Layout Objects

Layout Objects — Highlevel layout driver objects

Synopsis



            PangoLayout;
            PangoLayoutIter;
PangoLayout* pango_layout_new               (PangoContext *context);
PangoLayout* pango_layout_copy              (PangoLayout *src);
PangoContext* pango_layout_get_context      (PangoLayout *layout);
void        pango_layout_context_changed    (PangoLayout *layout);
void        pango_layout_set_text           (PangoLayout *layout,
                                             const char *text,
                                             int length);
const char* pango_layout_get_text           (PangoLayout *layout);
void        pango_layout_set_markup         (PangoLayout *layout,
                                             const char *markup,
                                             int length);
void        pango_layout_set_markup_with_accel
                                            (PangoLayout *layout,
                                             const char *markup,
                                             int length,
                                             gunichar accel_marker,
                                             gunichar *accel_char);
void        pango_layout_set_attributes     (PangoLayout *layout,
                                             PangoAttrList *attrs);
PangoAttrList* pango_layout_get_attributes  (PangoLayout *layout);
void        pango_layout_set_font_description
                                            (PangoLayout *layout,
                                             const PangoFontDescription *desc);
const PangoFontDescription* pango_layout_get_font_description
                                            (PangoLayout *layout);
void        pango_layout_set_width          (PangoLayout *layout,
                                             int width);
int         pango_layout_get_width          (PangoLayout *layout);
void        pango_layout_set_wrap           (PangoLayout *layout,
                                             PangoWrapMode wrap);
PangoWrapMode pango_layout_get_wrap         (PangoLayout *layout);
enum        PangoWrapMode;
#define     PANGO_TYPE_WRAP_MODE
void        pango_layout_set_ellipsize      (PangoLayout *layout,
                                             PangoEllipsizeMode ellipsize);
PangoEllipsizeMode pango_layout_get_ellipsize
                                            (PangoLayout *layout);
enum        PangoEllipsizeMode;
#define     PANGO_TYPE_ELLIPSIZE_MODE
void        pango_layout_set_indent         (PangoLayout *layout,
                                             int indent);
int         pango_layout_get_indent         (PangoLayout *layout);
int         pango_layout_get_spacing        (PangoLayout *layout);
void        pango_layout_set_spacing        (PangoLayout *layout,
                                             int spacing);
void        pango_layout_set_justify        (PangoLayout *layout,
                                             gboolean justify);
gboolean    pango_layout_get_justify        (PangoLayout *layout);
void        pango_layout_set_auto_dir       (PangoLayout *layout,
                                             gboolean auto_dir);
gboolean    pango_layout_get_auto_dir       (PangoLayout *layout);
void        pango_layout_set_alignment      (PangoLayout *layout,
                                             PangoAlignment alignment);
PangoAlignment pango_layout_get_alignment   (PangoLayout *layout);
void        pango_layout_set_tabs           (PangoLayout *layout,
                                             PangoTabArray *tabs);
PangoTabArray* pango_layout_get_tabs        (PangoLayout *layout);
void        pango_layout_set_single_paragraph_mode
                                            (PangoLayout *layout,
                                             gboolean setting);
gboolean    pango_layout_get_single_paragraph_mode
                                            (PangoLayout *layout);
enum        PangoAlignment;
#define     PANGO_TYPE_ALIGNMENT
void        pango_layout_get_log_attrs      (PangoLayout *layout,
                                             PangoLogAttr **attrs,
                                             gint *n_attrs);
gboolean    pango_layout_xy_to_index        (PangoLayout *layout,
                                             int x,
                                             int y,
                                             int *index_,
                                             int *trailing);
void        pango_layout_index_to_pos       (PangoLayout *layout,
                                             int index_,
                                             PangoRectangle *pos);
void        pango_layout_get_cursor_pos     (PangoLayout *layout,
                                             int index_,
                                             PangoRectangle *strong_pos,
                                             PangoRectangle *weak_pos);
void        pango_layout_move_cursor_visually
                                            (PangoLayout *layout,
                                             gboolean strong,
                                             int old_index,
                                             int old_trailing,
                                             int direction,
                                             int *new_index,
                                             int *new_trailing);
void        pango_layout_get_extents        (PangoLayout *layout,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_get_pixel_extents  (PangoLayout *layout,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_get_size           (PangoLayout *layout,
                                             int *width,
                                             int *height);
void        pango_layout_get_pixel_size     (PangoLayout *layout,
                                             int *width,
                                             int *height);
int         pango_layout_get_line_count     (PangoLayout *layout);
PangoLayoutLine* pango_layout_get_line      (PangoLayout *layout,
                                             int line);
GSList*     pango_layout_get_lines          (PangoLayout *layout);
PangoLayoutIter* pango_layout_get_iter      (PangoLayout *layout);
void        pango_layout_iter_free          (PangoLayoutIter *iter);
gboolean    pango_layout_iter_next_run      (PangoLayoutIter *iter);
gboolean    pango_layout_iter_next_char     (PangoLayoutIter *iter);
gboolean    pango_layout_iter_next_cluster  (PangoLayoutIter *iter);
gboolean    pango_layout_iter_next_line     (PangoLayoutIter *iter);
gboolean    pango_layout_iter_at_last_line  (PangoLayoutIter *iter);
int         pango_layout_iter_get_index     (PangoLayoutIter *iter);
int         pango_layout_iter_get_baseline  (PangoLayoutIter *iter);
PangoLayoutRun* pango_layout_iter_get_run   (PangoLayoutIter *iter);
PangoLayoutLine* pango_layout_iter_get_line (PangoLayoutIter *iter);
void        pango_layout_iter_get_char_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *logical_rect);
void        pango_layout_iter_get_cluster_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_iter_get_run_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_iter_get_line_yrange
                                            (PangoLayoutIter *iter,
                                             int *y0_,
                                             int *y1_);
void        pango_layout_iter_get_line_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_iter_get_layout_extents
                                            (PangoLayoutIter *iter,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);

