blocks|key|1937438|text|我是这样做的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1937439|//if+you+would+have+a+chapter+indentation
int+indentation+=+0;
//whatever
Image+image+=+coolPic;

float+scaler+=+((document.getPageSize().getWidth()+-+document.leftMargin()
+++++++++++++++-+document.rightMargin()+-+indentation)+/+image.getWidth())+*+100;

image.scalePercent(scaler);|code-block|syntax|javascript|1937440|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I do it like that:

<pre><code>//if you would have a chapter indentation
int indentation = 0;
//whatever
Image image = coolPic;

float scaler = ((document.getPageSize().getWidth() - document.leftMargin()
 - document.rightMargin() - indentation) / image.getWidth()) * 100;

image.scalePercent(scaler);
</code></pre>

blocks|key|1723900|text|您可以使用另一种方法：“手动”调整图像大小(即通过图像处理软件)，而不是通过iText编程。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1723901|由于最后的尺寸似乎是硬编码的，所以您可以使用已经调整大小的图像，并在每次为PDF文档添加水印时节省一些处理时间。|1723902|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

You could use another approach : resize the image "manually" (i.e. through an image processing software) instead of programmatically through iText. 

Since the final dimension seems hardcoded, you could use an already resized image and save yourself some processing time every time you watermark PDF documents.

blocks|key|1937457|text|使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1937458|watermark_image.scaleAbsolute(826,+1100);|code-block|syntax|javascript|1937459|而不是|1937460|watermark_image.scaleToFit(826,+1100);|1937461|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

use

<pre><code>watermark_image.scaleAbsolute(826, 1100);
</code></pre>

instead of

<pre><code>watermark_image.scaleToFit(826, 1100);
</code></pre>

blocks|key|1937471|text|您可以使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1937472|imageInstance.scaleAbsolute(requiredWidth,+requiredHeight);|code-block|syntax|javascript|1937473|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you can use 

<pre><code>imageInstance.scaleAbsolute(requiredWidth, requiredHeight);
</code></pre>

blocks|key|1937495|text|以防图像高度超过文档高度：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1937496|float+documentWidth+=+document.getPageSize().width()+-+document.leftMargin()+-+document.rightMargin();
float+documentHeight+=+document.getPageSize().height()+-+document.topMargin()+-+document.bottomMargin();
image.scaleToFit(documentWidth,+documentHeight);|code-block|syntax|javascript|1937497|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Just in case if the image height exceeds the document height:

<pre><code>float documentWidth = document.getPageSize().width() - document.leftMargin() - document.rightMargin();
float documentHeight = document.getPageSize().height() - document.topMargin() - document.bottomMargin();
image.scaleToFit(documentWidth, documentHeight);
</code></pre>

blocks|key|1723945|text|Document+document+=+new+Document();
PdfWriter.getInstance(document,+new+
FileOutputStream("F:\\Directory1\\sample1.pdf"));
document.open();

Image+img+=+
Image.getInstance("F:\\Server\\Xyz\\WebContent\\ImageRestoring\\Rohit.jpg");
img.scaleToFit(200,+200);
document.add(new+Paragraph("Sample+1:+This+is+simple+image+demo."));
document.add(img);
document.close();
System.out.println("Done");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1723946|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>Document document = new Document();
PdfWriter.getInstance(document, new 
FileOutputStream("F:\\Directory1\\sample1.pdf"));
document.open();

Image img = 
Image.getInstance("F:\\Server\\Xyz\\WebContent\\ImageRestoring\\Rohit.jpg");
img.scaleToFit(200, 200);
document.add(new Paragraph("Sample 1: This is simple image demo."));
document.add(img);
document.close();
System.out.println("Done");
</code></pre>

blocks|key|1724017|text|有时，只有当图像太大时才进行缩小，如果图像适合则不进行放大。换句话说，只有当宽度不适合可用宽度或高度不适合可用高度时，才会发生缩放。这可以按如下方式完成：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1724018|float+scaleRatio+=+calculateScaleRatio(doc,+image);
if+(scaleRatio+<+1F)+{
++++image.scalePercent(scaleRatio+*+100F);
}|code-block|syntax|javascript|1724019|使用此calculateScaleRatio方法：|offset|length|style|CODE|1724020|/**
+*+Calculate+scale+ratio+required+to+fit+supplied+image+in+the+supplied+PDF+document.
+*+@param+doc++++PDF+to+fit+image+in.
+*+@param+image++Image+to+be+converted+into+a+PDF.
+*+@return+++++++Scale+ratio+(0.0+-+1.0),+or+1.0+if+no+scaling+is+required.
+*/
private+float+calculateScaleRatio(Document+doc,+Image+image)+{
++++float+scaleRatio;
++++float+imageWidth+=+image.getWidth();
++++float+imageHeight+=+image.getHeight();
++++if+(imageWidth+>+0+&&+imageHeight+>+0)+{
++++++++//+Firstly+get+the+scale+ratio+required+to+fit+the+image+width
++++++++Rectangle+pageSize+=+doc.getPageSize();
++++++++float+pageWidth+=+pageSize.getWidth()+-+doc.leftMargin()+-+doc.rightMargin();
++++++++scaleRatio+=+pageWidth+/+imageWidth;

