struct PangoLayout

struct PangoLayout
{
  GObject parent_instance;

  /* If you add fields to PangoLayout, be sure to update both
   * the _copy function
   */
  
  PangoContext *context;
  PangoAttrList *attrs;
  PangoFontDescription *font_desc;
  
  gchar *text;
  int length;			/* length of text in bytes */
  int width;			/* wrap width, in device units */
  int indent;			/* amount by which first line should be shorter */
  int spacing;			/* spacing between lines */

  guint justify : 1;
  guint alignment : 2;

  guint single_paragraph : 1;
  
  gint n_chars;		        /* Total number of characters in layout */
  PangoLogAttr *log_attrs;	/* Logical attributes for layout's text */

  int tab_width;		/* Cached width of a tab. -1 == not yet calculated */

  PangoTabArray *tabs;
  
  GSList *lines;

  PangoWrapMode wrap;
};

The PangoLayout structure represents and entire paragraph of text. It 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 also a number of parameters to adjust the formatting of a PangoLayout, which are illustrated in Figure 1. It is possible, as well, to ignore the 2-D setup, and simply treat the results of a PangoLayout as a list of lines.

Figure 1. Adjustable parameters for a PangoLayout

The PangoLayout structure is opaque, and has no user-visible fields.

struct PangoLayoutIter

struct PangoLayoutIter;

A PangoLayoutIter structure can be used to iterate over the visual extents of a PangoLayout.

The PangoLayoutIter structure is opaque, and has no user-visible fields.

pango_layout_new ()

PangoLayout* pango_layout_new               (PangoContext *context);

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

pango_layout_copy ()

PangoLayout* pango_layout_copy              (PangoLayout *src);

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.

pango_layout_get_context ()

PangoContext* pango_layout_get_context      (PangoLayout *layout);

Retrieves the PangoContext used for this layout.

pango_layout_context_changed ()

void        pango_layout_context_changed    (PangoLayout *layout);

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.

pango_layout_set_text ()

void        pango_layout_set_text           (PangoLayout *layout,
                                             const char *text,
                                             int length);

Set the text of the layout.

pango_layout_get_text ()

const char* pango_layout_get_text           (PangoLayout *layout);

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

pango_layout_set_markup ()

void        pango_layout_set_markup         (PangoLayout *layout,
                                             const char *markup,
                                             int length);

Same as pango_layout_set_markup_with_accel(), but the markup text isn't scanned for accelerators.

pango_layout_set_markup_with_accel ()

void        pango_layout_set_markup_with_accel
                                            (PangoLayout *layout,
                                             const char *markup,
                                             int length,
                                             gunichar accel_marker,
                                             gunichar *accel_char);

Sets the layout text and attribute list from marked-up text (see markup format). Replaces the current text and attribute list.

If accel_marker is nonzero, the given character will mark the character following it as an accelerator. For example, the accel marker might be an ampersand or underscore. All characters marked as an accelerator will receive a PANGO_UNDERLINE_LOW attribute, and the first character so marked will be returned in accel_char. Two accel_marker characters following each other produce a single literal accel_marker character.

pango_layout_set_attributes ()

void        pango_layout_set_attributes     (PangoLayout *layout,
                                             PangoAttrList *attrs);

Sets the text attributes for a layout object

pango_layout_get_attributes ()

PangoAttrList* pango_layout_get_attributes  (PangoLayout *layout);

Gets the attribute list for the layout, if any

pango_layout_set_font_description ()

void        pango_layout_set_font_description
                                            (PangoLayout *layout,
                                             const PangoFontDescription *desc);

Set 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.

pango_layout_set_width ()

void        pango_layout_set_width          (PangoLayout *layout,
                                             int width);

Sets the width to which the lines of the PangoLayout should be wrapped.

pango_layout_get_width ()

int         pango_layout_get_width          (PangoLayout *layout);

Gets the width to which the lines of the PangoLayout should be wrapped.

pango_layout_set_wrap ()

void        pango_layout_set_wrap           (PangoLayout *layout,
                                             PangoWrapMode wrap);

Sets the wrap style; the wrap style only has an effect if a width is set on the layout with pango_layout_set_width(). To turn off wrapping, set the width to -1.

pango_layout_get_wrap ()

PangoWrapMode pango_layout_get_wrap         (PangoLayout *layout);

Get the wrap mode for the layout.

enum PangoWrapMode

typedef enum {
  PANGO_WRAP_WORD,
  PANGO_WRAP_CHAR,
  PANGO_WRAP_WORD_CHAR
} PangoWrapMode;

describes how to wrap the lines of a PangoLayout to the desired width.

