Blank screen with Qt5.7 and EGLFS
-
Hello!
Im working on custom Hardware, related to Beaglebone black. I compiled everything cross from source.
If I enable OpenGL and run an application, the screen turns black and nothing happens.
Here are my steps and environments:Kernel:
3.12.15-rt25 (A testing 4.6.7 kernel behaves similar. Let me know, if you need kernel config or device tree options)Steps to compile Qt:
wget http://download.qt.io/official_releases/qt/5.7/5.7.0/single/qt-everywhere-opensource-src-5.7.0.tar.gz tar xf qt-everywhere-opensource-src-5.7.0.tar.gz cd qt-everywhere-opensource-src-5.7.0 cat ../0001-patched-to-build-with-ELDK-5.3-and-Graphics_SDK_5_01.patch | patch -p1 cd .. mkdir qt-everywhere-opensource-src-5.7.0-build cd qt-everywhere-opensource-src-5.7.0-build export ARCH=arm export CROSS_COMPILE=armv7a- export PATH=/opt/eldk-5.3/armv7a/sysroots/i686-eldk-linux/usr/bin:/opt/eldk-5.3/armv7a/sysroots/i686-eldk-linux/usr/bin/armv7a-vfp-neon-linux-gnueabi:$PATH ../qt-everywhere-opensource-src-5.7.0/configure -opensource -confirm-license -prefix /opt/qt-embedded-v5.7.0-armv7a -platform linux-g++-64 -xplatform devices/linux-beagleboard-g++ -device beagleboard -device-option CROSS_COMPILE=/opt/eldk-5.3/armv7a/sysroots/i686-eldk-linux/usr/bin/armv7a-vfp-neon-linux-gnueabi/armv7a- -nomake examples -no-sse2 -no-glib -no-cups -no-largefile -no-accessibility -no-pch -qt-libpng -qt-libjpeg -tslib -linuxfb -no-xcb -I$PWD/../../../packages/tslib-1.0/src -I/opt/Graphics_SDK_5_01_01_02/include/OGLES2/ -L$PWD/../../../packages/tslib-1.0/src/.libs -L/tftpboot/linux/rootfs/usr/lib -opengl -pkg-config -v0001-patched-to-build-with-ELDK-5.3-and-Graphics_SDK_5_01.patch:
diff --git a/qtbase/mkspecs/common/g++-base.conf b/qtbase/mkspecs/common/g++-base.conf index c42c46b..ae22071 100644 --- a/qtbase/mkspecs/common/g++-base.conf +++ b/qtbase/mkspecs/common/g++-base.conf @@ -27,7 +27,7 @@ QMAKE_CFLAGS_USE_PRECOMPILE = -include ${QMAKE_PCH_OUTPUT_BASE} QMAKE_CXXFLAGS_PRECOMPILE = -x c++-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT} QMAKE_CXXFLAGS_USE_PRECOMPILE = $$QMAKE_CFLAGS_USE_PRECOMPILE -QMAKE_CXXFLAGS_CXX11 = -std=c++11 +QMAKE_CXXFLAGS_CXX11 = -std=c++0x QMAKE_CXXFLAGS_CXX14 = -std=c++1y QMAKE_CXXFLAGS_CXX1Z = -std=c++1z QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++11 diff --git a/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf b/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf index 604da50..9d8db69 100644 --- a/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf +++ b/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf @@ -36,8 +36,8 @@ QMAKE_CXXFLAGS_RELEASE += -O3 QMAKE_LIBS += -lrt -lpthread -ldl # Extra stuff (OpenGL, DirectFB, ...) -QMAKE_INCDIR_EGL = -QMAKE_LIBDIR_EGL = +QMAKE_INCDIR_EGL = /opt/Graphics_SDK_5_01_01_02/include +QMAKE_LIBDIR_EGL = /opt/gfxlibraries/gfx_rel_es8.x QMAKE_INCDIR_OPENGL_ES2 = $${QMAKE_INCDIR_EGL} QMAKE_LIBDIR_OPENGL_ES2 = $${QMAKE_LIBDIR_EGL} QMAKE_INCDIR_OPENVG = $${QMAKE_INCDIR_EGL} @@ -47,7 +47,7 @@ QMAKE_LIBS_EGL = -lEGL -lIMGegl -lsrv_um QMAKE_LIBS_OPENGL_ES2 = -lGLESv2 $${QMAKE_LIBS_EGL} QMAKE_LIBS_OPENVG = -lOpenVG $${QMAKE_LIBS_EGL} -DISTRO_OPTS += hard-float +#DISTRO_OPTS += hard-float # No need for any special EGL device integration. # Prioritize the default, compiled-in integration over any plugins. diff --git