More...

#include <gui_core/input/gui_pointer_drag.h>

Public Types
enum class	Ended : uint8_t { No , Click , Drag }
	How a press ended. More...

Public Member Functions
bool	IsHeld () const noexcept
	A press is held, on any element.
bool	IsPressed (ID element) const noexcept
	A press of element is held.
bool	IsDragging (ID element) const noexcept
	A press of element is held and has become a drag.
bool	Press (const ElementEvent &e, const ElementStorage &storage, MouseButtons button=MouseButtons::Left, bool atOnce=false)
	Starts tracking e when it is button going down: true then.
bool	Move (const ElementEvent &e, int32_t distance)
	For a move of the held press: true when it is a drag move, the one that goes past distance pixels (see IsDragTravel) included.
Ended	Release (const ElementEvent &e)
	For the held button coming up on e.id: how the press ended. There is no press after.
bool	Cancel (ID element) noexcept
	Drops the press of element (Escape, a lost capture): true when there was one.
void	Reset () noexcept
	Drops any press.
int2	ScreenDelta (const InputState &s) const noexcept
	Pointer travel since the press, in screen pixels.
int2	LocalDelta (const ElementEvent &e, const ElementStorage &storage) const
	Pointer travel since the press, in the space of the element's rect (follows zoom).

Public Attributes
ID	id = ID::Invalid()
	the element pressed; Invalid when there is no press
MouseButtons	button = MouseButtons::None
	the button held
int2	pressScreen { 0, 0 }
	pointer at the press, screen pixels
int2	pressLocal { 0, 0 }
	pointer at the press, in the space of the element's rect
bool	dragging = false
	moved the drag distance (or a drag from the press on)

Detailed Description

One press on an element that may become a drag.

A control keeps it in its own state and gives it that element's events: Press when a button goes down, Move on each move, Release when the button comes up and Cancel on Escape. What the drag changes, and the value to put back on a cancel, stay with the control.

The element that returns true for the press gets the mouse capture, so the moves and the release come to it wherever the pointer goes.

Member Enumeration Documentation

Ended

enum class tachyon::PointerDrag::Ended : uint8_t

strong

How a press ended.

Enumerator
No	not the release of the held press
Click	released before it became a drag
Drag	released after dragging

Member Function Documentation

IsHeld()

bool tachyon::PointerDrag::IsHeld ( ) const

inlinenoexcept

A press is held, on any element.

IsPressed()

bool tachyon::PointerDrag::IsPressed ( ID element ) const

inlinenoexcept

A press of element is held.

IsDragging()

bool tachyon::PointerDrag::IsDragging ( ID element ) const

inlinenoexcept

A press of element is held and has become a drag.

Press()

bool tachyon::PointerDrag::Press	(	const ElementEvent &	e,
		const ElementStorage &	storage,
		MouseButtons	button = MouseButtons::Left,
		bool	atOnce = false )

Starts tracking e when it is button going down: true then.

With atOnce the press is a drag from the start (a sizer, a scrollbar thumb) and never a click.

Move()

bool tachyon::PointerDrag::Move	(	const ElementEvent &	e,
		int32_t	distance )

For a move of the held press: true when it is a drag move, the one that goes past distance pixels (see IsDragTravel) included.

False for another element, without a press, or while the press is still under the distance.

Release()

Ended tachyon::PointerDrag::Release

(

const ElementEvent &

e

)

For the held button coming up on e.id: how the press ended. There is no press after.

Cancel()

bool tachyon::PointerDrag::Cancel ( ID element )

noexcept

Drops the press of element (Escape, a lost capture): true when there was one.

Reset()

void tachyon::PointerDrag::Reset ( )

inlinenoexcept

Drops any press.

ScreenDelta()

int2 tachyon::PointerDrag::ScreenDelta ( const InputState & s ) const

inlinenoexcept

Pointer travel since the press, in screen pixels.

LocalDelta()

int2 tachyon::PointerDrag::LocalDelta	(	const ElementEvent &	e,
		const ElementStorage &	storage ) const

Pointer travel since the press, in the space of the element's rect (follows zoom).

Member Data Documentation

id

ID tachyon::PointerDrag::id = ID::Invalid()

the element pressed; Invalid when there is no press

button

MouseButtons tachyon::PointerDrag::button = MouseButtons::None

the button held

pressScreen

int2 tachyon::PointerDrag::pressScreen { 0, 0 }

pointer at the press, screen pixels

pressLocal

int2 tachyon::PointerDrag::pressLocal { 0, 0 }

pointer at the press, in the space of the element's rect

dragging

bool tachyon::PointerDrag::dragging = false

moved the drag distance (or a drag from the press on)

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The documentation for this struct was generated from the following file:

• gui_core/input/gui_pointer_drag.h