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<div class="section" id="converting-sequences">
<h1>Converting sequences<a class="headerlink" href="#converting-sequences" title="Permalink to this headline"></a></h1>
<p>This module provides various functions and classes to access sequences and
buffer-style objects in different ways. It also provides conversion routines
to improve the interoperability of sequences with <a class="reference external" href="http://docs.python.org/library/ctypes.html#module-ctypes" title="(in Python v2.7)"><code class="xref py py-mod docutils literal"><span class="pre">ctypes</span></code></a> data types.</p>
<div class="section" id="providing-read-write-access-for-sequential-data">
<h2>Providing read-write access for sequential data<a class="headerlink" href="#providing-read-write-access-for-sequential-data" title="Permalink to this headline"></a></h2>
<p>Two classes allow you to access sequential data in different ways. The
<a class="reference internal" href="#sdl2.ext.CTypesView" title="sdl2.ext.CTypesView"><code class="xref py py-class docutils literal"><span class="pre">CTypesView</span></code></a> provides byte-wise access to iterable objects and allows
you to convert the object representation to matching byte-widths for
<a class="reference external" href="http://docs.python.org/library/ctypes.html#module-ctypes" title="(in Python v2.7)"><code class="xref py py-mod docutils literal"><span class="pre">ctypes</span></code></a> or other modules.</p>
<p>Depending on the the underlying object and the chosen size of each particular
item of the object, the <a class="reference internal" href="#sdl2.ext.CTypesView" title="sdl2.ext.CTypesView"><code class="xref py py-class docutils literal"><span class="pre">CTypesView</span></code></a> allows you to operate directly
on different representations of the object&#8217;s contents.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">text</span> <span class="o">=</span> <span class="nb">bytearray</span><span class="p">(</span><span class="s2">&quot;Hello, I am a simple ASCII string!&quot;</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ctview</span> <span class="o">=</span> <span class="n">CTypesView</span><span class="p">(</span><span class="n">text</span><span class="p">,</span> <span class="n">itemsize</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ctview</span><span class="o">.</span><span class="n">view</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">=</span> <span class="mh">0x61</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">text</span><span class="p">)</span>
<span class="go">aello, I am a simple ASCII string!&quot;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ctview</span><span class="o">.</span><span class="n">to_uint16</span><span class="p">()[</span><span class="mi">3</span><span class="p">]</span> <span class="o">=</span> <span class="mh">0x6554</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">text</span><span class="p">)</span>
<span class="go">aello,Te am a simple ASCII string!&quot;</span>
</pre></div>
</div>
<p>The snippet above provides a single-byte sized view on a <a class="reference external" href="http://docs.python.org/library/functions.html#bytearray" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">bytearray()</span></code></a>
object. Afterwards, the first item of the view is changed, which causes a
change on the <a class="reference external" href="http://docs.python.org/library/functions.html#bytearray" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">bytearray()</span></code></a>, on the first item as well, since both, the
<a class="reference internal" href="#sdl2.ext.CTypesView" title="sdl2.ext.CTypesView"><code class="xref py py-class docutils literal"><span class="pre">CTypesView</span></code></a> and the <a class="reference external" href="http://docs.python.org/library/functions.html#bytearray" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">bytearray()</span></code></a> provide a byte-wise access to
the contents.</p>
<p>By using <a class="reference internal" href="#sdl2.ext.CTypesView.to_uint16" title="sdl2.ext.CTypesView.to_uint16"><code class="xref py py-meth docutils literal"><span class="pre">CTypesView.to_uint16()</span></code></a>, we change the access representation to
a 2-byte unsigned integer <a class="reference external" href="http://docs.python.org/library/ctypes.html#module-ctypes" title="(in Python v2.7)"><code class="xref py py-mod docutils literal"><span class="pre">ctypes</span></code></a> pointer and change the fourth 2-byte
