Please I need help with QTextBlock::isVisible in QTextEdit

evanxg852000

I am writing a simple editor with a line number panel
I want to get the first visible block using this snipet in a slot that is connect to update when the text change and blockCount changed
@int total_line=this->TextEditor->document()->blockCount();
int line_ctr=0;
while(line_ctr<=total_line){
line_ctr++;
if(block.isVisible()){
first_visible_line=line_ctr;
break;
}
block.next();
}@

but no matter how first_visible_line is always 1 so block.isVisible() return always true .

I want to keep QTextEdit because I will be adding syntaxe coloring using QSyntaxHil..
Otherwise there is QPlainTextEdit::firstVisibleBlock() but I am not sure if QSyntaxHilighter can work on QPlainTextEdit

Please need help.
Thanks in advance

leon.anavi

Seems that other people have experienced the "same issue":http://stackoverflow.com/questions/2698129/how-to-set-visibility-for-textblocks-in-qtextedit

Btw I think you can simplify your code using something like this:

@int getFirstVisibleBlock()
{
QTextDocument *pDoc = TextEditor->document();
int nFirstVisible = 0;
for(QTextBlock block=pDoc->begin(); block!= pDoc->end(); block = block.next())
{
nFirstVisible += 1;
if (block.isVisible())
{
return nFirstVisible;
}
}
return nFirstVisible;
}@

Of course this will not solve an issue with isVisible() for blocks in QTextEdit if such exists :(

evanxg852000

thanks I could not figure it out . but Ifound that QplainTextEdit support QsyntaxHilither so I went that way . It is working fine . my code is even simpler. Yes indeed i saw that thread yesterday when searching . thks

golgauth

Actually, "isVisible" won't work for QTextEdit, but I managed to implement line numbers display for QTextEdit:

Here is the tricky part:

@
int QTextEditHighlighter::getFirstVisibleBlockId()
{
// Detect the first block for which bounding rect - once
// translated in absolute coordinates - is contained
// by the editor's text area

// Costly way of doing but since 
// "blockBoundingGeometry(...)" doesn't exist 
// for "QTextEdit"...

QTextCursor curs = QTextCursor(this->document());
curs.movePosition(QTextCursor::Start);
for(int i=0; i < this->document()->blockCount(); ++i)
{
    QTextBlock block = curs.block();

    QRect r1 = this->viewport()->geometry();
    QRect r2 = this->document()->documentLayout()->blockBoundingRect(block).translated(
                this->viewport()->geometry().x(), this->viewport()->geometry().y() - (
                    this->verticalScrollBar()->sliderPosition()
                    ) ).toRect();

    if (r1.contains(r2, true)) { return i; }

    curs.movePosition(QTextCursor::NextBlock);
}

return 0;

}
@

See full implementation here: http://stackoverflow.com/a/24596246/1715716

Hope it helps...