我正在尝试从 PDF 中提取文本坐标和行（或矩形）坐标。
The TextPosition班级有getXDirAdj() and getYDirAdj()根据相应 TextPosition 对象表示的文本片段的方向转换坐标的方法（根据 @mkl 的评论进行更正）
无论页面旋转如何，最终输出都是一致的。
输出所需的坐标是 X0,Y0（页面的左上角）
这是对 @Tilman Hausherr 的解决方案的轻微修改。 y 坐标被反转（高度 - y）以使其与文本提取过程中的坐标保持一致，并且输出也写入 csv。
public class LineCatcher extends PDFGraphicsStreamEngine
{
private static final GeneralPath linePath = new GeneralPath();
private static ArrayList<Rectangle2D> rectList= new ArrayList<Rectangle2D>();
private int clipWindingRule = -1;
private static String headerRecord = "Text|Page|x|y|width|height|space|font";
public LineCatcher(PDPage page)
{
super(page);
}
public static void main(String[] args) throws IOException
{
if( args.length != 4 )
{
usage();
}
else
{
PDDocument document = null;
FileOutputStream fop = null;
File file;
Writer osw = null;
int numPages;
double page_height;
try
{
document = PDDocument.load( new File(args[0], args[1]) );
numPages = document.getNumberOfPages();
file = new File(args[2], args[3]);
fop = new FileOutputStream(file);
// if file doesnt exists, then create it
if (!file.exists()) {
file.createNewFile();
}
osw = new OutputStreamWriter(fop, "UTF8");
osw.write(headerRecord + System.lineSeparator());
System.out.println("Line Processing numPages:" + numPages);
for (int n = 0; n < numPages; n++) {
System.out.println("Line Processing page:" + n);
rectList = new ArrayList<Rectangle2D>();
PDPage page = document.getPage(n);
page_height = page.getCropBox().getUpperRightY();
LineCatcher lineCatcher = new LineCatcher(page);
lineCatcher.processPage(page);
try{
for(Rectangle2D rect:rectList) {
String pageNum = Integer.toString(n + 1);
String x = Double.toString(rect.getX());
String y = Double.toString(page_height - rect.getY()) ;
String w = Double.toString(rect.getWidth());
String h = Double.toString(rect.getHeight());
writeToFile(pageNum, x, y, w, h, osw);
}
rectList = null;
page = null;
lineCatcher = null;
}
catch(IOException io){
throw new IOException("Failed to Parse document for line processing. Incorrect document format. Page:" + n);
}
};
}
catch(IOException io){
throw new IOException("Failed to Parse document for line processing. Incorrect document format.");
}
finally
{
if ( osw != null ){
osw.close();
}
if( document != null )
{
document.close();
}
}
}
}
private static void writeToFile(String pageNum, String x, String y, String w, String h, Writer osw) throws IOException {
String c = "^" + "|" +
pageNum + "|" +
x + "|" +
y + "|" +
w + "|" +
h + "|" +
"999" + "|" +
"marker-only";
osw.write(c + System.lineSeparator());
}
@Override
public void appendRectangle(Point2D p0, Point2D p1, Point2D p2, Point2D p3) throws IOException
{
// to ensure that the path is created in the right direction, we have to create
// it by combining single lines instead of creating a simple rectangle
linePath.moveTo((float) p0.getX(), (float) p0.getY());
linePath.lineTo((float) p1.getX(), (float) p1.getY());
linePath.lineTo((float) p2.getX(), (float) p2.getY());
linePath.lineTo((float) p3.getX(), (float) p3.getY());
// close the subpath instead of adding the last line so that a possible set line
// cap style isn't taken into account at the "beginning" of the rectangle
linePath.closePath();
}
@Override
public void drawImage(PDImage pdi) throws IOException
{
}
@Override
public void clip(int windingRule) throws IOException
{
// the clipping path will not be updated until the succeeding painting operator is called
clipWindingRule = windingRule;
}
@Override
public void moveTo(float x, float y) throws IOException
{
linePath.moveTo(x, y);
}
@Override
public void lineTo(float x, float y) throws IOException
{
linePath.lineTo(x, y);
}
@Override
public void curveTo(float x1, float y1, float x2, float y2, float x3, float y3) throws IOException
{
linePath.curveTo(x1, y1, x2, y2, x3, y3);
}
@Override
public Point2D getCurrentPoint() throws IOException
{
return linePath.getCurrentPoint();
}
@Override
public void closePath() throws IOException
{
linePath.closePath();
}
@Override
public void endPath() throws IOException
{
if (clipWindingRule != -1)
{
linePath.setWindingRule(clipWindingRule);
getGraphicsState().intersectClippingPath(linePath);
clipWindingRule = -1;
}
linePath.reset();
}
@Override
public void strokePath() throws IOException
{
rectList.add(linePath.getBounds2D());
linePath.reset();
}
@Override
public void fillPath(int windingRule) throws IOException
{
linePath.reset();
}
@Override
public void fillAndStrokePath(int windingRule) throws IOException
{
linePath.reset();
}
@Override
public void shadingFill(COSName cosn) throws IOException
{
}
/**
* This will print the usage for this document.
