On Thursday 18 December 2003 12:07 pm, Maurizio Colucci wrote:
> To make it faster, I thought of another approach: since Pango Layouts
> can wrap a text by themselves, by splitting it into lines, then we could
> make Pango do the wrapping and the read back the lines. We could
> use these lines to build the label text, putting a newline char
> between the lines. The code is in MyLabel3, but I can't extract
> the text from the LayoutLine! Do you happen to know if
> I can do that? ( A negative answer would be tragic :-))
Never mind! I did it, in a very dirty way:
/// A Label with the capability of wrapping itself if its
/// width exceeds P pixels.
class MyLabel3 : public Label{
public:
MyLabel3(string aTextWithoutNewlines) : Label(aTextWithoutNewlines){
mTextWithoutNewlines = aTextWithoutNewlines;
SetWrapPixel(100);
}
// SetWrapPixel: this function adds newlines to the
// label text, in order not to make it be wider than P
// pixels. Also it does not break words. Uses pango
// for the wrapping. This would be perfect but I can't
// write the function extract_text_of_line()!
void SetWrapPixel(int p){
Glib::ustring lTextWithNewlines = "";
Glib::RefPtr<Pango::Layout> lLayout = create_pango_layout(mTextWithoutNewlines);
lLayout->set_width(p * Pango::SCALE);
lLayout->set_wrap(Pango::WRAP_WORD_CHAR);
// Now Pango has correctly done the wrapping,
// since lLayout->get_line_count() returns
// more than 1. But I can't get the text of
// the lines!
for (int i = 0; i<lLayout->get_line_count(); i++){
Glib::RefPtr<Pango::LayoutLine> lCurrentLine = lLayout->get_line(i);
Glib::ustring lLineText = extract_text_of_line(lCurrentLine, lLayout->get_text());
lTextWithNewlines += lLineText;
// REGION add the newline but not at the end of the string
if (i!=lLayout->get_line_count()-1)
lTextWithNewlines += '\n';
// END
}
this->set_text(lTextWithNewlines);
}
private:
Glib::ustring mTextWithoutNewlines;
Glib::ustring extract_text_of_line(Glib::RefPtr<Pango::LayoutLine> aLayoutLine,
Glib::ustring aText){
PangoLayoutLine * lPtr = aLayoutLine->gobj();
const char * lText = aText.c_str();
string s = "";
for (int i=0; i< lPtr->length; i++){
char c = lText[(lPtr->start_index) + i];
s+=c;
}
return s;
}
};
Thanks again. I'll ask on the gtkmm list if this is possible without the dirtyness. :-)
Maurizio
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