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Trying to avoid control "wobble" when resizing controls according to mouse position

Answer 1

A:

Assuming you have good reason to not let windows handle the resizing on it's own, I would not draw anything till the user releases the mousebutton. Draw it once, no juddering. If they really need a guide, draw a dashed box similar to old style 'shadow' windows resizing.

Rob Elliott 2009-07-31 14:50:46

Um... Did you mean to answer someone else's question?

Frosty840 2009-07-31 14:55:13

No, but I did misunderstand what you wanted. :)

Rob Elliott 2009-07-31 15:12:04

Answer 2

+1 A:

Are you trying to implement a fish eye effect similar to the dock in OSX? Instead of handling mouse events on each individual control level, try to handle mouse on the parent level. When parent receive mouse move, calculate new positions for all controls and adjust them.

I've been using following approach to calculate positions for fish eye effect. Basically the idea is to scale/shift elements dependent on position from the mouse. pt is coordinate of mouse. target.Pos is unscaled coordinates. ScaledPos is new scaled coordinates

double dx = target.Pos.X + target.Pos.Width / 2 - pt.X;
double scale = DistanceToScale(Math.Sqrt(dx * dx + dy * dy));
double xRel = pt.X - target.Pos.X;
double dxTarget = xRel * scale - xRel;

target.ScaledPos = new Rect(target.Pos.X - dxTarget,
                            target.Pos.Y,
                            target.Pos.Width * scale,
                            target.Pos.Height);

You have to calculate positions for all elements. DistanceToScale function defines how fast scale changes from maximum scale (when mouse is over the top of the element) to 1 (items are not scaled). Function should be smooth to avoid jumping.

double DistanceToScale(double distance)
{
    double dblScale = _c1 / (1.0 + (distance * distance * _c2));
    if (dblScale < 1.0)
    {
        dblScale = 1.0;
    }

    return dblScale;
}

where c1 and c2

_c1 = maximun_scale;
_c2 = (c1 / scale_at_distance_dx) - 1 / (dx ^ 2);

AlexEzh 2009-07-31 15:01:59

Yup. Doing that. Need ideas on how to prevent side-effects occurring between one frame's repositioning and the next.

Frosty840 2009-07-31 17:38:39

Don't use layouts. Instead manually position controls where you want them to be and adjust the coordinates when applying effect.

AlexEzh 2009-07-31 19:38:48

Yes, but even if I do that, then the calculation being done will *still* produce the unwanted wobble effect.

Frosty840 2009-07-31 20:39:29

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Trying to avoid control "wobble" when resizing controls according to mouse position

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