Anchor.h

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// Copyright (c) 2025 Dave R. Smith.
// Malena Framework — Licensed under PolyForm Noncommercial 1.0.0; commercial use requires a paid license. See LICENSE.
 
//
// Anchor.h — a single retained relational-placement constraint.
//
// An Anchor records "keep me <op> <reference> by <spacing>". The reference is a
// live Positionable (re-read each solve) or the window (ref == nullptr). Anchors
// are stored per-object by AnchorManager and re-solved on window resize, so a
// layout expressed with the Align verbs stays correct when the window changes.
//
 
#ifndef MALENA_ANCHOR_H
#define MALENA_ANCHOR_H
 
#pragma once
 
namespace ml
{
    class Positionable;

    enum class AnchorOp
    {
        LeftOf,       
        RightOf,      
        Above,        
        Below,        
        CenterX,      
        CenterY,      
        CenterOn,     
        // Window inside-edge ops (ref is always the window; spacing = inward margin).
        WindowLeft,   
        WindowRight,  
        WindowTop,    
        WindowBottom  
    };

    inline bool anchorTouchesX(AnchorOp op)
    {
        return op == AnchorOp::LeftOf || op == AnchorOp::RightOf
            || op == AnchorOp::CenterX || op == AnchorOp::CenterOn
            || op == AnchorOp::WindowLeft || op == AnchorOp::WindowRight;
    }
    inline bool anchorTouchesY(AnchorOp op)
    {
        return op == AnchorOp::Above || op == AnchorOp::Below
            || op == AnchorOp::CenterY || op == AnchorOp::CenterOn
            || op == AnchorOp::WindowTop || op == AnchorOp::WindowBottom;
    }
 
    struct Anchor
    {
        AnchorOp            op;
        const Positionable* ref;      
        float               spacing;  
    };
 
} // namespace ml
 
#endif // MALENA_ANCHOR_H