问题描述
首先,这可能是措辞不佳,因为我不确定如何将想要的内容写进文字中。
让我说我有这张画布(我正在使用node-canvas
),我想让它显示用户输入的文字。但是,我这样做的方式将字符数限制为36-38(不为此寻求解决方案)。因此,我使用正则表达式textstr.match(/.{1,32}/g)
编写了一个脚本,该脚本每32个字符分割一次字符串(为了安全起见),计算新的画布高度,然后在需要打印字符串时执行join("\n")
。但是,当收到有关此内容的反馈时,我意识到最好沿字符串的最后一个空格分割并在其中添加换行符,但是我对此感到困惑。
我当前的代码是这样:
textStr = "123456789 01234567890 123456789012 34567890"
var splitStr
if(textstr.length > 32){
if(textstr.substring(1,32).includes(" ")){ //1,32 so it won't bug out if the first character is a space
//splitStr = textstr.something(test)
} else {
splitStr = textstr.match(/.{1,32}/g)
}
}
//canvas initialization blah blah blah
//load fonts yada yada yada
ctx.fillText(splitStr.join("\n"),20,55)
我想知道是否可以使用某种正则表达式。任何帮助/反馈/常识表示赞赏
解决方法
此解决方案有点复杂,可能会有些简化。但是,它应该可以带您到那里。
const input = "123456789 01234567890 123456789012 34567890 11444444444 424124 1234124124121 4444444444444444444444444444444444444444444444444444444444444444444444";
const split = (value,width) => {
const stack = value.split(' ').reverse();
const results = [];
let builder = "";
while (stack.length > 0) {
const item = stack.pop();
if (item.length > width) { // is the current chunk already larger than our desired width?
if (builder !== "") { // we have to push our buffer too
results.push(builder);
builder = "";
}
results.push(item);
} else {
const line = builder === ""
? item
: `${builder} ${item}`;
if (line.length > width) { // is our new line greater than our width?
stack.push(item); // push the item back,since consuming it would make our line length too long. we let the next iteration consume it. results.push(builder); // push the buffer into our results.
builder = "";
} else if (stack.length === 0) { // is this the last element? just add it to the results.
results.push(line);
} else {
builder = line; // update our buffer to the current appended chunk.
}
}
}
return results;
};
split(input,32).forEach((c) => console.log(c,c.length));
split(input,32).join("\n");