class: Layout

[36:7] extends: object

A PangoLayout structure represents an entire paragraph of text. While complete access to the layout capabilities of Pango is provided using the detailed interfaces for itemization and shaping, using that functionality directly involves writing a fairly large amount of code. PangoLayout provides a high-level driver for formatting entire paragraphs of text at once. This includes paragraph-level functionality such as line breaking, justification, alignment and ellipsization. A PangoLayout is initialized with a PangoContext, UTF-8 string and set of attributes for that string. Once that is done, the set of formatted lines can be extracted from the object, the layout can be rendered, and conversion between logical character positions within the layout's text, and the physical position of the resulting glyphs can be made. There are a number of parameters to adjust the formatting of a PangoLayout. The following image shows adjustable parameters (on the left) and font metrics (on the right): The following images demonstrate the effect of alignment and justification on the layout of text: | | | | --- | --- | | | | | | | | | | It is possible, as well, to ignore the 2-D setup, and simply treat the results of a PangoLayout as a list of lines.

Members

• handleObj
• lib
• retainedCallbacks
• signalHandlerNames
• signalSetterHandlers

Methods

• Layout (context = null)

  Create a new PangoLayout object with attributes initialized to default values for a particular PangoContext.

  • @p context is a PangoContext.

• toNativeHandle (Source)

  Normalizes a constructor argument into a raw pointer carrier. Accepts a raw NativeHandle, a raw NativeBuffer returned from fn.call(...), another generated wrapper exposing handle(), or null. Returns null when the argument carries no pointer.

  • @p Source is the raw handle, raw buffer, wrapper, or null.
  • @r A raw pointer carrier or null when no pointer is present.

• getLib ()

  Returns the opened native library for this generated wrapper.

  • @r The opened native library.

• handle ()

  Returns the wrapped NativeHandle.

  • @r The wrapped NativeHandle.

• isNull ()

  Returns true when the wrapped handle is null.

  • @r A bool.

• describe ()

  Returns a small string for debugging generated wrappers.

  • @r A string.

• asObject ()

  Wraps this handle as Object.

  • @r A Object object.

• context_changed ()

  Forces recomputation of any state in the PangoLayout 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.

  • @r None.

• copy ()

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

• get_alignment ()

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

• get_attributes ()

  Gets the attribute list for the layout, if any.

• get_auto_dir ()

  Gets whether to calculate the base direction for the layout according to its contents. See [method@Pango.Layout.set_auto_dir].

• get_baseline ()

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

• get_character_count ()

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

• get_context ()

  Retrieves the PangoContext used for this layout.

• get_direction (int index)

  Gets the text direction at the given character position in @layout.

  • @p index is the byte index of the char.

• get_ellipsize ()

  Gets the type of ellipsization being performed for @layout. See [method@Pango.Layout.set_ellipsize]. Use [method@Pango.Layout.is_ellipsized] to query whether any paragraphs were actually ellipsized.

• get_font_description ()

  Gets the font description for the layout, if any.

• get_height ()

  Gets the height of layout used for ellipsization. See [method@Pango.Layout.set_height] for details.

• get_indent ()

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

• get_iter ()

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

• get_justify ()

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

• get_justify_last_line ()

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

• get_line (int line)

  Retrieves a particular line from a PangoLayout. Use the faster [method@Pango.Layout.get_line_readonly] if you do not plan to modify the contents of the line (glyphs, glyph widths, etc.).

  • @p line is the index of a line, which must be between 0 and pango_layout_get_line_count(layout) - 1, inclusive..

• get_line_count ()

  Retrieves the count of lines for the @layout.

• get_line_readonly (int line)

  Retrieves a particular line from a PangoLayout. This is a faster alternative to [method@Pango.Layout.get_line], but the user is not expected to modify the contents of the line (glyphs, glyph widths, etc.).

  • @p line is the index of a line, which must be between 0 and pango_layout_get_line_count(layout) - 1, inclusive..

• get_line_spacing ()

  Gets the line spacing factor of @layout. See [method@Pango.Layout.set_line_spacing].

• get_lines ()

  Returns the lines of the @layout as a list. Use the faster [method@Pango.Layout.get_lines_readonly] if you do not plan to modify the contents of the lines (glyphs, glyph widths, etc.).

