Struct pango::GlyphItemIter[][src]

pub struct GlyphItemIter(_);
Expand description

A GlyphItemIter is an iterator over the clusters in a GlyphItem. The <firstterm>forward direction</firstterm> of the iterator is the logical direction of text. That is, with increasing start_index and start_char values. If glyph_item is right-to-left (that is, if <literal>``glyph_item->item->analysis.level</literal> is odd), then start_glyph decreases as the iterator moves forward. Moreover, in right-to-left cases, start_glyph is greater than end_glyph.

An iterator should be initialized using either of init_start() and init_end(), for forward and backward iteration respectively, and walked over using any desired mixture of next_cluster() and prev_cluster(). A common idiom for doing a forward iteration over the clusters is: <programlisting> PangoGlyphItemIter cluster_iter; gboolean have_cluster;

for (have_cluster = pango_glyph_item_iter_init_start (&cluster_iter, glyph_item, text); have_cluster; have_cluster = pango_glyph_item_iter_next_cluster (&cluster_iter)) { … } </programlisting>

Note that text is the start of the text for layout, which is then indexed by <literal>``glyph_item->item->offset</literal> to get to the text of glyph_item. The start_index and end_index values can directly index into text. The start_glyph, end_glyph, start_char, and end_char values however are zero-based for the glyph_item. For each cluster, the item pointed at by the start variables is included in the cluster while the one pointed at by end variables is not.

None of the members of a GlyphItemIter should be modified manually.

Implementations

Initializes a GlyphItemIter structure to point to the last cluster in a glyph item. See GlyphItemIter for details of cluster orders.

glyph_item

the glyph item to iterate over

text

text corresponding to the glyph item

Returns

false if there are no clusters in the glyph item

Initializes a GlyphItemIter structure to point to the first cluster in a glyph item. See GlyphItemIter for details of cluster orders.

glyph_item

the glyph item to iterate over

text

text corresponding to the glyph item

Returns

false if there are no clusters in the glyph item

Advances the iterator to the next cluster in the glyph item. See GlyphItemIter for details of cluster orders.

Returns

true if the iterator was advanced, false if we were already on the last cluster.

Moves the iterator to the preceding cluster in the glyph item. See GlyphItemIter for details of cluster orders.

Returns

true if the iterator was moved, false if we were already on the first cluster.

Trait Implementations

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