关于“Unity调用打印机打印图片”的完整攻略,我将分为以下几个部分详细介绍:
- 需求分析
- Unity调用打印机的底层实现原理
- Unity调用打印机打印图片的具体操作步骤
- 示例演示
需求分析
在我们的日常项目中,可能会有需要在Unity3d中实现打印图片的需求,例如实现游戏中的截图功能,或者游戏中的特定场景需要将当前画面截取下来并打印出来。因此,本文将介绍如何在Unity中调用打印机打印图片,从而实现上述需求。
Unity调用打印机的底层实现原理
在Unity中,调用打印机打印图片的实现原理是通过调用操作系统的打印接口实现的。因此,我们需要了解操作系统中打印接口的具体实现方式。
一般来说,不同的操作系统对于打印机的接口实现有所不同,因此我们需要根据不同的操作系统来实现相应的打印接口调用逻辑。
Unity调用打印机打印图片的具体操作步骤
下面,我们将介绍在Unity中调用打印机打印图片的具体操作步骤,分为以下几个步骤:
步骤一:准备打印接口
在Unity中调用打印机打印图片,我们需要准备相应的打印接口。在Windows中,我们可以通过以下方式来准备打印接口:
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool OpenPrinter(string pPrinterName, out IntPtr phPrinter, IntPtr pDefault);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool ResetPrinter(IntPtr hPrinter, ref PRINTER_DEFAULTS pd);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool SetDefaultPrinter(string pszPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool StartDocPrinter(IntPtr hPrinter, int Level, ref DOCINFO di);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
其中,winspool.drv是Windows的打印系统32位DLL文件,用于提供打印机服务接口,后面的各个方法都是该DLL文件提供的打印机服务接口方法。上述方法的作用分别是:关闭打印机、结束打印、结束页、打开打印机、重置默认打印机、设置默认打印机、开始打印、开始页。
步骤二:创建打印机文档
接下来,我们需要创建打印机文档,并将要打印的图片转换为打印机可识别格式。代码实现如下:
// 打印机文档信息
DOCIINFO di = new DOCIINFO();
di.pDocName = "Print Image";
// 打印机名字及打印机句柄
IntPtr hPrinter = new IntPtr(0);
int jobid = 0;
if (GetCurrentPrinterName(out string printerName))
{
OpenPrinter(printerName, out hPrinter, IntPtr.Zero);
// 如果打印机正被使用,则重置打印机
PRINTER_DEFAULTS pd = new PRINTER_DEFAULTS();
pd.pDatatype = "RAW";
ResetPrinter(hPrinter, ref pd);
// 开始打印任务
di.pDataType = "RAW";
StartDocPrinter(hPrinter, 1, ref di);
StartPagePrinter(hPrinter);
// 将图片转换为打印机格式
byte[] imageBytes = GetImageBytesFromFilePath(imagePath);
bool success = WritePrinter(hPrinter, imageBytes, imageBytes.Length, out int bytesWritten);
EndPagePrinter(hPrinter);
EndDocPrinter(hPrinter);
ClosePrinter(hPrinter);
}
上述代码中,我们创建了一个打印机文档(DOCINFO)和打印机句柄(hPrinter),并将其用于打印任务的开始。此时,我们需要将要打印的图片转换为打印机可识别的格式,例如,将其转换为byte[]。转换方式可以根据不同的需求进行实现。
步骤三:打印图片
最后,我们将转换后的图片内容打印到打印机上。代码实现如下:
// 打印图片
public static bool WritePrinter(IntPtr hPrinter, byte[] buffer, int bufLen, out int bytesWritten)
{
IntPtr unmanagedData = Marshal.AllocHGlobal(bufLen);
Marshal.Copy(buffer, 0, unmanagedData, bufLen);
bool success = WritePrinter(hPrinter, unmanagedData, bufLen, out int bWritten);
bytesWritten = success ? bWritten : 0;
Marshal.FreeHGlobal(unmanagedData);
return success;
}
上述方法就是将转换后的图片内容打印到打印机上的过程。
示例演示
下面,我们给出两个示例,演示如何在Unity中调用打印机打印图片。
示例一:打印截图
- 在Unity中实现截图功能,将截图保存为本地文件;
public static class ScreenShotUtil
{
public static void CaptureScreen(string filename)
{
var width = Screen.width;
var height = Screen.height;
var tex = new Texture2D(width, height, TextureFormat.RGB24, false);
tex.ReadPixels(new Rect(0, 0, width, height), 0, 0);
tex.Apply();
byte[] imageBytes = tex.EncodeToJPG();
File.WriteAllBytes(filename, imageBytes);
Debug.Log($"截图已保存:{filename}");
}
}
- 在需要打印的场景中,通过以下方式来进行打印:
string filename = "screenshot.jpg";
ScreenShotUtil.CaptureScreen(filename);
PrintImage(filename);
