Auto size (stretch) last column of a wxGrid

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iwbnwif
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Joined: Tue Mar 19, 2013 8:52 pm

Auto size (stretch) last column of a wxGrid

Post by iwbnwif »

One of the nice features of a wxDataViewCtrl and its derivatives is that the last column automatically resizes so that there is no blank space.

Unfortunately the wxGrid doesn't have a similar feature. Whilst this is somewhat understandable because the intended use of wxGrid is not really to display a list of data, it is a very flexible control and implements some features (notably displaying tooltips on cell hovering) that are useful for lists.

The following is a simple way of stretching the last column of a wxGrid to fill the full width.

I have only been able to test it so far on wxGTK (Ubuntu 14.04) and welcome any improvements, in particular the bind / unbind calls. There are also a few oddities, such as it doesn't always size properly on first creation and it will probably try to unhide the last column if it is hidden.

StretchGrid.h

Code: Select all

#include <wx/grid.h>

class StretchGrid : public wxGrid
{
public:
    StretchGrid (wxWindow *parent, wxWindowID id, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize,
	       long style = wxWANTS_CHARS, const wxString& name = wxGridNameStr);
    ~StretchGrid ();
    
protected:
    void OnGridWindowSize (wxSizeEvent& event);
    void OnColHeaderSize (wxGridSizeEvent& event);
    void AutoSizeLastCol ();
};
StretchGrid.cpp

Code: Select all

StretchGrid::StretchGrid (wxWindow *parent, wxWindowID id, const wxPoint& pos, const wxSize& size, long style, const wxString& name) :
			wxGrid (parent, id, pos, size, style, name)
{
    GetGridWindow()->Bind (wxEVT_SIZE, &StretchGrid::OnGridWindowSize, this);
    Bind (wxEVT_GRID_COL_SIZE, &StretchGrid::OnColHeaderSize, this);
}

StretchGrid::~StretchGrid()
{
    GetGridWindow()->Unbind (wxEVT_SIZE, &StretchGrid::OnGridWindowSize, this);
    Unbind (wxEVT_GRID_COL_SIZE, &StretchGrid::OnColHeaderSize, this);
}

void StretchGrid::OnGridWindowSize (wxSizeEvent& event)
{
    if (GetNumberCols() > 0)
        AutoSizeLastCol ();
}

void StretchGrid::OnColHeaderSize (wxGridSizeEvent& event)
{
    if (GetNumberCols() > 0)
        AutoSizeLastCol ();
}

void StretchGrid::AutoSizeLastCol ()
{
    int colWidths = 0;
    
    for (int i = 0; i < GetNumberCols() - 1; i++)
        colWidths += GetColWidth (i);
    
    int finalColWidth = GetGridWindow()->GetSize().x - colWidths;
    
    if (finalColWidth > 80)
        SetColSize (GetNumberCols() - 1, finalColWidth);
    else
        SetColSize (GetNumberCols() - 1, 80);
}
wxWidgets 3.1.2, MinGW64 8.1.0, g++ 8.1.0, Ubuntu 19.04, Windows 10, CodeLite + wxCrafter
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Asimov
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Re: Auto size (stretch) last column of a wxGrid

Post by Asimov »

Hi iwbnwif,
Thankyou for your code. I needed my wxGrid to stretch also, and I used your code as a basis for mine. My only problem was that I had a hidden column and your code would unhide my column, so I had to make a few adjustments, Like I had to set my max columns 1 (as I only had 2 columns and 1 hidden column at the end), and so here is how I adjusted your code to work for me.

Code: Select all

  int colWidths = 0;
  int myCol=1;
    for (int i = 0; i < myCol - 1; i++)
        colWidths += GetColWidth (i);
    int finalColWidth = GetGridWindow()->GetSize().x - colWidths;
    finalColWidth=finalColWidth-155;// Remove hidden column width.
    std::cout << finalColWidth << std::endl;
    if (finalColWidth > 80)
        SetColSize (myCol , (finalColWidth));
    else
        SetColSize (myCol , 80);
Now this worked, but because I only had two columns, it looked odd to have a really long right column and a really short left, and so I decided to work my wxGrid into percentages. I have also given my first column a minimum value that it can go down to as well, and if it hits that minimum then it sets the right hand column to fill in the rest. I suppose with a bit more work I could make this work for more columns too, but I only need two columns in my app,
Thank you.

Code: Select all

void tameMywxGrid::AutoSizeLastCol ()
{
    int panelWidth = GetGridWindow()->GetSize().x;
    SetColSize(0,getPercentage(panelWidth,30));
    SetColSize(1,getPercentage(panelWidth,70));
    int firstColMinWidth=140;
    int secondColWidth = panelWidth-firstColMinWidth;
    if(getPercentage(panelWidth,30) < firstColMinWidth)
    {
        SetColSize(0,firstColMinWidth);
        if(secondColWidth>0) SetColSize(1,secondColWidth);
    }
}

int tameMywxGrid::getPercentage(int number,int percent)
{
    return (number / 100.0) * percent;
}
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