CODEWITHSUNDEEP
winformsoptimizationresize
BenJacob
BenJacob

Reputation: 987

Smooth resize for Windows Form

I am recreating resize functionality for a Form with FixedSingle FormBorderStyle using the following methods to update the size/position:

private void resizeBottom()
{
    this.SuspendLayout();
    this.SetBoundsCore(this.Location.X, this.Location.Y, this.Width, Cursor.Position.Y - this.Location.Y, BoundsSpecified.Size);
}

…(other resize helpers)...

protected override void SetBoundsCore(int x, int y, int width, int height, BoundsSpecified specified)
{
    base.SetBoundsCore(x, y, width, height, specified);
    this.ResumeLayout();
}

However, when I attempt to resize the window I get a lot of artefacts, particularly if I resize at just the right speed, it looks like the window is being ’smeared’ across the screen. I have tried enabling double buffering but it doesn’t seem to make a difference.

Upvotes: 0

Views: 495

Answers (1)

Olivier Jacot-Descombes
Olivier Jacot-Descombes

Reputation: 112352

I made some tests and got a result very similar to what happens when you resize the form the regular way (by clicking and dragging a window edge with the mouse) with this code:

private void resizeBottom()
{
    SetBounds(Location.X, Location.Y, Width, Cursor.Position.Y + 30 - Location.Y);
}

protected override void SetBoundsCore(int x, int y, int width, int height,
                                      BoundsSpecified specified)
{
    base.SetBoundsCore(x, y, width, height, specified);
    Update();
}

Update() makes the form to redraw instantly.

Note: I used Cursor.Position.Y + 30, otherwise I can only make the form smaller, since the mouse leaves the window if I move down.

Upvotes: 2

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