Package ch.bailu.gtk.gtk

Class CellAreaContext

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.gtk.CellAreaContext
All Implemented Interfaces:
PointerInterface
public class CellAreaContext extends Object
Stores geometrical information for a series of rows in a GtkCellArea

The `GtkCellAreaContext` object is created by a given `GtkCellArea`
implementation via its `GtkCellAreaClass.create_context()` virtual
method and is used to store cell sizes and alignments for a series of
`GtkTreeModel` rows that are requested and rendered in the same context.

`GtkCellLayout` widgets can create any number of contexts in which to
request and render groups of data rows. However, it’s important that the
same context which was used to request sizes for a given `GtkTreeModel`
row also be used for the same row when calling other `GtkCellArea` APIs
such as gtk_cell_area_render() and gtk_cell_area_event().

https://docs.gtk.org/gtk4/class.CellAreaContext.html

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • allocate

      public void allocate(int width, int height)
      Allocates a width and/or a height for all rows which are to be
      rendered with @context.

      Usually allocation is performed only horizontally or sometimes
      vertically since a group of rows are usually rendered side by
      side vertically or horizontally and share either the same width
      or the same height. Sometimes they are allocated in both horizontal
      and vertical orientations producing a homogeneous effect of the
      rows. This is generally the case for `GtkTreeView` when
      `GtkTreeView:fixed-height-mode` is enabled.
      Parameters:
      width - the allocated width for all `GtkTreeModel` rows rendered with @context, or -1
      height - the allocated height for all `GtkTreeModel` rows rendered with @context, or -1

    • getAllocation

      public void getAllocation(@Nullable Int width, @Nullable Int height)
      Fetches the current allocation size for @context.

      If the context was not allocated in width or height, or if the
      context was recently reset with gtk_cell_area_context_reset(),
      the returned value will be -1.
      Parameters:
      width - location to store the allocated width
      height - location to store the allocated height

    • getArea

      public CellArea getArea()
      Fetches the `GtkCellArea` this @context was created by.

      This is generally unneeded by layouting widgets; however,
      it is important for the context implementation itself to
      fetch information about the area it is being used for.

      For instance at `GtkCellAreaContextClass.allocate()` time
      it’s important to know details about any cell spacing
      that the `GtkCellArea` is configured with in order to
      compute a proper allocation.
      Returns:
      the `GtkCellArea` this context was created by.

    • getPreferredHeight

      public void getPreferredHeight(@Nullable Int minimum_height, @Nullable Int natural_height)
      Gets the accumulative preferred height for all rows which have been
      requested with this context.

      After gtk_cell_area_context_reset() is called and/or before ever
      requesting the size of a `GtkCellArea`, the returned values are 0.
      Parameters:
      minimum_height - location to store the minimum height
      natural_height - location to store the natural height

    • getPreferredHeightForWidth

      public void getPreferredHeightForWidth(int width, @Nullable Int minimum_height, @Nullable Int natural_height)
      Gets the accumulative preferred height for @width for all rows
      which have been requested for the same said @width with this context.

      After gtk_cell_area_context_reset() is called and/or before ever
      requesting the size of a `GtkCellArea`, the returned values are -1.
      Parameters:
      width - a proposed width for allocation
      minimum_height - location to store the minimum height
      natural_height - location to store the natural height

    • getPreferredWidth

      public void getPreferredWidth(@Nullable Int minimum_width, @Nullable Int natural_width)
      Gets the accumulative preferred width for all rows which have been
      requested with this context.

      After gtk_cell_area_context_reset() is called and/or before ever
      requesting the size of a `GtkCellArea`, the returned values are 0.
      Parameters:
      minimum_width - location to store the minimum width
      natural_width - location to store the natural width

    • getPreferredWidthForHeight

      public void getPreferredWidthForHeight(int height, @Nullable Int minimum_width, @Nullable Int natural_width)
      Gets the accumulative preferred width for @height for all rows which
      have been requested for the same said @height with this context.

      After gtk_cell_area_context_reset() is called and/or before ever
      requesting the size of a `GtkCellArea`, the returned values are -1.
      Parameters:
      height - a proposed height for allocation
      minimum_width - location to store the minimum width
      natural_width - location to store the natural width

    • pushPreferredHeight

      public void pushPreferredHeight(int minimum_height, int natural_height)
      Causes the minimum and/or natural height to grow if the new
      proposed sizes exceed the current minimum and natural height.

      This is used by `GtkCellAreaContext` implementations during
      the request process over a series of `GtkTreeModel` rows to
      progressively push the requested height over a series of
      gtk_cell_area_get_preferred_height() requests.
      Parameters:
      minimum_height - the proposed new minimum height for @context
      natural_height - the proposed new natural height for @context

    • pushPreferredWidth

      public void pushPreferredWidth(int minimum_width, int natural_width)
      Causes the minimum and/or natural width to grow if the new
      proposed sizes exceed the current minimum and natural width.

      This is used by `GtkCellAreaContext` implementations during
      the request process over a series of `GtkTreeModel` rows to
      progressively push the requested width over a series of
      gtk_cell_area_get_preferred_width() requests.
      Parameters:
      minimum_width - the proposed new minimum width for @context
      natural_width - the proposed new natural width for @context

    • reset

      public void reset()
      Resets any previously cached request and allocation
      data.

      When underlying `GtkTreeModel` data changes its
      important to reset the context if the content
      size is allowed to shrink. If the content size
      is only allowed to grow (this is usually an option
      for views rendering large data stores as a measure
      of optimization), then only the row that changed
      or was inserted needs to be (re)requested with
      gtk_cell_area_get_preferred_width().

      When the new overall size of the context requires
      that the allocated size changes (or whenever this
      allocation changes at all), the variable row
      sizes need to be re-requested for every row.

      For instance, if the rows are displayed all with
      the same width from top to bottom then a change
      in the allocated width necessitates a recalculation
      of all the displayed row heights using
      gtk_cell_area_get_preferred_height_for_width().

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()