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//=============================================================================
// MusE Reader
// Music Score Reader
//
// Copyright (C) 2010 Werner Schweer
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2.
//
// 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., 675 Mass Ave, Cambridge, MA 02139, USA.
//=============================================================================
#include "pdf.h"
namespace Ms {
int Pdf::references;
//---------------------------------------------------------
// numPages
//---------------------------------------------------------
int Pdf::numPages() const
{
return _document->numPages();
}
//---------------------------------------------------------
// Pdf
//---------------------------------------------------------
Pdf::Pdf()
{
++references;
}
//---------------------------------------------------------
// open
//---------------------------------------------------------
bool Pdf::open(const QString& path)
{
_document = Poppler::Document::load(path);
if (!_document || _document->isLocked()) {
delete _document;
return false;
}
return true;
}
//---------------------------------------------------------
// ~Pdf
//---------------------------------------------------------
Pdf::~Pdf()
{
if(_document)
delete(_document);
--references;
}
//---------------------------------------------------------
// binarization
//---------------------------------------------------------
QImage Pdf::binarization(QImage image){
QImage bw = QImage(image.width(), image.height(), QImage::Format_MonoLSB);
QVector<QRgb> ct(2);
ct[0] = qRgb(255, 255, 255);
ct[1] = qRgb(0, 0, 0);
bw.setColorTable(ct);
bw.fill(0);
float thresh = 128;
float new_thresh = 0;
while (thresh != new_thresh) {
float sum_black = 0;
float sum_white = 0;
int num_black = 0;
int num_white = 0;
new_thresh = thresh;
for (int x = 0; x < image.width(); x++){
for (int y = 0; y < image.height(); y++) {
QRgb c = image.pixel(x, y);
float g = qGray(c);
if (g < thresh) {
sum_black += g;
num_black++;
}
else {
sum_white += g;
num_white++;
}
}
}
thresh = (sum_black/num_black + sum_white/num_white)/2.0;
}
int stride = (bw.width() + 7) / 8;
uchar* p = bw.bits();
for (int y = 0; y < bw.height(); ++y) {
p = bw.scanLine(y);
for (int x = 0; x < stride; ++x) {
int temp = 0;
for (int i = 0; i < 8; i++) {
if (x*8 + i >= bw.width()) continue;
QRgb c = image.pixel(x*8 + i, y);
float g = qGray(c);
temp += ((g<thresh) ? 1:0)<<i;
}
*p++ = temp;
}
}
return bw;
}
//---------------------------------------------------------
// page
//---------------------------------------------------------
QImage Pdf::page(int i)
{
QImage image;
// Paranoid safety check
if (_document == 0) {
return image;
}
Poppler::Page* pdfPage = _document->page(i); // Document starts at page 0
if (pdfPage == 0) {
return image;
}
QSize size = pdfPage->pageSize();
float scale = 2.0;
// the size can be decided more intelligently
image = pdfPage->renderToImage(scale*72.0, scale*72.0, 0, 0, scale*size.width(), scale*size.height());
delete pdfPage;
return binarization(image);
}
}
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