PANGO_TYPE_WRAP_MODE

#define PANGO_TYPE_WRAP_MODE (pango_wrap_mode_get_type())

The GObject type for PangoWrapMode.

pango_layout_set_indent ()

void        pango_layout_set_indent         (PangoLayout *layout,
                                             int indent);

Sets the amount by which the first line should be shorter than the rest of the lines. This may be negative, in which case the subsequent lines will be shorter than the first line. (However, in either case, the entire width of the layout will be given by the value

pango_layout_get_indent ()

int         pango_layout_get_indent         (PangoLayout *layout);

Gets the amount by which the first line should be shorter than the rest of the lines.

pango_layout_get_spacing ()

int         pango_layout_get_spacing        (PangoLayout *layout);

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

pango_layout_set_spacing ()

void        pango_layout_set_spacing        (PangoLayout *layout,
                                             int spacing);

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

pango_layout_set_justify ()

void        pango_layout_set_justify        (PangoLayout *layout,
                                             gboolean justify);

Sets whether or not 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 is done by extending the characters.

pango_layout_get_justify ()

gboolean    pango_layout_get_justify        (PangoLayout *layout);

Gets whether or not each complete line should be stretched to fill the entire width of the layout.

pango_layout_set_alignment ()

void        pango_layout_set_alignment      (PangoLayout *layout,
                                             PangoAlignment alignment);

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

pango_layout_get_alignment ()

PangoAlignment pango_layout_get_alignment   (PangoLayout *layout);

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

pango_layout_set_tabs ()

void        pango_layout_set_tabs           (PangoLayout *layout,
                                             PangoTabArray *tabs);

Sets the tabs to use for layout, overriding the default tabs (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.

pango_layout_get_tabs ()

PangoTabArray* pango_layout_get_tabs        (PangoLayout *layout);

Get 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 pango_tab_array_free().

pango_layout_set_single_paragraph_mode ()

void        pango_layout_set_single_paragraph_mode
                                            (PangoLayout *layout,
                                             gboolean setting);

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.

pango_layout_get_single_paragraph_mode ()

gboolean    pango_layout_get_single_paragraph_mode
                                            (PangoLayout *layout);

Obtains the value set by pango_layout_set_single_paragraph_mode().

enum PangoAlignment

typedef enum {
  PANGO_ALIGN_LEFT,
  PANGO_ALIGN_CENTER,
  PANGO_ALIGN_RIGHT
} PangoAlignment;

describes how to align the lines of a PangoLayout within the available space. If the PangoLayout is set to justify using pango_layout_set_justify(), then this only has an effect for partial lines.

PANGO_TYPE_ALIGNMENT

#define PANGO_TYPE_ALIGNMENT (pango_alignment_get_type())

The GObject type for PangoAlignment.

pango_layout_get_log_attrs ()

void        pango_layout_get_log_attrs      (PangoLayout *layout,
                                             PangoLogAttr **attrs,
                                             gint *n_attrs);

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

pango_layout_xy_to_index ()

gboolean    pango_layout_xy_to_index        (PangoLayout *layout,
                                             int x,
                                             int y,
                                             int *index_,
                                             int *trailing);

Convert from X and Y position within a layout to the byte index to the character at that logical position. If the position is not inside the layout, the closest position is chosen (the x/y position will be clamped inside the layout). If a closest position is chosen, then the function returns FALSE; on an exact hit, it returns TRUE.

pango_layout_index_to_pos ()

void        pango_layout_index_to_pos       (PangoLayout *layout,
                                             int index_,
                                             PangoRectangle *pos);

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

pango_layout_get_cursor_pos ()

void        pango_layout_get_cursor_pos     (PangoLayout *layout,
                                             int index_,
                                             PangoRectangle *strong_pos,
                                             PangoRectangle *weak_pos);

Given an index within a layout, determine 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.

pango_layout_move_cursor_visually ()

void        pango_layout_move_cursor_visually
                                            (PangoLayout *layout,
                                             gboolean strong,
                                             int old_index,
                                             int old_trailing,
                                             int direction,
                                             int *new_index,
                                             int *new_trailing);

