runtime/kioslave/thumbnail/textcreator.cpp

   1 /*  This file is part of the KDE libraries
   2     Copyright (C) 2000,2002 Carsten Pfeiffer <pfeiffer@kde.org>
   3                   2000 Malte Starostik <malte@kde.org>
   4
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Library General Public
   7     License as published by the Free Software Foundation; either
   8     version 2 of the License, or (at your option) any later version.
   9
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Library General Public License for more details.
  14
  15     You should have received a copy of the GNU Library General Public License
  16     along with this library; see the file COPYING.LIB.  If not, write to
  17     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18     Boston, MA 02110-1301, USA.
  19 */
  20
  21 #include "textcreator.h"
  22
  23 #include <QFile>
  24 #include <QPixmap>
  25 #include <QImage>
  26 #include <QPainter>
  27
  28 #include <kstandarddirs.h>
  29
  30 class FontSplitter {
  31 public:
  32     FontSplitter() {}
  33     virtual ~FontSplitter() {}
  34
  35 protected:
  36     int m_width;
  37     QSize m_itemSize;
  38     QPixmap m_pixmap;
  39
  40 public:
  41     void setPixmap(const QPixmap &pixmap) { m_pixmap = pixmap; }
  42     const QPixmap& pixmap() const { return m_pixmap; }
  43
  44     void setItemSize(const QSize &size) { m_itemSize = size; }
  45     const QSize& itemSize() const { return m_itemSize; }
  46
  47     QRect coordinates(const QChar& ch) const {
  48         int pos = (unsigned char)ch.toLatin1();
  49         int numCols = m_pixmap.width() / m_itemSize.width();
  50         if ( numCols == 0 )
  51             return QRect();
  52         int row = pos / numCols;
  53         int col = pos % numCols;
  54         return QRect( QPoint( col * m_itemSize.width(), row * m_itemSize.height() ),
  55                       m_itemSize );
  56     }
  57 };
  58
  59 extern "C"
  60 {
  61     KDE_EXPORT ThumbCreator *new_creator()
  62     {
  63         return new TextCreator;
  64     }
  65 }
  66
  67 TextCreator::TextCreator()
  68     : m_splitter(0),
  69       m_data(0),
  70       m_dataSize(0)
  71 {
  72 }
  73
  74 TextCreator::~TextCreator()
  75 {
  76     delete m_splitter;
  77     delete [] m_data;
  78 }
  79
  80 bool TextCreator::create(const QString &path, int width, int height, QImage &img)
  81 {
  82     if ( !m_splitter )
  83     {
  84         m_splitter = new FontSplitter;
  85         QString pixmap = KStandardDirs::locate( "data", "kio_thumbnail/pics/thumbnailfont_7x4.png" );
  86         if ( !pixmap.isEmpty() )
  87         {
  88             // FIXME: make font/glyphsize configurable...
  89             m_splitter->setPixmap( QPixmap( pixmap ));
  90             m_splitter->setItemSize( QSize( 4, 7 ));
  91         }
  92     }
  93
  94     bool ok = false;
  95
  96     // determine some sizes...
  97     // example: width: 60, height: 64
  98     QSize pixmapSize( width, height );
  99     if (height * 3 > width * 4)
 100         pixmapSize.setHeight( width * 4 / 3 );
 101     else
 102         pixmapSize.setWidth( height * 3 / 4 );
 103
 104     if ( pixmapSize != m_pixmap.size() )
 105         m_pixmap = QPixmap( pixmapSize );
 106
 107     // one pixel for the rectangle, the rest. whitespace
 108     int xborder = 1 + pixmapSize.width()/16;  // minimum x-border
 109     int yborder = 1 + pixmapSize.height()/16; // minimum y-border
 110
 111     QSize chSize = m_splitter->itemSize(); // the size of one char
 112     int xOffset = chSize.width();
 113     int yOffset = chSize.height();
 114
 115     // calculate a better border so that the text is centered
 116     int canvasWidth  = pixmapSize.width()  - 2*xborder;
 117     int canvasHeight = pixmapSize.height() -  2*yborder;
 118     int numCharsPerLine = (int) (canvasWidth / chSize.width());
 119     int numLines = (int) (canvasHeight / chSize.height());
 120
 121     // assumes an average line length of <= 120 chars
 122     const int bytesToRead = 120 * numLines;
 123
 124     // create text-preview
 125     QFile file( path );
 126     if ( file.open( QIODevice::ReadOnly ))
 127     {
 128         if ( !m_data || m_dataSize < bytesToRead + 1 )
 129         {
 130             delete [] m_data;
 131             m_data = new char[bytesToRead+1];
 132             m_dataSize = bytesToRead + 1;
 133         }
 134
 135         int read = file.read( m_data, bytesToRead );
 136         if ( read > 0 )
 137         {
 138             ok = true;
 139             m_data[read] = '\0';
 140             QString text = QString::fromLocal8Bit( m_data );
 141             // FIXME: maybe strip whitespace and read more?
 142
 143             m_pixmap.fill( QColor( 245, 245, 245 ) ); // light-grey background
 144
 145             QRect rect;
 146
 147             int rest = m_pixmap.width() - (numCharsPerLine * chSize.width());
 148             xborder = qMax( xborder, rest/2); // center horizontally
 149             rest = m_pixmap.height() - (numLines * chSize.height());
 150             yborder = qMax( yborder, rest/2); // center vertically
 151             // end centering
 152
 153             int x = xborder, y = yborder; // where to paint the characters
 154             int posNewLine  = m_pixmap.width() - (chSize.width() + xborder);
 155             int posLastLine = m_pixmap.height() - (chSize.height() + yborder);
 156             bool newLine = false;
 157             Q_ASSERT( posNewLine > 0 );
 158             const QPixmap *fontPixmap = &(m_splitter->pixmap());
 159             QPainter painter( &m_pixmap );
 160
 161             for ( int i = 0; i < text.length(); i++ )
 162             {
 163                 if ( x > posNewLine || newLine ) // start a new line?
 164                 {
 165                     x = xborder;
 166                     y += yOffset;
 167
 168                     if ( y > posLastLine ) // more text than space
 169                         break;
 170
 171                     // after starting a new line, we also jump to the next
 172                     // physical newline in the file if we don't come from one
 173                     if ( !newLine )
 174                     {
 175                         int pos = text.indexOf( '\n', i );
 176                         if ( pos == -1 )
 177                             break;
 178                         i = pos + 1;
 179                     }
 180
 181                     newLine = false;
 182                 }
 183
 184                 if (i>=text.length()) continue;
 185                 // check for newlines in the text (unix,dos)
 186                 QChar ch = text.at( i );
 187                 if ( ch == '\n' )
 188                 {
 189                     newLine = true;
 190                     continue;
 191                 }
 192                 else if ( ch == '\r' && text.at(i+1) == '\n' )
 193                 {
 194                     newLine = true;
 195                     i++; // skip the next character (\n) as well
 196                     continue;
 197                 }
 198
 199                 rect = m_splitter->coordinates( ch );
 200                 if ( !rect.isEmpty() )
 201                 {
 202                     painter.drawPixmap( QPoint(x,y), *fontPixmap, rect );
 203                 }
 204
 205                 x += xOffset; // next character
 206             }
 207             if (ok)
 208                 img = m_pixmap.toImage();
 209         }
 210
 211         file.close();
 212     }
 213     return ok;
 214 }
 215
 216 ThumbCreator::Flags TextCreator::flags() const
 217 {
 218     return (Flags)(DrawFrame | BlendIcon);
 219 }
 220