Change color of DrawGrid Cell
lazarus / 39-Graphics

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PeterATC · 2013-07-08 00:52

Hi I am trying to get the color of cells on a draw grid to change
color. Below is my code but it does not change the color.

procedure TfrmMain.DrawGridDrawCell;
var
 i, j : integer;
begin
     for i := 0 to frmMain.drwGrid.ColCount-1 do
       for j := 0 to frmMain.drwGrid.RowCount-1 do
        begin
            frmMain.drwGrid.CellRect(i,j);
            frmmain.drwGrid.FocusColor:= ColorOfBricks[i,j];

        end;
end;   

"ColorofBricks"  contains a two dimensional array of TColor values.

Any help much appreciated.

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Blaazen · 2013-07-08 01:04

Try OnPrepareCanvas:
Code: [Select]procedure TForm1.DrawGrid1PrepareCanvas(sender: TObject;
aCol, aRow: Integer;
  aState: TGridDrawState);
begin
  if aRow = 1
    then DrawGrid1.Canvas.Brush.Color := clRed
    else DrawGrid1.Canvas.Brush.Color := clGreen;
end;This will color all cells to green except cells in the row = 1.
You don't have to use loops. Event is triggered for each cell.

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PeterATC · 2013-07-10 02:02

HI that works but I am trying to create a grid with three colors in
random bricks. So the color of each cell needs to be read from the
colors in the two dimentional array "ColorOfBricks". Is there way to
cycle thru each cell and apply the color to the cell.

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taazz · 2013-07-10 02:10

no, cells are not objects per see just positions in the grid to be
drawn upon, why don't you use the acol,arow parameters to get the
color from the ColorOfBricks array? eg.

Code: [Select]procedure TForm1.DrawGrid1PrepareCanvas(sender: TObject;
aCol, aRow: Integer;
  aState: TGridDrawState);
begin
    DrawGrid1.Canvas.Brush.Color := ColorOfBricks[aRow,aCol];
end;

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PeterATC · 2013-07-11 11:54

Thank taazz. It works fine. never thought of using those paramaters.