*/
private static void usage()
{
System.err.println( "Usage: java " + LineCatcher.class.getName() + " <input-pdf>" + " <output-file>");
}
}
正在使用PDFGraphicsStreamEngine类来提取线和矩形坐标。线条和矩形的坐标与文本的坐标不对齐
绿色：文本 红色：按原样获取的线坐标 黑色：预期坐标（对输出应用变换后获得）
尝试过setRotation()在运行线提取之前校正旋转的方法。但结果并不一致。
使用 PDFBox 获得旋转并获得一致的线/矩形坐标输出有哪些可能的选项？
As far as I understand the requirements here, the OP works in a coordinate system with the origin in the upper left corner of the visible page (taking the page rotation into account), x coordinates increasing to the right, y coordinates increasing downwards, and the units being the PDF default user space units (usually 1/72 inch).
在这个坐标系中，他需要以以下形式提取（水平或垂直）线：
LineCatcher results辅助类LineCatcher另一方面，他从蒂尔曼那里得到的not考虑页面旋转。此外，它还返回bottom垂直线的终点，而不是顶部终点。因此，必须对其应用坐标变换LineCatcher结果。
为此，只需替换
for(Rectangle2D rect:rectList) {
String pageNum = Integer.toString(n + 1);
String x = Double.toString(rect.getX());
String y = Double.toString(page_height - rect.getY()) ;
String w = Double.toString(rect.getWidth());
String h = Double.toString(rect.getHeight());
writeToFile(pageNum, x, y, w, h, osw);
}
by
int pageRotation = page.getRotation();
PDRectangle pageCropBox = page.getCropBox();
for(Rectangle2D rect:rectList) {
String pageNum = Integer.toString(n + 1);
String x, y, w, h;
switch(pageRotation) {
case 0:
x = Double.toString(rect.getX() - pageCropBox.getLowerLeftX());
y = Double.toString(pageCropBox.getUpperRightY() - rect.getY() + rect.getHeight());
w = Double.toString(rect.getWidth());
h = Double.toString(rect.getHeight());
break;
case 90:
x = Double.toString(rect.getY() - pageCropBox.getLowerLeftY());
y = Double.toString(rect.getX() - pageCropBox.getLowerLeftX());
w = Double.toString(rect.getHeight());
h = Double.toString(rect.getWidth());
break;
case 180:
x = Double.toString(pageCropBox.getUpperRightX() - rect.getX() - rect.getWidth());
y = Double.toString(rect.getY() - pageCropBox.getLowerLeftY());
w = Double.toString(rect.getWidth());
h = Double.toString(rect.getHeight());
break;
case 270:
x = Double.toString(pageCropBox.getUpperRightY() - rect.getY() + rect.getHeight());
y = Double.toString(pageCropBox.getUpperRightX() - rect.getX() - rect.getWidth());
w = Double.toString(rect.getHeight());
h = Double.toString(rect.getWidth());
break;
default:
throw new IOException(String.format("Unsupported page rotation %d on page %d.", pageRotation, page));
}
writeToFile(pageNum, x, y, w, h, osw);
}
(带目录的提取行 test testExtractLineRotationTestWithDir)
TextPosition.get?DirAdj()坐标OP 通过参考描述坐标TextPosition类方法getXDirAdj() and getYDirAdj()。事实上，这些方法返回坐标系中的坐标，原点位于页面左上角，并且y坐标向下增加旋转页面以使文本垂直绘制后.
在示例文档的情况下，所有文本都被绘制，以便在应用页面旋转后它是直立的。由此我对上面写的要求的理解就得到了。
使用的问题TextPosition.get?DirAdj()然而，作为全局坐标的值的问题是，在具有沿不同方向绘制文本的页面的文档中，收集的文本坐标突然相对于不同的坐标系。因此，一般的解决方案不应该像那样疯狂地收集坐标。相反，它应该首先确定页面方向（例如，页面旋转给出的方向或大多数文本共享的方向），并使用由该方向给出的固定坐标系中的坐标加上文本书写方向的指示有问题的一块。