CellAreaContext

Deprecated since version 4.10: This object will be removed in GTK 5

class CellAreaContext(**properties: Any)

Superclasses: 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 event().

Methods

class CellAreaContext

allocate(width: int, height: int) → None

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.

Deprecated since version 4.10: This object will be removed in GTK 5

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

get_allocation() → tuple[int, int]

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 reset(), the returned value will be -1.

Deprecated since version 4.10: This object will be removed in GTK 5

get_area() → CellArea

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.

Deprecated since version 4.10: This object will be removed in GTK 5

get_preferred_height() → tuple[int, int]

Gets the accumulative preferred height for all rows which have been requested with this context.

After reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are 0.

Deprecated since version 4.10: This object will be removed in GTK 5

get_preferred_height_for_width(width: int) → tuple[int, int]

Gets the accumulative preferred height for width for all rows which have been requested for the same said width with this context.

After reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

Deprecated since version 4.10: This object will be removed in GTK 5

Parameters:

width – a proposed width for allocation

get_preferred_width() → tuple[int, int]

Gets the accumulative preferred width for all rows which have been requested with this context.

After reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are 0.

Deprecated since version 4.10: This object will be removed in GTK 5

get_preferred_width_for_height(height: int) → tuple[int, int]

Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context.

After reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

Deprecated since version 4.10: This object will be removed in GTK 5

Parameters:

height – a proposed height for allocation

push_preferred_height(minimum_height: int, natural_height: int) → None

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 get_preferred_height() requests.

Deprecated since version 4.10: This object will be removed in GTK 5

Parameters:

• minimum_height – the proposed new minimum height for context

• natural_height – the proposed new natural height for context

push_preferred_width(minimum_width: int, natural_width: int) → None

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 get_preferred_width() requests.

Deprecated since version 4.10: This object will be removed in GTK 5

Parameters:

• minimum_width – the proposed new minimum width for context

• natural_width – the proposed new natural width for context

reset() → None

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 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 get_preferred_height_for_width().

Deprecated since version 4.10: This object will be removed in GTK 5

Properties

class CellAreaContext

props.area: CellArea

The GtkCellArea this context was created by

Deprecated since version 4.10: This object will be removed in GTK 5

props.minimum_height: int

The minimum height for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using get_preferred_height().

Deprecated since version 4.10: This object will be removed in GTK 5

props.minimum_width: int

The minimum width for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using get_preferred_width().

Deprecated since version 4.10: This object will be removed in GTK 5

props.natural_height: int

The natural height for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using get_preferred_height().

Deprecated since version 4.10: This object will be removed in GTK 5

props.natural_width: int

The natural width for the GtkCellArea in this context for all GtkTreeModel rows that this context was requested for using get_preferred_width().

Deprecated since version 4.10: This object will be removed in GTK 5

Virtual Methods

class CellAreaContext

do_allocate(width: int, height: int) → None

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.

Deprecated since version 4.10: This object will be removed in GTK 5

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

do_get_preferred_height_for_width(width: int) → tuple[int, int]

Gets the accumulative preferred height for width for all rows which have been requested for the same said width with this context.

After reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

Deprecated since version 4.10: This object will be removed in GTK 5

Parameters:

width – a proposed width for allocation

do_get_preferred_width_for_height(height: int) → tuple[int, int]

Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context.

After reset() is called and/or before ever requesting the size of a GtkCellArea, the returned values are -1.

Deprecated since version 4.10: This object will be removed in GTK 5

Parameters:

height – a proposed height for allocation

do_reset() → None

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 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 get_preferred_height_for_width().

Deprecated since version 4.10: This object will be removed in GTK 5

Fields

class CellAreaContext

parent_instance