            PangoLayoutLine;
typedef     PangoLayoutRun;
void        pango_layout_line_ref           (PangoLayoutLine *line);
void        pango_layout_line_unref         (PangoLayoutLine *line);
void        pango_layout_line_get_extents   (PangoLayoutLine *line,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_line_get_pixel_extents
                                            (PangoLayoutLine *layout_line,
                                             PangoRectangle *ink_rect,
                                             PangoRectangle *logical_rect);
void        pango_layout_line_index_to_x    (PangoLayoutLine *line,
                                             int index_,
                                             gboolean trailing,
                                             int *x_pos);
gboolean    pango_layout_line_x_to_index    (PangoLayoutLine *line,
                                             int x_pos,
                                             int *index_,
                                             int *trailing);
void        pango_layout_line_get_x_ranges  (PangoLayoutLine *line,
                                             int start_index,
                                             int end_index,
                                             int **ranges,
                                             int *n_ranges);


Description

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. The objects and functions in this structure provide a high-level driver for formatting entire paragraphs of text at once.

Details

PangoLayout

typedef struct _PangoLayout PangoLayout;

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, “Adjustable parameters for a PangoLayout”. 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

Adjustable parameters for a PangoLayout

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


PangoLayoutIter

typedef struct _PangoLayoutIter 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.

context : a PangoContext
Returns : a new PangoLayout, with a reference count of one.

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.

src : a PangoLayout
Returns : a new PangoLayout identical to src

pango_layout_get_context ()

PangoContext* pango_layout_get_context      (PangoLayout *layout);

Retrieves the PangoContext used for this layout.

layout : a PangoLayout
Returns : The PangoContext for the layout. This does not have an additional refcount added, so if you want to keep a copy of this around, you must reference it yourself.

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.

layout : a PangoLayout

pango_layout_set_text ()

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

Sets the text of the layout.

layout : a PangoLayout
text : a UTF-8 string
length : the length of text, in bytes. -1 indicates that the string is nul-terminated and the length should be calculated.

