docs: horizontal plot split

help/C/org.udpscope.app/layout.page

@@ -5,8 +5,8 @@
   <info>
     <link type="guide" xref="index#main"/>
     <link type="seealso" xref="signals"/>
-    <desc>How the figure's rows and traces are arranged, how to drop a signal onto a row, and
-    how the layout editor adds and removes rows.</desc>
+    <desc>How the figure's rows, plots and traces are arranged, how to drop a signal onto a plot, and
+    how the layout editor adds and removes rows and splits a row into plots side by side.</desc>
     <credit type="author copyright">
       <name>Martino Ferrari</name>
     </credit>
@@ -14,9 +14,10 @@
 
   <title>Rows, layout and drag &amp; drop</title>
 
-  <p>The figure is a stack of rows, 1 to 8 of them, each holding up to 4 traces. Rows share
-  one time axis and one pair of side margins, so their y labels line up, their data areas
-  start and end on the same two columns, and their windows cannot drift apart. The left
+  <p>The figure is a stack of rows holding 1 to 8 plots in all, and a row can be split into up
+  to 4 plots side by side. Each plot holds up to 4 traces. Every plot shares one time axis and
+  the figure has one pair of side margins, so the y labels line up, the data areas start and
+  end on the same two columns, and the windows cannot drift apart. The left
   margin holds the y labels; the right one is empty, and is there so the newest tick's label
   and the newest sample's ink have somewhere to land instead of sitting on the frame.</p>
 
@@ -29,7 +30,7 @@
       </item>
       <item>
         <p>Press <key>l</key>, or pick <gui>Layout editor</gui> from the overflow menu, to add
-        and remove rows: a <gui>×</gui> appears at the top left of each row and a <gui>+</gui>
+        and remove rows: a <gui>×</gui> appears at the top left of each plot and a <gui>+</gui>
         on each boundary between rows, including above the first and below the last.</p>
       </item>
       <item>
@@ -38,6 +39,29 @@
     </steps>
   </section>
 
+  <section id="split">
+    <title>Splitting a row</title>
+    <steps>
+      <item>
+        <p>In the layout editor, click the <gui>+</gui> at a row's left or right edge, or the
+        <gui>+</gui> between two plots, to add a plot to that row. The new plot starts empty.</p>
+      </item>
+      <item>
+        <p>Drag the arrow on the boundary between two plots to resize them. Neither plot can be
+        made narrower than about 96 px, and the widths are saved with the session.</p>
+      </item>
+      <item>
+        <p>Click the <gui>×</gui> of a plot in a split row to remove that plot and its traces.
+        In a row with a single plot the <gui>×</gui> removes the row instead.</p>
+      </item>
+    </steps>
+    <p>All the plots of a row, and of the whole figure, share one time window: zooming or
+    panning along time in any of them moves all of them, and the vertical cursors are drawn in
+    every plot. The y axes, the horizontal cursors and the fits belong to each plot. Only the
+    bottom row carries the time labels. A row holds at most 4 plots and the figure at most 8
+    in total; the <gui>+</gui> buttons go grey at the limit.</p>
+  </section>
+
   <section id="knowing">
     <title>Worth knowing</title>
     <list>
@@ -47,10 +71,11 @@
       <gui>Back</gui> row to return. That is how a trace comes off a row without going through
       the layout editor.</p></item>
       <item><p>A drop <em>adds</em> a trace to the row's next free slot; it does not replace
-      one. With four traces already on a row the drop is refused.</p></item>
-      <item><p>Inserting a row moves the rows below it <em>with their contents</em>. Inserting
-      above row 1 puts what row 1 plotted onto row 2 and leaves the new row empty — the rows
-      are not renumbered under you.</p></item>
+      one. With four traces already on a plot the drop is refused.</p></item>
+      <item><p>Inserting a row moves the rows below it <em>with their contents</em>, split
+      rows included. Inserting above row 1 puts what row 1 plotted onto row 2 and leaves the
+      new row empty — the rows are not renumbered under you. A split row's plots are named
+      <em>2a</em>, <em>2b</em> and so on.</p></item>
       <item><p>A trace is remembered by the signal's <em>name</em>, not by its channel number,
       because a new CONFIG or an enable renumbers the channels and an index would silently
       re-point the trace.</p></item>
@@ -62,10 +87,11 @@
 
   <section id="example">
     <title>Example</title>
-    <p>With three traces on row 1, pressing <key>l</key> shows 3 buttons (one <gui>×</gui>,
-    two <gui>+</gui>). Clicking the <gui>+</gui> above row 1 gives 2 rows and 5 buttons, with
-    the three traces now on row 2 — the layout probe reports exactly this as
-    <code>rows=2 buttons=5 traces=[0:-|1:sine,ramp,noise]</code>.</p>
+    <p>With three traces on row 1, pressing <key>l</key> shows 7 buttons: the <gui>×</gui>,
+    the two <gui>+</gui> above and below the row with their two resize arrows, and the two
+    <gui>+</gui> at the row's left and right edges. Clicking the <gui>+</gui> above row 1 gives 2 rows and 12 buttons,
+    with the three traces now on row 2 — the layout probe reports exactly this as
+    <code>rows=2 buttons=12 traces=[0:-|1:sine,ramp,noise]</code>.</p>
   </section>
 
 </page>