Reformat table of images in step-18 results section

diff --git a/examples/step-18/doc/results.dox b/examples/step-18/doc/results.dox
index 3b97ae1fbd2c823240fb1cabc9455fd9c41ec74c..03dfeb2afc3eb28ddf1f7e3239e037d44619761b 100644 (file)
--- a/examples/step-18/doc/results.dox
+++ b/examples/step-18/doc/results.dox
@@ -130,41 +130,72 @@ of the disaster our forced compression wreaks on the cylinder (colors in the
 images encode the norm of the stress in the material):
 
 
-<table width="100%">
-  <tr width="100%">
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0002.0000.png" alt="">
-       Time = 2
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0005.0000.png" alt="">
-       Time = 5
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0007.0000.png" alt="">
-       Time = 7
-    </td>
-  </tr>
-
-  <tr width="100%">
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0008.0000.png" alt="">
+<div class="threecolumn" style="width: 80%">
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0002.0000.png"
+           alt="Time = 2"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 2
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0005.0000.png"
+           alt="Time = 5"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 5
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0007.0000.png"
+           alt="Time = 7"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 7
+    </div>
+  </div>
+</div>
+
+
+<div class="threecolumn" style="width: 80%">
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0008.0000.png"
+           alt="Time = 8"
+           width="400">
+    </div>
+    <div class="text" align="center">
       Time = 8
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0009.0000.png" alt="">
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0009.0000.png"
+           alt="Time = 9"
+           width="400">
+    </div>
+    <div class="text" align="center">
       Time = 9
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0010.0000.png" alt="">
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.sequential-0010.0000.png"
+           alt="Time = 10"
+           width="400">
+    </div>
+    <div class="text" align="center">
       Time = 10
-    </td>
-  </tr>
-</table>
+    </div>
+  </div>
+</div>
 
 
 As is clearly visible, as we keep compressing the cylinder, it starts
@@ -250,58 +281,99 @@ Here are first the mesh on which we compute as well as the partitioning
 for the 16 processors:
 
 
-<table width="100%">
-  <tr width="100%">
-    <td width="49%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-000mesh.png" alt="">
-    </td>
-
-    <td width="49%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0002.p.png" alt="">
-    </td>
-  </tr>
-</table>
+<div class="twocolumn" style="width: 80%">
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-000mesh.png"
+           alt="Discretization"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Discretization
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0002.p.png"
+           alt="Parallel partitioning"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Parallel partitioning
+    </div>
+  </div>
+</div>
 
 
 Finally, here is the same output as we have shown before for the much smaller
 sequential case:
 
-
-<table width="100%">
-  <tr width="100%">
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0002.s.png" alt="">
-       Time = 2
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0005.s.png" alt="">
-       Time = 5
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0007.s.png" alt="">
-       Time = 7
-    </td>
-  </tr>
-
-  <tr width="100%">
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0008.s.png" alt="">
-       Time = 8
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0009.s.png" alt="">
-       Time = 9
-    </td>
-
-    <td width="33%">
-      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0010.s.png" alt="">
-       Time = 10
-    </td>
-  </tr>
-</table>
+<div class="threecolumn" style="width: 80%">
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0002.s.png"
+           alt="Time = 2"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 2
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0005.s.png"
+           alt="Time = 5"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 5
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0007.s.png"
+           alt="Time = 7"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 7
+    </div>
+  </div>
+</div>
+
+
+<div class="threecolumn" style="width: 80%">
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0008.s.png"
+           alt="Time = 8"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 8
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0009.s.png"
+           alt="Time = 9"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 9
+    </div>
+  </div>
+  <div class="parent">
+    <div class="img" align="center">
+      <img src="https://www.dealii.org/images/steps/developer/step-18.parallel-0010.s.png"
+           alt="Time = 10"
+           width="400">
+    </div>
+    <div class="text" align="center">
+      Time = 10
+    </div>
+  </div>
+</div>
 
 
 As before, we observe that at high axial compression the cylinder begins