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.

layout : a PangoLayout
Returns : the text in the layout

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.

layout : a PangoLayout
markup : marked-up text
length : length of marked-up text in bytes, or -1

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.

layout : a PangoLayout
markup : some marked-up text (see markup format)
length : length of markup in bytes
accel_marker : marker for accelerators in the text
accel_char : return location for any located accelerators

pango_layout_set_attributes ()

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

Sets the text attributes for a layout object.

layout : a PangoLayout
attrs : a PangoAttrList

pango_layout_get_attributes ()

PangoAttrList* pango_layout_get_attributes  (PangoLayout *layout);

Gets the attribute list for the layout, if any.

layout : a PangoLayout
Returns : a PangoAttrList

pango_layout_set_font_description ()

void        pango_layout_set_font_description
                                            (PangoLayout *layout,
                                             const PangoFontDescription *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.

layout : a PangoLayout
desc : the new PangoFontDescription, or NULL to unset the current font description.

pango_layout_get_font_description ()

const PangoFontDescription* pango_layout_get_font_description
                                            (PangoLayout *layout);

Gets the font description for the layout, if any.

layout : a PangoLayout
Returns : a pointer to the layout's font description, or NULL if the font description from the layout's context is inherited. This value is owned by the layout and must not be modified or freed.

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.

layout : a PangoLayout.
width : the desired width, or -1 to indicate that no wrapping should be performed.

pango_layout_get_width ()

int         pango_layout_get_width          (PangoLayout *layout);

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

layout : a PangoLayout
Returns : the width

pango_layout_set_wrap ()

void        pango_layout_set_wrap           (PangoLayout *layout,
                                             PangoWrapMode wrap);

Sets the wrap mode; the wrap mode 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.

layout : a PangoLayout
wrap : the wrap mode

pango_layout_get_wrap ()

PangoWrapMode pango_layout_get_wrap         (PangoLayout *layout);

Gets the wrap mode for the layout.

layout : a PangoLayout
Returns : Active wrap mode.

enum PangoWrapMode

typedef enum {
  PANGO_WRAP_WORD,
  PANGO_WRAP_CHAR,
  PANGO_WRAP_WORD_CHAR
} PangoWrapMode;

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

PANGO_WRAP_WORDwrap lines at word boundaries.
PANGO_WRAP_CHARwrap lines at character boundaries.
PANGO_WRAP_WORD_CHARwrap lines at word boundaries, but fall back to character boundaries if there is not enough space for a full word.

PANGO_TYPE_WRAP_MODE

#define PANGO_TYPE_WRAP_MODE (pango_wrap_mode_get_type())

The GObject type for PangoWrapMode.


pango_layout_set_ellipsize ()

void        pango_layout_set_ellipsize      (PangoLayout *layout,
                                             PangoEllipsizeMode 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 lines so they fit within the width of layout set with pango_layout_set_width().

If the layout contains characters such as newlines that force it to be layed out in multiple lines, then each line is ellipsized separately.

layout : a PangoLayout
ellipsize : the new ellipsization mode for layout

Since 1.6


pango_layout_get_ellipsize ()

PangoEllipsizeMode pango_layout_get_ellipsize
                                            (PangoLayout *layout);

Gets the type of ellipsization being performed for layout. See pango_layout_set_ellipsize()

layout : a PangoLayout
Returns : the current ellipsization mode for layout

Since 1.6


enum PangoEllipsizeMode

typedef enum {
  PANGO_ELLIPSIZE_NONE,
  PANGO_ELLIPSIZE_START,
  PANGO_ELLIPSIZE_MIDDLE,
  PANGO_ELLIPSIZE_END
} PangoEllipsizeMode;

The PangoEllipsizeMode type describes what sort of (if any) ellipsization should be applied to a line of text. In the ellipsization process characters are removed from the text in order to make it fit to a given width and replaced with an ellipsis.

