Any example to use libcamera for Qt5 desktop application?

SGaist

You need to read the meson file to see what additional defines and paths/options they use.

Just in case, even if your Qt Creator does not support meson, nothing stops you from using from the command line to build the projet.

rollyng

@SGaist May I ask what are these requirements in the meson file? It is strange to me that Qt Creator complains that DNGWriter is not declared despite the dng_writer.h file is already in the same directory as shown above. Besides, how should I modify the qcam.pro as the following meson file? Thank you.

# SPDX-License-Identifier: CC0-1.0

qt5 = import('qt5')
qt5_dep = dependency('qt5',
                     method : 'pkg-config',
                     modules : ['Core', 'Gui', 'Widgets'],
                     required : get_option('qcam'),
                     version : '>=5.4')

if not qt5_dep.found()
    qcam_enabled = false
    subdir_done()
endif

qcam_enabled = true

qcam_sources = files([
    '../cam/image.cpp',
    '../cam/options.cpp',
    '../cam/stream_options.cpp',
    'format_converter.cpp',
    'main.cpp',
    'main_window.cpp',
    'message_handler.cpp',
    'viewfinder_qt.cpp',
])

qcam_moc_headers = files([
    'main_window.h',
    'viewfinder_qt.h',
])

qcam_resources = files([
    'assets/feathericons/feathericons.qrc',
])

qcam_deps = [
    libatomic,
    libcamera_public,
    qt5_dep,
]

qt5_cpp_args = ['-DQT_NO_KEYWORDS']

tiff_dep = dependency('libtiff-4', required : false)
if tiff_dep.found()
    qt5_cpp_args += ['-DHAVE_TIFF']
    qcam_deps += [tiff_dep]
    qcam_sources += files([
        'dng_writer.cpp',
    ])
endif

if cxx.has_header_symbol('QOpenGLWidget', 'QOpenGLWidget',
                         dependencies : qt5_dep, args : '-fPIC')
    qcam_sources += files([
        'viewfinder_gl.cpp',
    ])
    qcam_moc_headers += files([
        'viewfinder_gl.h',
    ])
    qcam_resources += files([
        'assets/shader/shaders.qrc'
    ])
endif

# gcc 9 introduced a deprecated-copy warning that is triggered by Qt until
# Qt 5.13. clang 10 introduced the same warning, but detects more issues
# that are not fixed in Qt yet. Disable the warning manually in both cases.
if ((cc.get_id() == 'gcc' and cc.version().version_compare('>=9.0') and
     qt5_dep.version().version_compare('<5.13')) or
    (cc.get_id() == 'clang' and cc.version().version_compare('>=10.0')))
    qt5_cpp_args += ['-Wno-deprecated-copy']
endif

resources = qt5.preprocess(moc_headers: qcam_moc_headers,
                           qresources : qcam_resources,
                           dependencies: qt5_dep)

qcam  = executable('qcam', qcam_sources, resources,
                   install : true,
                   dependencies : qcam_deps,
                   cpp_args : qt5_cpp_args)

rollyng

@SGaist Hi, I have finally successful to compile qcam as my first Qt GUI code. What I did is removing the dng_writer.h and dng_writer.cpp from the project. Plz have a look, thank you!

SGaist

Have a look for why you had to disable the dng_writer part ?

rollyng

@SGaist said in Any example to use libcamera for Qt5 desktop application?:

Have a look for why you had to disable the dng_writer part ?

Qt Creator seems unable to pickup dng_writer.h although it is included in the project.

This is due to a special definition in the dng_writer.h and I am including the file here for your quick look.

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2020, Raspberry Pi (Trading) Ltd.
 *
 * dng_writer.h - DNG writer
 */

#pragma once

#ifdef HAVE_TIFF /* what is this for? */
#define HAVE_DNG

#undef signals
#undef slots
#undef emit
#undef foreach

#include <libcamera/camera.h>
#include <libcamera/controls.h>
#include <libcamera/framebuffer.h>
#include <libcamera/stream.h>

class DNGWriter
{
public:
    static int write(const char *filename, const libcamera::Camera *camera,
                     const libcamera::StreamConfiguration &config,
                     const libcamera::ControlList &metadata,
                     const libcamera::FrameBuffer *buffer,
                     const void *data);
};

#endif /* HAVE_TIFF, this is going to break the definition for DNGWriter above*/

This is very strange to me whether to include the HAVE_TIFF option or not?
Thanks,
rolly

SGaist

It's a define that you can add to the DEFINES variable. The meson project defines it if memory serves well.

rollyng

@SGaist Thank you and I have decided not to include the dng_writer function as it is not my concern. Best, rolly

AlexKN

@rollyng Dear rollyng! Could you share a working qt project that you have successfully compiled and launched?

p1ng

@AlexKN here is the qt project. i did it myself.

https://github.com/henrihallik/myqam