Taborca Code

/****************************************************************************
** This file is part of the taborca project hosted at
** sf.net/projects/taborca
** Copyright (C) 2013 Shawn Rutledge
** Contact: s@ecloud.org
**
** 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 in a file called LICENSE; if not, write to the
** Free Software Foundation, Inc.,
** 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
****************************************************************************/
#include "pdfpager.h"
#include "common.h"
#include <QThreadPool>

PDFPager::PDFPager() :
		pdf(NULL),
		pageRange(this),
		m_pageNum(-1),
        m_renderSize(600, 600),
		m_thumbnailRenderSize(72, 72)
{
	setAutoDelete(false);
}

void PDFPager::openPDF(QString fpath)
{
	m_path = fpath;
	m_nullThumbnails.clear();
	pdf = Poppler::Document::load(fpath);
	if (!pdf || pdf->isLocked())
	{
		/// @todo ... error message ....
		if (pdf)
			delete pdf;
		pdf = NULL;
		return;
	}
	qDebug("open pdf success");
	int pages = pdf->numPages();
	m_cache.resize(pages);
	emit opened(fpath, pages);
	emit numPages(pages);
	for (int p = 0; p < pages; ++p)
	{
		Poppler::Page* pdfPage = pdf->page(p);
		if (pdfPage)
			emit thumbnail(p, pdfPage->thumbnail(), pdfPage->label());
		if (pdfPage)
		{
			QImage thumbnail = pdfPage->thumbnail();
			if (thumbnail.isNull())
			{
				qDebug("null thumbnail for page %d", p);
				m_nullThumbnails.append(p);
			}
			// Doesn't work.  WTF...
//			emit thumbnail(p, pdfPage->thumbnail(), pdfPage->label());
		}
	}
	page(0);
	pageRange.setRange(0, pages - 1);
    pdf->setRenderHint(Poppler::Document::Antialiasing);
    pdf->setRenderHint(Poppler::Document::TextAntialiasing);
    pdf->setRenderHint(Poppler::Document::TextHinting);

	// Start rendering thumbnails (if necessary) and pages in the background
	QThreadPool::globalInstance()->start(this, QThread::LowPriority);
}

void PDFPager::closePDF()
{
	if (!m_path.isEmpty() && pdf)
	{
		emit closed(m_path);
		delete pdf;
		pdf = NULL;
		page(-1);
	}
}

void PDFPager::page(int pnum)
{
	if (pnum < 0)
		return;
	if (pnum >= m_cache.size())
		return;

    m_pageNum = pnum;
//	Page fromCache = m_cache[pnum];
//	if (fromCache.isNull())
		render(pnum);
//	else
//	{
//		emit rendered(pnum, fromCache);
//		emit pageText(fromCache.textStrings);
//		emit pageChanged(pnum);
//		emit pageChanged(fromCache.label);
//	}
}

void PDFPager::nextPage(bool forward)
{
	if (forward)
		page(m_pageNum + 1);
	else
		page(m_pageNum - 1);
}

void PDFPager::renderSize(QSize s, bool reRender)
{
	qDebug("renderSize(%d x %d)", s.width(), s.height());
	m_renderSize = s;
    if (reRender)
        page(m_pageNum);
}

void PDFPager::render(int pnum, QSize renderSize, bool emitImage)
{
	m_renderMutex.lock();
	qDebug("render(%d, %d x %d)", pnum, renderSize.width(), renderSize.height());
	if (pnum >= pdf->numPages())
		return;
	if (!renderSize.isValid())
		renderSize = m_renderSize;
	emit rendering(true);
	// Access page of the PDF file
	if (!pdf)
		return;
	Poppler::Page* pdfPage = pdf->page(pnum);  // Document starts at page 0
	if (!pdfPage)
	{
		// ... error message ...
		emit rendering(false);
		return;
	}

	// Generate a QImage of the rendered page
	double res = MIN(((double)(renderSize.width())) /		// dots
					 (pdfPage->pageSizeF().width() / 72.0),	// inches
					 ((double)(renderSize.height())) /		// dots
					 (pdfPage->pageSizeF().height() / 72.0));	// inches

	qDebug("res would be %lf\n", res);

	//qDebug("renderToImage: res %f to fit %d x %d", res, renderSize.width(), renderSize.height());

	// @hack For now, fix the res at 72, because that way 1 point = 1 model unit,
	// which helps the text items to match the image.
	/// @todo define model units in terms of points:
	/// on load, choose an appropriate resolution and
	/// then convert TextBox point units to model units.
//	if (res > 8) // e.g. it's not a thumbnail
//        res = 144;  // this will break text items matchup
//        res = 72.0;

	QImage image = pdfPage->renderToImage(res, res);//, 0, 0, 1000, 1000);
	if (image.isNull())
	{
		// ... error message ...
		emit rendering(false);
		return;
	}
	//qDebug("renderDone: %d x %d", image.width(), image.height());

	QString label = pdfPage->label();
	if (label.isEmpty())
		label = QString::number(pnum);

	Page pcache = Page(label, image, pdfPage->textList());
    if (res < 8) // a thumbnail
        m_cache[pnum] = pcache;
	if (emitImage)
	{
		emit pageChanged(pnum);
		emit pageChanged(label);
		renderDone(pnum, image);
		emit pageText(pcache.textStrings);
	}
	// after reading everything of interest, the page can be deleted
	// (pdf->page(pnum) resulted in ownership of that copy of the data,
	// so this function is responsible to delete it)
	delete pdfPage;
	m_renderMutex.unlock();
}

void PDFPager::renderDone(int pnum, QImage pm)
{
	emit rendered(pnum, pm);
	emit rendering(false);
}

void PDFPager::run()
{
	qDebug("PDFPager::run()");
	int pages = pdf->numPages();
	for (int i = 0; i < pages; ++i)
	{
		if (m_nullThumbnails.contains(i))
		{
			render(i, m_thumbnailRenderSize, false);
			// @hack The cache happens to have a thumbnail right now,
			// if no other rendering happened between the line above and this one.
qDebug("for page %d, emitting thumbnail with width %d; requested size was %d", i, m_cache[i].width(), m_thumbnailRenderSize.width());
			emit thumbnail(i, m_cache[i], QString::number(i));
		}
		emit statusMessage(QString("pre-rendering page %1").arg(i));
		// Put the full-size image in the cache
        if (m_pageNum - 10 < i && i < m_pageNum + 10)
        {
            qDebug("pre-rendering page %d, near current page %d", i, m_pageNum);
            render(i, m_renderSize, false);
        }
	}
	emit statusClear();
}