c++使用gdi+将bmp图片发送到打印机打印

要使用GDI将BMP图像发送到打印机打印，您需要执行以下步骤：

1. 打开打印机设备上下文（DC）：

HDC hdcPrinter = CreateDC("WINSPOOL", printerName, NULL, NULL);

其中，`printerName`是您要打印的打印机的名称。

2. 创建一个内存DC，并将BMP图像绘制到该DC上：

HDC hdcMem = CreateCompatibleDC(NULL);
HBITMAP hBitmap = (HBITMAP)LoadImage(NULL, bmpFileName, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
HBITMAP hOldBitmap = (HBITMAP)SelectObject(hdcMem, hBitmap);

BITMAP bm;
GetObject(hBitmap, sizeof(BITMAP), &bm);

BitBlt(hdcMem, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY);

其中，`bmpFileName`是BMP图像文件的名称。

3. 获取打印机DC的打印机信息：

PRINTER_INFO_2 printerInfo;
DWORD dwBytesNeeded;
GetPrinter(hdcPrinter, 2, NULL, 0, &dwBytesNeeded);
BYTE* pBuffer = new BYTE[dwBytesNeeded];
GetPrinter(hdcPrinter, 2, pBuffer, dwBytesNeeded, &dwBytesNeeded);
memcpy(&printerInfo, pBuffer, sizeof(PRINTER_INFO_2));
delete[] pBuffer;

4. 创建一个打印机DC，并将其与打印机连接：

HDC hdcPrint = CreateDC(NULL, printerInfo.pPrinterName, NULL, NULL);

5. 设置打印机DC的打印机模式，并将内存DC中的BMP图像打印到打印机DC上：

DOCINFO di;
ZeroMemory(&di, sizeof(DOCINFO));
di.cbSize = sizeof(DOCINFO);
StartDoc(hdcPrint, &di);
StartPage(hdcPrint);

SetMapMode(hdcPrint, MM_ANISOTROPIC);
SetViewportExtEx(hdcPrint, bm.bmWidth, bm.bmHeight, NULL);
SetWindowExtEx(hdcPrint, bm.bmWidth, bm.bmHeight, NULL);

BitBlt(hdcPrint, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY);

EndPage(hdcPrint);
EndDoc(hdcPrint);

6. 释放所有DC和位图：

SelectObject(hdcMem, hOldBitmap);
DeleteDC(hdcMem);
DeleteDC(hdcPrint);
DeleteObject(hBitmap);

完整的代码示例：

void PrintBmpOnPrinter(LPCTSTR printerName, LPCTSTR bmpFileName)
{
    HDC hdcPrinter = CreateDC("WINSPOOL", printerName, NULL, NULL);

    HDC hdcMem = CreateCompatibleDC(NULL);
    HBITMAP hBitmap = (HBITMAP)LoadImage(NULL, bmpFileName, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
    HBITMAP hOldBitmap = (HBITMAP)SelectObject(hdcMem, hBitmap);

    BITMAP bm;
    GetObject(hBitmap, sizeof(BITMAP), &bm);

    BitBlt(hdcMem, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY);

    PRINTER_INFO_2 printerInfo;
    DWORD dwBytesNeeded;
    GetPrinter(hdcPrinter, 2, NULL, 0, &dwBytesNeeded);
    BYTE* pBuffer = new BYTE[dwBytesNeeded];
    GetPrinter(hdcPrinter, 2, pBuffer, dwBytesNeeded, &dwBytesNeeded);
    memcpy(&printerInfo, pBuffer, sizeof(PRINTER_INFO_2));
    delete[] pBuffer;

    HDC hdcPrint = CreateDC(NULL, printerInfo.pPrinterName, NULL, NULL);

    DOCINFO di;
    ZeroMemory(&di, sizeof(DOCINFO));
    di.cbSize = sizeof(DOCINFO);
    StartDoc(hdcPrint, &di);
    StartPage(hdcPrint);

    SetMapMode(hdcPrint, MM_ANISOTROPIC);
    SetViewportExtEx(hdcPrint, bm.bmWidth, bm.bmHeight, NULL);
    SetWindowExtEx(hdcPrint, bm.bmWidth, bm.bmHeight, NULL);

    BitBlt(hdcPrint, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, SRCCOPY);

    EndPage(hdcPrint);
    EndDoc(hdcPrint);

    SelectObject(hdcMem, hOldBitmap);
    DeleteDC(hdcMem);
    DeleteDC(hdcPrint);
    DeleteObject(hBitmap);
}