Inv(#1020): find a reliable way to determine extension of the canvas

bottom line
- seems we need to do that manually
- must wait until in the on_draw() callback
- use Container::foreach() to visit all child widgets
- Layout::set_size()

src/gui/panel/timeline-panel.cpp

@@ -128,7 +128,7 @@ namespace panel {
       scroller_.set_border_width(10);
       scroller_.add(canvas_);
       
-      adjustToNecessaryCanvasSize();
+      canvas_.adjustSize();
       
       // show everything....
       this->add(twoParts_);
@@ -148,24 +148,6 @@ namespace panel {
   }
   
   
-  void
-  TimelinePanel::adjustToNecessaryCanvasSize()
-  {
-    uint sizeX = 10;
-    uint sizeY = 10;
-    for (Widget* chld : childz_)
-      {
-        uint x = canvas_.child_property_x(*chld);
-        uint y = canvas_.child_property_y(*chld);
-        x += chld->get_allocated_width();
-        y += chld->get_allocated_height();
-        sizeX = max (sizeX, x);
-        sizeY = max (sizeY, y);
-      }
-    
-    canvas_.set_size (sizeX, sizeY);
-  }
-  
   
   void
   TimelinePanel::experiment_1()
@@ -178,7 +160,7 @@ namespace panel {
     uint y = rand() % 500;
     canvas_.put(*chld, x, y);
     chld->show();
-    adjustToNecessaryCanvasSize();
+    canvas_.adjustSize();
   }
   
   
@@ -197,7 +179,7 @@ namespace panel {
         
         canvas_.move (*chld, x,y);
       }
-    adjustToNecessaryCanvasSize();
+    canvas_.adjustSize();
   }
   
   
@@ -214,7 +196,7 @@ namespace panel {
         int width = chld->get_allocated_width();
         pos += 0.6 * width;
       }
-    adjustToNecessaryCanvasSize();
+    canvas_.adjustSize();
   }
   
   
@@ -258,10 +240,42 @@ namespace panel {
   }
   
   
+  
+  void
+  Canvas::adjustSize()
+  {
+    recalcExtension_ = true;
+  }
+  
+  void
+  Canvas::determineExtension()
+  {
+      if (not recalcExtension_) return;
+      
+      uint extH=20, extV=20;
+      Gtk::Container::ForeachSlot callback
+        = [&](Gtk::Widget& chld)
+                {
+                  cout << "hoya "<<chld;
+                  auto allo = chld.get_allocation();
+                  uint x = allo.get_x();
+                  uint y = allo.get_y();
+                  x += allo.get_width();
+                  y += allo.get_height();
+                  extH = max (extH, x);
+                  extV = max (extV, y);
+                  cout << "x="<<x<<" y="<<y<<endl;
+                };
+      foreach(callback);
+      recalcExtension_ = false;
+      set_size (extH, extV);
+  }
+  
   namespace {
     _Fmt debugAdj(" | Adj-%s(%3d<%5.2f<%3d)");
   }
   
+  
   bool
   Canvas::on_draw(Cairo::RefPtr<Cairo::Context> const& cox)
   {
@@ -269,8 +283,8 @@ namespace panel {
       {
         int h = get_allocation().get_width();
         int v = get_allocation().get_height();
-        
+        uint extH=20, extV=20;
-        uint extH, extV;
+        determineExtension();
         get_size (extH, extV);
         
         auto adjH = get_hadjustment();
@@ -295,8 +309,10 @@ namespace panel {
         cox->stroke();
         cox->restore();
         
+        // cause child widgets to be redrawn
         Gtk::Layout::on_draw(cox);
         
+        // any drawing which follows happens on top of child widgets...
         cox->save();
         cox->translate(-offH, -offV);
         

src/gui/panel/timeline-panel.hpp

@@ -75,12 +75,16 @@ namespace panel {
     : public Gtk::Layout
     {
       bool shallDraw_;
+      bool recalcExtension_ = false;
       
     public:
       void enableDraw (bool);
+      void adjustSize();
       
     private:
       virtual bool on_draw (Cairo::RefPtr<Cairo::Context> const&)  override;
+      
+      void determineExtension();
     };
   
   
@@ -138,8 +142,6 @@ namespace panel {
       using ChildV = std::vector<ChildEx*>;
       ChildV childz_;
       
