如何在 Pixi.js 中制作手绘文本 animation？

Question

There's a handful of questions and answers for creating animations that mimic drawing or handwriting text . Although I've found a canvas api example, and a svg-based solution, but I haven't seen anything using Pixi.js's API. I'm a rookie with canvas and Pixi.

Here's the jsfiddle code:

 var ctx = document.querySelector("canvas").getContext("2d"), dashLen = 220, dashOffset = dashLen, speed = 11, txt = "Wingardium Leviosa", x = 30, i = 0; ctx.font = "50px cursive, TSCu_Comic, sans-serif"; ctx.lineWidth = 5; ctx.lineJoin = "round"; ctx.globalAlpha = 2 / 3; ctx.strokeStyle = ctx.fillStyle = "black"; (function loop() { ctx.clearRect(x, 0, 60, 150); ctx.setLineDash([dashLen - dashOffset, dashOffset - speed]); // create a long dash mask ctx.setLineDash([dashLen - dashOffset, dashOffset]); // create a long dash mask dashOffset -= speed; // reduce dash length ctx.strokeText(txt[i], x, 90); // stroke letter if (dashOffset > 0) requestAnimationFrame(loop); // animate else { ctx.fillText(txt[i], x, 90); // fill final letter dashOffset = dashLen; // prep next char x += ctx.measureText(txt[i++]).width + ctx.lineWidth * Math.random(); ctx.setTransform(1, 0, 0, 1, 0, 3 * Math.random()); // random y-delta ctx.rotate(Math.random() * 0.005); // random rotation if (i < txt.length) { setTimeout(() => { requestAnimationFrame(loop); }, 300 * Math.random()) }; } })();

 <canvas width=600></canvas>

As I understand it, the canvas approach I liked to above is creating the draw effect largely from setLineDash which does not exist in Pixi. I like this approach, I'm just not sure how to implement it in Pixi.

Answer 1

I don't know Pixi, but a viable solution could be to use the routine in your example against an hidden canvas, then using ctx.getImageData you could grab the result, finally to use the grabbed image as a Pixi texture.

Another solution, maybe easier, but that can be only used when you don't need other Pixi effects (as an example, in a game, at game end or between two levels) you can stop the Pixi renderer and use the code you posted directly against Pixi canvas.

Hope this helps.