GraphicsPath.IsVisible(): Unexpected Results

  • Thread starter Thread starter Martijn Mulder
  • Start date Start date
M

Martijn Mulder

/*
GraphicsPath.IsVisible() gives unexpected results. I fill a
System.Drawing.Drawing2D.GraphicsPath-object with PointF-structures
that define the unit-square (0,0), (1,0), (1,1) and (0,1). Then I
test 3 different PointF-structures to see if they fall inside the unit-
square and the results are clearly wrong:

Point(-0.2, -0.2) falls inside the unit square... WRONG!!!
Point(0.2, 0.2) falls inside the unit square...
Point(0.7, 0.7) falls outside the unit square... WRONG!!!

It seems that the float numbers get rounded to the nearest integer, but
that is not what I want.
*/



//class TestGraphicsPath
class TestGraphicsPath
{


//data member graphicspath
System.Drawing.Drawing2D.GraphicsPath graphicspath=new
System.Drawing.Drawing2D.GraphicsPath();


//constructor
TestGraphicsPath()
{
graphicspath.AddLines
(
new System.Drawing.PointF[]
{
new System.Drawing.PointF(0f,0f),
new System.Drawing.PointF(1f,0f),
new System.Drawing.PointF(1f,1f),
new System.Drawing.PointF(0f,1f),
new System.Drawing.PointF(0f,0f),
}
);
TestPoint(new System.Drawing.PointF(-.2f,-.2f));
TestPoint(new System.Drawing.PointF(.2f,.2f));
TestPoint(new System.Drawing.PointF(.7f,.7f));
}


//TestPoint
void TestPoint(System.Drawing.PointF a)
{
System.Console.Write("Point({0}, {1}) falls ",a.X,a.Y);
System.Console.Write(graphicspath.IsVisible(a)?"inside ":"outside ");
System.Console.WriteLine("the unit square...");
}


//Main
static void Main()
{
new TestGraphicsPath();
}
}



/*
____________________
output:

Point(-0,2, -0,2) falls inside the unit square...
Point(0,2, 0,2) falls inside the unit square...
Point(0,7, 0,7) falls outside the unit square...
*/
 
GraphicsPath objects do indeed convert floats to integers. Oops on the part
of the GDI+ team eh?

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Bob Powell [MVP]
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GraphicsPath.IsVisible() gives unexpected results. I fill a
GraphicsPath objects do indeed convert floats to integers. Oops on the
part of the GDI+ team eh?
Click to expand...


Is this sloppy enough to call it a bug?
 
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