++++++++//+Get+scale+ratio+required+to+fit+image+height+-+if+smaller,+use+this+instead
++++++++float+pageHeight+=+pageSize.getHeight()+-+doc.topMargin()+-+doc.bottomMargin();
++++++++float+heightScaleRatio+=+pageHeight+/+imageHeight;
++++++++if+(heightScaleRatio+<+scaleRatio)+{
++++++++++++scaleRatio+=+heightScaleRatio;
++++++++}

++++++++//+Do+not+upscale+-+if+the+entire+image+can+fit+in+the+page,+leave+it+unscaled.
++++++++if+(scaleRatio+>+1F)+{
++++++++++++scaleRatio+=+1F;
++++++++}
++++}+else+{
++++++++//+No+scaling+if+the+width+or+height+is+zero.
++++++++scaleRatio+=+1F;
++++}
++++return+scaleRatio;
}|1724021|entityMap^0|0|0|3|J|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Sometimes it is useful to only scale down if the image is too large and not scale up if the image fits OK. In other words, the scaling will only happen if the width doesn't fit in the available width or the height doesn't fit in the available height. This can be done as follows:
<pre><code>float scaleRatio = calculateScaleRatio(doc, image);
if (scaleRatio &lt; 1F) {
 image.scalePercent(scaleRatio * 100F);
}
</code></pre>
with this <code>calculateScaleRatio</code> method:
<pre><code>/**
 * Calculate scale ratio required to fit supplied image in the supplied PDF document.
 * @param doc PDF to fit image in.
 * @param image Image to be converted into a PDF.
 * @return Scale ratio (0.0 - 1.0), or 1.0 if no scaling is required.
 */
private float calculateScaleRatio(Document doc, Image image) {
 float scaleRatio;
 float imageWidth = image.getWidth();
 float imageHeight = image.getHeight();
 if (imageWidth &gt; 0 &amp;&amp; imageHeight &gt; 0) {
 // Firstly get the scale ratio required to fit the image width
 Rectangle pageSize = doc.getPageSize();
 float pageWidth = pageSize.getWidth() - doc.leftMargin() - doc.rightMargin();
 scaleRatio = pageWidth / imageWidth;

 // Get scale ratio required to fit image height - if smaller, use this instead
 float pageHeight = pageSize.getHeight() - doc.topMargin() - doc.bottomMargin();
 float heightScaleRatio = pageHeight / imageHeight;
 if (heightScaleRatio &lt; scaleRatio) {
 scaleRatio = heightScaleRatio;
 }

 // Do not upscale - if the entire image can fit in the page, leave it unscaled.
 if (scaleRatio &gt; 1F) {
 scaleRatio = 1F;
 }
 } else {
 // No scaling if the width or height is zero.
 scaleRatio = 1F;
 }
 return scaleRatio;
}
</code></pre>

I have a watermark that I would like to put into my pdf. The watermark is a .bmp image, and is 2290 x 3026. I am having a lot of trouble trying to resize this picture to fit the page, does anyone have any suggestions?

<pre class="lang-java prettyprint-override"><code>Document document = new Document(); 
PdfWriter.getInstance(document, new FileOutputStream("result.pdf")); 
document.open(); 
document.add(new Paragraph("hello")); 
document.close(); 
PdfReader reader = new PdfReader("result.pdf"); 
int number_of_pages = reader.getNumberOfPages(); 
PdfStamper pdfStamper = new PdfStamper(reader, new FileOutputStream("result_watermark.pdf")); 
// Get the PdfContentByte type by pdfStamper. 
Image watermark_image = Image.getInstance("abstract(0307).bmp"); 
int i = 0; 
watermark_image.setAbsolutePosition(0, 0);
watermark_image.scaleToFit(826, 1100);
System.out.println(watermark_image.getScaledWidth());
System.out.println(watermark_image.getScaledHeight()); 
PdfContentByte add_watermark; 
while (i &lt; number_of_pages) { 
 i++; 
 add_watermark = pdfStamper.getUnderContent(i); 
 add_watermark.addImage(watermark_image); 
} 
pdfStamper.close();
</code></pre>

Here is the output for the <code>getScaled()</code> methods.

<pre><code>826.0 - Width
1091.4742 - Height
</code></pre>

I would share the picture of the pdf with you guys but unfortunately I can't.

Should I try using a .jpg instead? I don't really know how well iText handles different image extensions.

iText Image Resize

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋 

腾讯云代码助手

CODING DevOps

Cloud Studio

SDK中心

API中心

命令行工具

我有一个水印，我想放到我的pdf中。水印为.bmp图像，大小为2290x3026。我在尝试调整这张图片的大小以适应页面时遇到了很多麻烦，有人有什么建议吗？Document document = new Document(); PdfWriter.getInstance(document, new FileOutputS...

问iText图像调整大小
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问iText图像调整大小EN