问题描述
我有一个在VMware上安装了运行Ubuntu 1804x64的操作系统，使用Mupdf1.17并构建成功，通过命令安装Qt版本为5.9.8。
sudo apt-get install qt5-default qtcreator
我的代码：
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMessageBox>
#include <QDebug>
#include <QImage>
#include <Qpixmap>
#include <QLabel>
#include "mupdf/fitz.h"
#include "mupdf/pdf.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
char *input = const_cast< char* >("/home/john/work/123.pdf");
float zoom,rotate;
int page_number,page_count;
fz_context *ctx;
fz_document *doc;
fz_pixmap *pix;
fz_matrix ctm;//0
int x,y;
page_number=0;
//100%
zoom=100;
//0
rotate=0;
//
ctx = fz_new_context(NULL,NULL,FZ_STORE_UNLIMITED);
if (!ctx)
{
qDebug()<<stderr<<"cannot create mupdf context";
return;
}
//
fz_try(ctx)
fz_register_document_handlers(ctx);
fz_catch(ctx)
{
qDebug()<<stderr<<"cannot register document handlers:"<< fz_caught_message(ctx);
fz_drop_context(ctx);
return;
}
//
fz_try(ctx)
doc = fz_open_document(ctx,input);
fz_catch(ctx)
{
qDebug()<<stderr<< "cannot open document:"<< fz_caught_message(ctx);
fz_drop_context(ctx);
return;
}
//
fz_try(ctx)
page_count = fz_count_pages(ctx,doc);
fz_catch(ctx)
{
qDebug()<<stderr<< "cannot count number of pages:"<< fz_caught_message(ctx);
fz_drop_document(ctx,doc);
fz_drop_context(ctx);
return;
}
QString str;
str = str.setNum(page_count);
ui->textlabel->setText(str);
if (page_number < 0 || page_number >= page_count)
{
qDebug()<<stderr<< "page number out of range: "<< page_number + 1<<"page count:"<<page_count;
fz_drop_document(ctx,doc);
fz_drop_context(ctx);
return;
}
//
ctm=fz_scale(zoom / 100,zoom / 100);
ctm=fz_pre_rotate(ctm,rotate);
//pixmap
fz_try(ctx)
pix = fz_new_pixmap_from_page_number(ctx,doc,page_number,ctm,fz_device_rgb(ctx),0);
fz_catch(ctx)
{
qDebug()<<stderr<< "cannot render page: %s\n"<< fz_caught_message(ctx);
fz_drop_document(ctx,doc);
fz_drop_context(ctx);
return;
}
//
//unsigned char *samples = fz_pixmap_samples(ctx,pix);
unsigned char *samples = pix->samples;
int width = fz_pixmap_width(ctx,pix);
int height = fz_pixmap_height(ctx,pix);
str = str.setNum(width);
QString wid;
wid=wid.setNum(width);
ui->widthlabel->setText("width: "+wid);
QString hei;
hei=hei.setNum(height);
ui->heightlabel->setText("height: "+hei);
QImage image(samples,width,height,pix->stride,QImage::Format_RGB888);
QLabel *label=new QLabel;
label->setpixmap(Qpixmap::fromImage(image));
ui->layout->addWidget(label); // if (!image.save("a.png")) { // return; // } //
ui->textlabel->setText("Pdf open success");
fz_drop_pixmap(ctx,pix);
fz_drop_document(ctx,doc);
fz_drop_context(ctx);
}
MainWindow::~MainWindow()
{
delete ui;
}
发生分段错误。奇怪的是我安装了Qt5.14.2。运行官方安装包，并用Qt5.14重建，程序运行正确无分段错误。
我真正的当前环境是具有Arm架构的Linux系统，没有正式的安装软件包来安装qt，只能通过命令进行安装。是Qt错误吗？
1 do_scavenging_malloc 0x44b5f0
2 fz_calloc_no_throw 0x44b75e
3 hb_face_create_for_tables 0x642237
4 hb_qt_face_get_for_engine(QFontEngine *) 0x7ffff76712ea
5 QFontEngine::harfbuzzFace() const 0x7ffff75b9e00
6 ?? 0x7ffff3ca2447
7 ?? 0x7ffff3ca6f3a
8 ?? 0x7ffff3caba57
9 ?? 0x7ffff75d7244
10 QFontDatabase::findFont(QFontDef const&,int) 0x7ffff75d7760
11 QFontDatabase::load(QFontPrivate const *,int) 0x7ffff75d7e26
12 QFontPrivate::engineForScript(int) const 0x7ffff75ab9ab
13 QFontMetricsF::leading() const 0x7ffff75cd0a1
14 ?? 0x7ffff775f22f
15 QPainter::drawText(QRect const&,int,QString const&,QRect *) 0x7ffff7760206
16 qstyle::drawItemText(QPainter *,QRect const&,QPalette const&,bool,QPalette::ColorRole) const 0x7ffff7b42774
17 chameleon::ChameleonStyle::drawControl(qstyle::ControlElement,qstyleOption const *,QPainter *,QWidget const *) const 0x7ffff145260e
18 chameleon::ChameleonStyle::drawControl(qstyle::ControlElement,QWidget const *) const 0x7ffff1452351
19 QPushButton::paintEvent(QPaintEvent *) 0x7ffff7c5763e
20 QWidget::event(QEvent *) 0x7ffff7b134f8
！[https://i.stack.imgur.com/3VAaI.png] [https://i.stack.imgur.com/3VAaI.png]
其他发现：使用Qt5.14和使用Qt5.9具有不同的单位 QT5.14.2
linux-vdso.so.1 (0x00007ffcdcda8000)
libQt5Widgets.so.5 => /home/john/Qt5.14.2/5.14.2/gcc_64/lib/libQt5Widgets.so.5 (0x00007f950c550000)
libQt5Gui.so.5 => /home/john/Qt5.14.2/5.14.2/gcc_64/lib/libQt5Gui.so.5 (0x00007f950bc36000)
