cubic-bezier-editor.ts(文件已创建)
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| 1 | + | type ChangeListener = (x1: number, y1: number, x2: number, y2: number) => void; | |
| 2 | + | type Point = [number, number]; | |
| 3 | + | type Quad = [number, number, number, number]; | |
| 4 | + | ||
| 5 | + | const POINT_SIZE = 10; | |
| 6 | + | ||
| 7 | + | function toFixedNumber(num: number, digits = 2, base = 10) { | |
| 8 | + | const pow = Math.pow(base, digits); | |
| 9 | + | return Math.round(num * pow) / pow; | |
| 10 | + | } | |
| 11 | + | ||
| 12 | + | function clamp(x: number, min: number, max: number) { | |
| 13 | + | return Math.max(Math.min(x, max), min); | |
| 14 | + | } | |
| 15 | + | ||
| 16 | + | class CubicBezierEditor { | |
| 17 | + | #element = document.createElement('div'); | |
| 18 | + | #output = document.createElement('div'); | |
| 19 | + | #canvas = document.createElement('canvas'); | |
| 20 | + | #ctx = this.#canvas.getContext('2d')!; | |
| 21 | + | #onChangeListener: ChangeListener | undefined; | |
| 22 | + | #grabbedPoint: 0 | 1 | null = null; | |
| 23 | + | ||
| 24 | + | #x1 = 0; | |
| 25 | + | #y1 = 0; | |
| 26 | + | #x2 = 0; | |
| 27 | + | #y2 = 0; | |
| 28 | + | ||
| 29 | + | constructor(width: number, height: number, x1 = 0, y1 = 0, x2 = 0, y2 = 0) { | |
| 30 | + | this.#x1 = x1; | |
| 31 | + | this.#y1 = y1; | |
| 32 | + | this.#x2 = x2; | |
| 33 | + | this.#y2 = y2; | |
| 34 | + | ||
| 35 | + | this.#element.classList.add('cubic-bezier-wrapper'); | |
| 36 | + | this.#output.classList.add('cubic-bezier-output'); | |
| 37 | + | this.#element.appendChild(this.#canvas); | |
| 38 | + | this.#element.appendChild(this.#output); | |
| 39 | + | this.#canvas.width = width; | |
| 40 | + | this.#canvas.height = height; | |
| 41 | + | } | |
| 42 | + | ||
| 43 | + | mount(root: HTMLElement, onChange: ChangeListener) { | |
| 44 | + | root.appendChild(this.#element); | |
| 45 | + | this.#onChangeListener = onChange; | |
| 46 | + | this.#initialize(); | |
| 47 | + | } | |
| 48 | + | ||
| 49 | + | set(x1: number, y1: number, x2: number, y2: number) { | |
| 50 | + | this.#x1 = x1; | |
| 51 | + | this.#y1 = y1; | |
| 52 | + | this.#x2 = x2; | |
| 53 | + | this.#y2 = y2; | |
| 54 | + | this.#draw(); | |
| 55 | + | } | |
| 56 | + | ||
| 57 | + | get points(): Quad { | |
| 58 | + | return [this.#x1, this.#y1, this.#x2, this.#y2]; | |
| 59 | + | } | |
| 60 | + | ||
| 61 | + | get string() { | |
| 62 | + | return `${this.#x1},${this.#y1},${this.#x2},${this.#y2}`; | |
| 63 | + | } | |
| 64 | + | ||
| 65 | + | get #controlPoints() { | |
| 66 | + | const [w, h] = [this.#canvas.width, this.#canvas.height]; | |
| 67 | + | return [this.#x1 * w, h - this.#y1 * h, this.#x2 * w, h - this.#y2 * h]; | |
| 68 | + | } | |
| 69 | + | ||
| 70 | + | #draw() { | |
| 71 | + | const [w, h] = [this.#canvas.width, this.#canvas.height]; | |
| 72 | + | const [x1, y1, x2, y2] = this.#controlPoints; | |
| 73 | + | ||
| 74 | + | this.#ctx.clearRect(0, 0, w, h); | |
| 75 | + | ||
| 76 | + | // Linear line | |
| 77 | + | this.#ctx.beginPath(); | |
| 78 | + | this.#ctx.strokeStyle = 'grey'; | |
| 79 | + | this.#ctx.lineWidth = 2; | |
| 80 | + | this.#ctx.moveTo(0, h); | |
| 81 | + | this.#ctx.lineTo(w, 0); | |
| 82 | + | this.#ctx.stroke(); | |
| 83 | + | ||
| 84 | + | // Control point line | |
| 85 | + | this.#ctx.beginPath(); | |
| 86 | + | this.#ctx.strokeStyle = 'grey'; | |
| 87 | + | this.#ctx.moveTo(0, h); | |
| 88 | + | this.#ctx.lineTo(x1, y1); | |
| 89 | + | this.#ctx.stroke(); | |
| 90 | + | ||
| 91 | + | this.#ctx.beginPath(); | |
| 92 | + | this.#ctx.strokeStyle = 'grey'; | |
| 93 | + | this.#ctx.moveTo(w, 0); | |
| 94 | + | this.#ctx.lineTo(x2, y2); | |
| 95 | + | this.#ctx.stroke(); | |
| 96 | + | ||
| 97 | + | // Bezier | |
| 98 | + | this.#ctx.beginPath(); | |
| 99 | + | this.#ctx.lineWidth = 4; | |
| 100 | + | this.#ctx.strokeStyle = '#fff'; | |
