Memory-managed wrapper type.

Type class for types which can be safely cast to Layout, for instance with toLayout.

Cast to Layout, for types for which this is known to be safe. For general casts, use castTo.

A convenience alias for Nothing :: Maybe Layout.

Forces recomputation of any state in the Layout that might depend on the layout's context. This function should be called if you make changes to the context subsequent to creating the layout.

Does a deep copy-by-value of the src layout. The attribute list, tab array, and text from the original layout are all copied by value.

Gets the alignment for the layout: how partial lines are positioned within the horizontal space available.

Gets the attribute list for the layout, if any.

Gets whether to calculate the bidirectional base direction for the layout according to the contents of the layout. See layoutSetAutoDir.

Since: 1.4

Gets the Y position of baseline of the first line in layout.

Since: 1.22

Returns the number of Unicode characters in the the text of layout.

Since: 1.30

Retrieves the Context used for this layout.

Given an index within a layout, determines the positions that of the strong and weak cursors if the insertion point is at that index. The position of each cursor is stored as a zero-width rectangle. The strong cursor location is the location where characters of the directionality equal to the base direction of the layout are inserted. The weak cursor location is the location where characters of the directionality opposite to the base direction of the layout are inserted.

Gets the type of ellipsization being performed for layout. See layoutSetEllipsize

Since: 1.6

Computes the logical and ink extents of layout. Logical extents are usually what you want for positioning things. Note that both extents may have non-zero x and y. You may want to use those to offset where you render the layout. Not doing that is a very typical bug that shows up as right-to-left layouts not being correctly positioned in a layout with a set width.

The extents are given in layout coordinates and in Pango units; layout coordinates begin at the top left corner of the layout.

Gets the font description for the layout, if any.

Since: 1.8

Gets the height of layout used for ellipsization. See layoutSetHeight for details.

Since: 1.20

Gets the paragraph indent width in Pango units. A negative value indicates a hanging indentation.

Returns an iterator to iterate over the visual extents of the layout.

Gets whether each complete line should be stretched to fill the entire width of the layout.

Retrieves a particular line from a Layout.

Use the faster layoutGetLineReadonly if you do not plan to modify the contents of the line (glyphs, glyph widths, etc.).

Retrieves the count of lines for the layout.

Retrieves a particular line from a Layout.

This is a faster alternative to layoutGetLine, but the user is not expected to modify the contents of the line (glyphs, glyph widths, etc.).

Since: 1.16

Returns the lines of the layout as a list.

Use the faster layoutGetLinesReadonly if you do not plan to modify the contents of the lines (glyphs, glyph widths, etc.).

Returns the lines of the layout as a list.

This is a faster alternative to layoutGetLines, but the user is not expected to modify the contents of the lines (glyphs, glyph widths, etc.).

Since: 1.16

Retrieves an array of logical attributes for each character in the layout.

Retrieves an array of logical attributes for each character in the layout.

This is a faster alternative to layoutGetLogAttrs. The returned array is part of layout and must not be modified. Modifying the layout will invalidate the returned array.

The number of attributes returned in nAttrs will be one more than the total number of characters in the layout, since there need to be attributes corresponding to both the position before the first character and the position after the last character.

Since: 1.30

Computes the logical and ink extents of layout in device units. This function just calls layoutGetExtents followed by two extentsToPixels calls, rounding inkRect and logicalRect such that the rounded rectangles fully contain the unrounded one (that is, passes them as first argument to extentsToPixels).

Determines the logical width and height of a Layout in device units. (layoutGetSize returns the width and height scaled by SCALE.) This is simply a convenience function around layoutGetPixelExtents.

Returns the current serial number of layout. The serial number is initialized to an small number larger than zero when a new layout is created and is increased whenever the layout is changed using any of the setter functions, or the Context it uses has changed. The serial may wrap, but will never have the value 0. Since it can wrap, never compare it with "less than", always use "not equals".

This can be used to automatically detect changes to a Layout, and is useful for example to decide whether a layout needs redrawing. To force the serial to be increased, use layoutContextChanged.

Since: 1.32.4

Obtains the value set by layoutSetSingleParagraphMode.

Determines the logical width and height of a Layout in Pango units (device units scaled by SCALE). This is simply a convenience function around layoutGetExtents.

Gets the amount of spacing between the lines of the layout.

Gets the current TabArray used by this layout. If no TabArray has been set, then the default tabs are in use and Nothing is returned. Default tabs are every 8 spaces. The return value should be freed with tabArrayFree.

Gets the text in the layout. The returned text should not be freed or modified.

Counts the number unknown glyphs in layout. That is, zero if glyphs for all characters in the layout text were found, or more than zero otherwise.

This function can be used to determine if there are any fonts available to render all characters in a certain string, or when used in combination with AttrTypeFallback, to check if a certain font supports all the characters in the string.

Since: 1.16

Gets the width to which the lines of the Layout should wrap.

Gets the wrap mode for the layout.

Use layoutIsWrapped to query whether any paragraphs were actually wrapped.

Converts from byte index_ within the layout to line and X position. (X position is measured from the left edge of the line)

Converts from an index within a Layout to the onscreen position corresponding to the grapheme at that index, which is represented as rectangle. Note that <literal>pos->x</literal> is always the leading edge of the grapheme and <literal>pos->x + pos->width</literal> the trailing edge of the grapheme. If the directionality of the grapheme is right-to-left, then <literal>pos->width</literal> will be negative.

