Am 19.06.2016 um 08:52 schrieb John Hewson:
>>JIRA, and attach your code as a patch / diff.
>There is already some code handling those operators, see
PDFMarkedContentExtractor. It could be moved to a more generic place so that we
have to add some filtering only.
Yes, that's is the proper way to handle this. Operators are handled with a an
OperatorProcessor, not my modifying the parser (e.g. processStreamOperators).
Better yet, we already have the code to handle BMC/EMC. All that is needed is
for PDFRenderer to add a constructor which accepts a list of layer names to
render, which are then passed as part of PageDrawerParmeters.
The problem is that these two operators influence whether or not all the
other tokens in the content stream are used or not. So the method by C.
makes sense to me. The alternative would be to alter every operator
processor to check whether it is relevant or not.
Or they would have to be extended from some common class that does this
check.
PDFMarkedContentExtractor is not really helpful. Here's some code to
show what it does - it shows the objects that belong to a specific
group. The output cannot be used for rendering.
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import
org.apache.pdfbox.pdmodel.documentinterchange.markedcontent.PDMarkedContent;
import
org.apache.pdfbox.pdmodel.documentinterchange.markedcontent.PDPropertyList;
import
org.apache.pdfbox.pdmodel.graphics.optionalcontent.PDOptionalContentGroup;
import
org.apache.pdfbox.pdmodel.graphics.optionalcontent.PDOptionalContentProperties;
import org.apache.pdfbox.text.PDFMarkedContentExtractor;
public class ExtractMarkedContent extends PDFMarkedContentExtractor
{
public ExtractMarkedContent() throws IOException
{
}
public static void main(String[] args) throws IOException
{
PDDocument doc = PDDocument.load(new File("C......\\PDFBox
reactor\\pdfbox\\target\\test-output","ocg-generation.pdf"));
PDOptionalContentProperties ocp =
doc.getDocumentCatalog().getOCProperties();
System.out.println("Group names in document catalog: " +
Arrays.toString(ocp.getGroupNames()));
for (String groupName : ocp.getGroupNames())
{
PDOptionalContentGroup group = ocp.getGroup(groupName);
System.out.println(group.getCOSObject());
}
ExtractMarkedContent extractMarkedContent = new
ExtractMarkedContent();
PDPage page = doc.getPage(0);
System.out.println("Property names in page resources: " +
page.getResources().getPropertiesNames());
extractMarkedContent.processPage(page);
List<PDMarkedContent> markedContents =
extractMarkedContent.getMarkedContents();
System.out.println("Extracted contents: ");
for (PDMarkedContent mc : markedContents)
{
PDPropertyList propertyList =
page.getResources().getProperties(COSName.getPDFName(mc.getTag()));
String propName =
propertyList.getCOSObject().getString(COSName.NAME);
System.out.println(mc.getTag() + " (" + propName + "): " +
mc.getContents());
}
doc.close();
}
}
The output is:
Group names in document catalog: [background, enabled, disabled]
COSDictionary{(COSName{Type}:COSName{OCG})
(COSName{Name}:COSString{background}) }
COSDictionary{(COSName{Type}:COSName{OCG})
(COSName{Name}:COSString{enabled}) }
COSDictionary{(COSName{Type}:COSName{OCG})
(COSName{Name}:COSString{disabled}) }
Property names in page resources: [COSName{oc1}, COSName{oc2}, COSName{oc3}]
Extracted contents:
oc1 (background): [P, D, F, , 1, ., 5, :, , O, p, t, i, o, n, a, l, ,
C, o, n, t, e, n, t, , G, r, o, u, p, s, Y, o, u, , s, h, o, u, l, d,
, s, e, e, , a, , g, r, e, e, n, , t, e, x, t, l, i, n, e, ,, , b,
u, t, , n, o, , r, e, d, , t, e, x, t, , l, i, n, e, .]
oc2 (enabled): [T, h, i, s, , i, s, , f, r, o, m, , a, n, , e, n, a,
b, l, e, d, , l, a, y, e, r, ., , I, f, , y, o, u, , s, e, e, , t,
h, i, s, ,, , t, h, a, t, ', s, , g, o, o, d, .]
oc3 (disabled): [T, h, i, s, , i, s, , f, r, o, m, , a, , d, i, s,
a, b, l, e, d, , l, a, y, e, r, ., , I, f, , y, o, u, , s, e, e, ,
t, h, i, s, ,, , t, h, a, t, ', s, , N, O, T, , g, o, o, d, !]
