Update docs

Make a new image for layout parameters.

3 files changed, 498 insertions, 1 deletions

diff --git a/docs/layout.png b/docs/layout.png
new file mode 100644
index 00000000..bd28d5be
--- /dev/null
+++ b/docs/layout.png
diff --git a/docs/layout.svg b/docs/layout.svg
new file mode 100644
index 00000000..09f498b7
--- /dev/null
+++ b/docs/layout.svg
@@ -0,0 +1,497 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="210mm"
+   height="297mm"
+   viewBox="0 0 210 297"
+   version="1.1"
+   id="svg8"
+   sodipodi:docname="layout.svg"
+   inkscape:version="0.92.4 5da689c313, 2019-01-14">
+  <defs
+     id="defs2">
+    <marker
+       inkscape:stockid="TriangleInM"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="marker14051"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         id="path14049"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         transform="scale(-0.4)" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker7942"
+       refX="0.0"
+       refY="0.0"
+       orient="auto"
+       inkscape:stockid="TriangleOutM">
+      <path
+         transform="scale(0.4)"
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         id="path7940" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker7139"
+       refX="0.0"
+       refY="0.0"
+       orient="auto"
+       inkscape:stockid="TriangleOutM">
+      <path
+         transform="scale(0.4)"
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         id="path7137" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker7071"
+       refX="0.0"
+       refY="0.0"
+       orient="auto"
+       inkscape:stockid="TriangleOutM">
+      <path
+         transform="scale(0.4)"
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         id="path7069" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker6673"
+       refX="0.0"
+       refY="0.0"
+       orient="auto"
+       inkscape:stockid="TriangleInM"
+       inkscape:collect="always">
+      <path
+         transform="scale(-0.4)"
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         id="path6671" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleOutM"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="TriangleOutM"
+       style="overflow:visible"
+       inkscape:isstock="true"
+       inkscape:collect="always">
+      <path
+         id="path1067"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         transform="scale(0.4)" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleInM"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="TriangleInM"
+       style="overflow:visible"
+       inkscape:isstock="true"
+       inkscape:collect="always">
+      <path
+         id="path1058"
+         d="M 5.77,0.0 L -2.88,5.0 L -2.88,-5.0 L 5.77,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         transform="scale(-0.4)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow1Sstart"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Sstart"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         id="path934"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         transform="scale(0.2) translate(6,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow1Lend"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Lend"
+       style="overflow:visible;"
+       inkscape:isstock="true">
+      <path
+         id="path925"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         transform="scale(0.8) rotate(180) translate(12.5,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="Arrow1Lstart"
+       orient="auto"
+       refY="0.0"
+       refX="0.0"
+       id="Arrow1Lstart"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         id="path922"
+         d="M 0.0,0.0 L 5.0,-5.0 L -12.5,0.0 L 5.0,5.0 L 0.0,0.0 z "
+         style="fill-rule:evenodd;stroke:#000000;stroke-width:1pt;stroke-opacity:1;fill:#000000;fill-opacity:1"
+         transform="scale(0.8) translate(12.5,0)" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleInM"
+       orient="auto"
+       refY="0"
+       refX="0"
+       id="TriangleInM-0"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         inkscape:connector-curvature="0"
+         id="path1058-6"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         transform="scale(-0.4)" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleOutM"
+       orient="auto"
+       refY="0"
+       refX="0"
+       id="TriangleOutM-4"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         inkscape:connector-curvature="0"
+         id="path1067-6"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         transform="scale(0.4)" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleInM"
+       orient="auto"
+       refY="0"
+       refX="0"
+       id="TriangleInM-5"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         inkscape:connector-curvature="0"
+         id="path1058-8"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         transform="scale(-0.4)" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleOutM"
+       orient="auto"
+       refY="0"
+       refX="0"
+       id="TriangleOutM-6"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         inkscape:connector-curvature="0"
+         id="path1067-2"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         transform="scale(0.4)" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker6673-6"
+       refX="0"
+       refY="0"
+       orient="auto"
+       inkscape:stockid="TriangleInM">
+      <path