PANGO_ELLIPSIZE_NONE No ellipsization
PANGO_ELLIPSIZE_START Omit characters at the start of the text
PANGO_ELLIPSIZE_MIDDLE Omit characters in the middle of the text
PANGO_ELLIPSIZE_END Omit characters at the end of the text

PANGO_TYPE_ELLIPSIZE_MODE

#define PANGO_TYPE_ELLIPSIZE_MODE (pango_ellipsize_mode_get_type())

The GObject type for PangoEllipsizeMode.


pango_layout_set_indent ()

void        pango_layout_set_indent         (PangoLayout *layout,
                                             int indent);

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

layout : a PangoLayout.
indent : the amount by which to indentset

pango_layout_get_indent ()

int         pango_layout_get_indent         (PangoLayout *layout);

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

layout : a PangoLayout
Returns : the indent

pango_layout_get_spacing ()

int         pango_layout_get_spacing        (PangoLayout *layout);

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

layout : a PangoLayout
Returns : the spacing (in PangoGlyphUnit)

pango_layout_set_spacing ()

void        pango_layout_set_spacing        (PangoLayout *layout,
                                             int spacing);

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

layout : a PangoLayout.
spacing : the amount of spacing

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.

Note that as of Pango-1.4, this functionality is not yet implemented.

layout : a PangoLayout
justify : whether the lines in the layout should be justified.

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.

layout : a PangoLayout
Returns : the justify

pango_layout_set_auto_dir ()

void        pango_layout_set_auto_dir       (PangoLayout *layout,
                                             gboolean auto_dir);

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 by according to the base direction of the layout's PangoContext. (See pango_context_set_base_dir()).

When the auto-computed direction or a paragraph differs from the base direction of the context, then the interpretation of PANGO_ALIGN_LEFT and PANGO_ALIGN_RIGHT are swapped.

layout : a PangoLayout
auto_dir : if TRUE, compute the bidirectional base direction from the layout's contents.

pango_layout_get_auto_dir ()

gboolean    pango_layout_get_auto_dir       (PangoLayout *layout);

Gets whether to calculate the bidirectional base direction for the layout according to the contents of the layout. See pango_layout_set_auto_dir().

layout : a PangoLayout
Returns : if TRUE, the bidirectional base direction is computed from the layout's contents.

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.)

layout : a PangoLayout
alignment : the new alignment

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.)

layout : a PangoLayout
Returns : the alignment value

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.

layout : a PangoLayout
tabs : a PangoTabArray

pango_layout_get_tabs ()

PangoTabArray* pango_layout_get_tabs        (PangoLayout *layout);

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 pango_tab_array_free().

layout : a PangoLayout
Returns : a copy of the tabs for this layout, or NULL

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.

layout : a PangoLayout
setting : new setting

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().

layout : a PangoLayout
Returns : TRUE if the layout does not break paragraphs at paragraph separator characters

enum PangoAlignment

typedef enum {
  PANGO_ALIGN_LEFT,
  PANGO_ALIGN_CENTER,
  PANGO_ALIGN_RIGHT
} PangoAlignment;

A 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_ALIGN_LEFTPut all available space on the right
PANGO_ALIGN_CENTERCenter the line within the available space
PANGO_ALIGN_RIGHTPut all available space on the left

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);

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

layout : a PangoLayout
attrs : location to store a pointer to an array of logical attributes This value must be freed with g_free().
n_attrs : location to store the number of the attributes in the array. (The stored value 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.)

pango_layout_xy_to_index ()

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

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 pango_layout_x_to_index(). If either the X or Y positions were not inside the layout, then the function returns FALSE; on an exact hit, it returns TRUE.

layout : a PangoLayout
x : the X offset (in PangoGlyphUnit) from the left edge of the layout.
y : the Y offset (in PangoGlyphUnit) from the top edge of the layout
index_ : location to store calculated byte index
trailing : location to store a integer indicating where in the grapheme the user clicked. It will either be zero, or the number of characters in the grapheme. 0 represents the trailing edge of the grapheme.
Returns : TRUE if the coordinates were inside text

pango_layout_index_to_pos ()

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

Converts 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.

layout : a PangoLayout
index_ : byte index within layout
pos : rectangle in which to store the position of the grapheme

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, 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.

layout : a PangoLayout
index_ : the byte index of the cursor
strong_pos : location to store the strong cursor position (may be NULL)
weak_pos : location to store the weak cursor position (may be NULL)

