增加tkinter和pyqt5

docs/python/Pillow(PIL).html

@@ -12,25 +12,22 @@
   <a class="reference internal" href="../reference/Image.html#PIL.Image.Image" title="PIL.Image.Image"><tt class="xref py py-class docutils literal"><span class="pre">Image</span></tt></a> class, 你可以通过多种方法创建这个类的实例；你可以从文件加载图像，或者处理其他图像, 或者从 scratch 创建。</p>
   <p>要从文件加载图像，使用 <a class="reference internal" href="../reference/Image.html#PIL.Image.open" title="PIL.Image.open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a> 函数，
   在 <a class="reference internal" href="../reference/Image.html#module-PIL.Image" title="PIL.Image"><tt class="xref py py-mod docutils literal"><span class="pre">Image</span></tt></a> 模块:</p>
-  <div class="highlight-python"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
+  <pre><code class="language-python"><span class="gp">&gt;&gt;&gt; </span><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
   <span class="gp">&gt;&gt;&gt; </span><span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>加载成功将返回一个 <a class="reference internal" href="../reference/Image.html#PIL.Image.Image" title="PIL.Image.Image"><tt class="xref py py-class docutils literal"><span class="pre">Image</span></tt></a> 对象。
   你现在可以使用示例属性检查文件内容:</p>
-  <div class="highlight-python"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
+  <pre><code class="language-python"><span class="gp">&gt;&gt;&gt; </span><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
   <span class="gp">&gt;&gt;&gt; </span><span class="k">print</span><span class="p">(</span><span class="n">im</span><span class="o">.</span><span class="n">format</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">size</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">mode</span><span class="p">)</span>
   <span class="go">PPM (512, 512) RGB</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p><tt class="xref py py-attr docutils literal"><span class="pre">format</span></tt> 这个属性标识了图像来源。如果图像不是从文件读取它的值就是None。size属性是一个二元tuple，包含width和height（宽度和高度，单位都是px）。
   <tt class="xref py py-attr docutils literal"><span class="pre">mode</span></tt> 属性定义了图像bands的数量和名称，以及像素类型和深度。常见的modes 有 “L”
   (luminance) 表示灰度图像, “RGB” 表示真彩色图像, and “CMYK” 表示出版图像。</p>
   <p>如果文件打开错误，返回 <tt class="xref py py-exc docutils literal"><span class="pre">IOError</span></tt> 错误。</p>
   <p>只要你有了 <a class="reference internal" href="../reference/Image.html#PIL.Image.Image" title="PIL.Image.Image"><tt class="xref py py-class docutils literal"><span class="pre">Image</span></tt></a> 类的实例，你就可以通过类的方法处理图像。比如，下列方法可以显示图像:</p>
-  <div class="highlight-python"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="n">im</span><span class="o">.</span><span class="n">show</span><span class="p">()</span>
-  </pre></div>
-  </div>
+  <pre><code class="language-python"><span class="gp">&gt;&gt;&gt; </span><span class="n">im</span><span class="o">.</span><span class="n">show</span><span class="p">()</span>
+  </code></pre>
   <div class="admonition note">
   <p class="first admonition-title">注解</p>
   <p class="last">标准的 <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.show" title="PIL.Image.Image.show"><tt class="xref py py-meth docutils literal"><span class="pre">show()</span></tt></a> 效率并不高，它需要保存图像到临时文件然后通过
@@ -46,7 +43,7 @@
   <a class="reference internal" href="../reference/Image.html#PIL.Image.Image" title="PIL.Image.Image"><tt class="xref py py-class docutils literal"><span class="pre">Image</span></tt></a> 类的 <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.save" title="PIL.Image.Image.save"><tt class="xref py py-meth docutils literal"><span class="pre">save()</span></tt></a> 方法。保存文件的时候文件名变得重要了。除非你指定格式，否则这个库将会以文件名的扩展名作为格式保存。</p>
   <div class="section" id="jpeg">
   <h3>转换文件格式到JPEG</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
   <span class="kn">import</span> <span class="nn">os</span><span class="o">,</span> <span class="nn">sys</span>
   <span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
   
