1 files changed, 398 insertions, 0 deletions
diff --git a/src/renderer.cpp b/src/renderer.cpp
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+++ b/src/renderer.cpp
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+/***************************************************************************
+*   Copyright (C) 2005 - 2007 by Alexander Nemish                         *
+*   [email protected]                                                    *
+*                                                                         *
+*   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 <kdebug.h>
+#include <qfontmetrics.h>
+#include <qpainter.h>
+#include <vector>
+#include <cmath>
+#include <iostream>
+#include "renderer.h"
+
+Renderer::Renderer():
+		m_pageCount(0),
+		m_linesPerPage(0),
+		m_paraOffset(50),
+		m_fontMetrics(new QFontMetrics(m_font)),
+		m_curParagraph(0),
+		m_isRendering(false)
+{
+	connect(&m_timer, SIGNAL(timeout()), this, SLOT(timeout()));
+}
+
+
+Renderer::~Renderer()
+{
+}
+
+/**
+*	If the list is empty do nothing.
+*	\param a_list List of strings to render
+*/
+void Renderer::load(const QStringList & a_list)
+{
+	if (a_list.isEmpty())
+		return;
+	m_text.clear();
+		
+	QString string;
+	TStringIter it(a_list.constBegin());
+	
+	while (it != a_list.constEnd())
+	{
+		//skip spaces;
+		string = (*it).stripWhiteSpace();
+		//process string until paragraph ends
+		while (++it != a_list.constEnd())
+		{
+			QChar const ch((*it)[0]);
+			//insert empty lines
+			if ((*it).isEmpty())
+				break;
+			//check whether paragraph not ends
+			if (!ch.isSpace() && (ch != '-'))
+			{
+				string += " " + *it;
+			}
+			else break;
+		}
+		// add paragraph
+		m_text.push_back(string);
+		//add empty line if we have one
+		if ((*it).isEmpty())
+			m_text.push_back("");
+	}
+	render();
+}
+
+/**
+*	\note You need manually update your widget. Like
+*	\code
+*	renderer->render();
+*	update();
+*	\endcode
+*/
+void Renderer::render()
+{
+	if (isEmpty())
+		return;
+	if (busy())
+		cancel();
+	clear();
+	m_isRendering = true;
+	m_linesPerPage = m_pageSize.height() / (QFontMetrics(font()).height());
+	m_timer.start(0, false);
+}
+
+void Renderer::timeout()
+{
+	if (m_curParagraph < m_text.size())
+	{
+		parseParagraph(m_curParagraph);
+		m_curParagraph++;
+	}
+	else
+	{
+		cancel();
+		emit renderingFinished();
+	}
+	m_pageCount = m_linesPerPage ? (m_lines.size() / m_linesPerPage) + 1 : 0;
+}
+
+void Renderer::cancel()
+{
+	m_timer.stop();
+	m_curParagraph = 0;
+	m_isRendering = false;
+}
+
+/**
+ *	Call it for simple view clearing.
+*	\code
+*	renderer->clear();
+*	update();
+*	\endcode
+*/
+void Renderer::clear()
+{
+	m_lines.clear();
+	m_pageCount = 0;
+	m_linesPerPage = 0;
+}
+
+/**
+*	\param a_string Line to parse
+*/
+void Renderer::parseParagraph(TIndex paraIndex)
+{
+	//Don't parse empty lines
+	const QString a_string(m_text[paraIndex]);
+	if (a_string.isEmpty())
+		return;
+		
+	QString string(a_string);
+	const int avgCharWidth = m_fontMetrics->width(" ");
+	//calc approx string width
+	unsigned int avgLen = m_pageSize.width() / avgCharWidth;
+	unsigned int len;
+	int begin = 0;
+	m_isStartAdded = false;
+	int curWidth = width(string);
+	
+	// whole paragraph in single line
+	if (curWidth <= m_pageSize.width())
+	{
+		addLine(TextLine(paraIndex, 0, a_string.length(), TextLine::PARA_BOTH));
+		return;
+	}
+	
+	for (; curWidth > m_pageSize.width(); curWidth = width(string))
+	{
+		len = avgLen;
+		//turn left if missed
+		int w = width(string.left(len));
+		for (; (w > m_pageSize.width()) && (len > 0); w = width(string.left(len)))
+		{
+			int diff = w - m_pageSize.width();
+			int charDiff = diff / 10;
+			if (charDiff > len)
+				charDiff = charDiff % len;
+			charDiff = (charDiff == 0) ? 1 : charDiff;
+			len -= charDiff;
+		}
+		//turn right if missed
+		while ((width(string.left(len)) <= m_pageSize.width()) 
+				&& (len < string.length()))
+			++len;
+		--len;
+		
+		// update statistics on average length
+		avgLen = (unsigned int) (len / (1 + 1. / avgLen));
+		
+		//check whether we in a word
+		if (!(string[len - 1].isSpace() || string[len].isSpace()))
+		{
+			//find last word start index
+			const int wordBegin = wordAt(string, len);
+			//check whether its width less than page width
+			if (width(getWord(string, wordBegin)) <= m_pageSize.width())
+			{
+				//if so, move last word to the next line
+				// invariant: wordBegin > 0,
+				// because otherwise the word is greater than page width
+				
+				// i points to a space before the word
+				int i = wordBegin -1;
+				// skip spaces
+				while (i && string[i].isSpace())
+					--i;
+				addLine(TextLine(paraIndex, begin, begin + i + 1));
+				string = string.right(string.length() - wordBegin);
+				begin += wordBegin;
+			}
+			else
+			{
+				//if its width greater than page width - split it
+				addLine(TextLine(paraIndex, begin, begin + len));
+				string = string.right(string.length() - len);
+				begin += len;
+			}
+		}
+		// line ends with spaces and next line begins with spaces,
+		// trim them
+		else if (string[len - 1].isSpace() && string[len].isSpace())
+		{
+			int idx = len - 1;
+			while (string[--idx] == ' ');
+			addLine(TextLine(paraIndex, begin, begin + idx + 1));
+			idx = len;
+			while (string[++idx] == ' ');
+			string = string.right(string.length() - idx);
+			begin += idx;
+		}
+		else if (string[len - 1].isSpace())
+		{
+			int idx = len - 1;
+			while (string[--idx] == ' ');
+			addLine(TextLine(paraIndex, begin, begin + idx + 1));
+			string = string.right(string.length() - len);
+			begin += len;
+		}
+		else if (string[len].isSpace())
+		{
+			int idx = len;
+			while (string[++idx] == ' ');
+			addLine(TextLine(paraIndex, begin, begin + len));
+			string = string.right(string.length() - idx);
+			begin += idx;
+		}
+	}
+	//last line in multiline para.