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.

layout : a PangoLayout.
strong : whether the moving cursor is the strong cursor or the weak cursor. The strong cursor is the cursor corresponding to text insertion in the base direction for the layout.
old_index : the byte index of the grapheme for the old index
old_trailing : if 0, the cursor was at the trailing edge of the grapheme indicated by old_index, if > 0, the cursor was at the leading edge.
direction : direction to move cursor. A negative value indicates motion to the left.
new_index : location to store the new cursor byte index. A value of -1 indicates that the cursor has been moved off the beginning of the layout. A value of G_MAXINT indicates that the cursor has been moved off the end of the layout.
new_trailing : number of characters to move forward from the location returned for new_index to get the position where the cursor should be displayed. This allows distinguishing the position at the beginning of one line from the position at the end of the preceding line. new_index is always on the line where the cursor should be displayed.

pango_layout_get_extents ()

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

Computes 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.

layout : a PangoLayout
ink_rect : rectangle used to store the extents of the layout as drawn or NULL to indicate that the result is not needed.
logical_rect : rectangle used to store the logical extents of the layout or NULL to indicate that the result is not needed.

pango_layout_get_pixel_extents ()

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

Computes 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.

layout : a PangoLayout
ink_rect : rectangle used to store the extents of the layout as drawn or NULL to indicate that the result is not needed.
logical_rect : rectangle used to store the logical extents of the layout or NULL to indicate that the result is not needed.

pango_layout_get_size ()

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

Determines 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().

layout : a PangoLayout
width : location to store the logical width, or NULL
height : location to store the logical height, or NULL

pango_layout_get_pixel_size ()

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

Determines 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().

layout : a PangoLayout
width : location to store the logical width, or NULL
height : location to store the logical height, or NULL

pango_layout_get_line_count ()

int         pango_layout_get_line_count     (PangoLayout *layout);

Retrieves the count of lines for the layout.

layout : PangoLayout
Returns : the line count

pango_layout_get_line ()

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

Retrieves a particular line from a PangoLayout.

layout : a PangoLayout
line : the index of a line, which must be between 0 and pango_layout_get_line_count(layout) - 1, inclusive.
Returns : the requested PangoLayoutLine, or NULL if the index is out of range. This layout line can be ref'ed and retained, but will become invalid if changes are made to the PangoLayout.

pango_layout_get_lines ()

GSList*     pango_layout_get_lines          (PangoLayout *layout);

Returns the lines of the layout as a list.

layout : a PangoLayout
Returns : a GSList containing the lines in the layout. This points to internal data of the PangoLayout and must be used with care. It will become invalid on any change to the layout's text or properties.

pango_layout_get_iter ()

PangoLayoutIter* pango_layout_get_iter      (PangoLayout *layout);

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

layout : a PangoLayout
Returns : a new PangoLayoutIter

pango_layout_iter_free ()

void        pango_layout_iter_free          (PangoLayoutIter *iter);

Frees an iterator that's no longer in use.

iter : a PangoLayoutIter

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.

iter : a PangoLayoutIter
Returns : whether motion was possible

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.

iter : a PangoLayoutIter
Returns : whether motion was possible

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.

iter : a PangoLayoutIter
Returns : whether motion was possible

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.

iter : a PangoLayoutIter
Returns : whether motion was possible

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.

iter : a PangoLayoutIter
Returns : TRUE if iter is on the last line

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()).

iter : a PangoLayoutIter
Returns : current byte index

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).

iter : a PangoLayoutIter
Returns : baseline of current line

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.

iter : a PangoLayoutIter
Returns : the current run

pango_layout_iter_get_line ()

PangoLayoutLine* pango_layout_iter_get_line (PangoLayoutIter *iter);

Gets the current line.

iter : a PangoLayoutIter
Returns : 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.

iter : a PangoLayoutIter
logical_rect : rectangle to fill with logical extents

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).

iter : a PangoLayoutIter
ink_rect : rectangle to fill with ink extents
logical_rect : rectangle to fill with logical extents

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).