@@ -58,13 +55,12 @@
               <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">infile</span><span class="p">)</span><span class="o">.</span><span class="n">save</span><span class="p">(</span><span class="n">outfile</span><span class="p">)</span>
           <span class="k">except</span> <span class="ne">IOError</span><span class="p">:</span>
               <span class="k">print</span><span class="p">(</span><span class="s">"cannot convert"</span><span class="p">,</span> <span class="n">infile</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p><a class="reference internal" href="../reference/Image.html#PIL.Image.Image.save" title="PIL.Image.Image.save"><tt class="xref py py-meth docutils literal"><span class="pre">save()</span></tt></a> 方法的第二个参数可以指定文件格式，如果你使用非标准的扩展名你必须这样做：</p>
   </div>
   <div class="section" id="id3">
   <h3>创建 JPEG 缩略图</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
   <span class="kn">import</span> <span class="nn">os</span><span class="o">,</span> <span class="nn">sys</span>
   <span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
   
@@ -79,13 +75,12 @@
               <span class="n">im</span><span class="o">.</span><span class="n">save</span><span class="p">(</span><span class="n">outfile</span><span class="p">,</span> <span class="s">"JPEG"</span><span class="p">)</span>
           <span class="k">except</span> <span class="ne">IOError</span><span class="p">:</span>
               <span class="k">print</span><span class="p">(</span><span class="s">"cannot create thumbnail for"</span><span class="p">,</span> <span class="n">infile</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>很重要的一点是这个库不会直接解码或者加载图像栅格数据。当你打开一个文件，只会读取文件头信息用来确定格式，颜色模式，大小等等，文件的剩余部分不会主动处理。这意味着打开一个图像文件的操作十分快速，跟图片大小和压缩方式无关。下面是一个简单的脚本用来快速验证大量图片。</p>
   </div>
   <div class="section" id="id4">
   <h3>验证图像文件</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
   <span class="kn">import</span> <span class="nn">sys</span>
   <span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
   
@@ -95,8 +90,7 @@
               <span class="k">print</span><span class="p">(</span><span class="n">infile</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">format</span><span class="p">,</span> <span class="s">"</span><span class="si">%d</span><span class="s">x</span><span class="si">%d</span><span class="s">"</span> <span class="o">%</span> <span class="n">im</span><span class="o">.</span><span class="n">size</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">mode</span><span class="p">)</span>
       <span class="k">except</span> <span class="ne">IOError</span><span class="p">:</span>
           <span class="k">pass</span>
-  </pre></div>
-  </div>
+  </code></pre>
   </div>
   </div>
   <div class="section" id="id5">
@@ -104,23 +98,21 @@
   <p><a class="reference internal" href="../reference/Image.html#PIL.Image.Image" title="PIL.Image.Image"><tt class="xref py py-class docutils literal"><span class="pre">Image</span></tt></a> 类包含的方法允许你操作图像部分选区。使用:py:meth:<cite>~PIL.Image.Image.crop</cite> 方法获取图像的一个子矩形选区。</p>
   <div class="section" id="id6">
   <h3>从图像中复制出一个矩形选区</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">box</span> <span class="o">=</span> <span class="p">(</span><span class="mi">100</span><span class="p">,</span> <span class="mi">100</span><span class="p">,</span> <span class="mi">400</span><span class="p">,</span> <span class="mi">400</span><span class="p">)</span>
+  <pre><code class="language-python"><span class="n">box</span> <span class="o">=</span> <span class="p">(</span><span class="mi">100</span><span class="p">,</span> <span class="mi">100</span><span class="p">,</span> <span class="mi">400</span><span class="p">,</span> <span class="mi">400</span><span class="p">)</span>
   <span class="n">region</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">crop</span><span class="p">(</span><span class="n">box</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>矩形选区有一个4元元组定义，分别表示左、上、右、下的坐标。这个库以左上角为坐标原点，单位是px，所以上诉代码复制了一个 300x300 pixels 的矩形选区。这个选区现在可以被处理并且粘贴到原图。</p>
   </div>
   <div class="section" id="id7">
   <h3>处理复制的矩形选区并粘贴到原图</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">region</span> <span class="o">=</span> <span class="n">region</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">ROTATE_180</span><span class="p">)</span>
+  <pre><code class="language-python"><span class="n">region</span> <span class="o">=</span> <span class="n">region</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">ROTATE_180</span><span class="p">)</span>
   <span class="n">im</span><span class="o">.</span><span class="n">paste</span><span class="p">(</span><span class="n">region</span><span class="p">,</span> <span class="n">box</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>当你粘贴矩形选区的时候必须保证尺寸一致。此外，矩形选区不能在图像外。然而你不必保证矩形选区和原图的颜色模式一致，因为矩形选区会被自动转换颜色（参看下面的 <a class="reference internal" href="#color-transforms"><em>颜色变换</em></a>  部分），下面是一个例子：</p>
   </div>
   <div class="section" id="rolling-an-image">
   <h3>Rolling an image</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">roll</span><span class="p">(</span><span class="n">image</span><span class="p">,</span> <span class="n">delta</span><span class="p">):</span>
+  <pre><code class="language-python"><span class="k">def</span> <span class="nf">roll</span><span class="p">(</span><span class="n">image</span><span class="p">,</span> <span class="n">delta</span><span class="p">):</span>
       <span class="s">"Roll an image sideways"</span>
   