value, <em>I</em> to something else.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>&gt;&gt;&gt; text = bytearray(&quot;Hello, I am a simple ASCII string!&quot;)
&gt;&gt;&gt; ctview = CTypesView(text, itemsize=2)
&gt;&gt;&gt; ctview.view[0] = 0x61
&gt;&gt;&gt; print(text)
aello, I am a simple ASCII string!&quot;
&gt;&gt;&gt; ctview.to_uint16()[3] = 0x6554
&gt;&gt;&gt; print(text) aello,Te am a simple ASCII string!&quot;
</pre></div>
</div>
<p>If the encapsuled object does not provide a (writable) <a class="reference external" href="http://docs.python.org/library/functions.html#buffer" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">buffer()</span></code></a>
interface, but is iterable, the <a class="reference internal" href="#sdl2.ext.CTypesView" title="sdl2.ext.CTypesView"><code class="xref py py-class docutils literal"><span class="pre">CTypesView</span></code></a> will create an
internal copy of the object data using Python&#8217;s <a class="reference external" href="http://docs.python.org/library/array.html#module-array" title="(in Python v2.7)"><code class="xref py py-mod docutils literal"><span class="pre">array</span></code></a> module and
perform all operations on that copy.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">mylist</span> <span class="o">=</span> <span class="p">[</span><span class="mi">18</span><span class="p">,</span> <span class="mi">52</span><span class="p">,</span> <span class="mi">86</span><span class="p">,</span> <span class="mi">120</span><span class="p">,</span> <span class="mi">154</span><span class="p">,</span> <span class="mi">188</span><span class="p">,</span> <span class="mi">222</span><span class="p">,</span> <span class="mi">240</span><span class="p">]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ctview</span> <span class="o">=</span> <span class="n">CTypesView</span><span class="p">(</span><span class="n">mylist</span><span class="p">,</span> <span class="n">itemsize</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">docopy</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">ctview</span><span class="o">.</span><span class="n">object</span><span class="p">)</span>
<span class="go">array(&#39;B&#39;, [18, 52, 86, 120, 154, 188, 222, 240])</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ctview</span><span class="o">.</span><span class="n">view</span><span class="p">[</span><span class="mi">3</span><span class="p">]</span> <span class="o">=</span> <span class="mh">0xFF</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">mylist</span><span class="p">)</span>
<span class="go">[18, 52, 86, 120, 154, 188, 222, 240]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">ctview</span><span class="o">.</span><span class="n">object</span><span class="p">)</span>
<span class="go">array(&#39;B&#39;, [18, 52, 86, 255, 154, 188, 222, 240])</span>
</pre></div>
</div>
<p>As for directly accessible objects, you can define your own itemsize to
be used. If the iterable does not provide a direct byte access to their
contents, this won&#8217;t have any effect except for resizing the item
widths.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">mylist</span> <span class="o">=</span> <span class="p">[</span><span class="mi">18</span><span class="p">,</span> <span class="mi">52</span><span class="p">,</span> <span class="mi">86</span><span class="p">,</span> <span class="mi">120</span><span class="p">,</span> <span class="mi">154</span><span class="p">,</span> <span class="mi">188</span><span class="p">,</span> <span class="mi">222</span><span class="p">,</span> <span class="mi">240</span><span class="p">]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">ctview</span> <span class="o">=</span> <span class="n">CTypesView</span><span class="p">(</span><span class="n">mylist</span><span class="p">,</span> <span class="n">itemsize</span><span class="o">=</span><span class="mi">4</span><span class="p">,</span> <span class="n">docopy</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">ctview</span><span class="o">.</span><span class="n">object</span><span class="p">)</span>
<span class="go">array(&#39;I&#39;, [18L, 52L, 86L, 120L, 154L, 188L, 222L, 240L])</span>
</pre></div>
</div>
</div>
<div class="section" id="accessing-data-over-multiple-dimensions">
<h2>Accessing data over multiple dimensions<a class="headerlink" href="#accessing-data-over-multiple-dimensions" title="Permalink to this headline"></a></h2>
