C#

Guffa wrote:

There is no such overload.

Guffa wrote:

That's not surprising at all. Floating point values are not intended to be exact. You should use an integer value for the loop, and calculate the alpha value from that.

Guffa wrote:

ry to use an overload where you specify the coordinates as integers instead of floats, so that you don't risk getting any scaling when you draw the image.

John Simmons / outlaw programmer wrote:

I tried that and I still get the wierded out values (and I kinda figured I'd get them - I'm not new at this floating point stuff).

John Simmons / outlaw programmer wrote:

0) The indicated call to m_graphics.DrawImage() won't compile, despite my using what intellisense claims is a valid overload.

John Simmons / outlaw programmer wrote:

1) The for loop determines the new alpha channel value. The nature of float values causes the alpha value to eventually become some bizarre value (usually by the 7th iteration), which forces me to only do the loop while it's less than 1.0, and then perform the final DrawImage() call after the loop has exited.

John Simmons / outlaw programmer wrote:

2) Performance quite frankly sucks. I can see the image redraw itself from top to bottom. Is there a better (more efficient) way to fade an image on/off the screen?

Greeeg wrote:

Can't you put the image onto a PictureBox? You could then use the UpdateLayeredWindow interop to change the alpha of the control, which should be faster than your method.

Greeeg wrote:

Or just draw the image once on the form and set the Form.Opacity property in a loop.

Greeeg wrote:

Both methods will work only on Windows 2000 and upwards, though.

Greeeg wrote:

Of course the fastest method would be to use DirectX pixel shaders, but that'd be definitely overkill for your application.

private delegate void delegateUpdateTextInForm(string txt);
public void updateTextInForm(string txt)
{
    if(form.InvokeRequired) // true if calling from a different thread (not owner)
    {
        // delegate points to the "updateTextInForm" function.
        delegateUpdateTextInForm dFunc = new delegateUpdateTextInForm(updateTextInForm);

        // invoke the function from the "form" object.
        form.Invoke(dFunc , new object[] { txt });
    }
    else // calling from thread that "owns" the form
    {
        txtBox.Text = txt; // ta-dam!
    }
}

SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=northwind;Integrated Security=True");            
SqlCommand cmdSelect = new SqlCommand("select * from customers", con);            
SqlDataReader dr;            
DataTable dt = new DataTable();            
DataSet ds = new DataSet();            
con.Open();            
dr = cmdSelect.ExecuteReader();            
dt.Load(dr);            
con.Close();            
Microsoft.Reporting.WinForms.ReportDataSource rds = new Microsoft.Reporting.WinForms.ReportDataSource("Customers",dt);            
this.reportViewer2.LocalReport.DataSources.Add(rds);            this.reportViewer2.LocalReport.ReportEmbeddedResource= "ReportingServices.Report1.rdlc";           
this.reportViewer2.RefreshReport();