-      void adjustToNecessaryCanvasSize();
-      
       void experiment_1();
       void experiment_2();
       void experiment_3();

wiki/renderengine.html

@@ -2411,7 +2411,7 @@ Typically, when starting the draw operation, we retrieve our //allocation.// Thi
 Thus, if we want to use absolute canvas coordinates for our drawing, we need to adjust the cairo context prior to any drawing operations: we translate it in the opposite direction of the values retrieved from the scrollbar {{{Gtk::Adjustment}}}s. This causes the //user coordinates// to coincede with the absolute canvas coordinates.
 </pre>
 </div>
-<div title="GtkLayoutWidget" creator="Ichthyostega" modifier="Ichthyostega" created="201610141819" modified="201610141820" tags="GuiPattern impl" changecount="3">
+<div title="GtkLayoutWidget" creator="Ichthyostega" modifier="Ichthyostega" created="201610141819" modified="201611012211" tags="GuiPattern impl" changecount="4">
 <pre>//This is the canvas widget of ~GTK-3//
 It allows not only custom drawing, but also to embed other widgets at defined coordinates.
 
@@ -2425,9 +2425,9 @@ In order to build a sensible plan for our timeline structure, we need to investi
 
 !test setup
 we need a test setup for this investigation.
- * easy to launch
+* easy to launch
- * don't waste much time, it is disposable
+* don't waste much time, it is disposable
- * realistic: shall reflect the situation in our actual UI
+* realistic: shall reflect the situation in our actual UI
 </pre>
 </div>
 <div title="GuiCommandBinding" creator="Ichthyostega" modifier="Ichthyostega" created="201511272246" modified="201609091641" tags="design decision operational GuiPattern GuiIntegration draft discuss" changecount="26">
@@ -2648,7 +2648,7 @@ In the most general case, there can be per-track content and nested content at t
 &amp;rarr; important question: how to [[organise the widgets|GuiTimelineWidgetStructure]]
 </pre>
 </div>
-<div title="GuiTimelineWidgetStructure" creator="Ichthyostega" modifier="Ichthyostega" created="201410250002" modified="201610301605" tags="GuiPattern discuss decision impl" changecount="52">
+<div title="GuiTimelineWidgetStructure" creator="Ichthyostega" modifier="Ichthyostega" created="201410250002" modified="201611012218" tags="GuiPattern discuss decision impl" changecount="58">
 <pre>The Timeline is probably the most prominent place in the GUI where we need to come up with a custom UI design.
 Instead of combining standard components in one of the well-known ways, here we need to come up with our own handling solution -- which also means to write one or several custom GTK widgets. Thus the question of layout and screen space division and organisation becomes a crucial design decision. The ~GTK-2 Gui, as implemented currently, did already take some steps along this route, yet this kind of decision should be cast and documented explicitly (be it after the fact).
 
@@ -2736,6 +2736,28 @@ In order to build a sensible plan for our timeline structure, we need to investi
 :** when invoked //after// our custom drawing, the embedded widgets stay on top
 :* the {{{Gtk::Allocation}}} is precisely the visible screen area reserved for the widget.&lt;br/&gt;It is //not// the extension of the virtual canvas.
 :* ...consequently, if our drawing shall be stitched to the canvas, we need to care for translation and for clipping ourselves. &amp;rarr; see [[here|GtkCustomDrawing]]
+;determine canvas extension
+:when the extension of the (virtual) canvas area depends on position and size of child widgets, //we need to calculate this extension manually.//
+:* beware: the allocation for child widgets is not setup immediately, when adding or moving children
+:* rather, we need to wait until in the {{{on_draw()}}} callback for the {{{Gtk::Layout}}}
+:* at this point, we may use the //foreach// mechanism of the container
+{{{
+      uint extH=20, extV=20;
+      Gtk::Container::ForeachSlot callback
+        = [&amp;](Gtk::Widget&amp; chld)
+                {
+                  cout &lt;&lt; &quot;hoya &quot;&lt;&lt;chld;
+                  auto allo = chld.get_allocation();
+                  uint x = allo.get_x();
+                  uint y = allo.get_y();
+                  x += allo.get_width();
+                  y += allo.get_height();
+                  extH = max (extH, x);
+                  extV = max (extV, y);
+                };
+      foreach(callback);
+      set_size (extH, extV);
+}}}
 </pre>
 </div>
 <div title="HighLevelModel" modifier="Ichthyostega" created="200808152311" modified="201505310109" tags="Model spec design discuss img" changecount="2">