<p>The second class, <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a> provides an interface to access
data over multiple dimensions. You can layout and access a simple
byte stream over e.g. two or more axes, providing a greater flexibility
for functional operations and complex data.</p>
<p>Let&#8217;s assume, we are reading image data from a file stream into some buffer
object and want to access and manipulate the image data. Images feature two
axes, one being the width, the other being the height, defining a rectangular
graphics area.</p>
<p>When we read all data from the file, we have an one-dimensional view of the
image graphics. The <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a> allows us to define a
two-dimensional view over the image graphics, so that we can operate on
both, rows and columns of the image.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">imagedata</span> <span class="o">=</span> <span class="nb">bytearray</span><span class="p">(</span><span class="s2">&quot;some 1-byte graphics data&quot;</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">view</span> <span class="o">=</span> <span class="n">MemoryView</span><span class="p">(</span><span class="n">imagedata</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">5</span><span class="p">))</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">view</span><span class="p">)</span>
<span class="go">[[s, o, m, e, ], [1, -, b, y, t], [e, , g, r, a], [p, h, i, c, s], [ , d, a, t, a]]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">view</span><span class="p">:</span>
<span class="gp">... </span> <span class="nb">print</span><span class="p">(</span><span class="n">row</span><span class="p">)</span>
<span class="gp">...</span>
<span class="go">[s, o, m, e, ]</span>
<span class="go">[1, -, b, y, t]</span>
<span class="go">[e, , g, r, a]</span>
<span class="go">[p, h, i, c, s]</span>
<span class="go">[ , d, a, t, a]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">view</span><span class="p">:</span>
<span class="gp">... </span> <span class="n">row</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">=</span> <span class="s2">&quot;X&quot;</span>
<span class="gp">... </span> <span class="nb">print</span> <span class="n">row</span>
<span class="gp">...</span>
<span class="go">[s, X, m, e, ]</span>
<span class="go">[1, X, b, y, t]</span>
<span class="go">[e, X, g, r, a]</span>
<span class="go">[p, X, i, c, s]</span>
<span class="go">[ , X, a, t, a]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">imagedata</span><span class="p">)</span>
<span class="go">sXme 1XbyteXgrapXics Xata</span>
</pre></div>
</div>
<p>On accessing a particular dimension of a <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a>, a new
<a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a> is created, if it does not access a single
element.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">firstrow</span> <span class="o">=</span> <span class="n">view</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">type</span><span class="p">(</span><span class="n">firstrow</span><span class="p">)</span>
<span class="go">&lt;class &#39;sdl2.ext.array.MemoryView&#39;&gt;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">type</span><span class="p">(</span><span class="n">firstrow</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
<span class="go">&lt;type &#39;bytearray&#39;&gt;</span>
</pre></div>
</div>
<p>A <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a> features, similar to Python&#8217;s builtin
<a class="reference external" href="http://docs.python.org/library/stdtypes.html#memoryview" title="(in Python v2.7)"><code class="xref py py-class docutils literal"><span class="pre">memoryview</span></code></a>, dimensions and strides, accessible via the
<a class="reference internal" href="#sdl2.ext.MemoryView.ndim" title="sdl2.ext.MemoryView.ndim"><code class="xref py py-attr docutils literal"><span class="pre">MemoryView.ndim</span></code></a> and <a class="reference internal" href="#sdl2.ext.MemoryView.strides" title="sdl2.ext.MemoryView.strides"><code class="xref py py-attr docutils literal"><span class="pre">MemoryView.strides</span></code></a> attributes.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">view</span><span class="o">.</span><span class="n">ndim</span>
<span class="go">2</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">view</span><span class="o">.</span><span class="n">strides</span>
<span class="go">(5, 5)</span>
</pre></div>
</div>
