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KIO::PreviewJob Class

KIO Job to get a thumbnail picture. More...

• Header: #include <KIO/PreviewJob>
• CMake: find_package(KF6 REQUIRED COMPONENTS KIO)
target_link_libraries(mytarget PRIVATE KIOGui)
• Inherits: KIO::Job

List of all members, including inherited members
Deprecated members

#Public Types

• enum PreviewJob::ScaleType

#Public Functions

• PreviewJob(const KFileItemList &items, const QSize &size, const QStringList *enabledPlugins = nullptr)
• bool handlesSequences() const
• KIO::PreviewJob::ScaleType scaleType() const
• int sequenceIndex() const
• float sequenceIndexWraparoundPoint() const
• void setDevicePixelRatio(qreal dpr)
• void setIgnoreMaximumSize(bool ignoreSize = true)
• void setScaleType(KIO::PreviewJob::ScaleType type)
• void setSequenceIndex(int index)

#Signals

• void failed(const KFileItem &item)
• void generated(const KFileItem &item, const QImage &preview) (since 6.15)
• void gotPreview(const KFileItem &item, const QPixmap &preview)

#Static Public Members

• QStringList availablePlugins()
• QList<KPluginMetaData> availableThumbnailerPlugins()
• QStringList defaultPlugins()
• void setDefaultDevicePixelRatio(qreal devicePixelRatio)
• QStringList supportedMimeTypes()

#Detailed Description

This class catches a preview (thumbnail) for files.

#Member Type Documentation

#enum PreviewJob::ScaleType

Specifies the type of scaling that is applied to the generated preview. For HiDPI, pixel density scaling, see setDevicePixelRatio

Constant	Value	Description
KIO::PreviewJob::Unscaled	0	The original size of the preview will be returned. Most previews will return a size of 256 x 256 pixels.
KIO::PreviewJob::Scaled	1	The preview will be scaled to the size specified when constructing the PreviewJob. The aspect ratio will be kept.
KIO::PreviewJob::ScaledAndCached	2	The preview will be scaled to the size specified when constructing the PreviewJob. The result will be cached for later use. Per default ScaledAndCached is set.

#Member Function Documentation

#PreviewJob::PreviewJob(const KFileItemList &items, const QSize &size, const QStringList *enabledPlugins = nullptr)

items List of files to create previews for. size Desired size of the preview. enabledPlugins If non-zero it defines the list of plugins that are considered for generating the preview. If enabledPlugins is zero the plugins specified in the KConfigGroup "PreviewSettings" are used.

#[static] QStringList PreviewJob::availablePlugins()

Returns a list of all available preview plugins. The list contains the basenames of the plugins' .desktop files (no path, no .desktop). Returns the list of all available plugins

#[static] QList<KPluginMetaData> PreviewJob::availableThumbnailerPlugins()

Returns all plugins that are considered when a preview is generated The result is internally cached, meaning any further method call will not reload the plugins

#[static] QStringList PreviewJob::defaultPlugins()

Returns a list of plugins that should be enabled by default, which is all plugins Minus the plugins specified in an internal blacklist Returns the list of plugins that should be enabled by default

#[signal] void PreviewJob::failed(const KFileItem &item)

Emitted when a thumbnail for item could not be created, either because a ThumbCreator for its MIME type does not exist, or because something went wrong.

item the file that failed

#[signal, since 6.15] void PreviewJob::generated(const KFileItem &item, const QImage &preview)

Emitted when a preview for item has been successfully generated.

This function was introduced in Qt 6.15.

#[signal] void PreviewJob::gotPreview(const KFileItem &item, const QPixmap &preview)

Emitted when a thumbnail picture for item has been successfully retrieved.

item the file of the preview

preview the preview image

Note: If you need a preview as a QImage object, use the generated() signal.

See also generated()

#bool PreviewJob::handlesSequences() const

Determines whether the ThumbCreator in use is a ThumbSequenceCreator.

#KIO::PreviewJob::ScaleType PreviewJob::scaleType() const

Returns The scale type for the generated preview.

See also setScaleType(), PreviewJob::ScaleType

#int PreviewJob::sequenceIndex() const

Returns the currently set sequence index

See also setSequenceIndex()

#float PreviewJob::sequenceIndexWraparoundPoint() const

Returns the index at which the thumbs of a ThumbSequenceCreator start wrapping around ("looping"). Fractional values may be returned if the ThumbSequenceCreator supports sub-integer precision, but frontends supporting only integer sequence indices may choose to round it down.

#[static] void PreviewJob::setDefaultDevicePixelRatio(qreal devicePixelRatio)

Sets a default device Pixel Ratio used for Previews

Defaults to 1

See also setDevicePixelRatio

#void PreviewJob::setDevicePixelRatio(qreal dpr)

Request preview to use the device pixel ratio dpr. The returned thumbnail may not respect the device pixel ratio requested. Use QPixmap::devicePixelRatio to check, or paint as necessary.

#void PreviewJob::setIgnoreMaximumSize(bool ignoreSize = true)

If ignoreSize is true, then the preview is always generated regardless of the settings

#void PreviewJob::setScaleType(KIO::PreviewJob::ScaleType type)

Sets the scale type for the generated preview. Per default PreviewJob::ScaledAndCached is set.

See also scaleType(), PreviewJob::ScaleType

#void PreviewJob::setSequenceIndex(int index)

Sets the sequence index given to the thumb creators. Use the sequence index, it is possible to create alternative icons for the same item. For example it may allow iterating through the items of a directory, or the frames of a video.

See also sequenceIndex()

#[static] QStringList PreviewJob::supportedMimeTypes()

Returns a list of all supported MIME types. The list can contain entries like text/ * (without the space). Returns the list of MIME types

#Related Non-Members

#KIO::PreviewJob *filePreview(const KFileItemList &items, const QSize &size, const QStringList *enabledPlugins = nullptr)

Creates a PreviewJob to generate a preview image for the given items.

items List of files to create previews for.

size Desired size of the preview.

enabledPlugins If non-zero it defines the list of plugins that are considered for generating the preview. If enabledPlugins is zero the plugins specified in the KConfigGroup "PreviewSettings" are used.