Add wxGridCellRenderer::GetMaxBestSize()

This is another optimization, useful for the renderers that are used
with the values of a fixed form or part of a limited set, as it is much
faster to compute the best size for all values of the set rather than
computing them for all the cells in the column.

include/wx/generic/grid.h

@@ -212,6 +212,20 @@ public:
         return GetBestSize(grid, attr, dc, row, col).GetWidth();
     }
 
+
+    // Unlike GetBestSize(), this functions is optional: it is used when
+    // auto-sizing columns to determine the best width without iterating over
+    // all cells in this column, if possible.
+    //
+    // If it isn't, return wxDefaultSize as the base class version does by
+    // default.
+    virtual wxSize GetMaxBestSize(wxGrid& WXUNUSED(grid),
+                                  wxGridCellAttr& WXUNUSED(attr),
+                                  wxDC& WXUNUSED(dc))
+    {
+        return wxDefaultSize;
+    }
+
     // create a new object which is the copy of this one
     virtual wxGridCellRenderer *Clone() const = 0;
 };

include/wx/generic/gridctrl.h

@@ -141,6 +141,10 @@ public:
                                wxDC& dc,
                                int row, int col) wxOVERRIDE;
 
+    virtual wxSize GetMaxBestSize(wxGrid& grid,
+                                  wxGridCellAttr& attr,
+                                  wxDC& dc) wxOVERRIDE;
+
     virtual wxGridCellRenderer *Clone() const wxOVERRIDE
         { return new wxGridCellBoolRenderer; }
 };
@@ -175,6 +179,10 @@ public:
                                wxDC& dc,
                                int row, int col) wxOVERRIDE;
 
+    virtual wxSize GetMaxBestSize(wxGrid& grid,
+                                  wxGridCellAttr& attr,
+                                  wxDC& dc) wxOVERRIDE;
+
     virtual wxGridCellRenderer *Clone() const wxOVERRIDE;
 
     // output strptime()-like format string
@@ -232,6 +240,10 @@ public:
                                wxDC& dc,
                                int row, int col) wxOVERRIDE;
 
+    virtual wxSize GetMaxBestSize(wxGrid& grid,
+                                  wxGridCellAttr& attr,
+                                  wxDC& dc) wxOVERRIDE;
+
     virtual wxGridCellRenderer *Clone() const wxOVERRIDE;
 
     // parameters string format is "item1[,item2[...,itemN]]" where itemN will

interface/wx/grid.h

@@ -88,6 +88,26 @@ public:
     virtual int GetBestWidth(wxGrid& grid, wxGridCellAttr& attr, wxDC& dc,
                              int row, int col, int height);
 
+    /**
+        Get the maximum possible size for a cell using this renderer, if
+        possible.
+
+        This function may be overridden in the derived class if it can return
+        the maximum size needed for displaying the cells rendered it without
+        iterating over all cells. The base class version simply returns
+        ::wxDefaultSize, indicating that this is infeasible and that
+        GetBestSize() should be called for each cell individually.
+
+        Note that this method will only be used if
+        wxGridTableBase::CanMeasureColUsingSameAttr() is overriden to return
+        @true.
+
+        @since 3.1.4
+     */
+    virtual wxSize GetMaxBestSize(wxGrid& grid,
+                                  wxGridCellAttr& attr,
+                                  wxDC& dc);
+
 protected:
     /**
         The destructor is private because only DecRef() can delete us.

src/generic/grid.cpp

@@ -10017,6 +10017,21 @@ wxGrid::AutoSizeColOrRow(int colOrRow, bool setAsMin, wxGridDirection direction)
         {
             attr = GetCellAttrPtr(row, col);
             renderer = attr->GetRendererPtr(this, row, col);
+
+            if ( canReuseAttr )
+            {
+                // Try to get the best width for the entire column at once, if
+                // it's supported by the renderer.
+                extent = renderer->GetMaxBestSize(*this, *attr, dc).x;
+
+                if ( extent != wxDefaultCoord )
+                {
+                    extentMax = extent;
+
+                    // No need to check all the values.
+                    break;
+                }
+            }
         }
 
         if ( renderer )

src/generic/gridctrl.cpp

@@ -165,6 +165,24 @@ wxSize wxGridCellDateRenderer::GetBestSize(wxGrid& grid,
     return DoGetBestSize(attr, dc, GetString(grid, row, col));
 }
 
+wxSize wxGridCellDateRenderer::GetMaxBestSize(wxGrid& WXUNUSED(grid),
+                                              wxGridCellAttr& attr,
+                                              wxDC& dc)
+{
+    wxSize size;
+
+    // Try to produce the longest string in the current format: as we don't
+    // know which month is the longest, we need to try all of them.
+    for ( int m = wxDateTime::Jan; m <= wxDateTime::Dec; ++m )
+    {
+        const wxDateTime d(28, static_cast<wxDateTime::Month>(m), 9999);
+
+        size.IncTo(DoGetBestSize(attr, dc, d.Format(m_oformat, m_tz)));
+    }
+
+    return size;
+}
+
 void wxGridCellDateRenderer::SetParameters(const wxString& params)
 {
     if (!params.empty())
@@ -260,6 +278,20 @@ wxSize wxGridCellEnumRenderer::GetBestSize(wxGrid& grid,
     return DoGetBestSize(attr, dc, GetString(grid, row, col));
 }
 
+wxSize wxGridCellEnumRenderer::GetMaxBestSize(wxGrid& WXUNUSED(grid),
+                                              wxGridCellAttr& attr,
+                                              wxDC& dc)
+{
+    wxSize size;
+
+    for ( size_t n = 0; n < m_choices.size(); ++n )
+    {
+        size.IncTo(DoGetBestSize(attr, dc, m_choices[n]));
+    }
+
+    return size;
+}
+
 void wxGridCellEnumRenderer::SetParameters(const wxString& params)
 {
     if ( !params )
@@ -912,10 +944,17 @@ void wxGridCellFloatRenderer::SetParameters(const wxString& params)
 // ----------------------------------------------------------------------------
 
 wxSize wxGridCellBoolRenderer::GetBestSize(wxGrid& grid,
-                                           wxGridCellAttr& WXUNUSED(attr),
-                                           wxDC& WXUNUSED(dc),
+                                           wxGridCellAttr& attr,
+                                           wxDC& dc,
                                            int WXUNUSED(row),
                                            int WXUNUSED(col))
+{
+    return GetMaxBestSize(grid, attr, dc);
+}
+
+wxSize wxGridCellBoolRenderer::GetMaxBestSize(wxGrid& grid,
+                                              wxGridCellAttr& WXUNUSED(attr),
+                                              wxDC& WXUNUSED(dc))
 {
     static wxPrivate::DpiDependentValue<wxSize> s_sizeCheckMark;