       <span class="n">xsize</span><span class="p">,</span> <span class="n">ysize</span> <span class="o">=</span> <span class="n">image</span><span class="o">.</span><span class="n">size</span>
@@ -134,8 +126,7 @@
       <span class="n">image</span><span class="o">.</span><span class="n">paste</span><span class="p">(</span><span class="n">part1</span><span class="p">,</span> <span class="p">(</span><span class="n">xsize</span><span class="o">-</span><span class="n">delta</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="n">xsize</span><span class="p">,</span> <span class="n">ysize</span><span class="p">))</span>
   
       <span class="k">return</span> <span class="n">image</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>For more advanced tricks, the paste method can also take a transparency mask as
   an optional argument. In this mask, the value 255 indicates that the pasted
   image is opaque in that position (that is, the pasted image should be used as
@@ -149,10 +140,9 @@
   </div>
   <div class="section" id="id8">
   <h3>分离和合并颜色通道</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">r</span><span class="p">,</span> <span class="n">g</span><span class="p">,</span> <span class="n">b</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">split</span><span class="p">()</span>
+  <pre><code class="language-python"><span class="n">r</span><span class="p">,</span> <span class="n">g</span><span class="p">,</span> <span class="n">b</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">split</span><span class="p">()</span>
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">merge</span><span class="p">(</span><span class="s">"RGB"</span><span class="p">,</span> <span class="p">(</span><span class="n">b</span><span class="p">,</span> <span class="n">g</span><span class="p">,</span> <span class="n">r</span><span class="p">))</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>Note that for a single-band image, <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.split" title="PIL.Image.Image.split"><tt class="xref py py-meth docutils literal"><span class="pre">split()</span></tt></a> returns
   the image itself. To work with individual color bands, you may want to convert
   the image to “RGB” first.</p>
@@ -166,10 +156,9 @@
   degrees counter-clockwise.</p>
   <div class="section" id="id10">
   <h3>简单的几何变换</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">resize</span><span class="p">((</span><span class="mi">128</span><span class="p">,</span> <span class="mi">128</span><span class="p">))</span>
+  <pre><code class="language-python"><span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">resize</span><span class="p">((</span><span class="mi">128</span><span class="p">,</span> <span class="mi">128</span><span class="p">))</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">rotate</span><span class="p">(</span><span class="mi">45</span><span class="p">)</span> <span class="c"># degrees counter-clockwise</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>To rotate the image in 90 degree steps, you can either use the
   <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.rotate" title="PIL.Image.Image.rotate"><tt class="xref py py-meth docutils literal"><span class="pre">rotate()</span></tt></a> method or the
   <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.transpose" title="PIL.Image.Image.transpose"><tt class="xref py py-meth docutils literal"><span class="pre">transpose()</span></tt></a> method. The latter can also be used to
@@ -177,13 +166,12 @@
   </div>
   <div class="section" id="id11">
   <h3>旋转图像</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">FLIP_LEFT_RIGHT</span><span class="p">)</span>
+  <pre><code class="language-python"><span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">FLIP_LEFT_RIGHT</span><span class="p">)</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">FLIP_TOP_BOTTOM</span><span class="p">)</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">ROTATE_90</span><span class="p">)</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">ROTATE_180</span><span class="p">)</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="n">Image</span><span class="o">.</span><span class="n">ROTATE_270</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>There’s no difference in performance or result between <tt class="docutils literal"><span class="pre">transpose(ROTATE)</span></tt>
