Rework of execution policy (multithreading)

PdfForQtViewer/pdfviewersettingsdialog.ui

@@ -26,7 +26,7 @@
      <item>
       <widget class="QStackedWidget" name="stackedWidget">
        <property name="currentIndex">
-        <number>10</number>
+        <number>0</number>
        </property>
        <widget class="QWidget" name="enginePage">
         <layout class="QVBoxLayout" name="enginePageLayout">
@@ -113,7 +113,7 @@
             <item>
              <widget class="QLabel" name="engineInfoLabel">
               <property name="text">
-               <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Select rendering method according to your needs. &lt;span style=&quot; font-weight:600;&quot;&gt;Software rendering&lt;/span&gt; is much slower than hardware accelerated rendering using &lt;span style=&quot; font-weight:600;&quot;&gt;OpenGL rendering&lt;/span&gt;, but it works when OpenGL is not available at your platform. OpenGL rendering is selected as default and is recommended.&lt;/p&gt;&lt;p&gt;OpenGL rendering uses&lt;span style=&quot; font-weight:600;&quot;&gt; multisample antialiasing (MSAA)&lt;/span&gt;, which provides good quality antialiasing. You can turn this feature on or off, but without antialiasing, bad quality image can occur. Samples count affect how much samples per pixel are considered to determine pixel color. It can be a value 1, 2, 4, 8, and 16. Most modern GPUs support at least value 8. Lower this value, if your GPU doesn't support the desired sample count.&lt;/p&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Prefetch pages &lt;/span&gt;prefetches (pre-renders) pages next to currently viewed pages, to avoid flickering during scrolling. Prefetched pages are stored in the page cache.&lt;/p&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Multithreading strategy &lt;/span&gt;defines how program will use CPU cores. Engine can use multiple cores. Strategy defines, how engine will use these cores. &lt;span style=&quot; font-weight:600;&quot;&gt;Single thread&lt;/span&gt; strategy uses only one CPU core for rendering page, and for some operations, they aren't parallelized, at the cost of more time needed for operation to be finished. But still, each page will use its own thread to be compiled/drawn. On the other side, there are two multithreading strategies, former is load balanced, latter uses maximum threads. Load balanced strategy tries to optimize number of threads to fit CPU cores, while maximum threads strategy will spawn as much threads as possible to process operations, which can be sometimes unoptimal.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+               <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Select rendering method according to your needs. &lt;span style=&quot; font-weight:600;&quot;&gt;Software rendering&lt;/span&gt; is much slower than hardware accelerated rendering using &lt;span style=&quot; font-weight:600;&quot;&gt;OpenGL rendering&lt;/span&gt;, but it works when OpenGL is not available at your platform. OpenGL rendering is selected as default and is recommended.&lt;/p&gt;&lt;p&gt;OpenGL rendering uses&lt;span style=&quot; font-weight:600;&quot;&gt; multisample antialiasing (MSAA)&lt;/span&gt;, which provides good quality antialiasing. You can turn this feature on or off, but without antialiasing, bad quality image can occur. Samples count affect how much samples per pixel are considered to determine pixel color. It can be a value 1, 2, 4, 8, and 16. Most modern GPUs support at least value 8. Lower this value, if your GPU doesn't support the desired sample count.&lt;/p&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Prefetch pages &lt;/span&gt;prefetches (pre-renders) pages next to currently viewed pages, to avoid flickering during scrolling. Prefetched pages are stored in the page cache.&lt;/p&gt;&lt;p&gt;&lt;span style=&quot; font-weight:600;&quot;&gt;Multithreading strategy &lt;/span&gt;defines how program will use CPU cores. Engine can use multiple cores. Strategy defines, how engine will use these cores. &lt;span style=&quot; font-weight:600;&quot;&gt;Single thread&lt;/span&gt; strategy uses only one CPU core for rendering page, and for some operations, they aren't parallelized, at the cost of more time needed for operation to be finished. But still, each page will use its own thread to be compiled/drawn. On the other side, there are two multithreading strategies, former is load balanced, latter uses maximum threads. Load balanced strategy parallelizes only pages, but not processing each individual page content, while maximum threads strategy will spawn as much threads as possible to process operations to achieve best performance.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
               </property>
               <property name="wordWrap">
                <bool>true</bool>