+         inkscape:connector-curvature="0"
+         transform="scale(-0.4)"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         id="path6671-2" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker7139-9"
+       refX="0"
+       refY="0"
+       orient="auto"
+       inkscape:stockid="TriangleOutM">
+      <path
+         inkscape:connector-curvature="0"
+         transform="scale(0.4)"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         id="path7137-9" />
+    </marker>
+    <marker
+       inkscape:stockid="TriangleInM"
+       orient="auto"
+       refY="0"
+       refX="0"
+       id="marker14051-8"
+       style="overflow:visible"
+       inkscape:isstock="true">
+      <path
+         inkscape:connector-curvature="0"
+         id="path14049-1"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         transform="scale(-0.4)" />
+    </marker>
+    <marker
+       inkscape:isstock="true"
+       style="overflow:visible"
+       id="marker7942-3"
+       refX="0"
+       refY="0"
+       orient="auto"
+       inkscape:stockid="TriangleOutM">
+      <path
+         inkscape:connector-curvature="0"
+         transform="scale(0.4)"
+         style="fill:#000000;fill-opacity:1;fill-rule:evenodd;stroke:#000000;stroke-width:1.00000003pt;stroke-opacity:1"
+         d="M 5.77,0 -2.88,5 V -5 Z"
+         id="path7940-1" />
+    </marker>
+  </defs>
+  <sodipodi:namedview
+     id="base"
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1.0"
+     inkscape:pageopacity="0.0"
+     inkscape:pageshadow="2"
+     inkscape:zoom="2.8284271"
+     inkscape:cx="62.552344"
+     inkscape:cy="945.78705"
+     inkscape:document-units="mm"
+     inkscape:current-layer="layer1"
+     showgrid="false"
+     showguides="true"
+     inkscape:snap-global="false"
+     inkscape:window-width="1920"
+     inkscape:window-height="1016"
+     inkscape:window-x="0"
+     inkscape:window-y="27"
+     inkscape:window-maximized="1" />
+  <metadata
+     id="metadata5">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <g
+     inkscape:label="Layer 1"
+     inkscape:groupmode="layer"
+     id="layer1">
+    <flowRoot
+       xml:space="preserve"
+       id="flowRoot815"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:85.33333588px;line-height:1.25;font-family:'DejaVu Serif';-inkscape-font-specification:'DejaVu Serif';letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none"
+       transform="scale(0.26458333)"><flowRegion
+         id="flowRegion817"
+         style="font-size:85.33333588px"><rect
+           id="rect819"
+           width="351.42859"
+           height="708.57141"
+           x="211.42857"
+           y="182.51968"
+           style="font-size:85.33333588px" /></flowRegion><flowPara
+         id="flowPara821"
+         style="font-size:96.00000121px">Mg</flowPara></flowRoot>    <rect
+       style="fill:none;fill-opacity:1;stroke-width:0.26458333;stroke-miterlimit:4;stroke-dasharray:none;"
+       id="rect823"
+       width="47.624996"
+       height="24.209377"
+       x="52.255207"
+       y="52.260418" />
+    <rect
+       style="fill:none;fill-opacity:1;stroke-width:0.26458333;stroke-miterlimit:4;stroke-dasharray:none"
+       id="rect845"
+       width="47.624996"
+       height="24.209377"
+       x="52.255207"
+       y="52.260418" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.13229167;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 104.9316,52.260417 c -56.885887,0 -56.885887,0 -56.885887,0 v 0"
+       id="path849"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.13229167;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 104.72835,71.043661 c -56.605254,0 -56.605254,0 -56.605254,0 v 0"
+       id="path849-8"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.13229167;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 104.68306,76.469795 c -56.605249,0 -56.605249,0 -56.605249,0 v 0"
+       id="path849-8-0"
+       inkscape:connector-curvature="0" />
+    <flowRoot
+       transform="matrix(0.26458333,0,0,0.26458333,-0.49993439,29.92432)"
+       xml:space="preserve"
+       id="flowRoot815-2"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:85.33333588px;line-height:1.25;font-family:'DejaVu Serif';-inkscape-font-specification:'DejaVu Serif';letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none"><flowRegion
+         id="flowRegion817-1"
+         style="font-size:85.33333588px"><rect
+           id="rect819-0"
+           width="351.42859"
+           height="708.57141"
+           x="211.42857"
+           y="182.51968"
+           style="font-size:85.33333588px" /></flowRegion><flowPara
+         id="flowPara821-5"
+         style="font-size:96px">Mg</flowPara></flowRoot>    <rect
+       style="fill:none;fill-opacity:1;stroke-width:0.26458332;stroke-miterlimit:4;stroke-dasharray:none"
+       id="rect823-1"
+       width="47.624996"
+       height="24.209377"
+       x="51.75528"
+       y="82.184738" />
+    <rect
+       style="fill:none;fill-opacity:1;stroke-width:0.26458332;stroke-miterlimit:4;stroke-dasharray:none"
+       id="rect845-1"
+       width="47.624996"
+       height="24.209377"
+       x="51.75528"
+       y="82.184738" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.13229167;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 104.80585,82.184738 c -57.07298,0 -57.07298,0 -57.07298,0 v 0"
