node.js - node-gd 的复制功能无法识别

Question

我继承了Discord使用 node-gd 的机器人制作带有用户输入数据的横幅。制作横幅时，我使用 .copy功能将图像放置在基本图像的顶部。但是，当我运行我的代码时，它抛出一个错误，说它不是一个函数。

这是相关的代码( user.input 是一个数字 1-5 ，默认是 ? ):

   if (user.input != '?') {
    imgTemp = gd.createFromPng(`./img/INPUT_${user.input}.png`);
    imgTemp.copy(img, 213, 60, 0, 0, 37, 17);
}

这是错误:

> /home/discordbots/Desktop/bots/splatoonBot/splatBot2.js:676
>             imgTemp.copy(img, 213, 60, 0, 0, 37, 17);
>                     ^ TypeError: imgTemp.copy is not a function
>     at generateBanner (/home/discordbots/Desktop/bots/splatoonBot/splatBot2.js:676:21)
>     at Client.<anonymous> (/home/discordbots/Desktop/bots/splatoonBot/splatBot2.js:894:25)
>     at Client.emit (events.js:315:20)
>     at MessageCreateAction.handle (/home/discordbots/Desktop/bots/splatoonBot/node_modules/discord.js/src/client/actions/MessageCreate.js:31:14)
>     at Object.module.exports [as MESSAGE_CREATE] (/home/discordbots/Desktop/bots/splatoonBot/node_modules/discord.js/src/client/websocket/handlers/MESSAGE_CREATE.js:4:32)
>     at WebSocketManager.handlePacket (/home/discordbots/Desktop/bots/splatoonBot/node_modules/discord.js/src/client/websocket/WebSocketManager.js:386:31)
>     at WebSocketShard.onPacket (/home/discordbots/Desktop/bots/splatoonBot/node_modules/discord.js/src/client/websocket/WebSocketShard.js:436:22)
>     at WebSocketShard.onMessage (/home/discordbots/Desktop/bots/splatoonBot/node_modules/discord.js/src/client/websocket/WebSocketShard.js:293:10)
>     at WebSocket.onMessage (/home/discordbots/Desktop/bots/splatoonBot/node_modules/ws/lib/event-target.js:125:16)
>     at WebSocket.emit (events.js:315:20)

Answer 1

这是因为 gd.createFromPng返回一个 promise 。它不是包含方法 copy 的类.您可以在 node-gd documentation 中阅读更多相关信息。 .

所以本质上:

if (user.input != '?') {
    // the "await" keyword lets you grab the actual value from the promise
    let imgTemp = await gd.createFromPng(`./img/INPUT_${user.input}.png`);
    // You can then implement the copy method on this newly returned value
    imgTemp.copy(img, 213, 60, 0, 0, 37, 17);
}

希望这能解决您的问题。