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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 16:23:26 -0400
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+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html>
+<head>
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+<title>cairo_path_t: Cairo: A Vector Graphics Library</title>
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+<link rel="home" href="index.html" title="Cairo: A Vector Graphics Library">
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+<div class="sect1">
+<div class="titlepage"><div><div><h2 class="title" style="clear: both">
+<a name="bindings-path"></a>cairo_path_t</h2></div></div></div>
+<p>
+      The <a class="link" href="cairo-Paths.html#cairo-path-t" title="cairo_path_t"><span class="type">cairo_path_t</span></a> type is one
+      area in which most language bindings will differ significantly
+      from the C API. The C API for <span class="type">cairo_path_t</span> is
+      designed for efficiency and to avoid auxiliary objects that
+      would be have to be manually memory managed by the
+      application. However,
+      a language binding should not present <span class="type">cairo_path_t</span> as an
+      array, but rather as an opaque that can be iterated
+      over. Different languages have quite different conventions for
+      how iterators work, so it is impossible to give an exact
+      specification for how this API should work, but the type names
+      and methods should be similar to the language's mapping of the following:
+    </p>
+<pre class="programlisting">
+typedef struct cairo_path_iterator cairo_path_iterator_t;
+typedef struct cairo_path_element cairo_path_element_t;
+
+cairo_path_iterator_t *
+cairo_path_get_iterator (cairo_path_t *path);
+
+cairo_bool_t
+cairo_path_iterator_has_next (cairo_path_iterator_t *iterator);
+      
+cairo_path_element_t *
+cairo_path_iterator_next (cairo_path_iterator_t *iterator);
+
+cairo_path_element_type_t
+cairo_path_element_get_type (cairo_path_element_t *element);
+      
+void
+cairo_path_element_get_point (cairo_path_element_t *element,
+                              int                   index,
+                              double                *x,
+                              double                *y);
+    </pre>
+<p>
+      The above is written using the Java conventions for
+      iterators. To illustrate how the API for PathIterator might
+      depend on the native iteration conventions of the API, examine
+      three versions of the loop, first written in a hypothetical Java
+      binding:
+    </p>
+<pre class="programlisting">
+PathIterator iter = cr.copyPath().iterator();
+while (cr.hasNext()) {
+    PathElement element = iter.next();
+    if (element.getType() == PathElementType.MOVE_TO) {
+        Point p = element.getPoint(0);
+        doMoveTo (p.x, p.y);
+    }
+}</pre>
+<p>
+      And then in a hypothetical C++ binding:
+    </p>
+<pre class="programlisting">
+Path path = cr.copyPath();
+for (PathIterator iter = path.begin(); iter != path.end(); iter++) {
+    PathElement element = *iter;
+    if (element.getType() == PathElementType.MOVE_TO) {
+        Point p = element.getPoint(0);
+        doMoveTo (p.x, p.y);
+    }
+}</pre>
+<p>
+      And then finally in a Python binding:
+    </p>
+<pre class="programlisting">
+for element in cr.copy_path():
+    if element.getType == cairo.PATH_ELEMENT_MOVE_TO:
+        (x, y) = element.getPoint(0)
+        doMoveTo (x, y);</pre>
+<p>
+      While many of the API elements stay the same in the three
+      examples, the exact iteration mechanism is quite different, to
+      match how users of the language would expect to iterate over
+      a container.
+    </p>
+<p>
+      You should not present an API for mutating or for creating new
+      <span class="type">cairo_path_t</span> objects. In the future, these
+      guidelines may be extended to present an API for creating a
+      <span class="type">cairo_path_t</span> from scratch for use with
+      <a class="link" href="cairo-Paths.html#cairo-append-path" title="cairo_append_path ()"><code class="function">cairo_append_path()</code></a>
+      but the current expectation is that <code class="function">cairo_append_path()</code> will
+      mostly be used with paths from
+      <a class="link" href="cairo-Paths.html#cairo-append-path" title="cairo_append_path ()"><code class="function">cairo_copy_path()</code></a>.
+    </p>
+</div>
+<div class="footer">
+<hr>Generated by GTK-Doc V1.27</div>
+</body>
+</html>
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