   and corresponding <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.rotate" title="PIL.Image.Image.rotate"><tt class="xref py py-meth docutils literal"><span class="pre">rotate()</span></tt></a> operations.</p>
   <p>A more general form of image transformations can be carried out via the
@@ -196,9 +184,8 @@
   representations using the <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.convert" title="PIL.Image.Image.convert"><tt class="xref py py-meth docutils literal"><span class="pre">convert()</span></tt></a> method.</p>
   <div class="section" id="id13">
   <h3>颜色模式转换</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">)</span><span class="o">.</span><span class="n">convert</span><span class="p">(</span><span class="s">"L"</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  <pre><code class="language-python"><span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">)</span><span class="o">.</span><span class="n">convert</span><span class="p">(</span><span class="s">"L"</span><span class="p">)</span>
+  </code></pre>
   <p>The library supports transformations between each supported mode and the “L”
   and “RGB” modes. To convert between other modes, you may have to use an
   intermediate image (typically an “RGB” image).</p>
@@ -215,10 +202,9 @@
   <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.filter" title="PIL.Image.Image.filter"><tt class="xref py py-meth docutils literal"><span class="pre">filter()</span></tt></a> method.</p>
   <div class="section" id="id16">
   <h4>应用过滤器</h4>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">ImageFilter</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">ImageFilter</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">ImageFilter</span><span class="o">.</span><span class="n">DETAIL</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   </div>
   </div>
   <div class="section" id="id17">
@@ -229,17 +215,16 @@
   pixel is processed according to that function:</p>
   <div class="section" id="id18">
   <h4>应用点操作</h4>
-  <div class="highlight-python"><div class="highlight"><pre><span class="c"># multiply each pixel by 1.2</span>
+  <pre><code class="language-python"><span class="c"># multiply each pixel by 1.2</span>
   <span class="n">out</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">point</span><span class="p">(</span><span class="k">lambda</span> <span class="n">i</span><span class="p">:</span> <span class="n">i</span> <span class="o">*</span> <span class="mf">1.2</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>Using the above technique, you can quickly apply any simple expression to an
   image. You can also combine the <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.point" title="PIL.Image.Image.point"><tt class="xref py py-meth docutils literal"><span class="pre">point()</span></tt></a> and
   <a class="reference internal" href="../reference/Image.html#PIL.Image.Image.paste" title="PIL.Image.Image.paste"><tt class="xref py py-meth docutils literal"><span class="pre">paste()</span></tt></a> methods to selectively modify an image:</p>
   </div>
   <div class="section" id="bands">
   <h4>处理个别bands</h4>
-  <div class="highlight-python"><div class="highlight"><pre><span class="c"># split the image into individual bands</span>
+  <pre><code class="language-python"><span class="c"># split the image into individual bands</span>
   <span class="n">source</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">split</span><span class="p">()</span>
   
   <span class="n">R</span><span class="p">,</span> <span class="n">G</span><span class="p">,</span> <span class="n">B</span> <span class="o">=</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">2</span>
@@ -255,12 +240,10 @@
   
