3 Point Arc

[ceaser]

Hi All

How can I in Basic4ppc define 2 points on the screen and then tap on the 3rd point and have an arc (part of a circle) follow the 3rd point as I move my stylus across the screen?

How do I draw an ellipse?

How can I zoom in, zoom out and pan my drawing. Remember that the drawing consists of lines, circles, etc that has been defined by coordinates.

By the way on a scale from 1 to 10, NSBasic gets 1 and basic4ppc gets 10! It's a great development platform. Just waiting to get back to South Africa, so that I can buy a copy and start compiling!

Thanks
Michael

[Erel]

1. You will need to manually draw the arc. There is no DrawArc method.
2. See ImageLib.DrawEllipse
3. You can store the drawings data and then redraw all the drawings in a different scale.

[colin9876]

Yes Basic4ppc is great. The other day I had to use VB2008 which was a struggle! Micro$oft have a way of making things so complicated. I gave up and went back to Basic4ppc!

As to drawing an arc, Im sure we could write a small routine to do it.

I think its a quadratic equation to make an arc.
Do u want to be able to plot 2 points and then have the 3rd point in between those two (representing the maxima or minima of the curve) ?
Could easily plot a quadratic through those with a FOR NEXT loop

[ceaser]

Hi

Yes, I agree with you. I can program in Visual Studio, but what a battle and it slows the PPC down to a snails pace!

Coming back to the 3 Point Arc. Say I have picked up (Tachy Survey) 3 points on an existing bellmouth which has a radius of say 10m. In the field I will then pick up a point at the start, middel and end of the bellmouth. The bellmouth is not a full circle, but only part of it. I then want to tap on the "ARC" function in my program, tap on the 3 points and the program must then draw an arc (not a full circle) through those 3 points.

In visual studio one can define the midpoint, radius, color, start angle and end angle of the arc.

Do you think this is possible?

Excuse all my questions!

Thanks
Michael

[Erel]

If you are referring to Graphics.DrawArc then it is not supported on the .Net Compact Framework (which means it can only be used on the desktop).

[dennishea]

hi ceaser

this is what I use to draw an arc.

PHP Code:

Sub DrawArc
    x1 = Int(txtx1.Text)
    y1 = Int(txty1.Text)
    x2 = Int(txtx2.Text)
    y2 = Int(txty2.Text)
    r = Int(txtr.Text)    
    If x2 > y2 Then
        For l = x2 To y2 Step -1
            x = Round(x1 + r * Cos(l * cPI / 180))
            y = Round(y1 + r * Sin(l * cPI / 180))
            bmp.SetPixel(x,y,Color)
        Next
    Else
        For l = x2 To y2 Step 1
            x = Round(x1 + r * Cos(l * cPI / 180))
            y = Round(y1 + r * Sin(l * cPI / 180))
            bmp.SetPixel(x,y,Color)
        Next
    End If    
    form1.DrawImage(bmp.Value,0,0)
    form1.Refresh    
End Sub 


x1 and y1 represent center of arc
x2 represents starting angle
y2 represents ending angle
r represents radius

In a day or two depending on how fast I can document how to use what I have so far and then I will post it all in projects to see if there is any interest in trying make it better then what it is at present.

I also uploaded a screen capture of a doodle to show what the arcs look like.

[colin9876]

Just a point not great to have x2 y2 representing the angles as x1,y1 are co-ordinates {as expected}.

having x1,y1 as coords and a1,a2 as the angles would be clearer.

Also why do you draw these points to a bitmap then draw that rather than just plotting them to a form?

[ceaser]

Hi Dennishea

Thanks a million! It just shows what can be done, if one just uses one's grey matter a bit.

Thanks Again
Michael

[colin9876]

Sub Draw_Arc(x,y,r,a1,a2,color) 'Angles are in Radians

s = 1/r
For i=a1 To (a2-s) Step s
form1.line(x+r*Cos(i),y+r*Sin(i),x+r*Cos(i+s),y +r*Sin(i+s),color)
Next

End Sub

[dennishea]

ceaser

Here is what I have started. Hopefully some of the better programers will look at and give some critisum that I can learn from. Like what colin9876 pointed out.

Thanks colin9876.



http://www.basic4ppc.com/forum/open-...html#post12829