@extends('layouts.app')
@section('title', 'Flächen Rechner – Fläche und Umfang berechnen | kotsch.tech')
@section('meta_description', 'Flächen Rechner: Fläche und Umfang von Rechteck, Kreis, Dreieck, Trapez, Raute und Parallelogramm live berechnen. Formeln und Ergebnisse sofort.')
@section('meta_extra')
<meta name="keywords" content="Flächen Rechner, Fläche berechnen, Umfang berechnen, Rechteck, Kreis, Dreieck, Trapez, Geometrie Rechner">
@endsection
@section('content')
@include('tools._tool_base')
<style>
.shape-tabs { display:flex; gap:8px; flex-wrap:wrap; margin-bottom:20px; }
.shape-tab { padding:8px 16px; border-radius:999px; border:2px solid var(--line); background:var(--card); font:inherit; font-size:0.85rem; font-weight:700; cursor:pointer; color:var(--muted); transition:all 0.15s; display:flex; align-items:center; gap:6px; }
.shape-tab:hover { border-color:var(--ink); color:var(--ink); }
.shape-tab.active { background:var(--ink); color:#fff; border-color:var(--ink); }
.shape-pane { display:none; }
.shape-pane.active { display:block; }
.formula-box { background:var(--accent-soft); border:1px solid rgba(16,185,129,0.2); border-radius:var(--radius-md); padding:12px 16px; margin-top:12px; font-size:0.85rem; color:#065f46; font-weight:700; font-family:'JetBrains Mono','Fira Mono',monospace; }
</style>

<div class="tool-page">
<div class="tool-container">
    <div class="tool-header">
        <span class="t-tag"><i class="fas fa-shapes"></i> Mathematik</span>
        <h1 class="tool-h1">Flächen<span>rechner.</span></h1>
        <p class="tool-sub">Fläche und Umfang aller gängigen Formen live berechnen – mit Formel.</p>
    </div>

    <div class="t-panel">
        <div class="shape-tabs">
            <button class="shape-tab active" onclick="showShape('rect',this)">▭ Rechteck</button>
            <button class="shape-tab" onclick="showShape('circ',this)">● Kreis</button>
            <button class="shape-tab" onclick="showShape('tri',this)">▲ Dreieck</button>
            <button class="shape-tab" onclick="showShape('trap',this)">⬠ Trapez</button>
            <button class="shape-tab" onclick="showShape('rhom',this)">⬥ Raute</button>
            <button class="shape-tab" onclick="showShape('par',this)">▬ Parallelogramm</button>
            <button class="shape-tab" onclick="showShape('ell',this)">⬭ Ellipse</button>
        </div>

        <!-- Rechteck -->
        <div class="shape-pane active" id="sp-rect">
            <div class="t-grid-2">
                <div class="t-field"><label class="t-label">Breite a</label><input type="number" class="t-input" id="rect-a" placeholder="z.B. 10" min="0" oninput="calcRect()"></div>
                <div class="t-field"><label class="t-label">Höhe b</label><input type="number" class="t-input" id="rect-b" placeholder="z.B. 5" min="0" oninput="calcRect()"></div>
            </div>
            <div id="rect-r" class="t-result" style="display:none"></div>
            <div class="formula-box">A = a × b &nbsp;|&nbsp; U = 2 × (a + b)</div>
        </div>

        <!-- Kreis -->
        <div class="shape-pane" id="sp-circ">
            <div class="t-field"><label class="t-label">Radius r</label><input type="number" class="t-input" id="circ-r" placeholder="z.B. 7" min="0" oninput="calcCirc()"></div>
            <div id="circ-r-res" class="t-result" style="display:none"></div>
            <div class="formula-box">A = π × r² &nbsp;|&nbsp; U = 2 × π × r</div>
        </div>

        <!-- Dreieck -->
        <div class="shape-pane" id="sp-tri">
            <div class="t-grid-2">
                <div class="t-field"><label class="t-label">Grundlinie a</label><input type="number" class="t-input" id="tri-a" placeholder="z.B. 8" min="0" oninput="calcTri()"></div>
                <div class="t-field"><label class="t-label">Höhe h</label><input type="number" class="t-input" id="tri-h" placeholder="z.B. 6" min="0" oninput="calcTri()"></div>
            </div>
            <div id="tri-r" class="t-result" style="display:none"></div>
            <div class="formula-box">A = (a × h) ÷ 2</div>
        </div>

        <!-- Trapez -->
        <div class="shape-pane" id="sp-trap">
            <div class="t-grid-3">
                <div class="t-field"><label class="t-label">Seite a (oben)</label><input type="number" class="t-input" id="trap-a" placeholder="6" min="0" oninput="calcTrap()"></div>
                <div class="t-field"><label class="t-label">Seite b (unten)</label><input type="number" class="t-input" id="trap-b" placeholder="10" min="0" oninput="calcTrap()"></div>
                <div class="t-field"><label class="t-label">Höhe h</label><input type="number" class="t-input" id="trap-h" placeholder="4" min="0" oninput="calcTrap()"></div>
            </div>
            <div id="trap-r" class="t-result" style="display:none"></div>
            <div class="formula-box">A = ((a + b) ÷ 2) × h</div>
        </div>

