我正在尝试从具有 alpha 值(半透明的东西)的画布上下载 png,但是每次我下载画布时,所有 alpha 通道都会ff
由于某种原因重置回。这是我的代码:
const download = (canvas, filename) => {
const link = document.createElement('a');
link.download = `${filename}.png`;
link.href = canvas.toDataURL("image/png");
console.log(link.href);
link.click();
};
const drawAndDownloa = str => {
const canvas = document.createElement("canvas");
canvas.width = pixels.length;
canvas.height = 1; // intentionally small
const ctx = canvas.getContext("2d");
// pixels is an array of "rrggbbaa" strings
pixels.forEach((rgba, i) => {
const r = parseInt(rgba.slice(0, 2), 16);
const g = parseInt(rgba.slice(2, 4), 16);
const b = parseInt(rgba.slice(4, 6), 16);
const a = parseInt(rgba.slice(6, 8), 16);
ctx.fillStyle = `rgba(${r}, ${g}, ${b}, ${a})`;
ctx.fillRect(i, 0, 1, 1);
});
download(canvas, str.replace(/\W/g, "_"));
};
我知道您需要 png-24 才能拥有 alpha 通道,但我现在知道如何下载到 png-24 中。我也不知道如何检查它是否是 png-24。