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

In the presence of bidirection 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 pango_layout_move_cursor_visually() may move the cursor over multiple characters when multiple characters combine to form a single grapheme.

pango_layout_get_extents ()

void        pango_layout_get_extents        (PangoLayout *layout,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Compute the logical and ink extents of layout. Logical extents are usually what you want for positioning things. The extents are given in layout coordinates; layout coordinates begin at the top left corner of the layout.

pango_layout_get_pixel_extents ()

void        pango_layout_get_pixel_extents  (PangoLayout *layout,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Compute the logical and ink extents of layout in device units. See pango_layout_get_extents(); this function just calls pango_layout_get_extents() and then converts the extents to device units using the PANGO_SCALE factor.

pango_layout_get_size ()

void        pango_layout_get_size           (PangoLayout *layout,
                                             int *width,
                                             int *height);

Determine the logical width and height of a PangoLayout in Pango units. (device units divided by PANGO_SCALE). This is simply a convenience function around pango_layout_get_extents.

pango_layout_get_pixel_size ()

void        pango_layout_get_pixel_size     (PangoLayout *layout,
                                             int *width,
                                             int *height);

Determine the logical width and height of a PangoLayout in device units. (pango_layout_get_size() returns the width and height in thousandths of a device unit.) This is simply a convenience function around pango_layout_get_extents.

pango_layout_get_line_count ()

int         pango_layout_get_line_count     (PangoLayout *layout);

Retrieve the count of lines for the layout.

pango_layout_get_line ()

PangoLayoutLine* pango_layout_get_line      (PangoLayout *layout,
                                             int line);

Retrieves a particular line from a PangoLayout.

pango_layout_get_lines ()

GSList*     pango_layout_get_lines          (PangoLayout *layout);

Return the lines of the layout as a list.

pango_layout_get_iter ()

PangoLayoutIter* pango_layout_get_iter      (PangoLayout *layout);

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

pango_layout_iter_free ()

void        pango_layout_iter_free          (PangoLayoutIter *iter);

Frees an iterator that's no longer in use.

pango_layout_iter_next_run ()

gboolean    pango_layout_iter_next_run      (PangoLayoutIter *iter);

Moves iter forward to the next run in visual order. If iter was already at the end of the layout, returns FALSE.

pango_layout_iter_next_char ()

gboolean    pango_layout_iter_next_char     (PangoLayoutIter *iter);

Moves iter forward to the next character in visual order. If iter was already at the end of the layout, returns FALSE.

pango_layout_iter_next_cluster ()

gboolean    pango_layout_iter_next_cluster  (PangoLayoutIter *iter);

Moves iter forward to the next cluster in visual order. If iter was already at the end of the layout, returns FALSE.

pango_layout_iter_next_line ()

gboolean    pango_layout_iter_next_line     (PangoLayoutIter *iter);

Moves iter forward to the start of the next line. If iter is already on the last line, returns FALSE.

pango_layout_iter_at_last_line ()

gboolean    pango_layout_iter_at_last_line  (PangoLayoutIter *iter);

Determines whether iter is on the last line of the layout.

pango_layout_iter_get_index ()

int         pango_layout_iter_get_index     (PangoLayoutIter *iter);

Gets the current byte index. Note that iterating forward by char moves in visual order, not logical order, so indexes may not be sequential. Also, the index may be equal to the length of the text in the layout, if on the NULL run (see pango_layout_iter_get_run()).

pango_layout_iter_get_baseline ()

int         pango_layout_iter_get_baseline  (PangoLayoutIter *iter);

Gets the y position of the current line's baseline, in layout coordinates (origin at top left of the entire layout).

pango_layout_iter_get_run ()

PangoLayoutRun* pango_layout_iter_get_run   (PangoLayoutIter *iter);

Gets the current run. When iterating by run, at the end of each line, there's a position with a NULL run, so this function can return NULL. The NULL run at the end of each line ensures that all lines have at least one run, even lines consisting of only a newline.

pango_layout_iter_get_line ()

PangoLayoutLine* pango_layout_iter_get_line (PangoLayoutIter *iter);

Gets the current line.

pango_layout_iter_get_char_extents ()

void        pango_layout_iter_get_char_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *logical_rect);

Gets the extents of the current character, in layout coordinates (origin is the top left of the entire layout). Only logical extents can sensibly be obtained for characters; ink extents make sense only down to the level of clusters.