   <span class="c"># build a new multiband image</span>
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">merge</span><span class="p">(</span><span class="n">im</span><span class="o">.</span><span class="n">mode</span><span class="p">,</span> <span class="n">source</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>Note the syntax used to create the mask:</p>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">imout</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">point</span><span class="p">(</span><span class="k">lambda</span> <span class="n">i</span><span class="p">:</span> <span class="n">expression</span> <span class="ow">and</span> <span class="mi">255</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  <pre><code class="language-python"><span class="n">imout</span> <span class="o">=</span> <span class="n">im</span><span class="o">.</span><span class="n">point</span><span class="p">(</span><span class="k">lambda</span> <span class="n">i</span><span class="p">:</span> <span class="n">expression</span> <span class="ow">and</span> <span class="mi">255</span><span class="p">)</span>
+  </code></pre>
   <p>Python only evaluates the portion of a logical expression as is necessary to
   determine the outcome, and returns the last value examined as the result of the
   expression. So if the expression above is false (0), Python does not look at
@@ -275,12 +258,11 @@
   <p>You can adjust contrast, brightness, color balance and sharpness in this way.</p>
   <div class="section" id="id20">
   <h4>增强图形</h4>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">ImageEnhance</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">ImageEnhance</span>
   
   <span class="n">enh</span> <span class="o">=</span> <span class="n">ImageEnhance</span><span class="o">.</span><span class="n">Contrast</span><span class="p">(</span><span class="n">im</span><span class="p">)</span>
   <span class="n">enh</span><span class="o">.</span><span class="n">enhance</span><span class="p">(</span><span class="mf">1.3</span><span class="p">)</span><span class="o">.</span><span class="n">show</span><span class="p">(</span><span class="s">"30% more contrast"</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   </div>
   </div>
   </div>
@@ -295,7 +277,7 @@
   frames:</p>
   <div class="section" id="id22">
   <h3>读取序列</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
   
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"animation.gif"</span><span class="p">)</span>
   <span class="n">im</span><span class="o">.</span><span class="n">seek</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span> <span class="c"># skip to the second frame</span>
@@ -306,8 +288,7 @@
           <span class="c"># do something to im</span>
   <span class="k">except</span> <span class="ne">EOFError</span><span class="p">:</span>
       <span class="k">pass</span> <span class="c"># end of sequence</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>As seen in this example, you’ll get an <tt class="xref py py-exc docutils literal"><span class="pre">EOFError</span></tt> exception when the
   sequence ends.</p>
   <p>Note that most drivers in the current version of the library only allow you to
@@ -340,7 +321,7 @@
   graphics on Postscript printers. Here’s a simple example:</p>
   <div class="section" id="drawing-postscript">
   <h3>Drawing Postscript</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">Image</span>
   <span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">PSDraw</span>
   
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">)</span>
@@ -360,8 +341,7 @@
   <span class="n">ps</span><span class="o">.</span><span class="n">text</span><span class="p">((</span><span class="mi">4</span><span class="o">*</span><span class="mi">72</span><span class="o">-</span><span class="n">w</span><span class="o">/</span><span class="mi">2</span><span class="p">,</span> <span class="mi">1</span><span class="o">*</span><span class="mi">72</span><span class="o">-</span><span class="n">h</span><span class="p">),</span> <span class="n">title</span><span class="p">)</span>
   
   <span class="n">ps</span><span class="o">.</span><span class="n">end_document</span><span class="p">()</span>
-  </pre></div>
-  </div>
+  </code></pre>
   </div>
   </div>
   <div class="section" id="id23">
@@ -369,9 +349,8 @@
   <p>As described earlier, the <a class="reference internal" href="../reference/Image.html#PIL.Image.open" title="PIL.Image.open"><tt class="xref py py-func docutils literal"><span class="pre">open()</span></tt></a> function of the
   <a class="reference internal" href="../reference/Image.html#module-PIL.Image" title="PIL.Image"><tt class="xref py py-mod docutils literal"><span class="pre">Image</span></tt></a> module is used to open an image file. In most cases, you
   simply pass it the filename as an argument:</p>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  <pre><code class="language-python"><span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">)</span>
+  </code></pre>
   <p>If everything goes well, the result is an <a class="reference internal" href="../reference/Image.html#PIL.Image.Image" title="PIL.Image.Image"><tt class="xref py py-class docutils literal"><span class="pre">PIL.Image.Image</span></tt></a> object.
   Otherwise, an <tt class="xref py py-exc docutils literal"><span class="pre">IOError</span></tt> exception is raised.</p>
   <p>You can use a file-like object instead of the filename. The object must
@@ -379,20 +358,18 @@
   <a class="reference external" href="http://docs.python.org/2/library/stdtypes.html#file.tell" title="(in Python v2.7)"><tt class="xref py py-meth docutils literal"><span class="pre">tell()</span></tt></a> methods, and be opened in binary mode.</p>
   <div class="section" id="id24">
   <h3>从文件读取</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">fp</span> <span class="o">=</span> <span class="nb">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">,</span> <span class="s">"rb"</span><span class="p">)</span>
+  <pre><code class="language-python"><span class="n">fp</span> <span class="o">=</span> <span class="nb">open</span><span class="p">(</span><span class="s">"lena.ppm"</span><span class="p">,</span> <span class="s">"rb"</span><span class="p">)</span>
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">fp</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>To read an image from string data, use the <a class="reference external" href="http://docs.python.org/2/library/stringio.html#StringIO.StringIO" title="(in Python v2.7)"><tt class="xref py py-class docutils literal"><span class="pre">StringIO</span></tt></a>
   class:</p>
   </div>
   <div class="section" id="string">
   <h3>从 string 读取</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">StringIO</span>
+  <pre><code class="language-python"><span class="kn">import</span> <span class="nn">StringIO</span>
   
