Podzimní atmosféra

client/src/FallingLeaves.tsx

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+import React, { useEffect, useRef, useCallback } from 'react';
+
+// Různé barevné varianty listů
+const LEAF_VARIANTS = [
+    'leaf.svg',        // Původní tmavě hnědá
+    'leaf-orange.svg', // Oranžová
+    'leaf-yellow.svg', // Žlutá
+    'leaf-red.svg',    // Červená
+    'leaf-brown.svg',  // Světle hnědá
+    'leaf-green.svg',  // Zelená
+] as const;
+
+interface LeafData {
+    el: HTMLDivElement;
+    x: number;
+    y: number;
+    z: number;
+    rotation: {
+        axis: 'X' | 'Y' | 'Z';
+        value: number;
+        speed: number;
+        x: number;
+    };
+    xSpeedVariation: number;
+    ySpeed: number;
+    path: {
+        type: number;
+        start: number;
+    };
+    image: number;
+}
+
+interface WindOptions {
+    magnitude: number;
+    maxSpeed: number;
+    duration: number;
+    start: number;
+    speed: (t: number, y: number) => number;
+}
+
+interface LeafSceneOptions {
+    numLeaves: number;
+    wind: WindOptions;
+}
+
+interface FallingLeavesProps {
+    /** Počet padających listů (výchozí: 20) */
+    numLeaves?: number;
+    /** CSS třída pro kontejner (výchozí: 'falling-leaves') */
+    className?: string;
+    /** Barevné varianty listů k použití (výchozí: všechny) */
+    leafVariants?: readonly string[];
+}
+
+class LeafScene {
+    private viewport: HTMLElement;
+    private world: HTMLDivElement;
+    private leaves: LeafData[] = [];
+    private options: LeafSceneOptions;
+    private width: number;
+    private height: number;
+    private timer: number = 0;
+    private animationId: number | null = null;
+    private leafVariants: readonly string[];
+
+    constructor(el: HTMLElement, numLeaves: number = 20, leafVariants: readonly string[] = LEAF_VARIANTS) {
+        this.viewport = el;
+        this.world = document.createElement('div');
+        this.leafVariants = leafVariants;
+
+        this.options = {
+            numLeaves,
+            wind: {
+                magnitude: 1.2,
+                maxSpeed: 12,
+                duration: 300,
+                start: 0,
+                speed: () => 0
+            },
+        };
+
+        this.width = this.viewport.offsetWidth;
+        this.height = this.viewport.offsetHeight;
+    }
+
+    private resetLeaf = (leaf: LeafData): LeafData => {
+        // place leaf towards the top left
+        leaf.x = this.width * 2 - Math.random() * this.width * 1.75;
+        leaf.y = -10;
+        leaf.z = Math.random() * 200;
+
+        if (leaf.x > this.width) {
+            leaf.x = this.width + 10;
+            leaf.y = Math.random() * this.height / 2;
+        }
+
+        // at the start, the leaf can be anywhere
+        if (this.timer === 0) {
+            leaf.y = Math.random() * this.height;
+        }
+
+        // Choose axis of rotation.
+        // If axis is not X, chose a random static x-rotation for greater variability
+        leaf.rotation.speed = Math.random() * 10;
+        const randomAxis = Math.random();
+
+        if (randomAxis > 0.5) {
+            leaf.rotation.axis = 'X';
+        } else if (randomAxis > 0.25) {
+            leaf.rotation.axis = 'Y';
+            leaf.rotation.x = Math.random() * 180 + 90;
+        } else {
+            leaf.rotation.axis = 'Z';
+            leaf.rotation.x = Math.random() * 360 - 180;
+            // looks weird if the rotation is too fast around this axis
+            leaf.rotation.speed = Math.random() * 3;
+        }
+
+        // random speed
+        leaf.xSpeedVariation = Math.random() * 0.8 - 0.4;
+        leaf.ySpeed = Math.random() + 1.5;
+
+        // randomly select leaf color variant
+        const randomVariantIndex = Math.floor(Math.random() * this.leafVariants.length);
+        leaf.image = randomVariantIndex;
+
+        // apply the background image to the leaf element
+        const leafVariant = this.leafVariants[randomVariantIndex];
+        leaf.el.style.backgroundImage = `url(${leafVariant})`;
+
+        return leaf;
+    };
+
+    private updateLeaf = (leaf: LeafData): void => {
+        const leafWindSpeed = this.options.wind.speed(this.timer - this.options.wind.start, leaf.y);
+
+        const xSpeed = leafWindSpeed + leaf.xSpeedVariation;
+        leaf.x -= xSpeed;
+        leaf.y += leaf.ySpeed;
+        leaf.rotation.value += leaf.rotation.speed;
+
+        const transform = `translateX(${leaf.x}px) translateY(${leaf.y}px) translateZ(${leaf.z}px) rotate${leaf.rotation.axis}(${leaf.rotation.value}deg)${leaf.rotation.axis !== 'X' ? ` rotateX(${leaf.rotation.x}deg)` : ''
+            }`;
+
+        leaf.el.style.transform = transform;
+
+        // reset if out of view
+        if (leaf.x < -10 || leaf.y > this.height + 10) {
+            this.resetLeaf(leaf);
+        }
+    };
+
+    private updateWind = (): void => {
+        // wind follows a sine curve: asin(b*time + c) + a
+        // where a = wind magnitude as a function of leaf position, b = wind.duration, c = offset
+        // wind duration should be related to wind magnitude, e.g. higher windspeed means longer gust duration
+
+        if (this.timer === 0 || this.timer > (this.options.wind.start + this.options.wind.duration)) {
