Problems with a thumbnail viewer for Konqueror [Archive]

Valheru

20th January 2008, 00:39

I am writing a program to render NFO files, and I want to write a thumbnail viewer so that you can select or mouse over NFO files in Konqueror and see them rendered correctly. To this end, I wrote a text codec for Qt3 for the CP/IBM 437 encoding. It works in the program.

I copied the code for the HTML file preview in Konqueror. It works for NFO files, but the moment I uncomment the file.open() code it stops working.

/************************************************** *************************
* Copyright (C) 2007 by Lawrence Lee *
* valheru@facticius.net *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
************************************************** *************************/
#include <kstandarddirs.h>
#include <kapplication.h>
#include <kmimetype.h>
#include <time.h>
#include <qpixmap.h>
#include <qimage.h>
#include <qpainter.h>
#include <khtml_part.h>
#include <qfile.h>
#include <qimage.h>
#include <qtextstream.h>
#include "knfoviewerthumbnail.h"
#include "cp437codec.h"

extern "C"
{
ThumbCreator *new_creator()
{
return new KNfoViewerThumbnail();
}
}

/*
* This code is taken nearly verbatim from htmlcreator.cpp
* in kdebase/kioslave/thumbnail/ with minor changes to
* ensure the correct rendering of CP437 encoded characters.
*/
KNfoViewerThumbnail::KNfoViewerThumbnail() : m_html( 0 )
{
}

KNfoViewerThumbnail::~KNfoViewerThumbnail()
{
delete m_html;
}

bool KNfoViewerThumbnail::create( const QString &path, int width, int height, QImage &img ){
if (!m_html)
{
m_html = new KHTMLPart;
connect(m_html, SIGNAL(completed()), SLOT(slotCompleted()));
m_html->setJScriptEnabled(false);
m_html->setJavaEnabled(false);
m_html->setPluginsEnabled(false);
m_html->setMetaRefreshEnabled(false);
m_html->setOnlyLocalReferences(true);
}
KURL url;
url.setPath( path );
// QFile file( url.url() );

// if( !file.open( IO_ReadOnly ) )
// return false;

// QString text;
// QTextStream stream( &file );
// CP437Codec codec;
// stream.setCodec( &codec );
//
// while( !stream.atEnd() ){
// text += stream.readLine() + "\n";
// }

// m_html->begin();
// m_html->write( htmlCode( text ) );
// m_html->end();

m_html->openURL(url);

int t = startTimer(5000);

qApp->enter_loop();

killTimer(t);

// render the HTML page on a bigger pixmap and use smoothScale,
// looks better than directly scaling with the QPainter (malte)
QPixmap pix;
if (width > 400 || height > 600)
{
if (height * 3 > width * 4)
pix.resize(width, width * 4 / 3);
else
pix.resize(height * 3 / 4, height);
}
else
pix.resize(400, 600);

// light-grey background, in case loadind the page failed
pix.fill( QColor( 245, 245, 245 ) );

int borderX = pix.width() / width, borderY = pix.height() / height;
QRect rc(borderX, borderY, pix.width() - borderX * 2,
pix.height() - borderY * 2);

QPainter p;
p.begin(&pix);
m_html->paint(&p, rc);
p.end();

img = pix.convertToImage();

m_html->closeURL();

return true;
}

const QString KNfoViewerThumbnail::htmlCode( const QString &text )
{
QString code = "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">\n\
<html>\n\
<head>\n\
<meta http-equiv=\"Content-Type\" content=\"text/html; charset=ISO-8859-1\" />\n\
<style type=\"text/css\" media=\"screen\"></style>\n\
</head>\n\
<body>\n\
<div id\"nfo\">\n\
<div id=\"data\">\n";

code += text;
code += "<br></div></div><br/></body></html>";

return code;
}

void KNfoViewerThumbnail::timerEvent(QTimerEvent *)
{
qApp->exit_loop();
}

void KNfoViewerThumbnail::slotCompleted()
{
qApp->exit_loop();
}

ThumbCreator::Flags KNfoViewerThumbnail::flags() const
{
return DrawFrame;
}

#include "knfoviewerthumbnail.moc"

Valheru

20th January 2008, 01:06

Upon further examination it appears that it is "failing" on the line

if( !file.open( IO_ReadOnly ) )
return false;

So evidently it can't read the file. If I comment that out and use m_file->openURL() it renders, albiet with incorrect encoding.

jacek

20th January 2008, 14:43

Can you open the file if you use "QFile file( path );"?

Valheru

21st January 2008, 21:17

Nope, it doesn't :(

jacek

21st January 2008, 21:52

Could you post a sample path value?

Valheru

22nd January 2008, 18:23

Ugh, that was retarded. In the end it was a linker error. It wasn't immediately apparent because the library compiled fine. It was just crashing at runtime because I hadn't linked it correctly.