第13章-Word图片与多媒体
第十三章：Word图片与多媒体
13.1 插入图片
13.1.1 从文件插入图片
using NPOI.XWPF.UserModel;
using System.IO;
/// <summary>
/// 从文件插入图片到段落
/// </summary>
public static void InsertImageFromFile(XWPFDocument doc, string imagePath,
int widthEmu, int heightEmu)
{
// 创建段落
XWPFParagraph para = doc.CreateParagraph();
para.Alignment = ParagraphAlignment.CENTER;
XWPFRun run = para.CreateRun();
// 读取图片文件
using FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read);
// 确定图片类型
string extension = Path.GetExtension(imagePath).ToLower();
PictureType pictureType = extension switch
{
".png" => PictureType.PNG,
".jpg" or ".jpeg" => PictureType.JPEG,
".gif" => PictureType.GIF,
".bmp" => PictureType.BMP,
".tiff" or ".tif" => PictureType.TIFF,
_ => PictureType.PNG
};
// 添加图片
run.AddPicture(fs, (int)pictureType, Path.GetFileName(imagePath), widthEmu, heightEmu);
}
// EMU（English Metric Units）转换
// 1英寸 = 914400 EMU
// 1厘米 = 360000 EMU
// 1像素 ≈ 9525 EMU（96 DPI）
/// <summary>
/// 像素转EMU
/// </summary>
public static int PixelToEmu(int pixels)
{
return pixels * 9525;
}
/// <summary>
/// 厘米转EMU
/// </summary>
public static int CmToEmu(double cm)
{
return (int)(cm * 360000);
}
/// <summary>
/// 英寸转EMU
/// </summary>
public static int InchToEmu(double inch)
{
return (int)(inch * 914400);
}
13.1.2 从字节数组插入图片
/// <summary>
/// 从字节数组插入图片
/// </summary>
public static void InsertImageFromBytes(XWPFDocument doc, byte[] imageBytes,
PictureType pictureType, string fileName, int widthEmu, int heightEmu)
{
XWPFParagraph para = doc.CreateParagraph();
XWPFRun run = para.CreateRun();
using MemoryStream ms = new MemoryStream(imageBytes);
run.AddPicture(ms, (int)pictureType, fileName, widthEmu, heightEmu);
}
/// <summary>
/// 从Base64字符串插入图片
/// </summary>
public static void InsertImageFromBase64(XWPFDocument doc, string base64Image,
PictureType pictureType, string fileName, int widthEmu, int heightEmu)
{
// 处理可能的data URI前缀
if (base64Image.Contains(","))
{
base64Image = base64Image.Substring(base64Image.IndexOf(",") + 1);
}
byte[] imageBytes = Convert.FromBase64String(base64Image);
InsertImageFromBytes(doc, imageBytes, pictureType, fileName, widthEmu, heightEmu);
}
13.1.3 在表格单元格中插入图片
/// <summary>
/// 在表格单元格中插入图片
/// </summary>
public static void InsertImageInCell(XWPFTableCell cell, string imagePath,
int widthEmu, int heightEmu)
{
// 获取或创建段落
XWPFParagraph para = cell.Paragraphs.Count > 0
? cell.Paragraphs[0]
: cell.AddParagraph();
para.Alignment = ParagraphAlignment.CENTER;
XWPFRun run = para.CreateRun();
using FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read);
string extension = Path.GetExtension(imagePath).ToLower();
PictureType pictureType = extension switch
{
".png" => PictureType.PNG,
".jpg" or ".jpeg" => PictureType.JPEG,
_ => PictureType.PNG
};
run.AddPicture(fs, (int)pictureType, Path.GetFileName(imagePath), widthEmu, heightEmu);
}
13.2 图片尺寸处理
13.2.1 自动计算尺寸
using System.Drawing;
/// <summary>
/// 获取图片原始尺寸并按比例缩放
/// </summary>
public static (int width, int height) GetScaledImageSize(string imagePath, int maxWidthEmu)
{
using var image = Image.FromFile(imagePath);
int originalWidthEmu = PixelToEmu(image.Width);