a/qtbase/src/corelib/global/qnumeric_p.h b/qtbase/src/corelib/global/qnumeric_p.h index 5705bc2..d8bf403 100644 --- a/qtbase/src/corelib/global/qnumeric_p.h +++ b/qtbase/src/corelib/global/qnumeric_p.h @@ -71,12 +71,12 @@ QT_BEGIN_NAMESPACE namespace qnumeric_std_wrapper { // the 'using namespace std' below is cases where the stdlib already put the math.h functions in the std namespace and undefined the macros. -static inline bool math_h_isnan(double d) { using namespace std; return isnan(d); } -static inline bool math_h_isinf(double d) { using namespace std; return isinf(d); } -static inline bool math_h_isfinite(double d) { using namespace std; return isfinite(d); } -static inline bool math_h_isnan(float f) { using namespace std; return isnan(f); } -static inline bool math_h_isinf(float f) { using namespace std; return isinf(f); } -static inline bool math_h_isfinite(float f) { using namespace std; return isfinite(f); } +static inline bool math_h_isnan(double d) { return std::isnan(d); } +static inline bool math_h_isinf(double d) { return std::isinf(d); } +static inline bool math_h_isfinite(double d) { return std::isfinite(d); } +static inline bool math_h_isnan(float f) { return std::isnan(f); } +static inline bool math_h_isinf(float f) { return std::isinf(f); } +static inline bool math_h_isfinite(float f) { return std::isfinite(f); } } QT_END_NAMESPACE // These macros from math.h conflict with the real functions in the std namespace.Configurte output:
Build options: Configuration .......... audio-backend c++11 clock-gettime clock-monotonic compile_examples concurrent cross_compile dbus doubleconversion egl eglfs enable_new_dtags evdev eventfd freetype full-config getaddrinfo getifaddrs harfbuzz iconv inotify ipv6ifname large-config libudev linuxfb medium-config minimal-config mremap neon nis opengl opengles2 openssl pcre png poll_poll posix_fallocate qpa qpa reduce_exports release rpath shared small-config system-zlib threadsafe-cloexec tslib xinput2 xlib xrender Build parts ............ libs Mode ................... release Using sanitizer(s)...... none Using C++ standard ..... c++11 Using gold linker....... no Using new DTAGS ........ yes Using PCH .............. no Using LTCG ............. no Target compiler supports: Neon ................. yes Qt modules and options: Qt D-Bus ............... yes (loading dbus-1 at runtime) Qt Concurrent .......... yes Qt GUI ................. yes Qt Widgets ............. yes Large File ............. no QML debugging .......... yes Use system proxies ..... no Support enabled for: Accessibility .......... no ALSA ................... no CUPS ................... no DoubleConversion........ yes (bundled copy) Evdev .................. yes FontConfig ............. no FreeType ............... yes (bundled copy) Glib ................... no GStreamer .............. no GTK platformtheme ...... no HarfBuzz ............... yes (bundled copy) Iconv .................. yes ICU .................... no Image formats: GIF .................. yes (plugin, using bundled copy) JPEG ................. yes (plugin, using bundled copy) PNG .................. yes (in QtGui, using bundled copy) libinput................ no Logging backends: journald ............... no syslog ............... no mtdev .................. no Networking: getaddrinfo .......... yes getifaddrs ........... yes IPv6 ifname .......... yes libproxy.............. no OpenSSL .............. yes (loading libraries at run-time) NIS .................... yes OpenGL / OpenVG: EGL .................. yes OpenGL ............... yes (OpenGL ES 2.0+) OpenVG ............... no PCRE ................... yes (bundled copy) pkg-config ............. yes PulseAudio ............. no QPA backends: DirectFB ............. no EGLFS ................ yes EGLFS i.MX6 ........ no EGLFS i.MX6 Wayland. no EGLFS EGLDevice .... no EGLFS GBM .......... no EGLFS Mali ......... no EGLFS Raspberry Pi . no EGLFS X11 .......... no LinuxFB .............. yes Mir client............ no XCB .................. no Session management ..... yes SQL drivers: DB2 .................. no InterBase ............ no MySQL ................ no OCI .................. no ODBC ................. no PostgreSQL ........... no SQLite 2 ............. no SQLite ............... yes (plugin, using bundled copy) TDS .................. no tslib .................. yes udev ................... yes xkbcommon-x11........... no xkbcommon-evdev......... no zlib ................... yes (system library)Target environment (shorted):
TSLIB_CONFFILE=/etc/ts.conf POINTERCAL_FILE=/app/pointercal TSLIB_CALIBFILE=/app/pointercal LD_LIBRARY_PATH=/opt/qt-embedded-v5.7.0-armv7a/lib:/opt/qt-embedded-v5.7.0-armv7a/plugins/platforms/ QWS_MOUSE_PROTO=Tslib:/dev/input/by-path/platform-44e0b000.i2c-event-mouse PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin QTARGS=--platform eglfs -plugin tslib TSLIB_TSDEVICE=/dev/input/by-path/platform-44e0b000.i2c-event-mouse QWS_DISPLAY=Multi: LinuxFb: VNC::size=1024x768ldd on hellogl2 example:
root@ppc3xx:/app# ldd hellogl2 libQt5Widgets.so.5 => /opt/qt-embedded-v5.7.0-armv7a/lib/libQt5Widgets.so.5 (0xb6b99000) libQt5Gui.so.5 => /opt/qt-embedded-v5.7.0-armv7a/lib/libQt5Gui.so.5 (0xb683d000) libQt5Core.so.5 => /opt/qt-embedded-v5.7.0-armv7a/lib/libQt5Core.so.5 (0xb6429000) librt.so.1 => /lib/librt.so.1 (0x4b9d8000) libdl.so.2 => /lib/libdl.so.2 (0x4b840000) libGLESv2.so => /usr/lib/libGLESv2.so (0xb63b4000) libEGL.so => /usr/lib/libEGL.so (0xb63a9000) libIMGegl.so => /usr/lib/libIMGegl.so (0xb638f000) libsrv_um.so => /usr/lib/libsrv_um.so (0xb635c000) libpthread.so.0 => /lib/libpthread.so.0 (0x4b9b0000) libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x4ba88000) libm.so.6 => /lib/libm.so.6 (0x4ba10000) libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x4b988000) libc.so.6 => /lib/libc.so.6 (0x4b850000) libz.so.1 => /usr/lib/libz.so.1 (0x4b9f0000) /lib/ld-linux.so.3 (0x4b810000) ld-linux-armhf.so.3 => /lib/ld-linux-armhf.so.3 (0xb6333000)(Why doesn't it depend on libQt5OpenGL.so.5?)
starting hellogl2 example:
root@ppc3xx:/app# ./hellogl2 QIconvCodec::convertToUnicode: using Latin-1 for conversion, iconv_open failed QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv_open failed Unable to query physical screen size, defaulting to 100 dpi. To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).At this point, nothing else happens and Display tungs black.
Let me know, if you need any more infos to solve the problem.Kind Regards, Daniel
-
Hello!
Im working on custom Hardware, related to Beaglebone black. I compiled everything cross from source.
If I enable OpenGL and run an application, the screen turns black and nothing happens.