<p>The <a class="reference internal" href="#sdl2.ext.MemoryView.strides" title="sdl2.ext.MemoryView.strides"><code class="xref py py-attr docutils literal"><span class="pre">MemoryView.strides</span></code></a>, which have to be passed on creating a
new <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a>, define the layout of the data over different
dimensions. In the example above, we created a 5x5 two-dimensional view
to the image graphics.</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">twobytes</span> <span class="o">=</span> <span class="n">MemoryView</span><span class="p">(</span><span class="n">imagedata</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">1</span><span class="p">))</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">twobytes</span><span class="p">)</span>
<span class="go">[[sX, me, 1, Xb, yt], [eX, gr, ap, Xi, cs]]</span>
</pre></div>
</div>
</div>
<div class="section" id="array-api">
<h2>Array API<a class="headerlink" href="#array-api" title="Permalink to this headline"></a></h2>
<dl class="class">
<dt id="sdl2.ext.CTypesView">
<em class="property">class </em><code class="descclassname">sdl2.ext.</code><code class="descname">CTypesView</code><span class="sig-paren">(</span><em>obj : iterable</em><span class="optional">[</span>, <em>itemsize=1</em><span class="optional">[</span>, <em>docopy=False</em><span class="optional">[</span>, <em>objsize=None</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sdl2.ext.CTypesView" title="Permalink to this definition"></a></dt>
<dd><p>A proxy class for byte-wise accessible data types to be used in
ctypes bindings. The CTypesView provides a read-write access to
arbitrary objects that are iterable.</p>
<p>In case the object does not provide a <a class="reference external" href="http://docs.python.org/library/functions.html#buffer" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">buffer()</span></code></a> interface for
direct access, the CTypesView can copy the object&#8217;s contents into an
internal buffer, from which data can be retrieved, once the necessary
operations have been performed.</p>
<p>Depending on the item type stored in the iterable object, you might
need to provide a certain <em>itemsize</em>, which denotes the size per
item in bytes. The <em>objsize</em> argument might be necessary of iterables,
for which len() does not return the correct amount of objects or is not
implemented.</p>
<dl class="attribute">
<dt id="sdl2.ext.CTypesView.bytesize">
<code class="descname">bytesize</code><a class="headerlink" href="#sdl2.ext.CTypesView.bytesize" title="Permalink to this definition"></a></dt>
<dd><p>Returns the length of the encapsuled object in bytes.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.CTypesView.is_shared">
<code class="descname">is_shared</code><a class="headerlink" href="#sdl2.ext.CTypesView.is_shared" title="Permalink to this definition"></a></dt>
<dd><p>Indicates, if changes on the CTypesView data effect the encapsuled
object directly. if not, this means that the object was copied
internally and needs to be updated by the user code outside of the
CTypesView.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.CTypesView.object">
<code class="descname">object</code><a class="headerlink" href="#sdl2.ext.CTypesView.object" title="Permalink to this definition"></a></dt>
<dd><p>The encapsuled object.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.CTypesView.view">
<code class="descname">view</code><a class="headerlink" href="#sdl2.ext.CTypesView.view" title="Permalink to this definition"></a></dt>
<dd><p>Provides a read-write aware view of the encapsuled object data
that is suitable for usage from <a class="reference external" href="http://docs.python.org/library/ctypes.html#module-ctypes" title="(in Python v2.7)"><code class="xref py py-mod docutils literal"><span class="pre">ctypes</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="sdl2.ext.CTypesView.to_bytes">
<code class="descname">to_bytes</code><span class="sig-paren">(</span><span class="sig-paren">)</span> &rarr; ctypes.POINTER<a class="headerlink" href="#sdl2.ext.CTypesView.to_bytes" title="Permalink to this definition"></a></dt>
<dd><p>Returns a byte representation of the encapsuled object. The return
value allows a direct read-write access to the object data, if it
is not copied. The <a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.POINTER" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">ctypes.POINTER()</span></code></a> points to an array of
