More on @crxjs/vite-plugin
将图片自适应大小插入到word文档
概述
如果手工新建word文档，插入图片是可以做到图片自适应等比缩放的，那么如何通过程序的方式来完成呢。
demo
通过一番搜索，了解到Java操作word添加图片的方法，Adding Images to a Word Document using Java; 重要的就是这几步
Step 1: Creating a blank document
Step 2: Creating a Paragraph
Step 3: Creating a File output stream of word document at the required location
Step 4: Creating a file input stream of the image by specifying its path
Step 5: Retrieving the image file name and image type
Step 6: Setting the width and height of the image in pixels
Step 7: Adding the picture using the addPicture() method and writing into the document
Step 8: Closing the connections
其中添加图片的重要代码如下，
XWPFParagraph paragraph
= document.createParagraph();
XWPFRun run = paragraph.createRun();
// Step 3: Creating a File output stream of word
// document at the required location
FileOutputStream fout = new FileOutputStream(
new File("D:\\WordFile.docx"));
// Step 4: Creating a file input stream of image by
// specifying its path
File image = new File("D:\\Images\\image.jpg");
FileInputStream imageData
= new FileInputStream(image);
// Step 5: Retrieving the image file name and image
// type
int imageType = XWPFDocument.PICTURE_TYPE_JPEG;
String imageFileName = image.getName();
// Step 6: Setting the width and height of the image
// in pixels.
int width = 450;
int height = 400;
// Step 7: Adding the picture using the addPicture()
// method and writing into the document
run.addPicture(imageData, imageType, imageFileName,
Units.toEMU(width),
Units.toEMU(height));
首先创建一个段落，然后XWPFRun辅助类来添加图片，添加图片需要知道图片的像素大小。
优化1
关于图片大小的获取，demo代码中并没有处理，应该这么操作，
BufferedImage img = ImageIO.read(image);
int width = img.getWidth();
int height = img.getHeight()
优化2
重要的是图片缩放计算，首先要直到常规A4纸张的大小，A4纸内容区域的大小。 A4纸宽=210mm，高=297mm，页面的内容左右边距分别都是31.8mm，上下边距分别是25.4mm； 只有这些尺寸是不够的，还不清楚这些尺寸可以保存多少像素。
通过搜索发现，A4纸在屏幕上的像素尺寸信息，https://cloud.tencent.com/developer/article/1505088； 分辨率是96像素/英寸时，A4纸的尺寸的图像的像素是794×1123；(默认)，而1英寸=2.54cm。
这句话的意思是，如果一个图片的宽度是1280px那么换算成尺寸应该是，1280 / 96.0 * 25.4 = 330.2mm
优化3
直到了怎么处理图片像素到尺寸的转换，那么就可以考虑如何处理等比例缩放问题了。 1、计算图片宽带与内容区域宽度的比例 2、计算图片高度与内容区域高度的比例 3、取两个比例之中最小的值，如果比例大于1则图片不缩放保持原来的宽度和高度，否则执行缩放
BufferedImage img = ImageIO.read(image);
int width = img.getWidth();
int height = img.getHeight();
// image size
double mw = width / 96.0 * 25.4;
double mh = height / 96.0 * 25.4;
// content size
double cw = 210 - (2*31.8);
double ch = 297 - (2*25.4);
double scaling = 1.0;
if (mw > cw) {
scaling = cw / mw;
}
if (mh > ch) {
if (ch / mh < scaling) {
scaling = ch / mh;
}
}
汇总
// add image
private static void addPicture(File image, XWPFDocument document, FileOutputStream fout) throws IOException, InvalidFormatException {
FileInputStream imageData = new FileInputStream(image);
// Step 2: Creating a Paragraph using
// createParagraph() method
XWPFParagraph paragraph
= document.createParagraph();
XWPFRun run = paragraph.createRun();
//run.addCarriageReturn();
// Step 5: Retrieving the image file name and image
// type
int imageType = XWPFDocument.PICTURE_TYPE_JPEG;
String imageFileName = image.getName();
// Step 6: Setting the width and height of the image
// in pixels.
BufferedImage img = ImageIO.read(image);
int width = img.getWidth();
int height = img.getHeight();
// image size
double mw = width / 96.0 * 25.4;
double mh = height / 96.0 * 25.4;
// content size
double cw = 210 - (2*31.8);
double ch = 297 - (2*25.4);
double scaling = 1.0;
if (mw > cw) {
scaling = cw / mw;
}
if (mh > ch) {
if (ch / mh < scaling) {
scaling = ch / mh;
}
}
// Step 7: Adding the picture using the addPicture()
// method and writing into the document
run.addPicture(imageData, imageType, imageFileName,
Units.pixelToEMU((int) (width * scaling * .9)),
Units.pixelToEMU((int) (height * scaling * .9)));
}
完整的代码
public static void main(String[] args) throws IOException, InvalidFormatException {
// Step 4: Creating a file input stream of image by
// specifying its path
String year = "2021";
File[] months = FileUtil.ls("d:/data/" + year);
// Step 1: Creating a blank document
XWPFDocument document = new XWPFDocument();
// Step 3: Creating a File output stream of word
// document at the required location
FileOutputStream fout = new FileOutputStream(
new File("D:\\WordFile-" + year + ".docx"));
// months
for (File month : months) {
// dates
File[] dates = FileUtil.ls(month.getAbsolutePath());
for (File date : dates) {
// images
File[] images = FileUtil.ls(date.getAbsolutePath());
for (File image : images) {
String mimeType = FileUtil.getMimeType(image.getAbsolutePath());
if ("image/jpeg".equals(mimeType)) {
addPicture(image, document, fout);
} else {
}
}
}
}
document.write(fout);
// Step 8: Closing the connections
fout.close();
document.close();
}
重要的依赖
<dependencies>
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>5.7.18</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>5.1.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>5.1.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml-schemas -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml-schemas</artifactId>
<version>4.1.2</version>
</dependency>