Proportional scaling

[hog]

I'm sure this must be a maths thing, if it is I stuffed as I am naff at math!

 

I have a picture box sized at 960 * 536 pixels and I am using the code below to put images of different sizes into it. Some look OK others are distorted.

 

m_bmpNewImage = New Bitmap(m_bmpNewImage, 960, 536)

 

I have an image I am looking at now and it is distorted. Its dimensions are 2142*2856.

 

Is there some magical formula needed to scale it to look right? Any help gratefully received!

 

Thnx

[techmanbd]

can you set the

PictureBox2.SizeMode = PictureBoxSizeMode.StretchImage

this will allow the picture to size according to the size of the picturebox

 

or

PictureBox2.SizeMode = PictureBoxSizeMode.Autoimage

this will size the picturebox to tyhe picture, so if the picture is much bigger it could take up the whole form

[hog]

Unfortunately these do not fit the bill :(

 

The stretch image just distorts the image and as you say the autosize just makes it too big to fit in the form :(

 

I am trying to have it so the image is scaled correctly to fit into the picture box.

[techmanbd]

I think you will always have some distortion. You have a picture where your length is shorter than the width and putting that into the picturebox which your length is longer than your width. So you will always have a distorted look.

 

But if you don't mind space in the box. here is a formula. You need a ratio formula

 

536/2856 = L/2142 ------- L = 2142(536/2856)

 

SInce your width is the longest on the picture, You know you can make it the same width as the picturebox and need the length. Now if you have a picture that is the width that is shorter then you need to find the scale for the width

 

say your picture is 2500x2000 with youre picbox dimensions

 

w/2000 = 960/2500 ---------- w =2000(960/2500)

 

give this a go and hopefully is works

[hog]

:confused:

 

I get an even more distorted image but now have a blank area at the bottom of the picture box?

 

The sizes used in this code are as follows

 

Image = length 2142, width 2856

 

Picturebox = length 536, width 960

 

           intWidth = m_bmpNewImage.Width

           intHeight = m_bmpNewImage.Height

           If intWidth > intHeight Then

               intHeight = intHeight * (intPictureBoxHeight / intWidth)

           Else

               intWidth = intHeight * (intPictureBoxWidth / intWidth)

           End If

           ' resize it to fit the picture box

           m_bmpNewImage = New Bitmap(m_bmpNewImage, intWidth, intHeight)

 

confused as hell :(

[hog]

The idea was to try to make this a generic program that I could realise as a freebie on my website, but this looks like that won't happen.

 

I realsie now that my camera will always take the same size images, (I never change the resolution), so the image length will always be 70% of the width in normal view or the width will always be 70% of the height when taking picture with camera on its side.

 

Therefore I have created to picture boxes with this ration and it works :)

 

Still would like to now how to go about making it generic tho :confused:

[DiverDan]

Hi Hog,

 

You can re-size the images without distoration. Here's a resizing function that should work ok for you.

 

To use it check if your loading bitmap is larger in either width or height than the picture box.

 

   Private Function ResizeBitmap(ByVal bmpTooBig As Bitmap, ByVal maxWidth As Integer, ByVal maxHeight As Integer) As Bitmap
       Dim ratio, ratioW, ratioH As Decimal

       If bmpTooBig.Width > maxWidth Then
           ratioW = maxWidth / bmpTooBig.Width
       Else : ratioW = 1
       End If
       If bmpTooBig.Height > maxHeight Then
           ratioH = maxHeight / bmpTooBig.Height
       Else : ratioH = 1
       End If
       'determine which dimension is the smallest
       If ratioW <= ratioH Then
           ratio = ratioW
       Else : ratio = ratioH
       End If
       Dim bmpResized As New Bitmap(CInt(bmpTooBig.Width * ratio), CInt(bmpTooBig.Height * ratio))
       'Make a Graphics object for the resized bitmap.
       Dim g As Graphics = Graphics.FromImage(bmpResized)
       g.DrawImage(bmpTooBig, 0, 0, bmpResized.Width + 1, bmpResized.Height + 1)
       Return bmpResized

       'dispose of graphic objects
       g.Dispose()
   End Function

 

I hope that helps

[hog]

Thnx DiverDan :)

 

I will try this out and let you know...

 

:D

[hog]

Kool :D :D :D

 

It works a treat :p

 

Thnx DiverDan ;)