QML Svg in qt 5.15 static build, using CMake - qt

Question

I would like to migrate from 5.9 to 5.15 and I don't get to load svg from QML.
The original version, using qt provided by Ubuntu (5.9) did load svg from QML with
no extra steps. The new build uses a static Qt.
I use:
Ubuntu 18
In the house static build of Qt 5.15
CMake (3.18)
build Qt
./configure \
-confirm-license \
-release \
-static \
-no-pch \
-nomake tests \
-nomake examples \
-nomake tools \
-nomake examples \
-nomake tests \
-skip qtdoc \
-skip wayland \
-skip qtwebengine \
--prefix=/opt/Qt-5.15.0
CMake
cmake_minimum_required(VERSION 3.18)
project(test VERSION 0.0.0 LANGUAGES CXX)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
find_package(Qt5 5.15
PATHS /opt/Qt-5.15.0
COMPONENTS
Core
Widgets
Qml
Svg
Quick
QuickControls2
Charts
Multimedia
LinguistTools
QmlImportScanner
Xml
REQUIRED QUIET
)
add_executable(test_qt
# c++ code files
main.cpp
# qml code files
qml/Main.qml
# resource files
qml/resources.qrc
)
target_include_directories(test_qt PRIVATE ${CMAKE_CURRENT_LIST_DIR})
target_link_libraries(test_qt
PRIVATE
Qt5::Widgets
Qt5::Qml
Qt5::Quick
Qt5::QuickControls2
Qt5::Svg
Qt5::Xml
Qt5::Gui
)
qt_import_qml_plugins(test_qt
INCLUDE
Qt5::QtQuick2Plugin
Qt5::QSvgPlugin
Qt5::QtQuickControls2Plugin
)
main.cpp
#include <QGuiApplication>
#include <QObject>
#include <QQmlApplicationEngine>
#include <QQmlComponent>
#include <QQmlContext>
int main(int argc, char *argv[]) {
int status = 0;
try {
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
engine.load(QUrl("qrc:/Main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::quit, &QGuiApplication::quit);
if (engine.rootObjects().isEmpty())
return -1;
status = app.exec();
} catch (std::exception &) {
return -1;
}
return status;
}
Main.qml
import QtQuick 2.15
import QtQuick.Controls 2.15
ApplicationWindow {
id: window
width: 850
height: 850
visible: true
color: "lightgray"
Image{
source: "image.svg"
}
}
I omit the resource file, but it lists qml, png and svg files.
When using PNG image is loaded successfully, but when using SVG the following error appears:
qrc:/Main.qml:13:5: QML Image: Error decoding: qrc:/image.svg: Unsupported image format
The current Qt build contains the following files related to SVG handling:
./lib/libQt5Svg.a
./lib/libQt5Svg.la
./lib/cmake/Qt5Svg
./lib/cmake/Qt5Svg/Qt5SvgConfigVersion.cmake
./lib/cmake/Qt5Svg/Qt5SvgConfig.cmake
./lib/cmake/Qt5Gui/Qt5Gui_QSvgIconPlugin.cmake
./lib/cmake/Qt5Gui/Qt5Gui_QSvgPlugin_Import.cpp
./lib/cmake/Qt5Gui/Qt5Gui_QSvgIconPlugin_Import.cpp
./lib/cmake/Qt5Gui/Qt5Gui_QSvgPlugin.cmake
./lib/pkgconfig/Qt5Svg.pc
./lib/libQt5Svg.prl
./include/QtSvg
./include/QtSvg/QGraphicsSvgItem
./include/QtSvg/5.15.0/QtSvg
./include/QtSvg/QSvgRenderer
./include/QtSvg/QSvgWidget
./include/QtSvg/QSvgGenerator
./include/QtSvg/QtSvg
./include/QtSvg/QtSvgVersion
./include/QtSvg/QtSvgDepends
EDIT
I added the missing Svg library dependency to the find_package command. The issue remains unsolved.
If I link against a shared build of the Qt libraries, this project works correctly.

Answer 1

The solution for me was in addition to including Qt5::Svg in find_package and target_link_libraries, eg:
find_package(Qt5 REQUIRED COMPONENTS Core Quick Qml Xml Charts Gui Svg QuickControls2)
target_link_libraries(${PROJECT_NAME} PRIVATE Qt5::Core Qt5::Quick Qt5::Qml Qt5::Xml Qt5::Charts Qt5::Gui Qt5::Svg Qt5::QuickControls2)
To also include the following when statically linking Qt 5.15:
qt5_import_plugins(${PROJECT_NAME} INCLUDE Qt5::QSvgPlugin)
That resolved errors such as "QML ButtonIcon: Error decoding: qrc:/resources/images/add-white-36dp.svg: Unsupported image format"

Answer 2

You are using cmake, but in a qmake .pro project,using static linking, you
must add
QT += svg
Note that svg plugin depends of widgets:
"QT += svg" is the same that "QT += svg widgets"
In android/IOS is better skip svg images to reduce app size.
/opt/Qt/5.15.1/gcc_64/lib$ ldd libQt5Svg.so
linux-vdso.so.1 (0x00007fff7bff0000)
libQt5Widgets.so.5 => /opt/Qt/5.15.1/gcc_64/lib/./libQt5Widgets.so.5 (0x00007ff0cbf55000)
libQt5Gui.so.5 => /opt/Qt/5.15.1/gcc_64/lib/./libQt5Gui.so.5 (0x00007ff0cb624000)
You can try to add some C++ QTSVG code in your main.cpp ,to test linking
https://doc.qt.io/qt-5/qsvggenerator.html