# class ThumbCreator

### abstract

Module | kio
Namespace |
Class | ThumbCreator
Inherits |

This is the baseclass for "thumbnail-plugins" in KDE. Using the class KIO.PreviewJob allows you to generate small images (thumbnails) for any kind of file, where a "ThumbCreator" is available. Have a look at kdebase/kioslave/thumbnail/ for existing ThumbCreators.

What you need to do to create and register a ThumbCreator:

- Inherit from this class and reimplement the create() method to
generate a thumbnail for the given file-path.
- Provide a factory method in your implementation file to instantiate
your plugin, e.g.:

    extern "C"
    {
    KDE_EXPORT ThumbCreator *new_creator()
    {
    return new YourThumbCreator();
    }
    };

Compile your ThumbCreator as a module. The contents of CMakeLists.txt should look something like this, with "filetype" replaced by the type of file this plugin creates thumbnails for:

    project(filetypethumbcreator)

    find_package(KDE4 REQUIRED)
    include (KDE4Defaults)
    include(MacroOptionalAddSubdirectory)

    set(filetypethumbnail_SRCS filetypethumbnail.cpp)

    kde4_add_ui_files(filetypethumbnail_SRCS config.ui )

    kde4_add_plugin(filetypethumbnail ${filetypethumbnail_SRCS})
    target_link_libraries(filetypethumbnail ${KDE4_KIO_LIBS})

    install(TARGETS filetypethumbnail DESTINATION ${PLUGIN_INSTALL_DIR})
    install(FILES filetypethumbcreator.desktop DESTINATION ${SERVICES_INSTALL_DIR})

- Create a file filetypethumbcreator.desktop with the following contents:

    [Desktop Entry]
    Encoding=UTF-8
    Type=Service
    Name=Name of the type of files your ThumbCreator supports
    ServiceTypes=ThumbCreator
    MimeType=application/x-somemimetype;
    CacheThumbnail=true
    X-KDE-Library=yourthumbcreator

You can supply a comma-separated list of mimetypes to the MimeTypes entry, naming all mimetypes your ThumbCreator supports. You can also use simple wildcards, like (where you see [slash], put a /)

    text[slash]* or image[slash]*.

If your plugin is rather inexpensive (e.g. like the text preview ThumbCreator), you can set CacheThumbnail=false to prevent your thumbnails from being cached on disk.

Baseclass for thumbnail-generating plugins.

### enums

- Flags { None, DrawFrame, BlendIcon }

enum details

### methods

- create (path, width, height, img)

  returns bool
  pure virtual

  Argument | Type | Default
  --- | --- | ---
  path | QString |
  width | int |
  height | int |
  img | QImage |

  Creates a thumbnail Note that the width and height parameters should not be used for scaling. Only plugins that create an image "from scratch", like the TextCreator should directly use the specified size. If the resulting preview is larger than width x height, it will be scaled down.

  path - the (always local) file path to create a preview for

  width - maximum width for the preview

  height - maximum height for the preview

  img - this image will contain the preview on success

  Returns true if preview generation succeeded

- flags ( )

  returns ThumbCreator.Flags

  The flags of this plugin:

- None nothing special
- DrawFrame a frame should be painted around the preview
- BlendIcon the mimetype icon should be blended over the preview

Returns flags for this plugin

### enums - detail

- Flags { None, DrawFrame, BlendIcon }

  The flags of this plugin.

  See also flags()

  | None | - 0 | - |
  | DrawFrame | - 1 | - |
  | BlendIcon | - 2 | - |