[qtimageformats] 6.5.3#0 can't load jpeg and webp

[Hlongyu]

Describe the bug QImageReader::supportedImageFormats() not include jpeg and webp

Environment

• OS: [Windows]
• Compiler: MSVC/14.40.33807/bin/Hostx64/x64/cl.exe

To Reproduce Steps to reproduce the behavior:

1. cmake -S . -B build --preset windows-x64-Release
2. Run exe

vcpkg.json

{
    "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
    "dependencies": [
        {
            "name": "qtbase",
            "version>=": "6.5.3#0",
            "platform": "windows"
        },
        {
            "name": "qtimageformats",
            "default-features": false,
            "version>=": "6.5.3#0",
            "features": [
                "webp"
            ],
            "platform": "windows"
        }
    ],
    "builtin-baseline": "02745e0f4749d1f51d2025824209408f5a6c3614",
    "overrides": [
        {
            "name": "qtbase",
            "version": "6.5.3#0"
        },
        {
            "name": "qtimageformats",
            "version": "6.5.3#0"
        }
    ]
}

main.cpp

#include <QApplication>
#include <QImageReader>
#include <iostream>
int main(int argc, char **argv) {
  QApplication app(argc, argv);
  auto support = QImageReader::supportedImageFormats();
  for (auto &i : support) {
    qDebug() << i;
  }
  app.exec();
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.9)

project(QtImageFormatTest VERSION 0.1 LANGUAGES CXX)

find_package(Qt6 CONFIG REQUIRED)
find_package(Qt6Core CONFIG REQUIRED)
find_package(Qt6Widgets CONFIG REQUIRED)
find_package(Qt6Gui CONFIG REQUIRED)

add_executable(QtImageFormatTest main.cpp)

target_link_libraries(QtImageFormatTest PRIVATE Qt6::Widgets Qt6::Core Qt6::Gui)

if(WIN32)
    if (CMAKE_BUILD_TYPE STREQUAL "Debug")
        find_program(TOOL_WINDEPLOYQT NAMES windeployqt.debug.bat)
    else()
        find_program(TOOL_WINDEPLOYQT NAMES windeployqt)
    endif()

add_custom_command(TARGET QtImageFormatTest POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E echo "Run windeployqt"

    COMMAND ${TOOL_WINDEPLOYQT}
            $<TARGET_FILE:QtImageFormatTest>
    COMMAND ${CMAKE_COMMAND} -E echo "end windeployqt"
)
endif()

CMakePresets.json

{
    "version": 5,
    "configurePresets": [
        {
            "name": "windows-x64-Debug",
            "generator": "Ninja",
            "binaryDir": "${sourceDir}/out/build/${presetName}",
            "architecture": {
                "value": "x64",
                "strategy": "external"
            },
            "toolset": {
                "value": "host=x64",
                "strategy": "external"
            },
            "cacheVariables": {
                "CMAKE_BUILD_TYPE": "Debug",
                "CMAKE_CXX_COMPILER": "cl.exe",
                "CMAKE_C_COMPILER": "cl.exe",
                "CMAKE_TOOLCHAIN_FILE": "D:/dev/vcpkg/scripts/buildsystems/vcpkg.cmake",
                "CMAKE_INSTALL_PREFIX": "${sourceDir}/out/install/${presetName}"
            }
        },
        {
            "name": "windows-x64-Release",
            "generator": "Ninja",
            "binaryDir": "${sourceDir}/out/build/${presetName}",
            "architecture": {
                "value": "x64",
                "strategy": "external"
            },
            "toolset": {
                "value": "host=x64",
                "strategy": "external"
            },
            "cacheVariables": {
                "CMAKE_BUILD_TYPE": "RelWithDebInfo",
                "CMAKE_CXX_COMPILER": "cl.exe",
                "CMAKE_C_COMPILER": "cl.exe",
                "CMAKE_TOOLCHAIN_FILE": "D:/dev/vcpkg/scripts/buildsystems/vcpkg.cmake",
                "CMAKE_INSTALL_PREFIX": "${sourceDir}/out/install/${presetName}"
            }
        }
    ]
}

Expected behavior Support jpeg and webp.

Failure logs

Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qgifd.dll'. Symbols loaded.
Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qicnsd.dll'. Symbols loaded.
Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qicod.dll'. Symbols loaded.
Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qjpegd.dll'. Symbols loaded.
Unloaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qjpegd.dll'.
Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qtgad.dll'. Symbols loaded.
Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qwbmpd.dll'. Symbols loaded.
Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qwebpd.dll'. Symbols loaded.
Unloaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qwebpd.dll'.
"bmp"
"cur"
"gif"
"icns"
"ico"
"pbm"
"pgm"
"png"
"ppm"
"tga"
"wbmp"
"xbm"
"xpm"

[dg0yt]

Check that the DLLs for jpeg and webp libs are deployed and found, too. When it comes to plugins, deployment of transitive runtime dependencies is ... tricky.

[Hlongyu]

Check that the DLLs for jpeg and webp libs are deployed and found, too.

Directory: D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats

Mode LastWriteTime Length Name

---

-a--- 2024/8/30 10:39 130560 qgifd.dll -a--- 2024/8/30 10:49 157696 qicnsd.dll -a--- 2024/8/30 10:39 137216 qicod.dll -a--- 2024/8/30 10:39 162816 qjpegd.dll -a--- 2024/8/30 10:49 97280 qtgad.dll -a--- 2024/8/30 10:49 93184 qwbmpd.dll -a--- 2024/8/30 10:49 105984 qwebpd.dll

[dg0yt]

These are the Qt plugins. Some plugins need DLLs with the actual implementation.

[Hlongyu]

When i debug step by step. I found it will call LoadLibrary() for qjpegd.dll.

hnd = LoadLibrary(reinterpret_cast<const wchar_t*>(QDir::toNativeSeparators(attempt).utf16()));

Loaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qjpegd.dll'. Symbols loaded.
Unloaded 'D:\dev\qt-bug-report\out\build\windows-x64-Debug\imageformats\qjpegd.dll'. 

[dg0yt]

That's just the same information as in the initial post: It fails to load the plugin. But the plugin is there. I already suggest that it might be failing because the plugin fails find runtime dependencies (DLLs), here the jpeg DLL from port libjpeg-turbo.