Queries whether the layout had to ellipsize any paragraphs.

This returns True if the ellipsization mode for layout is not EllipsizeModeNone, a positive width is set on layout, and there are paragraphs exceeding that width that have to be ellipsized.

Since: 1.16

Queries whether the layout had to wrap any paragraphs.

This returns True if a positive width is set on layout, ellipsization mode of layout is set to EllipsizeModeNone, and there are paragraphs exceeding the layout width that have to be wrapped.

Since: 1.16

Computes a new cursor position from an old position and a count of positions to move visually. If direction is positive, then the new strong cursor position will be one position to the right of the old cursor position. If direction is negative, then the new strong cursor position will be one position to the left of the old cursor position.

In the presence of bidirectional text, the correspondence between logical and visual order will depend on the direction of the current run, and there may be jumps when the cursor is moved off of the end of a run.

Motion here is in cursor positions, not in characters, so a single call to layoutMoveCursorVisually may move the cursor over multiple characters when multiple characters combine to form a single grapheme.

Create a new Layout object with attributes initialized to default values for a particular Context.

Sets the alignment for the layout: how partial lines are positioned within the horizontal space available.

Sets the text attributes for a layout object. References attrs, so the caller can unref its reference.

Sets whether to calculate the bidirectional base direction for the layout according to the contents of the layout; when this flag is on (the default), then paragraphs in layout that begin with strong right-to-left characters (Arabic and Hebrew principally), will have right-to-left layout, paragraphs with letters from other scripts will have left-to-right layout. Paragraphs with only neutral characters get their direction from the surrounding paragraphs.

When False, the choice between left-to-right and right-to-left layout is done according to the base direction of the layout's Context. (See contextSetBaseDir).

When the auto-computed direction of a paragraph differs from the base direction of the context, the interpretation of AlignmentLeft and AlignmentRight are swapped.

Since: 1.4

Sets the type of ellipsization being performed for layout. Depending on the ellipsization mode ellipsize text is removed from the start, middle, or end of text so they fit within the width and height of layout set with layoutSetWidth and layoutSetHeight.

If the layout contains characters such as newlines that force it to be layed out in multiple paragraphs, then whether each paragraph is ellipsized separately or the entire layout is ellipsized as a whole depends on the set height of the layout. See layoutSetHeight for details.

Since: 1.6

Sets the default font description for the layout. If no font description is set on the layout, the font description from the layout's context is used.

Sets the height to which the Layout should be ellipsized at. There are two different behaviors, based on whether height is positive or negative.

If height is positive, it will be the maximum height of the layout. Only lines would be shown that would fit, and if there is any text omitted, an ellipsis added. At least one line is included in each paragraph regardless of how small the height value is. A value of zero will render exactly one line for the entire layout.

If height is negative, it will be the (negative of) maximum number of lines per paragraph. That is, the total number of lines shown may well be more than this value if the layout contains multiple paragraphs of text. The default value of -1 means that first line of each paragraph is ellipsized. This behvaior may be changed in the future to act per layout instead of per paragraph. File a bug against pango at <ulink url="http://bugzilla.gnome.org/">http://bugzilla.gnome.org/</ulink> if your code relies on this behavior.

Height setting only has effect if a positive width is set on layout and ellipsization mode of layout is not EllipsizeModeNone. The behavior is undefined if a height other than -1 is set and ellipsization mode is set to EllipsizeModeNone, and may change in the future.

Since: 1.20

Sets the width in Pango units to indent each paragraph. A negative value of indent will produce a hanging indentation. That is, the first line will have the full width, and subsequent lines will be indented by the absolute value of indent.

The indent setting is ignored if layout alignment is set to AlignmentCenter.

Sets whether each complete line should be stretched to fill the entire width of the layout. This stretching is typically done by adding whitespace, but for some scripts (such as Arabic), the justification may be done in more complex ways, like extending the characters.

Note that this setting is not implemented and so is ignored in Pango older than 1.18.

Same as layoutSetMarkupWithAccel, but the markup text isn't scanned for accelerators.

If setting is True, do not treat newlines and similar characters as paragraph separators; instead, keep all text in a single paragraph, and display a glyph for paragraph separator characters. Used when you want to allow editing of newlines on a single text line.

Sets the amount of spacing in Pango unit between the lines of the layout.

Sets the tabs to use for layout, overriding the default tabs (by default, tabs are every 8 spaces). If tabs is Nothing, the default tabs are reinstated. tabs is copied into the layout; you must free your copy of tabs yourself.

Sets the text of the layout.

Note that if you have used layoutSetMarkup or layoutSetMarkupWithAccel on layout before, you may want to call layoutSetAttributes to clear the attributes set on the layout from the markup as this function does not clear attributes.

Sets the width to which the lines of the Layout should wrap or ellipsized. The default value is -1: no width set.

Sets the wrap mode; the wrap mode only has effect if a width is set on the layout with layoutSetWidth. To turn off wrapping, set the width to -1.

Converts from X and Y position within a layout to the byte index to the character at that logical position. If the Y position is not inside the layout, the closest position is chosen (the position will be clamped inside the layout). If the X position is not within the layout, then the start or the end of the line is chosen as described for layoutLineXToIndex. If either the X or Y positions were not inside the layout, then the function returns False; on an exact hit, it returns True.