Here are my steps and environments:Kernel:
3.12.15-rt25 (A testing 4.6.7 kernel behaves similar. Let me know, if you need kernel config or device tree options)Steps to compile Qt:
wget http://download.qt.io/official_releases/qt/5.7/5.7.0/single/qt-everywhere-opensource-src-5.7.0.tar.gz tar xf qt-everywhere-opensource-src-5.7.0.tar.gz cd qt-everywhere-opensource-src-5.7.0 cat ../0001-patched-to-build-with-ELDK-5.3-and-Graphics_SDK_5_01.patch | patch -p1 cd .. mkdir qt-everywhere-opensource-src-5.7.0-build cd qt-everywhere-opensource-src-5.7.0-build export ARCH=arm export CROSS_COMPILE=armv7a- export PATH=/opt/eldk-5.3/armv7a/sysroots/i686-eldk-linux/usr/bin:/opt/eldk-5.3/armv7a/sysroots/i686-eldk-linux/usr/bin/armv7a-vfp-neon-linux-gnueabi:$PATH ../qt-everywhere-opensource-src-5.7.0/configure -opensource -confirm-license -prefix /opt/qt-embedded-v5.7.0-armv7a -platform linux-g++-64 -xplatform devices/linux-beagleboard-g++ -device beagleboard -device-option CROSS_COMPILE=/opt/eldk-5.3/armv7a/sysroots/i686-eldk-linux/usr/bin/armv7a-vfp-neon-linux-gnueabi/armv7a- -nomake examples -no-sse2 -no-glib -no-cups -no-largefile -no-accessibility -no-pch -qt-libpng -qt-libjpeg -tslib -linuxfb -no-xcb -I$PWD/../../../packages/tslib-1.0/src -I/opt/Graphics_SDK_5_01_01_02/include/OGLES2/ -L$PWD/../../../packages/tslib-1.0/src/.libs -L/tftpboot/linux/rootfs/usr/lib -opengl -pkg-config -v0001-patched-to-build-with-ELDK-5.3-and-Graphics_SDK_5_01.patch:
diff --git a/qtbase/mkspecs/common/g++-base.conf b/qtbase/mkspecs/common/g++-base.conf index c42c46b..ae22071 100644 --- a/qtbase/mkspecs/common/g++-base.conf +++ b/qtbase/mkspecs/common/g++-base.conf @@ -27,7 +27,7 @@ QMAKE_CFLAGS_USE_PRECOMPILE = -include ${QMAKE_PCH_OUTPUT_BASE} QMAKE_CXXFLAGS_PRECOMPILE = -x c++-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT} QMAKE_CXXFLAGS_USE_PRECOMPILE = $$QMAKE_CFLAGS_USE_PRECOMPILE -QMAKE_CXXFLAGS_CXX11 = -std=c++11 +QMAKE_CXXFLAGS_CXX11 = -std=c++0x QMAKE_CXXFLAGS_CXX14 = -std=c++1y QMAKE_CXXFLAGS_CXX1Z = -std=c++1z QMAKE_CXXFLAGS_GNUCXX11 = -std=gnu++11 diff --git a/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf b/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf index 604da50..9d8db69 100644 --- a/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf +++ b/qtbase/mkspecs/devices/linux-beagleboard-g++/qmake.conf @@ -36,8 +36,8 @@ QMAKE_CXXFLAGS_RELEASE += -O3 QMAKE_LIBS += -lrt -lpthread -ldl # Extra stuff (OpenGL, DirectFB, ...) -QMAKE_INCDIR_EGL = -QMAKE_LIBDIR_EGL = +QMAKE_INCDIR_EGL = /opt/Graphics_SDK_5_01_01_02/include +QMAKE_LIBDIR_EGL = /opt/gfxlibraries/gfx_rel_es8.x QMAKE_INCDIR_OPENGL_ES2 = $${QMAKE_INCDIR_EGL} QMAKE_LIBDIR_OPENGL_ES2 = $${QMAKE_LIBDIR_EGL} QMAKE_INCDIR_OPENVG = $${QMAKE_INCDIR_EGL} @@ -47,7 +47,7 @@ QMAKE_LIBS_EGL = -lEGL -lIMGegl -lsrv_um QMAKE_LIBS_OPENGL_ES2 = -lGLESv2 $${QMAKE_LIBS_EGL} QMAKE_LIBS_OPENVG = -lOpenVG $${QMAKE_LIBS_EGL} -DISTRO_OPTS += hard-float +#DISTRO_OPTS += hard-float # No need for any special EGL device integration. # Prioritize the default, compiled-in integration over any plugins. diff --git a/qtbase/src/corelib/global/qnumeric_p.h b/qtbase/src/corelib/global/qnumeric_p.h index 5705bc2..d8bf403 100644 --- a/qtbase/src/corelib/global/qnumeric_p.h +++ b/qtbase/src/corelib/global/qnumeric_p.h @@ -71,12 +71,12 @@ QT_BEGIN_NAMESPACE namespace