        <!-- Raute -->
        <div class="shape-pane" id="sp-rhom">
            <div class="t-grid-2">
                <div class="t-field"><label class="t-label">Diagonale e</label><input type="number" class="t-input" id="rh-e" placeholder="8" min="0" oninput="calcRhom()"></div>
                <div class="t-field"><label class="t-label">Diagonale f</label><input type="number" class="t-input" id="rh-f" placeholder="6" min="0" oninput="calcRhom()"></div>
            </div>
            <div id="rh-r" class="t-result" style="display:none"></div>
            <div class="formula-box">A = (e × f) ÷ 2</div>
        </div>

        <!-- Parallelogramm -->
        <div class="shape-pane" id="sp-par">
            <div class="t-grid-2">
                <div class="t-field"><label class="t-label">Seite a</label><input type="number" class="t-input" id="par-a" placeholder="9" min="0" oninput="calcPar()"></div>
                <div class="t-field"><label class="t-label">Höhe h</label><input type="number" class="t-input" id="par-h" placeholder="5" min="0" oninput="calcPar()"></div>
            </div>
            <div id="par-r" class="t-result" style="display:none"></div>
            <div class="formula-box">A = a × h</div>
        </div>

        <!-- Ellipse -->
        <div class="shape-pane" id="sp-ell">
            <div class="t-grid-2">
                <div class="t-field"><label class="t-label">Halbachse a</label><input type="number" class="t-input" id="ell-a" placeholder="8" min="0" oninput="calcEll()"></div>
                <div class="t-field"><label class="t-label">Halbachse b</label><input type="number" class="t-input" id="ell-b" placeholder="5" min="0" oninput="calcEll()"></div>
            </div>
            <div id="ell-r" class="t-result" style="display:none"></div>
            <div class="formula-box">A = π × a × b &nbsp;|&nbsp; U ≈ π × (3(a+b) − √((3a+b)(a+3b)))</div>
        </div>
    </div>
</div>
@include('tools._ads_banner')
</div>

<script>
const f = n => Number.isFinite(n) ? n.toLocaleString('de-DE',{maximumFractionDigits:4}) : '0';
const val = id => Number(document.getElementById(id)?.value || 0);
function showResult(id, html){ const el=document.getElementById(id); el.innerHTML=html; el.style.display=''; }
function showShape(id, btn){
    document.querySelectorAll('.shape-tab').forEach(b=>b.classList.remove('active'));
    document.querySelectorAll('.shape-pane').forEach(p=>p.classList.remove('active'));
    btn.classList.add('active'); document.getElementById('sp-'+id).classList.add('active');
}
function calcRect(){ const a=+document.getElementById('rect-a').value,b=+document.getElementById('rect-b').value; if(!a||!b)return; showResult('rect-r',`<b>Fläche:</b> ${f(a*b)} &nbsp;|&nbsp; <b>Umfang:</b> ${f(2*(a+b))}`); }
function calcCirc(){ const r=+document.getElementById('circ-r').value; if(!r)return; showResult('circ-r-res',`<b>Fläche:</b> ${f(Math.PI*r*r)} &nbsp;|&nbsp; <b>Umfang:</b> ${f(2*Math.PI*r)}`); }
function calcTri(){ const a=+document.getElementById('tri-a').value,h=+document.getElementById('tri-h').value; if(!a||!h)return; showResult('tri-r',`<b>Fläche:</b> ${f(a*h/2)}`); }
function calcTrap(){ const a=val('trap-a'),b=val('trap-b'),h=val('trap-h'); if(!a||!b||!h)return; showResult('trap-r',`<b>Fläche:</b> ${f((a+b)/2*h)}`); }
function calcRhom(){ const e=+document.getElementById('rh-e').value,f2=+document.getElementById('rh-f').value; if(!e||!f2)return; showResult('rh-r',`<b>Fläche:</b> ${f(e*f2/2)}`); }
function calcPar(){ const a=+document.getElementById('par-a').value,h=+document.getElementById('par-h').value; if(!a||!h)return; showResult('par-r',`<b>Fläche:</b> ${f(a*h)}`); }
function calcEll(){ const a=+document.getElementById('ell-a').value,b=+document.getElementById('ell-b').value; if(!a||!b)return; const perim=Math.PI*(3*(a+b)-Math.sqrt((3*a+b)*(a+3*b))); showResult('ell-r',`<b>Fläche:</b> ${f(Math.PI*a*b)} &nbsp;|&nbsp; <b>Umfang ≈:</b> ${f(perim)}`); }
</script>

@include('tools._seo_content', ['toolSlug' => 'flaechen-rechner', 'toolName' => 'Flächen Rechner'])

@endsection