iter : a PangoLayoutIter
ink_rect : rectangle to fill with ink extents
logical_rect : rectangle to fill with logical extents

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).

iter : a PangoLayoutIter
y0_ : start of line
y1_ : end of line

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().

iter : a PangoLayoutIter
ink_rect : rectangle to fill with ink extents
logical_rect : rectangle to fill with logical 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.

iter : a PangoLayoutIter
ink_rect : rectangle to fill with ink extents
logical_rect : rectangle to fill with logical extents

PangoLayoutLine

typedef struct {
  PangoLayout *layout;
  gint         start_index;     /* start of line as byte index into layout->text */
  gint         length;		/* length of line in bytes */
  GSList      *runs;
  guint        is_paragraph_start : 1;  /* TRUE if this is the first line of the paragraph */ 
  guint        resolved_dir : 3;  /* Resolved direction of line */
} PangoLayoutLine;

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.

PangoLayout *layout;the parent layout for this line.
gint start_index;the start of the line as byte index into layout->text.
gint length;the length of the line in bytes.
GSList *runs;a list containing the runs of the line in visual order.
guint is_paragraph_start : 1;TRUE if this is the first line of the paragraph.
guint resolved_dir : 3;

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);

Increases the reference count of a PangoLayoutLine by one.

line : a PangoLayoutLine

pango_layout_line_unref ()

void        pango_layout_line_unref         (PangoLayoutLine *line);

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

line : a PangoLayoutLine

pango_layout_line_get_extents ()

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

Computes 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.

line : a PangoLayoutLine
ink_rect : rectangle used to store the extents of the glyph string as drawn or NULL to indicate that the result is not needed.
logical_rect : rectangle used to store the logical extents of the glyph string or NULL to indicate that the result is not needed.

pango_layout_line_get_pixel_extents ()

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

Computes 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.

layout_line : a PangoLayoutLine
ink_rect : rectangle used to store the extents of the glyph string as drawn or NULL to indicate that the result is not needed.
logical_rect : rectangle used to store the logical extents of the glyph string or NULL to indicate that the result is not needed.

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.

line : a PangoLayoutLine
index_ : byte offset of a grapheme within the layout
trailing : an integer indicating the edge of the grapheme to retrieve the position of. If 0, the trailing edge of the grapheme, if > 0, the leading of the grapheme.
x_pos : location to store the x_offset (in PangoGlyphUnit)

pango_layout_line_x_to_index ()

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

Converts from x offset to the byte index of the corresponding character within the text of the layout. If x_pos is outside the line, index_ and trailing will point to the very first or very last position in the line. This determination is based on the resolved direction of the paragraph; for example, if the resolved direction is right-to-left, then an X position to the right of the line (after it) results in 0 being stored in index_ and trailing. An X position to the left of the line results in index_ pointing to the (logical) last grapheme in the line and trailing being set to the number of characters in that grapheme. The reverse is true for a left-to-right line.

line : a PangoLayoutLine
x_pos : the x offset (in PangoGlyphUnit) from the left edge of the line.
index_ : location to store calculated byte index for the grapheme in which the user clicked.
trailing : location to store a integer indicating where in the grapheme the user clicked. It will either be zero, or the number of characters in the grapheme. 0 represents the trailing edge of the grapheme.
Returns : FALSE if x_pos was outside the line, TRUE if inside

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);

Gets 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.

line : a PangoLayoutLine
start_index : Start byte index of the logical range. If this value is less than the start index for the line, then the first range will extend all the way to the leading edge of the layout. Otherwise it will start at the leading edge of the first character.
end_index : Ending byte index of the logical range. If this value is greater than the end index for the line, then the last range will extend all the way to the trailing edge of the layout. Otherwise, it will end at the trailing edge of the last character.
ranges : location to store a pointer to an array of ranges. The array will be of length 2*n_ranges, with each range starting at (*ranges)[2*n] and of width (*ranges)[2*n + 1] - (*ranges)[2*n]. This array must be freed with g_free(). The coordinates are relative to the layout and are in PangoGlyphUnit.
n_ranges : The number of ranges stored in ranges.