• get_lines_readonly ()

  Returns the lines of the @layout as a list. This is a faster alternative to [method@Pango.Layout.get_lines], but the user is not expected to modify the contents of the lines (glyphs, glyph widths, etc.).

• get_serial ()

  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 PangoContext 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 PangoLayout, and is useful for example to decide whether a layout needs redrawing. To force the serial to be increased, use [method@Pango.Layout.context_changed].

• get_single_paragraph_mode ()

  Obtains whether @layout is in single paragraph mode. See [method@Pango.Layout.set_single_paragraph_mode].

• get_spacing ()

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

• get_tabs ()

  Gets the current PangoTabArray used by this layout. If no PangoTabArray has been set, then the default tabs are in use and %NULL is returned. Default tabs are every 8 spaces. The return value should be freed with [method@Pango.TabArray.free].

• get_text ()

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

• get_unknown_glyphs_count ()

  Counts the number of unknown glyphs in @layout. 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 %PANGO_ATTR_FALLBACK, to check if a certain font supports all the characters in the string.

• get_width ()

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

• get_wrap ()

  Gets the wrap mode for the layout. Use [method@Pango.Layout.is_wrapped] to query whether any paragraphs were actually wrapped.

• is_ellipsized ()

  Queries whether the layout had to ellipsize any paragraphs. This returns %TRUE if the ellipsization mode for @layout is not %PANGO_ELLIPSIZE_NONE, a positive width is set on @layout, and there are paragraphs exceeding that width that have to be ellipsized.

• is_wrapped ()

  Queries whether the layout had to wrap any paragraphs. This returns %TRUE if a positive width is set on @layout, and there are paragraphs exceeding the layout width that have to be wrapped.

• serialize (string flags)

  Serializes the @layout for later deserialization via [func@Pango.Layout.deserialize]. There are no guarantees about the format of the output across different versions of Pango and [func@Pango.Layout.deserialize] will reject data that it cannot parse. The intended use of this function is testing, benchmarking and debugging. The format is not meant as a permanent storage format.

  • @p flags is PangoLayoutSerializeFlags.

• set_alignment (string alignment)

  Sets the alignment for the layout: how partial lines are positioned within the horizontal space available. The default alignment is %PANGO_ALIGN_LEFT.

  • @p alignment is the alignment.
  • @r None.

• set_attributes (object attrs)

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

  • @p attrs is a PangoAttrList.
  • @r None.

• set_auto_dir (bool auto_dir)

  Sets whether to calculate the base direction for the layout according to its contents. 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 PangoContext. (See [method@Pango.Context.set_base_dir]). When the auto-computed direction of a paragraph differs from the base direction of the context, the interpretation of %PANGO_ALIGN_LEFT and %PANGO_ALIGN_RIGHT are swapped.
  • @p auto_dir is if %TRUE, compute the bidirectional base direction from the layout's contents.
  • @r None.

• set_ellipsize (string ellipsize)

  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 [method@Pango.Layout.set_width] and [method@Pango.Layout.set_height]. 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. The default value is %PANGO_ELLIPSIZE_NONE. See [method@Pango.Layout.set_height] for details.

  • @p ellipsize is the new ellipsization mode for @layout.
  • @r None.

• set_font_description (object desc)

  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.

  • @p desc is the new PangoFontDescription to unset the current font description.
  • @r None.

• set_height (int height)

  Sets the height to which the PangoLayout 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 the first line of each paragraph is ellipsized. This behavior may be changed in the future to act per layout instead of per paragraph. File a bug against pango at https://gitlab.gnome.org/gnome/pango 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 %PANGO_ELLIPSIZE_NONE. The behavior is undefined if a height other than -1 is set and ellipsization mode is set to %PANGO_ELLIPSIZE_NONE, and may change in the future.

  • @p height is the desired height of the layout in Pango units if positive, or desired number of lines if negative..
  • @r None.

• set_indent (int indent)

  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 %PANGO_ALIGN_CENTER. The default value is 0.

  • @p indent is the amount by which to indent.
  • @r None.

• set_justify (bool justify)

  Sets whether each complete line should be stretched to fill the entire width of the layout. 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. Note that tabs and justification conflict with each other: Justification will move content away from its tab-aligned positions. The default value is %FALSE. Also see [method@Pango.Layout.set_justify_last_line].

  • @p justify is whether the lines in the layout should be justified.
  • @r None.