qnumeric_std_wrapper { // the 'using namespace std' below is cases where the stdlib already put the math.h functions in the std namespace and undefined the macros. -static inline bool math_h_isnan(double d) { using namespace std; return isnan(d); } -static inline bool math_h_isinf(double d) { using namespace std; return isinf(d); } -static inline bool math_h_isfinite(double d) { using namespace std; return isfinite(d); } -static inline bool math_h_isnan(float f) { using namespace std; return isnan(f); } -static inline bool math_h_isinf(float f) { using namespace std; return isinf(f); } -static inline bool math_h_isfinite(float f) { using namespace std; return isfinite(f); } +static inline bool math_h_isnan(double d) { return std::isnan(d); } +static inline bool math_h_isinf(double d) { return std::isinf(d); } +static inline bool math_h_isfinite(double d) { return std::isfinite(d); } +static inline bool math_h_isnan(float f) { return std::isnan(f); } +static inline bool math_h_isinf(float f) { return std::isinf(f); } +static inline bool math_h_isfinite(float f) { return std::isfinite(f); } } QT_END_NAMESPACE // These macros from math.h conflict with the real functions in the std namespace.Configurte output:
Build options: Configuration .......... audio-backend c++11 clock-gettime clock-monotonic compile_examples concurrent cross_compile dbus doubleconversion egl eglfs enable_new_dtags evdev eventfd freetype full-config getaddrinfo getifaddrs harfbuzz iconv inotify ipv6ifname large-config libudev linuxfb medium-config minimal-config mremap neon nis opengl opengles2 openssl pcre png poll_poll posix_fallocate qpa qpa reduce_exports release rpath shared small-config system-zlib threadsafe-cloexec tslib xinput2 xlib xrender Build parts ............ libs Mode ................... release Using sanitizer(s)...... none Using C++ standard ..... c++11 Using gold linker....... no Using new DTAGS ........ yes Using PCH .............. no Using LTCG ............. no Target compiler supports: Neon ................. yes Qt modules and options: Qt D-Bus ............... yes (loading dbus-1 at runtime) Qt Concurrent .......... yes Qt GUI ................. yes Qt Widgets ............. yes Large File ............. no QML debugging .......... yes Use system proxies ..... no Support enabled for: Accessibility .......... no ALSA ................... no CUPS ................... no DoubleConversion........ yes (bundled copy) Evdev .................. yes FontConfig ............. no FreeType ............... yes (bundled copy) Glib ................... no GStreamer .............. no GTK platformtheme ...... no HarfBuzz ............... yes (bundled copy) Iconv .................. yes ICU .................... no Image formats: GIF .................. yes (plugin, using bundled copy) JPEG ................. yes (plugin, using bundled copy) PNG .................. yes (in QtGui, using bundled copy) libinput................ no Logging backends: journald ............... no syslog ............... no mtdev .................. no Networking: getaddrinfo .......... yes getifaddrs ........... yes IPv6 ifname .......... yes libproxy.............. no OpenSSL .............. yes (loading libraries at run-time) NIS .................... yes OpenGL / OpenVG: EGL .................. yes OpenGL ............... yes (OpenGL ES 2.0+) OpenVG ............... no PCRE ................... yes (bundled copy) pkg-config ............. yes PulseAudio ............. no QPA backends: DirectFB ............. no EGLFS ................ yes EGLFS i.MX6 ........ no EGLFS i.MX6 Wayland. no EGLFS EGLDevice .... no EGLFS GBM .......... no EGLFS Mali ......... no EGLFS Raspberry Pi . no EGLFS X11 .......... no LinuxFB .............. yes Mir client............ no XCB .................. no Session management ..... yes SQL drivers: DB2 .................. no InterBase ............ no MySQL ................ no OCI .................. no ODBC ................. no PostgreSQL ........... no SQLite 2 ............. no SQLite ............... yes (plugin, using bundled copy) TDS .................. no tslib .................. yes udev ................... yes xkbcommon-x11........... no xkbcommon-evdev......... no zlib ................... yes (system library)Target environment (shorted):
TSLIB_CONFFILE=/etc/ts.conf POINTERCAL_FILE=/app/pointercal TSLIB_CALIBFILE=/app/pointercal LD_LIBRARY_PATH=/opt/qt-embedded-v5.7.0-armv7a/lib:/opt/qt-embedded-v5.7.0-armv7a/plugins/platforms/ QWS_MOUSE_PROTO=Tslib:/dev/input/by-path/platform-44e0b000.i2c-event-mouse PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin QTARGS=--platform eglfs -plugin tslib TSLIB_TSDEVICE=/dev/input/by-path/platform-44e0b000.i2c-event-mouse QWS_DISPLAY=Multi: LinuxFb: VNC::size=1024x768ldd on hellogl2 example:
root@ppc3xx:/app# ldd hellogl2 libQt5Widgets.so.5 => /opt/qt-embedded-v5.7.0-armv7a/lib/libQt5Widgets.so.5 (0xb6b99000) libQt5Gui.so.5 => /opt/qt-embedded-v5.7.0-armv7a/lib/libQt5Gui.so.5 (0xb683d000) libQt5Core.so.5 => /opt/qt-embedded-v5.7.0-armv7a/lib/libQt5Core.so.5 (0xb6429000) librt.so.1 => /lib/librt.so.1 (0x4b9d8000) libdl.so.2 => /lib/libdl.so.2 (0x4b840000) libGLESv2.so => /usr/lib/libGLESv2.so (0xb63b4000) libEGL.so => /usr/lib/libEGL.so (0xb63a9000) libIMGegl.so => /usr/lib/libIMGegl.so (0xb638f000) libsrv_um.so => /usr/lib/libsrv_um.so (0xb635c000) libpthread.so.0 => /lib/libpthread.so.0 (0x4b9b0000) libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x4ba88000) libm.so.6 => /lib/libm.so.6 (0x4ba10000) libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x4b988000) libc.so.6 => /lib/libc.so.6 (0x4b850000) libz.so.1 => /usr/lib/libz.so.1 (0x4b9f0000) /lib/ld-linux.so.3 (0x4b810000) ld-linux-armhf.so.3 => /lib/ld-linux-armhf.so.3 (0xb6333000)(Why doesn't it depend on libQt5OpenGL.so.5?)
starting hellogl2 example:
root@ppc3xx:/app# ./hellogl2 QIconvCodec::convertToUnicode: using Latin-1 for conversion, iconv_open failed QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv_open failed Unable to query physical screen size, defaulting to 100 dpi. To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT (in millimeters).At this point, nothing else happens and Display tungs black.
Let me know, if you need any more infos to solve the problem.Kind Regards, Daniel
@danielesd It looks like you are using Qt5.7 and the QWS environment and I think instead with eglfs you should be using QPA environment settings. I am not an expert but I have recently brought up a custom platform using BBB with a touchscreen using qt5.6.1, kernel 4.1, and using QPA environment. QWA is for Qt4.x.
Here is a link that might get you pointed toward qpa: http://doc.qt.io/qt-5/embedded-linux.html
