[英]Print bitmap full page width using ESC/POS
I am currently implementing Android PrintService, that is able to print PDFs via thermal printers. 我目前正在实现Android PrintService,该服务能够通过热敏打印机打印PDF。 I managed to convert PDF to bitmap using PDFRenderer and I am even able to print the document. 我设法使用PDFRenderer将PDF转换为位图,甚至可以打印文档。
The thing is, the document (bitmap) is not full page width. 问题是,文档(位图)不是完整的页面宽度。
I am receiving the document in 297x420 resolution and I am using printer with 58mm paper. 我正在以297x420分辨率接收文档,并且正在使用58mm纸张的打印机。
This is how I process the document (written in C#, using Xamarin): 这是我处理文档(使用Xamarin用C#编写)的方式:
// Create PDF renderer
var pdfRenderer = new PdfRenderer(fileDescriptor);
// Open page
PdfRenderer.Page page = pdfRenderer.OpenPage(index);
// Create bitmap for page
Bitmap bitmap = Bitmap.CreateBitmap(page.Width, page.Height, Bitmap.Config.Argb8888);
// Now render page into bitmap
page.Render(bitmap, null, null, PdfRenderMode.ForPrint);
And then, converting the bitmap into ESC/POS: 然后,将位图转换为ESC / POS:
// Initialize result
List<byte> result = new List<byte>();
// Init ESC/POS
result.AddRange(new byte[] { 0x1B, 0x33, 0x21 });
// Init ESC/POS bmp commands (will be reapeated)
byte[] escBmp = new byte[] { 0x1B, 0x2A, 0x01, (byte)(bitmap.Width % 256), (byte)(bitmap.Height / 256) };
// Iterate height
for (int i = 0; i < (bitmap.Height / 24 + 1); i++)
{
// Add bitmapp commands to result
result.AddRange(escBmp);
// Init pixel color
int pixelColor;
// Iterate width
for (int j = 0; j < bitmap.Width; j++)
{
// Init data
byte[] data = new byte[] { 0x00, 0x00, 0x00 };
for (int k = 0; k < 24; k++)
{
if (((i * 24) + k) < bitmap.Height)
{
// Get pixel color
pixelColor = bitmap.GetPixel(j, (i * 24) + k);
// Check pixel color
if (pixelColor != 0)
{
data[k / 8] += (byte)(128 >> (k % 8));
}
}
}
// Add data to result
result.AddRange(data);
}
// Add some... other stuff
result.AddRange(new byte[] { 0x0D, 0x0A });
}
// Return data
return result.ToArray();
Current result looks like this: 当前结果如下:
Thank you all in advance. 谢谢大家。
There is no magic "scale-to-page-width" command in the ESC/POS command-set, you need to know the max width of your printer, available in the manual, and then you can: ESC / POS命令集中没有神奇的“ scale-to-page-width”命令,您需要了解打印机的最大宽度(手册中提供),然后您可以:
ESC *
, which supports low-density, but height and width change in different ratios. 对于某些图像输出命令,将宽度和高度加倍-您正在使用ESC *
,它支持低密度,但是高度和宽度会以不同的比率变化。 Aside, your ESC *
implementation is incorrect. 另外,您的ESC *
实现不正确。 There are two bytes for the width- Check the ESC/POS manual for the correct usage, or read over the correct implementations in PHP or Python that I've linked in another question: ESC POS command ESC* for printing bit image on printer 宽度有两个字节-检查ESC / POS手册的正确用法,或阅读我在另一个问题中链接的PHP或Python的正确实现: ESC POS命令ESC *,用于在打印机上打印位图
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