wiki/thinkPad.ichthyo.mm

@@ -57,8 +57,7 @@
       und welchen Teil des Verhaltens überlassen wir GTK
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 <icon BUILTIN="help"/>
 </node>
 <node CREATED="1477600216950" ID="ID_1935952349" MODIFIED="1477600219202" TEXT="focus">
@@ -119,8 +118,7 @@
       mehr als ein top-level Fenster offen
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 </node>
 <node CREATED="1477342868574" ID="ID_679226593" MODIFIED="1477342875681" TEXT="WorkspaceWindow">
@@ -142,8 +140,7 @@
       which reference actions from one or more action groups.
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 <node CREATED="1477343041295" ID="ID_1874325062" MODIFIED="1477343048450" TEXT="PanelManager">
 <node CREATED="1477343244428" ID="ID_513688853" MODIFIED="1477343252255" TEXT="managed die Docks"/>
@@ -162,8 +159,7 @@
       realisiert Vererbung <i>zu fu&#223;</i>
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 <richcontent TYPE="NOTE"><html>
   <head>
     
@@ -182,8 +178,7 @@
       AUA!
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 </node>
 <node CREATED="1477347390430" HGAP="46" ID="ID_138529757" MODIFIED="1477347400283" TEXT="Panel" VSHIFT="31">
@@ -227,8 +222,7 @@
       auch nicht im Application-Shutdown!
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 <node CREATED="1477617185582" ID="ID_634277803" MODIFIED="1477617217049" TEXT="PanelManager::createPanels()">
 <richcontent TYPE="NOTE"><html>
@@ -243,8 +237,7 @@
       dock_.add_item(timelinePanel-&gt;getDockItem(),Gdl::DOCK_BOTTOM);
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 <icon BUILTIN="info"/>
 </node>
 </node>
@@ -260,8 +253,7 @@
       Helper to build the menu and for&#160;registering and handling of user action events
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 </node>
 <node CREATED="1477344354329" ID="ID_1683945104" MODIFIED="1477344359708" TEXT="createUi()">
@@ -287,8 +279,7 @@
       aber es kann davon mehrere geben
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 <node CREATED="1477343152288" ID="ID_1267678981" MODIFIED="1477343164378" TEXT="Vermengung von Fenster und Workspace"/>
 </node>
@@ -9277,8 +9268,7 @@
       ...nicht mehr das <i>klassische</i>&#160;gtk::Main
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 </node>
 <node CREATED="1477785704584" ID="ID_528329491" MODIFIED="1477785711408" TEXT="event handling">
@@ -9314,8 +9304,7 @@
       Siehe Beschreibung im Beispiel/Tutorial
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 <icon BUILTIN="info"/>
 </node>
 </node>
@@ -9337,8 +9326,7 @@
       und auch ein Signal f&#252;r Parse-Fehler anschlie&#223;t
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 <linktarget COLOR="#a9b4c1" DESTINATION="ID_1810760662" ENDARROW="Default" ENDINCLINATION="1846;-61;" ID="Arrow_ID_1610122569" SOURCE="ID_1164942946" STARTARROW="None" STARTINCLINATION="-227;-646;"/>
 <icon BUILTIN="info"/>
 </node>
@@ -9434,12 +9422,11 @@
       i.e. the enclosing parent widget also gets a chance to redraw itself
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 </node>
-<node CREATED="1477791881630" ID="ID_1823256674" MODIFIED="1477843569686" TEXT="coordinates">
+<node CREATED="1477791881630" ID="ID_1823256674" MODIFIED="1478038049036" TEXT="coordinates">
-<icon BUILTIN="pencil"/>
+<icon BUILTIN="button_ok"/>
 <node CREATED="1477791885614" ID="ID_380369648" MODIFIED="1477791916343">
 <richcontent TYPE="NODE"><html>
   <head>
@@ -9450,8 +9437,7 @@
       <font color="#bd0053">Warning</font>: allocation is the <i>visible</i>&#160;area
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 <icon BUILTIN="messagebox_warning"/>
 </node>
