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Drawing A Grid Onto A CView.

RichJackson
RichJackson asked
on
Hi,

I am trying to draw a grid onto a CView.

The grid doesn't fit into the far right and lower bottom regions correctly. And it varies with the size of the window, it's a strange effect when you resize the window.
My suspicion is its some strange effect with rounding,

Anyway it's only a small code fragment, if anyone is willing to give it a whirl, I'd be grateful.



void CTestView::OnPaint()
{

CPaintDC dc(this); // device context for painting


CRect ScreenDimensions;
GetClientRect(ScreenDimensions);

POINT line[2];

//Draw The Columns
for (int col=0; col <=m_cols; col++)
{
line[0].x = ScreenDimensions.Width() / m_cols * col;
line[0].y = 0;

line[1].x = ScreenDimensions.Width() / m_cols * col;
line[1].y = ScreenDimensions.Height();


dc.Polyline(line,2);
}

//Draw The Rows
for (int row=0; row <=m_rows; row++)
{
line[0].x = 0;
line[0].y = ScreenDimensions.Height() / 50 * row;

line[1].x = ScreenDimensions.Width() ;
line[1].y = ScreenDimensions.Height() / 50 * row;


dc.Polyline(line,2);
}
}



Cheers
Richard Jackson
Comment
Watch Question

Commented:
This is due to error in the Division. For example, the decimal portion of "ScreenDimensions.Width()
/ m_cols" is rounded up and multiplied with the "col" variable value which is an integer. Make m_cols
and m_rows to float or double, It will work perfectly.
Also change this line  "line[0].y = ScreenDimensions.Height() / 50 * row;" to line[0].y = ScreenDimensions.Height()
/ m_rows * row;".

Hope this will work for you also.

-Thangs

Commented:
RichJackson,
Are you trying out the solutions which I have proposed. I have tested this program with the solution I have proposed and works fine for me.

Commented:
Hi RichJackson,
What's going on?. Are you able to get the right grids?. If yes why don't you qualify the answer

Thangs

Commented:
RichJackson,
Why are you just posting the question and keep silent???. Others are helping you by spending their useful time and effort. Why don't you evaulate the answer????????

Thangs
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