<a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.c_ubyte" title="(in Python v2.7)"><code class="xref py py-class docutils literal"><span class="pre">ctypes.c_ubyte</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="sdl2.ext.CTypesView.to_uint16">
<code class="descname">to_uint16</code><span class="sig-paren">(</span><span class="sig-paren">)</span> &rarr; ctypes.POINTER<a class="headerlink" href="#sdl2.ext.CTypesView.to_uint16" title="Permalink to this definition"></a></dt>
<dd><p>Returns a 16-bit representation of the encapsuled object. The return
value allows a direct read-write access to the object data, if it
is not copied. The <a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.POINTER" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">ctypes.POINTER()</span></code></a> points to an array of
<a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.c_ushort" title="(in Python v2.7)"><code class="xref py py-class docutils literal"><span class="pre">ctypes.c_ushort</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="sdl2.ext.CTypesView.to_uint32">
<code class="descname">to_uint32</code><span class="sig-paren">(</span><span class="sig-paren">)</span> &rarr; ctypes.POINTER<a class="headerlink" href="#sdl2.ext.CTypesView.to_uint32" title="Permalink to this definition"></a></dt>
<dd><p>Returns a 32-bit representation of the encapsuled object. The return
value allows a direct read-write access to the object data, if it
is not copied. The <a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.POINTER" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">ctypes.POINTER()</span></code></a> points to an array of
<a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.c_uint" title="(in Python v2.7)"><code class="xref py py-class docutils literal"><span class="pre">ctypes.c_uint</span></code></a>.</p>
</dd></dl>
<dl class="method">
<dt id="sdl2.ext.CTypesView.to_uint64">
<code class="descname">to_uint64</code><span class="sig-paren">(</span><span class="sig-paren">)</span> &rarr; ctypes.POINTER<a class="headerlink" href="#sdl2.ext.CTypesView.to_uint64" title="Permalink to this definition"></a></dt>
<dd><p>Returns a 64-bit representation of the encapsuled object. The return
value allows a direct read-write access to the object data, if it
is not copied. The <a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.POINTER" title="(in Python v2.7)"><code class="xref py py-func docutils literal"><span class="pre">ctypes.POINTER()</span></code></a> points to an array of
<a class="reference external" href="http://docs.python.org/library/ctypes.html#ctypes.c_ulonglong" title="(in Python v2.7)"><code class="xref py py-class docutils literal"><span class="pre">ctypes.c_ulonglong</span></code></a>.</p>
</dd></dl>
</dd></dl>
<dl class="class">
<dt id="sdl2.ext.MemoryView">
<em class="property">class </em><code class="descclassname">sdl2.ext.</code><code class="descname">MemoryView</code><span class="sig-paren">(</span><em>source : object</em>, <em>itemsize : int</em>, <em>strides : tuple</em><span class="optional">[</span>, <em>getfunc=None</em><span class="optional">[</span>, <em>setfunc=None</em><span class="optional">[</span>, <em>srcsize=None</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#sdl2.ext.MemoryView" title="Permalink to this definition"></a></dt>
<dd><p>The <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a> provides a read-write access to arbitrary
data objects, which can be indexed.</p>
<p><em>itemsize</em> denotes the size of a single item. <em>strides</em> defines
the dimensions and the length (n items * <em>itemsize</em>) for each
dimension. <em>getfunc</em> and <em>setfunc</em> are optional parameters to
provide specialised read and write access to the underlying
<em>source</em>. <em>srcsize</em> can be used to provide the correct source
size, if <code class="docutils literal"><span class="pre">len(source)</span></code> does not return the absolute size of the
source object in all dimensions.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The MemoryView is a pure Python-based implementation and makes
heavy use of recursion for multi-dimensional access. If you aim
for speed on accessing a n-dimensional object, you want to
consider using a specialised library such as numpy. If you need
n-dimensional access support, where such a library is not
supported, or if you need to provide access to objects, which do
not fulfill the requirements of that particular libray,