libQt5Core.so.5 => /home/john/Qt5.14.2/5.14.2/gcc_64/lib/libQt5Core.so.5 (0x00007f950b45b000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f950b23c000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f950aeb3000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f950ab15000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f950a8fd000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f950a50c000)
libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007f950a280000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f950a063000)
libicui18n.so.56 => /home/john/Qt5.14.2/5.14.2/gcc_64/lib/libicui18n.so.56 (0x00007f9509bca000)
libicuuc.so.56 => /home/john/Qt5.14.2/5.14.2/gcc_64/lib/libicuuc.so.56 (0x00007f9509812000)
libicudata.so.56 => /home/john/Qt5.14.2/5.14.2/gcc_64/lib/libicudata.so.56 (0x00007f9507e2f000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9507c2b000)
libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f9507a29000)
libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f9507712000)
/lib64/ld-linux-x86-64.so.2 (0x00007f950f3e6000)
libGLX.so.0 => /usr/lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f95074e1000)
libGLdispatch.so.0 => /usr/lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f950722b000)
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f9506fb9000)
libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f9506c81000)
libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f9506a59000)
libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f9506855000)
libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f950664f000)
libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f950643a000)
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f9506232000)
QT5.9.8
linux-vdso.so.1 (0x00007ffc6ddf8000)
libQt5Widgets.so.5 => /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 (0x00007f95c72f2000)
libQt5Gui.so.5 => /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 (0x00007f95c6b89000)
libQt5Core.so.5 => /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 (0x00007f95c643e000)
libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007f95c61b2000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f95c5f93000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f95c5c0a000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f95c586c000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f95c5654000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f95c5263000)
libpng16.so.16 => /usr/lib/x86_64-linux-gnu/libpng16.so.16 (0x00007f95c5031000)
libharfbuzz.so.0 => /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0 (0x00007f95c4d93000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f95c4b76000)
libicui18n.so.60 => /usr/lib/x86_64-linux-gnu/libicui18n.so.60 (0x00007f95c46d5000)
libicuuc.so.60 => /usr/lib/x86_64-linux-gnu/libicuuc.so.60 (0x00007f95c431d000)
libdouble-conversion.so.1 => /usr/lib/x86_64-linux-gnu/libdouble-conversion.so.1 (0x00007f95c410c000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f95c3f08000)
libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f95c3bf1000)
/lib64/ld-linux-x86-64.so.2 (0x00007f95c7b39000)
libGLX.so.0 => /usr/lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f95c39c0000)
libGLdispatch.so.0 => /usr/lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f95c370a000)
libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007f95c3456000)
libgraphite2.so.3 => /usr/lib/x86_64-linux-gnu/libgraphite2.so.3 (0x00007f95c3229000)
libicudata.so.60 => /usr/lib/x86_64-linux-gnu/libicudata.so.60 (0x00007f95c1680000)
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f95c140e000)
libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f95c10d6000)
libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f95c0eae000)
libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f95c0caa000)
libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f95c0aa4000)
libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f95c088f000)
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f95c0687000)
解决方法
给出堆栈跟踪的这一部分：
hb_qt_face_get_for_engine(QFontEngine *)
QFontEngine::harfbuzzFace() const
您可能看到的是mupdf中包含的harfbuzz版本与qt正在使用的版本之间存在冲突。可能是API发生了一些变化，qt正在调用mupdf提供的版本，该版本的API与预期的有所不同。
有许多可能的解决方案。您可以将mupdf（以及所有类似harfbuzz的第三方依赖项）构建到.so中，并确保从.so外部看不到harfbuzz符号，这意味着qt无法看到harfbuzz的mupdf版本，因此将其称为意向的。另一种解决方案是尝试针对harfbuzz的系统版本而不是mupdf中的版本来构建mupdf，但是如果API已更改，则需要将代码更改为mupdf。