 <node CREATED="1477791921953" ID="ID_555455740" MODIFIED="1477791952896" TEXT="...not the extension of the canvas!"/>
@@ -9486,8 +9472,7 @@
       by printing values from the on_draw() callback
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 <node CREATED="1477841809741" ID="ID_1400891730" MODIFIED="1477841816024" TEXT="context-&gt;translate">
 <node CREATED="1477841816516" ID="ID_642580279" MODIFIED="1477841841348" TEXT="by -value"/>
@@ -9506,8 +9491,7 @@
       causing us to adjust too much
     </p>
   </body>
-</html>
+</html></richcontent>
-</richcontent>
 </node>
 </node>
 </node>
@@ -9515,6 +9499,68 @@
 <node CREATED="1477843534095" ID="ID_1261380784" MODIFIED="1477843541259" TEXT="Problem: widget extension">
 <icon BUILTIN="messagebox_warning"/>
 <node CREATED="1477843543126" ID="ID_1096450231" MODIFIED="1477843556632" TEXT="seems to be defined only after drawing it"/>
+<node CREATED="1478032584364" ID="ID_1961636905" MODIFIED="1478032597162" TEXT="need to find the right signal">
+<icon BUILTIN="yes"/>
+</node>
+<node CREATED="1478032598165" ID="ID_275509060" MODIFIED="1478032625203" TEXT="need to get foreach working">
+<icon BUILTIN="yes"/>
+<node CREATED="1478032633704" ID="ID_1067159761" MODIFIED="1478032641714" TEXT="Hint: show_all_children"/>
+<node CREATED="1478032642310" ID="ID_246127915" LINK="https://developer.gnome.org/gtkmm-tutorial/stable/sec-custom-containers.html.en" MODIFIED="1478032658384" TEXT="Tutorial: custom container"/>
+<node CREATED="1478037794935" HGAP="41" ID="ID_614099643" MODIFIED="1478037886314" TEXT="geht doch" VSHIFT="38">
+<icon BUILTIN="ksmiletris"/>
+<node CREATED="1478037802776" ID="ID_1706111079" MODIFIED="1478037817305" TEXT="keine Ahnung warums neulich einen SEGFAULT gab"/>
+<node CREATED="1478037818037" ID="ID_1257597772" MODIFIED="1478037846037" TEXT="wichtig: Funktor inline bestehen lassen"/>
+<node CREATED="1478037849449" ID="ID_171841689" MODIFIED="1478037859121" TEXT="habe diesmal sogar ein Lambda verwendet">
+<icon BUILTIN="idea"/>
+</node>
+</node>
+</node>
+<node CREATED="1478037888539" ID="ID_1261247197" MODIFIED="1478037996248" TEXT="wie">
+<icon BUILTIN="idea"/>
+<node CREATED="1478037893658" ID="ID_1711061664" MODIFIED="1478037896669" TEXT="trigger-Variable"/>
+<node CREATED="1478037899458" ID="ID_132096735" MODIFIED="1478037907973" TEXT="im on_draw()-Callback">
+<node CREATED="1478037908465" ID="ID_1414994452" MODIFIED="1478037915835" TEXT="erst hier sind die Allokationen gesetzt"/>
+<node CREATED="1478037916303" ID="ID_1781865207" MODIFIED="1478037977495" TEXT="konnte keine anderen sinnvollen callbacks finden">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      ...die anderen, die noch in Frage kommen w&#252;rden,
+    </p>
+    <p>
+      sind nur f&#252;r den Fall, da&#223; ein Widget neu instantiiert wird
+    </p>
+    <p>
+      oder neu in das Window-System gemappt wird.
+    </p>
+    <p>
+      
+    </p>
+  </body>
+</html>
+</richcontent>
+</node>
+<node CREATED="1478037986046" ID="ID_1293899679" MODIFIED="1478037990857">
+<richcontent TYPE="NODE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      on_check_resize() wird nicht aufgerufen
+    </p>
+  </body>
+</html>
+</richcontent>
+<icon BUILTIN="smily_bad"/>
+</node>
+</node>
+<node CREATED="1478038003892" ID="ID_477362495" MODIFIED="1478038010982" TEXT="rufe foreach mit inline-Lambda auf"/>
+<node CREATED="1478038011427" ID="ID_399044896" MODIFIED="1478038019797" TEXT="melde per max in die lokalen Variablen zur&#xfc;ck"/>
+<node CREATED="1478038020338" ID="ID_541293489" MODIFIED="1478038026524" TEXT="Layout-&gt;set_size()"/>
+</node>
 </node>
 </node>
 <node CREATED="1477784943797" ID="ID_298493039" MODIFIED="1477791972306" TEXT="layering">