在 PhaserJS 中将像素艺术图下载为 .png

Question

我需要通过 FilesSaver.js 从这个 Phaser example 下载创建的像素绘图作为 .png 图片，但是 canvas returns空。

错误：

Uncaught TypeError: Cannot read properties of null (reading 'toBlob')

这是保存函数：

function save() { 
var canvasX = document.getElementById("canvas");
canvasX.toBlob(function(blob) { saveAs(blob, "image.png"); }); }

绘图区域：（PhaserJS 2）

function createDrawingArea() {

    game.create.grid('drawingGrid', 16 * canvasZoom, 16 * canvasZoom, canvasZoom, canvasZoom, 'rgba(0,191,243,0.8)');

    canvas = game.make.bitmapData(spriteWidth * canvasZoom, spriteHeight * canvasZoom);
    canvasBG = game.make.bitmapData(canvas.width + 2, canvas.height + 2);

    canvasBG.rect(0, 0, canvasBG.width, canvasBG.height, '#fff');
    canvasBG.rect(1, 1, canvasBG.width - 2, canvasBG.height - 2, '#3f5c67');

    var x = 10;
    var y = 64;

    canvasBG.addToWorld(x, y);
    canvasSprite = canvas.addToWorld(x + 1, y + 1);
    canvasGrid = game.add.sprite(x + 1, y + 1, 'drawingGrid');
    canvasGrid.crop(new Phaser.Rectangle(0, 0, spriteWidth * canvasZoom, spriteHeight * canvasZoom));

}

如何获取绘图的数据以从中创建 .png？

Answer 1

嗯，我认为 canvas 没有 ID canvas。这就是为什么，我认为这就是 null 错误的原因。无论如何，我都将 原始示例代码 作为此工作解决方案的基础。

免责声明： 此代码只会从“绘制图像”创建图像，而不是整个 UI.

主要思想，On Save：

新建一个canvas
将目标区域绘制到新的canvas
创建图像，filesave.js

信息： 我从全局定义的变量 canvasGrid 和 canvas 得到 information/values，如果您的代码不包含它们，此代码将不起作用。

希望对您有所帮助。

    function saveImage() { 
        // I assume there will be only one canvas on the page
        let realCanvas = document.querySelector('canvas');
        let ouputCanvas = document.createElement('canvas');
        let ctx = ouputCanvas.getContext('2d');

        // Get the target area (Details are from example code)
        let xOfGrid = canvasGrid.x - 1; // Info from Linie 267 from example
        let yOfGrid = canvasGrid.y - 1; // Info from Linie 267 from example

        // Info: this "canvas" is not a HTML Canvas Element
        let width = canvas.width;   // Info from Linie 256 from example
        let height = canvas.height; // Info from Linie 256 from example

        // Set initial Canvas Size
        ouputCanvas.width = width;
        ouputCanvas.height = height;

        // draw Image onto new Canvas
        ctx.drawImage(realCanvas, xOfGrid, yOfGrid, width, height, 0, 0, width, height);

        // Output Image, with filesaver.js
        ouputCanvas.toBlob(function onDone(blob) {
            saveAs(blob, "image.png");
        });
    }

    // An extra "Save Button", for testing
    window.addEventListener('DOMContentLoaded', function(){
        let btn = document.createElement('button');
        btn.innerText = 'SAVE FILE';
        btn.addEventListener('click', saveImage);
        document.body.prepend( btn );
    });

在 PhaserJS 中将像素艺术图下载为 .png

Download pixel art drawing as .png in PhaserJS

javascript

html5-canvas

phaser-framework

filesaver.js