+	len = string.length();
+	addLine(TextLine(paraIndex, begin, begin + len, TextLine::PARA_END));
+}
+
+int Renderer::width(const QString & a_string) const
+{
+	int w = m_fontMetrics->width(a_string);
+	return m_isStartAdded ? w : w + paraOffset();
+}
+
+void Renderer::addLine(TextLine line)
+{
+	if (!m_isStartAdded)
+		line.setParagraphFlags(line.paragraphFlags() | TextLine::PARA_START);
+	m_lines.push_back(line);
+	m_isStartAdded = true;
+}
+
+int Renderer::wordAt(const QString & string, int len)
+{
+	while (--len >= 0)
+		if (string[len] == ' ')
+			return ++len;
+	return 0;
+}
+
+QString Renderer::getWord(const QString & a_string, int a_idx)
+{
+	int idx = a_idx;
+	while (a_string[++idx] != ' ' && idx < a_string.length());
+	return QString(a_string.mid(a_idx, idx - a_idx));
+}
+
+/**
+*	Draws page number \c pageNumber on \c paint 
+*	bounding \c rect rectangle
+*/
+void Renderer::drawPage(QPainter & paint, QRect rect, int pageNumber)
+{
+	int height = m_fontMetrics->height();
+	int line = 1;
+	TLines::size_type count = m_lines.size();
+	
+	if (count == 0)
+		return;
+	
+	if ((pageNumber * m_linesPerPage) >= count)
+		return;
+	
+	TLines::size_type idx = pageNumber * m_linesPerPage;
+	for (; (line <= m_linesPerPage) && idx < m_lines.size(); ++idx, ++line)
+		drawLine(paint, rect.left(), rect.top() + line * height, idx);
+}
+
+void Renderer::drawLine(QPainter & paint, int x, int y, const TLines::size_type index)
+{
+	const TextLine textLine(m_lines[index]);
+	const int length = textLine.size();
+	const QString & paragraph = m_text[textLine.paragraphIndex()];
+	const QString string = paragraph.mid(textLine.begin(), textLine.size());
+	
+	// indent paragraph
+	if (textLine.isParaStart())
+		x += paraOffset();
+	
+	// don't justify on paragraph end
+	if (textLine.isParaEnd())
+	{
+		paint.drawText(x, y, string);
+		return;
+	}
+	
+	const int pageWidth = m_pageSize.width();
+	const int spaceWidth = m_fontMetrics->width(" ");
+	int width = m_fontMetrics->width(string);
+	const int curWidth = textLine.isParaStart() ? width + paraOffset() : width;
+	
+	if (curWidth == pageWidth)
+	{
+		paint.drawText(x, y, string);
+	}
+	
+	// string width is lower than page width. justify by space width
+	long pos = 0, off = 0;
+	
+	//count spaces
+	std::vector<int> spaces;
+	spaces.reserve(50);
+	while (((pos = string.find(' ', off)) != -1) && (pos < length))
+	{
+		spaces.push_back(pos);
+		off = pos + 1;
+	}
+	const std::vector<int>::size_type spacesCount = spaces.size();
+	// no spaces no justifications
+	if (!spacesCount)
+	{
+		paint.drawText(x, y, string);
+		return;
+	}
+	// justify line
+	double x1 = x;
+	// calc average space width
+	const double avgLen = ((double)(pageWidth - curWidth) / spacesCount);
+	int start = 0;
+	QString tmp;
+	for (std::vector<int>::size_type i = 0; i < spacesCount; ++i)
+	{
+		pos = spaces[i];
+		tmp = string.mid(start, pos - start);
+		paint.drawText((int)std::ceil(x1), y, tmp);
+		x1 += m_fontMetrics->width(tmp);
+		x1 += spaceWidth + avgLen;
+		start = pos + 1;
+	}
+	//last chunk
+	paint.drawText((int)std::ceil(x1), y, string.right(length - start));
+}
+
+/**
+ *	Sets current font to \c font and re-renders text.
+ *	You don't need to directly call render().
+ */
+void Renderer::setFont(const QFont & font)
+{
+	if (font == m_font) return;
+	m_font = font;
+	m_fontMetrics.reset(new QFontMetrics(m_font));
+	render();
+}
+
+/**
+*	Sets current paragraph offset to \c offset 
+*	and re-renders text if it's changed.
+*/
+void Renderer::setParaOffset(int offset)
+{
+	if (offset == m_paraOffset) return;
+	m_paraOffset = offset;
+	render();
+}
+
+/**
+ *	Sets current page size to \c size. 
+ *	\note It don't call render() after changing.
+ */
+void Renderer::setPageSize(const QSize & size)
+{
+	m_pageSize = size;
+}
+
+#include "renderer.moc"