I'm printing a receipt using the Custom TG2480-H printer. I've got all of the receipt working except for the logo.
I've got a monochrome .bmp
file that represents the logo and has the right dimenions.
I'm retrieving the file, using different response types:
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()));
});
Here's the documentation on ResponseContentType and the different values it can have.
This is the code for getBytesFromText
:
getBytesFromText(text: string) {
const bytes: number[] = [];
for (let i = 0; i < text.length; i++) {
bytes.push(text.charCodeAt(i));
}
return bytes;
}
Converting the responses to bytes prints these values:
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…]
These all seem to be wrong, the amount of Blob bytes is way too low, and the other two both contain numbers that are bigger than bytes (>255).
I've tried sending these bytes to the printer anyway and came up with the following:
Blob prints nothing
Text
ArrayBuffer
EDIT: Tried to add 'content-type': 'image/bmp'
header:
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()));
});
Logs this:
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…]
Which looks like it's the same as the text response
You're using response.text() for ALL of the return types. In the case of binary data, you should keep it as a blob. You can access the underlying bytes without converting to text by using
response.arrayBuffer()
That should give you the correct byte array that you're expecting.
This question is also relevant: Get Image or byte data with http
The top answer takes the approach of doing:
var blob = new Blob([new Uint8Array(response._body)]
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