其中,PrintImage方法就是我们上述实现的打印图片方法。实现示例可以参考下面的完整代码:
using System;
using System.IO;
using System.Runtime.InteropServices;
using UnityEngine;
public class PrintImageDemo : MonoBehaviour
{
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool OpenPrinter(string pPrinterName, out IntPtr phPrinter, IntPtr pDefault);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool ResetPrinter(IntPtr hPrinter, ref PRINTER_DEFAULTS pd);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool SetDefaultPrinter(string pszPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool StartDocPrinter(IntPtr hPrinter, int Level, ref DOCINFO di);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, int dwCount, out int dwWritten);
public struct PRINTER_DEFAULTS
{
public IntPtr pDatatype;
public IntPtr pDevMode;
public int DesiredAccess;
}
public struct DOCINFO
{
public string pDocName;
public string pOutputFile;
public string pDataType;
}
public static bool GetCurrentPrinterName(out string printerName)
{
printerName = null;
bool success = false;
IntPtr hPrinter = new IntPtr(0);
int size = 0;
if (!OpenPrinter(null, out hPrinter, IntPtr.Zero))
return false;
if (GetPrinterDriver(hPrinter, null, 1, IntPtr.Zero, 0, out size) || size == 0)
{
ClosePrinter(hPrinter);
return false;
}
IntPtr info = Marshal.AllocHGlobal((int)size);
GetPrinterDriver(hPrinter, null, 1, info, size, out size);
PRINTER_INFO_1 pi = (PRINTER_INFO_1)Marshal.PtrToStructure(info, typeof(PRINTER_INFO_1));
printerName = pi.pName;
ClosePrinter(hPrinter);
Marshal.FreeHGlobal(info);
return true;
}
public struct PRINTER_INFO_1
{
public string pName;
public string pDescription;
public string pLocation;
public IntPtr pDevMode;
public string pSepFile;
public string pPrintProcessor;
public string pDatatype;
public string pParameters;
public IntPtr pSecurityDescriptor;
}
public static byte[] GetImageBytesFromFilePath(string imagePath)
{
return File.ReadAllBytes(imagePath);
}
// 打印图片
public static void PrintImage(string imagePath)
{
try
{
// 打印机文档信息
DOCINFO di = new DOCINFO();
di.pDocName = "Print Image";
// 打印机名字及打印机句柄
IntPtr hPrinter = new IntPtr(0);
int jobid = 0;
if (GetCurrentPrinterName(out string printerName))
{
OpenPrinter(printerName, out hPrinter, IntPtr.Zero);
// 如果打印机正被使用,则重置打印机
PRINTER_DEFAULTS pd = new PRINTER_DEFAULTS();
pd.pDatatype = "RAW";
ResetPrinter(hPrinter, ref pd);
// 开始打印任务
di.pDataType = "RAW";
StartDocPrinter(hPrinter, 1, ref di);
StartPagePrinter(hPrinter);
// 将图片转换为打印机格式
byte[] imageBytes = GetImageBytesFromFilePath(imagePath);
bool success = WritePrinter(hPrinter, imageBytes, imageBytes.Length, out int bytesWritten);
EndPagePrinter(hPrinter);
EndDocPrinter(hPrinter);
ClosePrinter(hPrinter);
}
else
{
Debug.LogError("没有找到可用的打印机!");
}
}
catch (Exception ex)
{
Debug.LogError($"打印出错,错误信息:{ex.Message}");
}
}
// 显示调用打印功能按钮
private void OnGUI()
{
if (GUILayout.Button("Print"))
{
string filename = "screenshot.jpg";
ScreenShotUtil.CaptureScreen(filename);
PrintImage(filename);
}
}
}
示例二:从网络上下载图片并打印
这个示例的过程与示例一类似,只是在获取图片时,需要通过URL从网络上下载图片。实现示例代码如下:
using System;
using System.IO;
using System.Net;
using System.Runtime.InteropServices;
using UnityEngine;
public class PrintImageDemo : MonoBehaviour
{
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool OpenPrinter(string pPrinterName, out IntPtr phPrinter, IntPtr pDefault);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool ResetPrinter(IntPtr hPrinter, ref PRINTER_DEFAULTS pd);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool SetDefaultPrinter(string pszPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool StartDocPrinter(IntPtr hPrinter, int Level, ref DOCINFO di);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, int dwCount, out int dwWritten);
public struct PRINTER_DEFAULTS
{
public IntPtr pDatatype;
public IntPtr pDevMode;
public int DesiredAccess;
}
public struct DOCINFO
{
public string pDocName;
public string pOutputFile;
public string pDataType;
}
public static bool GetCurrentPrinterName(out string printerName)
{
printerName = null;
bool success = false;
IntPtr hPrinter = new IntPtr(0);
int size = 0;
if (!OpenPrinter(null, out hPrinter, IntPtr.Zero))
return false;
if (GetPrinterDriver(hPrinter, null, 1, IntPtr.Zero, 0, out size) || size == 0)
{
ClosePrinter(hPrinter);
return false;
}
IntPtr info = Marshal.AllocHGlobal((int)size);
GetPrinterDriver(hPrinter, null, 1, info, size, out size);
PRINTER_INFO_1 pi = (PRINTER_INFO_1)Marshal.PtrToStructure(info, typeof(PRINTER_INFO_1));
printerName = pi.pName;
ClosePrinter(hPrinter);
Marshal.FreeHGlobal(info);
return true;
}
public struct PRINTER_INFO_1
{
public string pName;
public string pDescription;
public string pLocation;
public IntPtr pDevMode;
public string pSepFile;
public string pPrintProcessor;
public string pDatatype;
public string pParameters;
public IntPtr pSecurityDescriptor;
}
public static byte[] DownloadImageFromUrl(string url)
{
using (var wc = new WebClient())
{
return wc.DownloadData(url);
}
}
// 打印图片
public static void PrintImage(string imagePath)
{
try
{
// 打印机文档信息
DOCINFO di = new DOCINFO();
di.pDocName = "Print Image";
// 打印机名字及打印机句柄
IntPtr hPrinter = new IntPtr(0);
int jobid = 0;
if (GetCurrentPrinterName(out string printerName))
{
OpenPrinter(printerName, out hPrinter, IntPtr.Zero);
// 如果打印机正被使用,则重置打印机
PRINTER_DEFAULTS pd = new PRINTER_DEFAULTS();
pd.pDatatype = "RAW";
ResetPrinter(hPrinter, ref pd);
// 开始打印任务
di.pDataType = "RAW";
StartDocPrinter(hPrinter, 1, ref di);
StartPagePrinter(hPrinter);
// 将图片转换为打印机格式
byte[] imageBytes = DownloadImageFromUrl(imagePath);
bool success = WritePrinter(hPrinter, imageBytes, imageBytes.Length, out int bytesWritten);
EndPagePrinter(hPrinter);
EndDocPrinter(hPrinter);
ClosePrinter(hPrinter);
}
else
{
Debug.LogError("没有找到可用的打印机!");
}
}
catch (Exception ex)
{
Debug.LogError($"打印出错,错误信息:{ex.Message}");
}
}
// 显示调用打印功能按钮
private void OnGUI()
{
if (GUILayout.Button("Print"))
{
string imageUrl = "https://www.example.com/image.jpg";
PrintImage(imageUrl);
}
}
}
到这里,我们已经介绍了在Unity中调用打印机打印图片的完整攻略,并给出了两个不同的示例演示。
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