int originalHeightEmu = PixelToEmu(image.Height);
if (originalWidthEmu <= maxWidthEmu)
{
return (originalWidthEmu, originalHeightEmu);
}
double ratio = (double)maxWidthEmu / originalWidthEmu;
int scaledWidthEmu = maxWidthEmu;
int scaledHeightEmu = (int)(originalHeightEmu * ratio);
return (scaledWidthEmu, scaledHeightEmu);
}
/// <summary>
/// 插入自适应大小的图片
/// </summary>
public static void InsertAutoSizedImage(XWPFDocument doc, string imagePath, double maxWidthCm = 15)
{
int maxWidthEmu = CmToEmu(maxWidthCm);
var (width, height) = GetScaledImageSize(imagePath, maxWidthEmu);
InsertImageFromFile(doc, imagePath, width, height);
}
13.2.2 固定宽度保持比例
/// <summary>
/// 按固定宽度等比例插入图片
/// </summary>
public static void InsertImageWithFixedWidth(XWPFDocument doc, string imagePath, double widthCm)
{
using var image = Image.FromFile(imagePath);
double ratio = (double)image.Height / image.Width;
int widthEmu = CmToEmu(widthCm);
int heightEmu = (int)(widthEmu * ratio);
InsertImageFromFile(doc, imagePath, widthEmu, heightEmu);
}
13.3 图片位置
13.3.1 图片居中
/// <summary>
/// 插入居中图片
/// </summary>
public static void InsertCenteredImage(XWPFDocument doc, string imagePath,
int widthEmu, int heightEmu)
{
XWPFParagraph para = doc.CreateParagraph();
para.Alignment = ParagraphAlignment.CENTER;
XWPFRun run = para.CreateRun();
using FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read);
PictureType pictureType = GetPictureType(imagePath);
run.AddPicture(fs, (int)pictureType, Path.GetFileName(imagePath), widthEmu, heightEmu);
}
private static PictureType GetPictureType(string imagePath)
{
string ext = Path.GetExtension(imagePath).ToLower();
return ext switch
{
".png" => PictureType.PNG,
".jpg" or ".jpeg" => PictureType.JPEG,
".gif" => PictureType.GIF,
".bmp" => PictureType.BMP,
_ => PictureType.PNG
};
}
13.3.2 图片说明文字
/// <summary>
/// 插入带说明的图片
/// </summary>
public static void InsertImageWithCaption(XWPFDocument doc, string imagePath,
int widthEmu, int heightEmu, string caption)
{
// 插入图片
XWPFParagraph imagePara = doc.CreateParagraph();
imagePara.Alignment = ParagraphAlignment.CENTER;
XWPFRun imageRun = imagePara.CreateRun();
using (FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read))
{
PictureType pictureType = GetPictureType(imagePath);
imageRun.AddPicture(fs, (int)pictureType, Path.GetFileName(imagePath), widthEmu, heightEmu);
}
// 插入说明文字
XWPFParagraph captionPara = doc.CreateParagraph();
captionPara.Alignment = ParagraphAlignment.CENTER;
XWPFRun captionRun = captionPara.CreateRun();
captionRun.SetText(caption);
captionRun.FontSize = 10;
captionRun.SetColor("666666");
captionRun.IsItalic = true;
}
13.4 图片辅助类
/// <summary>
/// Word图片辅助类
/// </summary>
public static class WordImageHelper
{
/// <summary>
/// 像素转EMU
/// </summary>
public static int PixelToEmu(int pixels) => pixels * 9525;
/// <summary>
/// 厘米转EMU
/// </summary>
public static int CmToEmu(double cm) => (int)(cm * 360000);
/// <summary>
/// 英寸转EMU
/// </summary>
public static int InchToEmu(double inch) => (int)(inch * 914400);
/// <summary>
/// 获取图片类型
/// </summary>
public static PictureType GetPictureType(string imagePath)
{
string ext = Path.GetExtension(imagePath).ToLower();