+       id="path849-0"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.13229167;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 104.88322,100.82767 c -56.885878,0 -56.885878,0 -56.885878,0 v 0"
+       id="path849-8-8"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.13229167;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 104.83794,106.39412 c -56.979428,0 -56.979428,0 -56.979428,0 v 0"
+       id="path849-8-0-5"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.25984162px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1;marker-start:url(#TriangleInM);marker-end:url(#TriangleOutM)"
+       d="m 102.52459,70.326803 c -0.0936,-17.322528 -0.0936,-17.322528 -0.0936,-17.322528"
+       id="path920"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.26465496px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1;marker-start:url(#marker6673);marker-end:url(#marker7139)"
+       d="m 102.45365,72.131518 c -0.13882,3.407593 -0.13882,3.407593 -0.13882,3.407593"
+       id="path10620"
+       inkscape:connector-curvature="0" />
+    <text
+       xml:space="preserve"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:4.23333311px;line-height:1.25;font-family:Cantarell;-inkscape-font-specification:Cantarell;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.26458332"
+       x="107.29259"
+       y="62.917221"
+       id="text13750"><tspan
+         sodipodi:role="line"
+         id="tspan13748"
+         x="107.29259"
+         y="62.917221"
+         style="stroke-width:0.26458332">Ascent</tspan><tspan
+         sodipodi:role="line"
+         x="107.29259"
+         y="68.208885"
+         style="stroke-width:0.26458332"
+         id="tspan13752" /></text>
+    <text
+       xml:space="preserve"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:4.23333311px;line-height:1.25;font-family:Cantarell;-inkscape-font-specification:Cantarell;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.26458332"
+       x="107.10825"
+       y="74.800102"
+       id="text13756"><tspan
+         sodipodi:role="line"
+         id="tspan13754"
+         x="107.10825"
+         y="74.800102"
+         style="stroke-width:0.26458332">Descent</tspan></text>
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.26465496px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1;marker-start:url(#marker6673-6);marker-end:url(#marker7139-9)"
+       d="m 49.428752,77.64513 c -0.13882,3.407594 -0.13882,3.407594 -0.13882,3.407594"
+       id="path10620-0"
+       inkscape:connector-curvature="0" />
+    <text
+       xml:space="preserve"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:4.23333311px;line-height:1.25;font-family:Cantarell;-inkscape-font-specification:Cantarell;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.26458332"
+       x="28.730095"
+       y="80.757591"
+       id="text14031"><tspan
+         sodipodi:role="line"
+         id="tspan14029"
+         x="28.730095"
+         y="80.757591"
+         style="stroke-width:0.26458332">Spacing</tspan></text>
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.26399428px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1;marker-start:url(#marker14051);marker-end:url(#marker7942)"
+       d="M 102.41047,105.39271 C 102.21678,77.415754 102.21678,77.415754 102.21678,77.415754"
+       id="path14041"
+       inkscape:connector-curvature="0" />
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.26399428px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1;marker-start:url(#marker14051-8);marker-end:url(#marker7942-3)"
+       d="M 53.385014,99.776343 C 53.19133,71.79943 53.19133,71.79943 53.19133,71.79943"
+       id="path14041-1"
+       inkscape:connector-curvature="0" />
+    <text
+       xml:space="preserve"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:4.23333311px;line-height:1.25;font-family:Cantarell;-inkscape-font-specification:Cantarell;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.26458332"
+       x="107.14215"
+       y="92.602859"
+       id="text16168"><tspan
+         sodipodi:role="line"
+         id="tspan16166"
+         x="107.14215"
+         y="92.602859"
+         style="stroke-width:0.26458332">Height</tspan></text>
+    <text
+       xml:space="preserve"
+       style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:4.23333333px;line-height:1.25;font-family:Cantarell;-inkscape-font-specification:'Cantarell, Normal';font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-feature-settings:normal;text-align:start;letter-spacing:0px;word-spacing:0px;writing-mode:lr;text-anchor:start;fill:#000000;fill-opacity:1;stroke:none;stroke-width:0.26458332;"
+       x="12.434073"
+       y="62.795258"
+       id="text16172"><tspan
+         sodipodi:role="line"
+         id="tspan16188">Baseline-to-baseline</tspan><tspan
+         sodipodi:role="line"
+         id="tspan16190">distance</tspan></text>
+    <path
+       style="fill:none;stroke:#000000;stroke-width:0.12913886;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+       d="m 53.1315,74.164103 c 0,0 -4.818074,0.125651 -7.969503,-0.151187 -2.845534,-0.249967 -5.290399,-0.985067 -7.513672,-1.679659 -4.72719,-1.476863 -7.250826,-3.884947 -7.250826,-3.884947"
+       id="path16192"
+       inkscape:connector-curvature="0"
+       sodipodi:nodetypes="cssc" />
+  </g>
+</svg>
diff --git a/docs/meson.build b/docs/meson.build
index 9122dc3c..fbfb6072 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -58,7 +58,7 @@ content_files = [
 ]
 
 html_images = [
-  'layout.gif',
+  'layout.png',
   'rotated-text.png',
 ]