hi again, thanks a lot again. i have doing some test and i have got to load the plugin in qt creator. you are right, finally a include QtSvgPixmapCache.h and cpp to my .pro and i thinks it works. The .pro is this:

Qt Code: 
  1. CONFIG      += designer plugin 
  2. TARGET      = $$qtLibraryTarget($$TARGET)
  3. TEMPLATE    = lib
  4. QT += svg
  5. QTDIR_build:DESTDIR     = $$QT_BUILD_TREE/plugins/designer
  6.  
  7. HEADERS     = qt5waybutton.h \
  8.               qt5waybuttonplugin.h qtsvgpixmapcache.h
  9. SOURCES     = qt5waybutton.cpp \
  10.               qt5waybuttonplugin.cpp qtsvgpixmapcache.cpp
  11.  
  12. # install
  13. target.path = $$[QT_INSTALL_PLUGINS]/designer
  14. sources.files = $$SOURCES $$HEADERS *.pro
  15. sources.path = $$[QT_INSTALL_EXAMPLES]/designer/qt5waybuttonplugin
  16. INSTALLS += target sources
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Now, i am going to try the plugin in the designer.
Thanks a lot for your help.