return ext switch
{
".png" => PictureType.PNG,
".jpg" or ".jpeg" => PictureType.JPEG,
".gif" => PictureType.GIF,
".bmp" => PictureType.BMP,
".tiff" or ".tif" => PictureType.TIFF,
".emf" => PictureType.EMF,
".wmf" => PictureType.WMF,
_ => PictureType.PNG
};
}
/// <summary>
/// 插入图片（简化方法）
/// </summary>
public static void InsertImage(XWPFDocument doc, string imagePath,
double widthCm, double heightCm, ParagraphAlignment alignment = ParagraphAlignment.CENTER)
{
XWPFParagraph para = doc.CreateParagraph();
para.Alignment = alignment;
XWPFRun run = para.CreateRun();
int widthEmu = CmToEmu(widthCm);
int heightEmu = CmToEmu(heightCm);
using FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read);
run.AddPicture(fs, (int)GetPictureType(imagePath),
Path.GetFileName(imagePath), widthEmu, heightEmu);
}
/// <summary>
/// 插入图片保持原始比例
/// </summary>
public static void InsertImageKeepRatio(XWPFDocument doc, string imagePath,
double maxWidthCm = 15, ParagraphAlignment alignment = ParagraphAlignment.CENTER)
{
using var image = Image.FromFile(imagePath);
double ratio = (double)image.Height / image.Width;
double widthCm = image.Width / 37.8; // 大约的厘米值
if (widthCm > maxWidthCm)
{
widthCm = maxWidthCm;
}
double heightCm = widthCm * ratio;
InsertImage(doc, imagePath, widthCm, heightCm, alignment);
}
/// <summary>
/// 在Run中插入图片
/// </summary>
public static void InsertImageInRun(XWPFRun run, string imagePath,
double widthCm, double heightCm)
{
int widthEmu = CmToEmu(widthCm);
int heightEmu = CmToEmu(heightCm);
using FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Read);
run.AddPicture(fs, (int)GetPictureType(imagePath),
Path.GetFileName(imagePath), widthEmu, heightEmu);
}
}
13.5 综合示例
13.5.1 创建图文混排文档
public class ImageDocumentExample
{
public static void CreateImageDocument()
{
XWPFDocument doc = new XWPFDocument();
// 标题
XWPFParagraph titlePara = doc.CreateParagraph();
titlePara.Alignment = ParagraphAlignment.CENTER;
XWPFRun titleRun = titlePara.CreateRun();
titleRun.SetText("产品介绍");
titleRun.IsBold = true;
titleRun.FontSize = 22;
doc.CreateParagraph(); // 空行
// 产品图片（如果有）
string imagePath = "product.jpg";
if (File.Exists(imagePath))
{
WordImageHelper.InsertImageKeepRatio(doc, imagePath, 12);
// 图片说明
XWPFParagraph captionPara = doc.CreateParagraph();
captionPara.Alignment = ParagraphAlignment.CENTER;
XWPFRun captionRun = captionPara.CreateRun();
captionRun.SetText("图1：产品外观");
captionRun.FontSize = 10;
captionRun.IsItalic = true;
captionRun.SetColor("666666");
}
doc.CreateParagraph();
// 产品说明文字
XWPFParagraph descPara = doc.CreateParagraph();
descPara.IndentationFirstLine = 420;
XWPFRun descRun = descPara.CreateRun();
descRun.SetText("这是一款高品质的产品，具有优秀的性能和美观的外观设计。" +
"采用先进的技术和优质的材料，为用户提供卓越的使用体验。");
descRun.FontSize = 12;
// 保存
using (FileStream fs = new FileStream("图文文档.docx", FileMode.Create))
{
doc.Write(fs);
}
Console.WriteLine("图文文档创建成功！");
}
}
13.6 本章小结
本章详细介绍了NPOI中Word图片的操作。通过本章学习，你应该掌握：
- 从文件、字节数组、Base64插入图片
- 在表格单元格中插入图片
- 图片尺寸的计算和转换（EMU单位）
- 图片的定位和对齐
- 图片说明文字的添加
- 图片辅助类的封装
图片是文档中重要的视觉元素，掌握图片操作可以创建更加丰富的Word文档。
下一章预告：第十四章将介绍Word页眉页脚与页面设置。
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