package dnd

import "github.com/gogpu/ui/geometry"

// DragVisual describes how to render drag feedback.

//

// Applications can inspect the active Session and its Feedback to render

// custom drag visuals (ghost widgets, drop indicators, etc.). This type

// provides common visual parameters that painters can use.

type DragVisual struct {

// CursorPos is the current cursor position during the drag.

CursorPos geometry.Point

// Offset is the distance from the cursor to the drag ghost's origin.

// Typically set to the offset from the original click point within

// the source widget.

Offset geometry.Point

// Effect is the current drop effect for visual feedback.

Effect DropEffect

// OverTarget is true when the cursor is over a valid drop target.

OverTarget bool

// Label is optional text to display near the cursor.

Label string

}

// NewDragVisual creates a DragVisual from an active Session.

//

// Returns a zero DragVisual if the session is nil or inactive.

func NewDragVisual(session *Session) DragVisual {

if session == nil || !session.active {

return DragVisual{}

}

offset := session.currentPos.Sub(session.startPos)

return DragVisual{

CursorPos: session.currentPos,

Offset: offset,

Effect: session.feedback.Effect,

OverTarget: session.target != nil,

Label: session.feedback.Label,

}

}