When programming
for a graphical application, I noticed that the GraphicsPath.IsVisible() method,
sometimes, is not working fine for small
path figures when using scale matrix for the Graphics of the object or Control.
I googled
for the problem and found a solution in Java. Then I translated the code to C#
as an extension method to the GraphicsPath. It works fine now. The translated
code is as follows:
/// <summary>
/// Indicates whether the graphics path contains the specified point or not.
/// </summary>
/// <param name="graphicsPath">The graphics path to check if it contains the point.</param>
/// <param name="location">The specified location to check if it is inside the path or not.</param>
/// <returns>True if the point is within the graphics path, otherwise false.</returns>
public static bool Contains(this GraphicsPath graphicsPath, PointF location)
{
GraphicsPath actualPath = (GraphicsPath)graphicsPath.Clone();
bool oddTransitions = false;
actualPath.Flatten(null, .25f);
for (int i = 0, j = actualPath.PointCount - 1; i < actualPath.PointCount; j = i++)
if ((actualPath.PathPoints[i].Y < location.Y && actualPath.PathPoints[j].Y >= location.Y) ||
(actualPath.PathPoints[j].Y < location.Y && actualPath.PathPoints[i].Y >= location.Y))
if (actualPath.PathPoints[i].X +
((location.Y - actualPath.PathPoints[i].Y) /
(actualPath.PathPoints[j].Y - actualPath.PathPoints[i].Y) *
(actualPath.PathPoints[j].X - actualPath.PathPoints[i].X)) < location.X)
oddTransitions = !oddTransitions;
return oddTransitions;
}
I cloned
and flattened the original path to be sure the result is correct even if it
contains Beziers. Hope it can help you.
Enjoy
programming.