| 101 | + | this.#ctx.moveTo(0, h); | |
| 102 | + | this.#ctx.bezierCurveTo(x1, y1, x2, y2, w, 0); | |
| 103 | + | this.#ctx.stroke(); | |
| 104 | + | ||
| 105 | + | // Control point fill | |
| 106 | + | this.#ctx.beginPath(); | |
| 107 | + | this.#ctx.fillStyle = 'red'; | |
| 108 | + | this.#ctx.arc(x1, y1, POINT_SIZE, 0, Math.PI * 2); | |
| 109 | + | this.#ctx.fill(); | |
| 110 | + | ||
| 111 | + | this.#ctx.beginPath(); | |
| 112 | + | this.#ctx.fillStyle = 'blue'; | |
| 113 | + | this.#ctx.arc(x2, y2, POINT_SIZE, 0, Math.PI * 2); | |
| 114 | + | this.#ctx.fill(); | |
| 115 | + | ||
| 116 | + | this.#output.innerText = `cubic-bezier(${this.string})`; | |
| 117 | + | } | |
| 118 | + | ||
| 119 | + | #initialize() { | |
| 120 | + | this.#draw(); | |
| 121 | + | ||
| 122 | + | window.addEventListener('pointerdown', (evt) => { | |
| 123 | + | const pos = this.#getMousePosition(evt); | |
| 124 | + | this.#grabbedPoint = this.#intersectsControlPoint(pos); | |
| 125 | + | }); | |
| 126 | + | ||
| 127 | + | window.addEventListener('pointermove', (evt) => { | |
| 128 | + | if (this.#grabbedPoint === null) return; | |
| 129 | + | const pos = this.#getMousePosition(evt); | |
| 130 | + | const [xp, yp] = this.#positionToControlPoint(pos); | |
| 131 | + | ||
| 132 | + | if (this.#grabbedPoint === 0) { | |
| 133 | + | this.#x1 = clamp(xp, 0, 1); | |
| 134 | + | this.#y1 = clamp(yp, 0, 1); | |
| 135 | + | ||
| 136 | + | // Symmetrize when CTRL is held | |
| 137 | + | if (evt.ctrlKey || evt.metaKey) { | |
| 138 | + | this.#x2 = clamp(toFixedNumber(1 - xp), 0, 1); | |
| 139 | + | this.#y2 = clamp(toFixedNumber(1 - yp), 0, 1); | |
| 140 | + | } | |
| 141 | + | } else { | |
| 142 | + | this.#x2 = clamp(xp, 0, 1); | |
| 143 | + | this.#y2 = clamp(yp, 0, 1); | |
| 144 | + | ||
| 145 | + | // Symmetrize when CTRL is held | |
| 146 | + | if (evt.ctrlKey || evt.metaKey) { | |
| 147 | + | this.#x1 = clamp(toFixedNumber(1 - xp), 0, 1); | |
| 148 | + | this.#y1 = clamp(toFixedNumber(1 - yp), 0, 1); | |
| 149 | + | } | |
| 150 | + | } | |
| 151 | + | ||
| 152 | + | this.#draw(); | |
| 153 | + | this.#onChangeListener?.(...this.points); | |
| 154 | + | }); | |
| 155 | + | ||
| 156 | + | window.addEventListener('pointerup', () => { | |
| 157 | + | this.#grabbedPoint = null; | |
| 158 | + | this.#onChangeListener?.(...this.points); | |
| 159 | + | }); | |
| 160 | + | ||
| 161 | + | window.addEventListener('pointerleave', () => { | |
| 162 | + | this.#grabbedPoint = null; | |
| 163 | + | this.#onChangeListener?.(...this.points); | |
| 164 | + | }); | |
| 165 | + | ||
| 166 | + | this.#output.addEventListener('click', () => { | |
| 167 | + | navigator.clipboard?.writeText(`cubic-bezier(${this.string})`); | |
| 168 | + | }); | |
| 169 | + | } | |
| 170 | + | ||
| 171 | + | #intersectsControlPoint([x, y]: Point): 0 | 1 | null { | |
| 172 | + | const [x1, y1, x2, y2] = this.#controlPoints; | |
| 173 | + | ||
| 174 | + | if (Math.hypot(Math.abs(x - x1), Math.abs(y - y1)) < POINT_SIZE) { | |
| 175 | + | return 0; | |
| 176 | + | } | |
| 177 | + | ||
| 178 | + | if (Math.hypot(Math.abs(x - x2), Math.abs(y - y2)) < POINT_SIZE) { | |
| 179 | + | return 1; | |
| 180 | + | } | |
| 181 | + | ||
| 182 | + | return null; | |
| 183 | + | } | |
| 184 | + | ||
| 185 | + | #positionToControlPoint([x, y]: Point): Point { | |
| 186 | + | const [w, h] = [this.#canvas.width, this.#canvas.height]; | |
| 187 | + | return [toFixedNumber(x / w), toFixedNumber((h - y) / h)]; | |
| 188 | + | } | |
| 189 | + | ||
| 190 | + | #getMousePosition(evt: PointerEvent): Point { | |
| 191 | + | const rect = this.#canvas.getBoundingClientRect(); | |
| 192 | + | const xpos = evt.clientX - rect.left; | |
| 193 | + | const ypos = evt.clientY - rect.top; | |
| 194 | + | return [xpos, ypos]; | |
| 195 | + | } | |
| 196 | + | } | |
| 197 | + | ||
| 198 | + | export default CubicBezierEditor; | |
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