Question

我使用Custom TG2480-H打印机打印收据。除了徽标外，我收到了所有收据。

我有一个代表徽标的单色.bmp文件，并且有正确的尺寸。

我正在使用不同的响应类型检索文件：

this.http.get('/assets/images/brand/logo-bnw.bmp', {
  responseType: ResponseContentType.Blob
}).subscribe((response: Response) => {
  console.log('Blob bytes', this.kiowarePrintService.getBytesFromText(response.text()));
});
this.http.get('/assets/images/brand/logo-bnw.bmp', {
  responseType: ResponseContentType.Text
}).subscribe((response: Response) => {
  console.log('Text bytes', this.kiowarePrintService.getBytesFromText(response.text()));
});
this.http.get('/assets/images/brand/logo-bnw.bmp', {
  responseType: ResponseContentType.ArrayBuffer
}).subscribe((response: Response) => {
  console.log('ArrayBuffer bytes', this.kiowarePrintService.getBytesFromText(response.text()));
});

以下是ResponseContentType的文档及其可能具有的不同值。

这是getBytesFromText的代码：

getBytesFromText(text: string) {
    const bytes: number[] = [];
    for (let i = 0; i < text.length; i++) {
      bytes.push(text.charCodeAt(i));
    }
    return bytes;
  }

将响应转换为字节会打印这些值：

Blob bytes (2) [123, 125]

Text bytes (951) [66, 77, 65533, 3, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 40, 0, 0, 0, 120, 0, 0, 0, 56, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 65533, 3, 0, 0, 65533, 14, 0, 0, 65533, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 65533, 65533, 65533, 0, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 0, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 0, 65533, 65533, 65533, 65533, 65533, 65533…]

ArrayBuffer bytes (479) [19778, 958, 0, 0, 0, 62, 0, 40, 0, 120, 0, 56, 0, 1, 1, 0, 0, 896, 0, 3780, 0, 3780, 0, 0, 0, 0, 0, 0, 0, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535, 65535, 65535, 255, 65535, 65535, 65535, 65535, 65535…]

这些似乎都是错误的，Blob字节的数量太低，而其他两个都包含大于字节的数字（> 255）。

我已尝试将这些字节发送到打印机并提出以下内容：

Blob不打印任何内容
Text
ArrayBuffer

编辑：尝试添加'content-type': 'image/bmp'标题：

    const headers: Headers = new Headers({'Content-Type': 'image/bmp'});
    const options: RequestOptions = new RequestOptions({headers: headers});
    this.http.get('/assets/images/brand/logo-bnw.bmp', options).subscribe((response: Response) => {
      console.log('image/bmp bytes', this.kiowarePrintService.getBytesFromText(response.text()));
    });

记录下来：

image/bmp bytes (951) [66, 77, 65533, 3, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 40, 0, 0, 0, 120, 0, 0, 0, 56, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 65533, 3, 0, 0, 65533, 14, 0, 0, 65533, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 65533, 65533, 65533, 0, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 0, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 0, 65533, 65533, 65533, 65533, 65533, 65533…]

它看起来与文本回复相同

Answer 1

您正在对所有返回类型使用response.text（）。对于二进制数据，您应该将其保留为blob。您可以使用

访问基础字节而无需转换为文本

response.arrayBuffer()

这应该为您提供正确的字节数组。

这个问题也很相关：Get Image or byte data with http

最佳答案采取的做法：

var blob = new Blob([new Uint8Array(response._body)]

在Custom TG2480H打印机上打印徽标

1 个答案: