Q: I need to know how to create or modify link annotation style
related to highlighting.
The expected behavior is the dotted rectangle instead of the invert
which seems to be the default. What do I need to do? I checked the
examples and did not find anything.
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A: To change annotation's highlighting mode you need to set the value
of "H" entry in the annotation dictionary (see TABLE 8.24 'Additional
entries specific to a link annotation' in PDF Reference).
The annotation's highlighting mode is the visual effect to be used
when the mouse button is pressed or held down inside its active area.
The "H" entry can assume the following values:
N - (None) No highlighting.
I - (Invert) Invert the contents of the annotation rectangle.
Default value.
O - (Outline) Invert the annotation's border.
P - (Push) Display the annotation as if it were being pushed below
the surface of the page
For example:
I forgot to mention that setting the highlight mode is as simple as
the following line:
// Set highlight mode to 'Invert'
annot.GetSDFObj().PutName("H", "N"); // Do not invert the link.
Similarly you can extract The 'Highlight Style' property from the
annotation
is not available in the high-level 'PDF.Annot' class however just like
with any other high-level class in PDFNet it very simple to extract
any required property. For example, you can obtain the 'Highlight
Style' from an existing annotation as follows:
Obj highlight = annot.GetSDFObj().FindObj("H");
if (highlight != null && highlight.IsName()) {
string st = highlight.GetName();
if (st == "N") { // No highlighting.
}
else if (st == "I") { // Invert
}
else if (st == "O") { // Outline
}
else if (st == "P") { // Push
}
}