• set_justify_last_line (bool justify)

  Sets whether the last line should be stretched to fill the entire width of the layout. This only has an effect if [method@Pango.Layout.set_justify] has been called as well. The default value is %FALSE.

  • @p justify is whether the last line in the layout should be justified.
  • @r None.

• set_line_spacing (double factor)

  Sets a factor for line spacing. Typical values are: 0, 1, 1.5, 2. The default values is 0. If @factor is non-zero, lines are placed so that baseline2 = baseline1 + factor * height2 where height2 is the line height of the second line (as determined by the font(s)). In this case, the spacing set with [method@Pango.Layout.set_spacing] is ignored. If @factor is zero (the default), spacing is applied as before. Note: for semantics that are closer to the CSS line-height property, see [func@Pango.attr_line_height_new].

  • @p factor is the new line spacing factor.
  • @r None.

• set_markup (string markup, int length)

  Sets the layout text and attribute list from marked-up text. See Pango Markup). Replaces the current text and attribute list. This is the same as [method@Pango.Layout.set_markup_with_accel], but the markup text isn't scanned for accelerators.

  • @p markup is marked-up text.
  • @p length is length of marked-up text in bytes, or -1 if @markup is NUL-terminated.
  • @r None.

• set_single_paragraph_mode (bool setting)

  Sets the single paragraph mode of @layout. 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. The default value is %FALSE.

  • @p setting is new setting.
  • @r None.

• set_spacing (int spacing)

  Sets the amount of spacing in Pango units between the lines of the layout. When placing lines with spacing, Pango arranges things so that line2.top = line1.bottom + spacing The default value is 0. Note: Since 1.44, Pango is using the line height (as determined by the font) for placing lines when the line spacing factor is set to a non-zero value with [method@Pango.Layout.set_line_spacing]. In that case, the @spacing set with this function is ignored. Note: for semantics that are closer to the CSS line-height property, see [func@Pango.attr_line_height_new].

  • @p spacing is the amount of spacing.
  • @r None.

• set_tabs (object tabs)

  Sets the tabs to use for @layout, overriding the default tabs. PangoLayout will place content at the next tab position whenever it meets a Tab character (U+0009). By default, tabs are every 8 spaces. If

  • @tabs is %NULL, the default tabs are reinstated. @tabs is copied into the layout; you must free your copy of @tabs yourself. Note that tabs and justification conflict with each other: Justification will move content away from its tab-aligned positions. The same is true for alignments other than %PANGO_ALIGN_LEFT.
  • @p tabs is a PangoTabArray.
  • @r None.

• set_text (string text, int length)

  Sets the text of the layout. This function validates @text and renders invalid UTF-8 with a placeholder glyph. Note that if you have used [method@Pango.Layout.set_markup] or [method@Pango.Layout.set_markup_with_accel] on @layout before, you may want to call [method@Pango.Layout.set_attributes] to clear the attributes set on the layout from the markup as this function does not clear attributes.

  • @p text is the text.
  • @p length is maximum length of @text, in bytes. -1 indicates that the string is nul-terminated and the length should be calculated. The text will also be truncated on encountering a nul-termination even when
  • @length is positive..
  • @r None.

• set_width (int width)

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

  • @p width is the desired width in Pango units, or -1 to indicate that no wrapping or ellipsization should be performed..
  • @r None.

• set_wrap (string wrap)

  Sets the wrap mode. The wrap mode only has effect if a width is set on the layout with [method@Pango.Layout.set_width]. To turn off wrapping, set the width to -1. The default value is %PANGO_WRAP_WORD.

  • @p wrap is the wrap mode.
  • @r None.

• write_to_file (string flags, string filename)

  A convenience method to serialize a layout to a file. It is equivalent to calling [method@Pango.Layout.serialize] followed by [func@GLib.file_set_contents]. See those two functions for details on the arguments. It is mostly intended for use inside a debugger to quickly dump a layout to a file for later inspection.

  • @p flags is PangoLayoutSerializeFlags.
  • @p filename is the file to save it to.

• lines ()

  Returns get_lines as an Aussom list of wrapper objects. This companion method materializes the full collection up front; use get_lines() when lazy or change-notify access is required.

  • @r An Aussom list of elements.

• lines_readonly ()

  Returns get_lines_readonly as an Aussom list of wrapper objects. This companion method materializes the full collection up front; use get_lines_readonly() when lazy or change-notify access is required.

  • @r An Aussom list of elements.