我正在使用以下脚本来获取页面中的图像位置 . 如何将它们传输到左上角的像素坐标？因为我想根据图像的位置和大小创建一个Rectangle，并将其与另一个Rectangle进行比较 .
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package org.apache.pdfbox.examples.util;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.graphics.PDXObject;
import org.apache.pdfbox.pdmodel.graphics.form.PDFormXObject;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.util.Matrix;
import org.apache.pdfbox.contentstream.operator.DrawObject;
import org.apache.pdfbox.contentstream.operator.Operator;
import org.apache.pdfbox.contentstream.PDFStreamEngine;
import java.io.File;
import java.io.IOException;
import java.util.List;
import org.apache.pdfbox.contentstream.operator.state.Concatenate;
import org.apache.pdfbox.contentstream.operator.state.Restore;
import org.apache.pdfbox.contentstream.operator.state.Save;
import org.apache.pdfbox.contentstream.operator.state.SetGraphicsStateParameters;
import org.apache.pdfbox.contentstream.operator.state.SetMatrix;
/**
* This is an example on how to get the x/y coordinates of image locations.
*
* @author Ben Litchfield
*/
public class PrintImageLocations extends PDFStreamEngine
{
/**
* Default constructor.
*
* @throws IOException If there is an error loading text stripper properties.
*/
public PrintImageLocations() throws IOException
{
addOperator(new Concatenate());
addOperator(new DrawObject());
addOperator(new SetGraphicsStateParameters());
addOperator(new Save());
addOperator(new Restore());
addOperator(new SetMatrix());
}
/**
* This will print the documents data.
*
* @param args The command line arguments.
*
* @throws IOException If there is an error parsing the document.
*/
public static void main( String[] args ) throws IOException
{
if( args.length != 1 )
{
usage();
}
else
{
PDDocument document = null;
try
{
document = PDDocument.load( new File(args[0]) );
PrintImageLocations printer = new PrintImageLocations();
int pageNum = 0;
for( PDPage page : document.getPages() )
{
pageNum++;
System.out.println( "Processing page: " + pageNum );
printer.processPage(page);
}
}
finally
{
if( document != null )
{
document.close();
}
}
}
}
/**
* This is used to handle an operation.
*
* @param operator The operation to perform.
* @param operands The list of arguments.
*
* @throws IOException If there is an error processing the operation.
*/
@Override
protected void processOperator( Operator operator, List<COSBase> operands) throws IOException
{
String operation = operator.getName();
if( "Do".equals(operation) )
{
COSName objectName = (COSName) operands.get( 0 );
PDXObject xobject = getResources().getXObject( objectName );
if( xobject instanceof PDImageXObject)
{
PDImageXObject image = (PDImageXObject)xobject;
int imageWidth = image.getWidth();
int imageHeight = image.getHeight();
System.out.println("*******************************************************************");
System.out.println("Found image [" + objectName.getName() + "]");
Matrix ctmNew = getGraphicsState().getCurrentTransformationMatrix();
float imageXScale = ctmNew.getScalingFactorX();
float imageYScale = ctmNew.getScalingFactorY();
// position in user space units. 1 unit = 1/72 inch at 72 dpi
System.out.println("position in PDF = " + ctmNew.getTranslateX() + ", " + ctmNew.getTranslateY() + " in user space units");
// raw size in pixels
System.out.println("raw image size = " + imageWidth + ", " + imageHeight + " in pixels");
// displayed size in user space units
System.out.println("displayed size = " + imageXScale + ", " + imageYScale + " in user space units");
// displayed size in inches at 72 dpi rendering
imageXScale /= 72;
imageYScale /= 72;
System.out.println("displayed size = " + imageXScale + ", " + imageYScale + " in inches at 72 dpi rendering");
// displayed size in millimeters at 72 dpi rendering
imageXScale *= 25.4;
imageYScale *= 25.4;
System.out.println("displayed size = " + imageXScale + ", " + imageYScale + " in millimeters at 72 dpi rendering");
System.out.println();
}
else if(xobject instanceof PDFormXObject)
{
PDFormXObject form = (PDFormXObject)xobject;
showForm(form);
}
}
else
{
super.processOperator( operator, operands);
}
}
/**
* This will print the usage for this document.
*/
private static void usage()
{
System.err.println( "Usage: java " + PrintImageLocations.class.getName() + " <input-pdf>" );
}
}
获取左上边缘坐标的可能公式：
X1 = ctmNew.getTranslateX() * topixelfactor
Y1 = pageheight - ctmNew.getTranslateY() * toPixelFactor - imageHeight
我可以通过page.getMediaBox（）获取pageHeight.getHeight（）;但问题是计算“toPixelFactor”，因为ctmNew.getTranslateY（）的翻译是以用户空间单位而不是Pixel中给出的 .