tdebase/kioslave/thumbnail/textcreator.cpp

/*  This file is part of the KDE libraries
    Copyright (C) 2000,2002 Carsten Pfeiffer <pfeiffer@kde.org>
                  2000 Malte Starostik <malte@kde.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/

#include <tqfile.h>
#include <tqpixmap.h>
#include <tqimage.h>

#include <kstandarddirs.h>
#include <kpixmapsplitter.h>
#include <kmimetype.h>

#include "textcreator.h"

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

TextCreator::TextCreator()
    : m_splitter(0),
      m_data(0),
      m_dataSize(0)
{
}

TextCreator::~TextCreator()
{
    delete m_splitter;
    delete [] m_data;
}

bool TextCreator::create(const TQString &path, int width, int height, TQImage &img)
{
    // Filter out unwanted mimetypes
    KMimeType::Ptr mimeType = KMimeType::findByPath( path );
    if ( mimeType->is( "text/rtf" ) )
        return false;

    if ( !m_splitter )
    {
        m_splitter = new KPixmapSplitter;
        TQString pixmap = locate( "data", "konqueror/pics/thumbnailfont_7x4.png" );
        if ( !pixmap.isEmpty() )
        {
            // FIXME: make font/glyphsize configurable...
            m_splitter->setPixmap( TQPixmap( pixmap ));
            m_splitter->setItemSize( TQSize( 4, 7 ));
        }
    }

    bool ok = false;

    // determine some sizes...
    // example: width: 60, height: 64
    TQSize pixmapSize( width, height );
    if (height * 3 > width * 4)
        pixmapSize.setHeight( width * 4 / 3 );
    else
        pixmapSize.setWidth( height * 3 / 4 );

    if ( pixmapSize != m_pixmap.size() )
        m_pixmap.resize( pixmapSize );
    
    // one pixel for the rectangle, the rest. whitespace
    int xborder = 1 + pixmapSize.width()/16;  // minimum x-border
    int yborder = 1 + pixmapSize.height()/16; // minimum y-border

    TQSize chSize = m_splitter->itemSize(); // the size of one char
    int xOffset = chSize.width();
    int yOffset = chSize.height();

    // calculate a better border so that the text is centered
    int canvasWidth  = pixmapSize.width()  - 2*xborder;
    int canvasHeight = pixmapSize.height() -  2*yborder;
    int numCharsPerLine = (int) (canvasWidth / chSize.width());
    int numLines = (int) (canvasHeight / chSize.height());

    // assumes an average line length of <= 120 chars
    const int bytesToRead = 120 * numLines;

    // create text-preview
    TQFile file( path );
    if ( file.open( IO_ReadOnly ))
    {
        if ( !m_data || m_dataSize < bytesToRead + 1 )
        {
            delete [] m_data;
            m_data = new char[bytesToRead+1];
            m_dataSize = bytesToRead + 1;
        }

        int read = file.readBlock( m_data, bytesToRead );
        if ( read > 0 )
        {
            ok = true;
            m_data[read] = '\0';
            TQString text = TQString::fromLocal8Bit( m_data );
            // FIXME: maybe strip whitespace and read more?

            m_pixmap.fill( TQColor( 245, 245, 245 ) ); // light-grey background

            TQRect rect;

            int rest = m_pixmap.width() - (numCharsPerLine * chSize.width());
            xborder = QMAX( xborder, rest/2); // center horizontally
            rest = m_pixmap.height() - (numLines * chSize.height());
            yborder = QMAX( yborder, rest/2); // center vertically
            // end centering

            int x = xborder, y = yborder; // where to paint the characters
            int posNewLine  = m_pixmap.width() - (chSize.width() + xborder);
            int posLastLine = m_pixmap.height() - (chSize.height() + yborder);
            bool newLine = false;
            Q_ASSERT( posNewLine > 0 );
            const TQPixmap *fontPixmap = &(m_splitter->pixmap());

            for ( uint i = 0; i < text.length(); i++ )
            {
                if ( x > posNewLine || newLine ) // start a new line?
                {
                    x = xborder;
                    y += yOffset;

                    if ( y > posLastLine ) // more text than space
                        break;

                    // after starting a new line, we also jump to the next
                    // physical newline in the file if we don't come from one
                    if ( !newLine )
                    {
                        int pos = text.find( '\n', i );
                        if ( pos == -1 )
			    break;
                        i = pos + 1;
                    }

                    newLine = false;
                }

                // check for newlines in the text (unix,dos)
                TQChar ch = text.at( i );
                if ( ch == '\n' )
                {
                    newLine = true;
                    continue;
                }
                else if ( ch == '\r' && text.at(i+1) == '\n' )
                {
                    newLine = true;
                    i++; // skip the next character (\n) as well
                    continue;
                }

                rect = m_splitter->coordinates( ch );
                if ( !rect.isEmpty() )
                {
                    bitBlt( &m_pixmap, TQPoint(x,y), fontPixmap, rect, Qt::CopyROP );
                }

                x += xOffset; // next character
            }
            if (ok)
                img = m_pixmap.convertToImage();
        }

        file.close();
    }
    return ok;
}

ThumbCreator::Flags TextCreator::flags() const
{
    return (Flags)(DrawFrame | BlendIcon);
}