wxGrid and wxBitmap Topic is solved

[BigFreeze]

Hi everyone,

here is my problem: I have a class derived from wxGrid. I want to show a bitmap in one column. I derived a class from wxGridCellRenderer and do the drawing in the Draw(...) method. The bitmap is shown in the grid, but even if I use SetCellOverflow for the specific cell, the bitmap is fully displayed and not only in the cell.

My problem is, that I have to clear the device context at redraw the bitmap at runtime. But when I use the Clear() method the whole wxGrid is cleared, not only the bitmap.

Can anybody help me?

Thanks in advance. BigFreeze

[tan]

Hi.

Hi everyone,

here is my problem: I have a class derived from wxGrid. I want to show a bitmap in one column. I derived a class from wxGridCellRenderer and do the drawing in the Draw(...) method. The bitmap is shown in the grid, but even if I use SetCellOverflow for the specific cell, the bitmap is fully displayed and not only in the cell.

wxGridCellRenderer::Draw() method takes wxRect parameter. It is cell rectangle. You can get subbitmap from the bitmap with specified width and height and draw the subbitmap. Or you can set clipping region on the DC.

[BigFreeze]

Thanks for your reply.

If I set the clipping region for the bitmap, the whole wxGrid is not shown. The wxGrid has the same size like the image. If I clear the device context, the whole wxGrid is shown correctly.

It seems, that the device context ist the whole wxGrid and not only the cell, I specified with SetCellRenderer.

Maybe I should post some code. It is like this:

Code: Select all

MyGrid* grid;
grid->SetCellRenderer(0, 0, new MySymbol(speak_xpm));

MySymbol::Draw(...)
{
  dc.DrawBitmap(m_bmp, 5, 3+17*row, true); 
}

[tan]

May be i don't understand exactly what do you want.
Do you want draw bitmap ONLY in specific cell? Try anything like this:

Code: Select all

MySymbol::Draw(wxGrid& grid, wxGridCellAttr& attr, wxDC& dc,
               const wxRect& rect, int row, int col, bool isSelected))
{
  dc.DrawBitmap(m_bmp.GetSubBitmap(wxRect(0, 0, rect.width, rect.height)), rect.x, rect.y, true);
}

[BigFreeze]

Ok, the image is drawn into a cell without an overflow into other cells. But if I do a dc.Clear() the whole wxGrid is cleared not only the image. I just want to delete the image in the cell and show again after some time.

[tan]

Ok, the image is drawn into a cell without an overflow into other cells. But if I do a dc.Clear() the whole wxGrid is cleared not only the image. I just want to delete the image in the cell and show again after some time.

Just draw rectangle with default background color to hide image:

Code: Select all

MySymbol::Draw(wxGrid& grid, wxGridCellAttr& attr, wxDC& dc,
               const wxRect& rect, int row, int col, bool isSelected))
{
     wxColour BgColor = attr.GetBackgroundColour();
     dc.SetBrush(wxBrush(BgColor, wxSOLID));
     dc.SetPen(*wxTRANSPARENT_PEN);
     dc.DrawRectangle(rect.x, rect.y, rect.width, rect.height);
}    

[BigFreeze]

Thanks. It works fine. Good job! Now I understand the whole topic a little better...