+            this.options.wind.magnitude = Math.random() * this.options.wind.maxSpeed;
+            this.options.wind.duration = this.options.wind.magnitude * 50 + (Math.random() * 20 - 10);
+            this.options.wind.start = this.timer;
+
+            const screenHeight = this.height;
+
+            this.options.wind.speed = function (t: number, y: number) {
+                // should go from full wind speed at the top, to 1/2 speed at the bottom, using leaf Y
+                const a = this.magnitude / 2 * (screenHeight - 2 * y / 3) / screenHeight;
+                return a * Math.sin(2 * Math.PI / this.duration * t + (3 * Math.PI / 2)) + a;
+            };
+        }
+    };
+
+    public init = (): void => {
+        // Clear existing leaves
+        this.leaves = [];
+        this.world.innerHTML = '';
+
+        for (let i = 0; i < this.options.numLeaves; i++) {
+            const leaf: LeafData = {
+                el: document.createElement('div'),
+                x: 0,
+                y: 0,
+                z: 0,
+                rotation: {
+                    axis: 'X',
+                    value: 0,
+                    speed: 0,
+                    x: 0
+                },
+                xSpeedVariation: 0,
+                ySpeed: 0,
+                path: {
+                    type: 1,
+                    start: 0,
+                },
+                image: 1
+            };
+
+            this.resetLeaf(leaf);
+            this.leaves.push(leaf);
+            this.world.appendChild(leaf.el);
+        }
+
+        this.world.className = 'leaf-scene';
+        this.viewport.appendChild(this.world);
+
+        // set perspective
+        this.world.style.perspective = "400px";
+
+        // reset window height/width on resize
+        const handleResize = (): void => {
+            this.width = this.viewport.offsetWidth;
+            this.height = this.viewport.offsetHeight;
+        };
+
+        window.addEventListener('resize', handleResize);
+    };
+
+    public render = (): void => {
+        this.updateWind();
+
+        for (let i = 0; i < this.leaves.length; i++) {
+            this.updateLeaf(this.leaves[i]);
+        }
+
+        this.timer++;
+        this.animationId = requestAnimationFrame(this.render);
+    };
+
+    public destroy = (): void => {
+        if (this.animationId) {
+            cancelAnimationFrame(this.animationId);
+            this.animationId = null;
+        }
+
+        if (this.world && this.world.parentNode) {
+            this.world.parentNode.removeChild(this.world);
+        }
+
+        window.removeEventListener('resize', () => {
+            this.width = this.viewport.offsetWidth;
+            this.height = this.viewport.offsetHeight;
+        });
+    };
+}
+
+/**
+ * Komponenta pro zobrazení padajících listů na pozadí stránky
+ * 
+ * @param numLeaves - Počet padajících listů (výchozí: 20)
+ * @param className - CSS třída pro kontejner (výchozí: 'falling-leaves')
+ * @param leafVariants - Barevné varianty listů k použití (výchozí: všechny)
+ * 
+ * @example
+ * // Základní použití s výchozím počtem listů
+ * <FallingLeaves />
+ * 
+ * @example  
+ * // Použití s vlastním počtem listů
+ * <FallingLeaves numLeaves={50} />
+ * 
+ * @example
+ * // Použití s vlastní CSS třídou a pouze podzimními barvami
+ * <FallingLeaves 
+ *   numLeaves={15} 
+ *   className="autumn-leaves"
+ *   leafVariants={['leaf-orange.svg', 'leaf-red.svg', 'leaf-yellow.svg']}
+ * />
+ */
+const FallingLeaves: React.FC<FallingLeavesProps> = ({
+    numLeaves = 20,
+    className = 'falling-leaves',
+    leafVariants = LEAF_VARIANTS
+}) => {
+    const containerRef = useRef<HTMLDivElement>(null);
+    const leafSceneRef = useRef<LeafScene | null>(null);
+
+    const initializeLeafScene = useCallback(() => {
+        if (containerRef.current) {
+            leafSceneRef.current = new LeafScene(containerRef.current, numLeaves, leafVariants);
+            leafSceneRef.current.init();
+            leafSceneRef.current.render();
+        }
+    }, [numLeaves, leafVariants]);
+
+    useEffect(() => {
+        initializeLeafScene();
+
+        return () => {
+            if (leafSceneRef.current) {
+                leafSceneRef.current.destroy();
+                leafSceneRef.current = null;
+            }
+        };
+    }, [initializeLeafScene]);
+
+    return <div ref={containerRef} className={className} />;
+};
+
+// Přednastavení pro různé účely
+export const LEAF_PRESETS = {
+    LIGHT: 10,      // Lehký podzimní efekt
+    NORMAL: 20,     // Standardní množství  
+    HEAVY: 40,      // Silný podzimní vítr
+    BLIZZARD: 80    // Hustý pád listí
+} as const;
+
+// Přednastavené barevné kombinace
+export const LEAF_COLOR_THEMES = {
+    ALL: LEAF_VARIANTS,                                          // Všechny barvy
+    AUTUMN: ['leaf-orange.svg', 'leaf-red.svg', 'leaf-yellow.svg', 'leaf-brown.svg'] as const, // Podzimní barvy
+    WARM: ['leaf-orange.svg', 'leaf-red.svg', 'leaf-brown.svg'] as const,           // Teplé barvy
+    CLASSIC: ['leaf.svg', 'leaf-brown.svg'] as const,                               // Klasické hnědé odstíny
+    BRIGHT: ['leaf-yellow.svg', 'leaf-orange.svg'] as const,                        // Světlé barvy
+} as const;
+
+export default FallingLeaves;