<a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a> can act as solid fallback solution.</p>
</div>
<dl class="attribute">
<dt id="sdl2.ext.MemoryView.itemsize">
<code class="descname">itemsize</code><a class="headerlink" href="#sdl2.ext.MemoryView.itemsize" title="Permalink to this definition"></a></dt>
<dd><p>The size of a single item in bytes.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.MemoryView.ndim">
<code class="descname">ndim</code><a class="headerlink" href="#sdl2.ext.MemoryView.ndim" title="Permalink to this definition"></a></dt>
<dd><p>The number of dimensions of the <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a>.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.MemoryView.size">
<code class="descname">size</code><a class="headerlink" href="#sdl2.ext.MemoryView.size" title="Permalink to this definition"></a></dt>
<dd><p>The size in bytes of the underlying source object.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.MemoryView.source">
<code class="descname">source</code><a class="headerlink" href="#sdl2.ext.MemoryView.source" title="Permalink to this definition"></a></dt>
<dd><p>The underlying data source.</p>
</dd></dl>
<dl class="attribute">
<dt id="sdl2.ext.MemoryView.strides">
<code class="descname">strides</code><a class="headerlink" href="#sdl2.ext.MemoryView.strides" title="Permalink to this definition"></a></dt>
<dd><p>A tuple defining the length in bytes for accessing all
elements in each dimension of the <a class="reference internal" href="#sdl2.ext.MemoryView" title="sdl2.ext.MemoryView"><code class="xref py py-class docutils literal"><span class="pre">MemoryView</span></code></a>.</p>
</dd></dl>
</dd></dl>
<dl class="function">
<dt id="sdl2.ext.to_ctypes">
<code class="descclassname">sdl2.ext.</code><code class="descname">to_ctypes</code><span class="sig-paren">(</span><em>dataseq : iterable</em>, <em>dtype</em><span class="optional">[</span>, <em>mcount=0</em><span class="optional">]</span><span class="sig-paren">)</span> &rarr; array, int<a class="headerlink" href="#sdl2.ext.to_ctypes" title="Permalink to this definition"></a></dt>
<dd><p>Converts an arbitrary sequence to a ctypes array of the specified
<em>dtype</em> and returns the ctypes array and amount of items as
two-value tuple.</p>
<p>Raises a <code class="xref py py-exc docutils literal"><span class="pre">TypeError</span></code>, if one or more elements in the passed
sequence do not match the passed <em>dtype</em>.</p>
</dd></dl>
<dl class="function">
<dt id="sdl2.ext.to_list">
<code class="descclassname">sdl2.ext.</code><code class="descname">to_list</code><span class="sig-paren">(</span><em>dataseq : iterable</em><span class="sig-paren">)</span> &rarr; list<a class="headerlink" href="#sdl2.ext.to_list" title="Permalink to this definition"></a></dt>
<dd><p>Converts a ctypes array to a list.</p>
</dd></dl>
<dl class="function">
<dt id="sdl2.ext.to_tuple">
<code class="descclassname">sdl2.ext.</code><code class="descname">to_tuple</code><span class="sig-paren">(</span><em>dataseq : iterable</em><span class="sig-paren">)</span> &rarr; tuple<a class="headerlink" href="#sdl2.ext.to_tuple" title="Permalink to this definition"></a></dt>
<dd><p>Converts a ctypes array to a tuple.</p>
</dd></dl>
<dl class="function">
<dt id="sdl2.ext.create_array">
<code class="descclassname">sdl2.ext.</code><code class="descname">create_array</code><span class="sig-paren">(</span><em>obj : object</em>, <em>itemsize : int</em><span class="sig-paren">)</span> &rarr; array.array<a class="headerlink" href="#sdl2.ext.create_array" title="Permalink to this definition"></a></dt>
<dd><p>Creates an <a class="reference external" href="http://docs.python.org/library/array.html#array.array" title="(in Python v2.7)"><code class="xref py py-class docutils literal"><span class="pre">array.array</span></code></a> based copy of the passed object.
<em>itemsize</em> denotes the size in bytes for a single element within
<em>obj</em>.</p>
</dd></dl>
</div>
</div>
</div>
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<h3><a href="../index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Converting sequences</a><ul>
<li><a class="reference internal" href="#providing-read-write-access-for-sequential-data">Providing read-write access for sequential data</a></li>
<li><a class="reference internal" href="#accessing-data-over-multiple-dimensions">Accessing data over multiple dimensions</a></li>
<li><a class="reference internal" href="#array-api">Array API</a></li>
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