pango_layout_iter_get_cluster_extents ()

void        pango_layout_iter_get_cluster_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Gets the extents of the current cluster, in layout coordinates (origin is the top left of the entire layout).

pango_layout_iter_get_run_extents ()

void        pango_layout_iter_get_run_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Gets the extents of the current run in layout coordinates (origin is the top left of the entire layout).

pango_layout_iter_get_line_yrange ()

void        pango_layout_iter_get_line_yrange
                                            (PangoLayoutIter *iter,
                                             int *y0_,
                                             int *y1_);

Divides the vertical space in the PangoLayout being iterated over between the lines in the layout, and returns the space belonging to the current line. A line's range includes the line's logical extents, plus half of the spacing above and below the line, if pango_layout_set_spacing() has been called to set layout spacing. The y positions are in layout coordinates (origin at top left of the entire layout).

pango_layout_iter_get_line_extents ()

void        pango_layout_iter_get_line_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Obtains the extents of the current line. ink_rect or logical_rect can be NULL if you aren't interested in them. Extents are in layout coordinates (origin is the top-left corner of the entire PangoLayout). Thus the extents returned by this function will be the same width/height but not at the same x/y as the extents returned from pango_layout_line_get_extents().

pango_layout_iter_get_layout_extents ()

void        pango_layout_iter_get_layout_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Obtains the extents of the PangoLayout being iterated over. ink_rect or logical_rect can be NULL if you aren't interested in them.

struct PangoLayoutLine

struct PangoLayoutLine
{
  PangoLayout *layout;
  gint         start_index;     /* start of line as byte index into layout->text */
  gint         length;		/* length of line in bytes */
  GSList      *runs;
};

The PangoLayoutLine structure represents one of the lines resulting from laying out a paragraph via PangoLayout. PangoLayoutLine structures are obtained by calling pango_layout_get_line() and are only valid until the text, attributes, or settings of the parent PangoLayout are modified.

Routines for rendering PangoLayout objects are provided in code specific to each rendering system.

PangoLayoutRun

typedef PangoGlyphItem PangoLayoutRun;

The PangoLayoutRun structure represents a single run within a PangoLayoutLine; it is simply an alternate name for PangoGlyphItem, present for backwards compatibility. See the PangoGlyphItem docs for details on the fields.

pango_layout_line_ref ()

void        pango_layout_line_ref           (PangoLayoutLine *line);

Increase the reference count of a PangoLayoutLine by one.

pango_layout_line_unref ()

void        pango_layout_line_unref         (PangoLayoutLine *line);

Decrease the reference count of a PangoLayoutLine by one. if the result is zero, the line and all associated memory will be freed.

pango_layout_line_get_extents ()

void        pango_layout_line_get_extents   (PangoLayoutLine *line,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Compute the logical and ink extents of a layout line. See the documentation for pango_font_get_glyph_extents() for details about the interpretation of the rectangles.

pango_layout_line_get_pixel_extents ()

void        pango_layout_line_get_pixel_extents
                                            (PangoLayoutLine *layout_line,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

Compute the logical and ink extents of a layout line. See the documentation for pango_font_get_glyph_extents() for details about the interpretation of the rectangles. The returned rectangles are in device units, as opposed to pango_layout_line_get_extents(), which returns the extents in PangoGlyphUnit.

pango_layout_line_index_to_x ()

void        pango_layout_line_index_to_x    (PangoLayoutLine *line,
                                             int index_,
                                             gboolean trailing,
                                             int *x_pos);

Converts an index within a line to a X position.

pango_layout_line_x_to_index ()

gboolean    pango_layout_line_x_to_index    (PangoLayoutLine *line,
                                             int x_pos,
                                             int *index_,
                                             int *trailing);

Convert from x offset to the byte index of the corresponding character within the text of the layout. If x_pos is outside the line, the start or end of the line will be stored at index_.

pango_layout_line_get_x_ranges ()

void        pango_layout_line_get_x_ranges  (PangoLayoutLine *line,
                                             int start_index,
                                             int end_index,
                                             int **ranges,
                                             int *n_ranges);

Get a list of visual ranges corresponding to a given logical range. This list is not necessarily minimal - there may be consecutive ranges which are adjacent. The ranges will be sorted from left to right. The ranges are with respect to the left edge of the entire layout, not with respect to the line.