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/* This file is part of the KDE libraries
SPDX-FileCopyrightText: 2000, 2002 Carsten Pfeiffer <pfeiffer@kde.org>
SPDX-FileCopyrightText: 2000 Malte Starostik <malte@kde.org>
SPDX-License-Identifier: LGPL-2.0-or-later
*/
#include "textcreator.h"
#include <QFile>
#include <QFontDatabase>
#include <QImage>
#include <QPainter>
#include <QPalette>
#include <QStringDecoder>
#include <QTextDocument>
#include <KDesktopFile>
#include <KPluginFactory>
#include <KSyntaxHighlighting/Definition>
#include <KSyntaxHighlighting/SyntaxHighlighter>
#include <KSyntaxHighlighting/Theme>
// TODO Fix or remove kencodingprober code
// #include <kencodingprober.h>
K_PLUGIN_CLASS_WITH_JSON(TextCreator, "textthumbnail.json")
TextCreator::TextCreator(QObject *parent, const QVariantList &args)
: KIO::ThumbnailCreator(parent, args)
, m_data(nullptr)
, m_dataSize(0)
{
}
TextCreator::~TextCreator()
{
delete[] m_data;
}
static QStringDecoder codecFromContent(const char *data, int dataSize)
{
#if 0 // ### Use this when KEncodingProber does not return junk encoding for UTF-8 data)
KEncodingProber prober;
prober.feed(data, dataSize);
return QStringDecoder(prober.encoding());
#else
// try to detect UTF text, fall back to locale default (which is usually UTF-8)
return QStringDecoder(QStringDecoder::encodingForData(QByteArrayView(data, dataSize)).value_or(QStringDecoder::System));
#endif
}
KIO::ThumbnailResult TextCreator::create(const KIO::ThumbnailRequest &request)
{
const QString path = request.url().toLocalFile();
// Desktop files, .directory files, and flatpakrefs aren't traditional
// text files, so their icons should be shown instead
if (KDesktopFile::isDesktopFile(path) || path.endsWith(QStringLiteral(".directory")) || path.endsWith(QStringLiteral(".flatpakref"))) {
return KIO::ThumbnailResult::fail();
}
bool ok = false;
// determine some sizes...
// example: width: 60, height: 64
const int width = request.targetSize().width();
const int height = request.targetSize().height();
const qreal dpr = request.devicePixelRatio();
QImage img;
QSize 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 = QPixmap(pixmapSize);
m_pixmap.setDevicePixelRatio(dpr);
}
// one pixel for the rectangle, the rest. whitespace
int xborder = 1 + pixmapSize.width() / 16 / dpr; // minimum x-border
int yborder = 1 + pixmapSize.height() / 16 / dpr; // minimum y-border
// this font is supposed to look good at small sizes
QFont font = QFontDatabase::systemFont(QFontDatabase::SmallestReadableFont);
font.setPixelSize(qMax(7.0, qMin(10.0, (pixmapSize.height() / dpr - 2 * yborder) / 16)));
QFontMetrics fm(font);
// calculate a better border so that the text is centered
const QSizeF canvasSize(pixmapSize.width() / dpr - 2 * xborder, pixmapSize.height() / dpr - 2 * yborder);
const int numLines = (int)(canvasSize.height() / fm.height());
// assumes an average line length of <= 120 chars
const int bytesToRead = 120 * numLines;
// create text-preview
QFile file(path);
if (file.open(QIODevice::ReadOnly)) {
if (!m_data || m_dataSize < bytesToRead + 1) {
delete[] m_data;
m_data = new char[bytesToRead + 1];
m_dataSize = bytesToRead + 1;
}
int read = file.read(m_data, bytesToRead);
if (read > 0) {
ok = true;
m_data[read] = '\0';
QString text = QString(codecFromContent(m_data, read).decode(QByteArrayView(m_data, read))).trimmed();
// FIXME: maybe strip whitespace and read more?
// If the text contains tabs or consecutive spaces, it is probably
// formatted using white space. Use a fixed pitch font in this case.
const auto textLines = QStringView(text).split(QLatin1Char('\n'));
for (const auto &line : textLines) {
const auto trimmedLine = line.trimmed();
if (trimmedLine.contains('\t') || trimmedLine.contains(QLatin1String(" "))) {
font.setFamily(QFontDatabase::systemFont(QFontDatabase::FixedFont).family());
break;
}
}
QColor bgColor = QColor(245, 245, 245); // light-grey background
m_pixmap.fill(bgColor);
QPainter painter(&m_pixmap);
QTextDocument textDocument(text);
// QTextDocument only supports one margin value for all borders,
// so we do a page-in-page behind its back, and do our own borders
textDocument.setDocumentMargin(0);
textDocument.setPageSize(canvasSize);
textDocument.setDefaultFont(font);
QTextOption textOption(Qt::AlignTop | Qt::AlignLeft);
textOption.setTabStopDistance(8 * painter.fontMetrics().horizontalAdvance(QLatin1Char(' ')));
textOption.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);
textDocument.setDefaultTextOption(textOption);
KSyntaxHighlighting::SyntaxHighlighter syntaxHighlighter;
syntaxHighlighter.setDefinition(m_highlightingRepository.definitionForFileName(path));
const auto highlightingTheme = m_highlightingRepository.defaultTheme(KSyntaxHighlighting::Repository::LightTheme);
syntaxHighlighter.setTheme(highlightingTheme);
syntaxHighlighter.setDocument(&textDocument);
syntaxHighlighter.rehighlight();
// draw page-in-page, with clipping as needed
painter.translate(xborder, yborder);
textDocument.drawContents(&painter, QRectF(QPointF(0, 0), canvasSize));
painter.end();
img = m_pixmap.toImage();
}
file.close();
}
return ok ? KIO::ThumbnailResult::pass(img) : KIO::ThumbnailResult::fail();
}
#include "moc_textcreator.cpp"
#include "textcreator.moc"
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