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">StringIO</span><span class="o">.</span><span class="n">StringIO</span><span class="p">(</span><span class="nb">buffer</span><span class="p">))</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>Note that the library rewinds the file (using <tt class="docutils literal"><span class="pre">seek(0)</span></tt>) before reading the
   image header. In addition, seek will also be used when the image data is read
   (by the load method). If the image file is embedded in a larger file, such as a
@@ -401,12 +378,11 @@
   </div>
   <div class="section" id="id25">
   <h3>从压缩包读取</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">TarIO</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">PIL</span> <span class="kn">import</span> <span class="n">TarIO</span>
   
   <span class="n">fp</span> <span class="o">=</span> <span class="n">TarIO</span><span class="o">.</span><span class="n">TarIO</span><span class="p">(</span><span class="s">"Imaging.tar"</span><span class="p">,</span> <span class="s">"Imaging/test/lena.ppm"</span><span class="p">)</span>
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="n">fp</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   </div>
   </div>
   <div class="section" id="id26">
@@ -420,19 +396,17 @@
   is done by reconfiguring the image decoder.</p>
   <div class="section" id="reading-in-draft-mode">
   <h3>Reading in draft mode</h3>
-  <div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
+  <pre><code class="language-python"><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">print_function</span>
   <span class="n">im</span> <span class="o">=</span> <span class="n">Image</span><span class="o">.</span><span class="n">open</span><span class="p">(</span><span class="nb">file</span><span class="p">)</span>
   <span class="k">print</span><span class="p">(</span><span class="s">"original ="</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">mode</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">size</span><span class="p">)</span>
   
   <span class="n">im</span><span class="o">.</span><span class="n">draft</span><span class="p">(</span><span class="s">"L"</span><span class="p">,</span> <span class="p">(</span><span class="mi">100</span><span class="p">,</span> <span class="mi">100</span><span class="p">))</span>
   <span class="k">print</span><span class="p">(</span><span class="s">"draft ="</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">mode</span><span class="p">,</span> <span class="n">im</span><span class="o">.</span><span class="n">size</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>This prints something like:</p>
-  <div class="highlight-python"><div class="highlight"><pre><span class="n">original</span> <span class="o">=</span> <span class="n">RGB</span> <span class="p">(</span><span class="mi">512</span><span class="p">,</span> <span class="mi">512</span><span class="p">)</span>
+  <pre><code class="language-python"><span class="n">original</span> <span class="o">=</span> <span class="n">RGB</span> <span class="p">(</span><span class="mi">512</span><span class="p">,</span> <span class="mi">512</span><span class="p">)</span>
   <span class="n">draft</span> <span class="o">=</span> <span class="n">L</span> <span class="p">(</span><span class="mi">128</span><span class="p">,</span> <span class="mi">128</span><span class="p">)</span>
-  </pre></div>
-  </div>
+  </code></pre>
   <p>Note that the resulting image may not exactly match the requested mode and
   size. To make sure that the image is not larger than the given size, use the
   thumbnail method instead.</p>