Asp net core Dividing does not work

Question

I am trying to resize a Image
the perfect size needs to be Width= 250px and Height= 200px

But because not all images have this Ratio
I need to do some math to make it fit

so for example Image Width = 1000px
and Height = 667px

I just need to (250 / 1000) * 667 = 166,75

so new Width = 250 and new Height = 167

But this does not work in Asp net core and I dont know why

string Headername = Guid.NewGuid().ToString() + "_" + dto.HeaderImg.FileName;  
                string filepath = Path.Combine(root, Headername);  
  
                  
                    Image image = Image.FromStream(TheFile.OpenReadStream(), true, true);  
  
                    int newWidth = 250;  
                    int newHeight = 200;  
  
                int OldWidth = image.Width;  
                int OldHeight = image.Height;  
  
                    if (image.Width > image.Height)  
                        newHeight = (newWidth / OldWidth) * OldHeight; // returns 0;  
                    else if (image.Width < image.Height)  
                        newWidth = (newHeight / OldHeight) * OldWidth; returns 0;  
                    else if (image.Width == image.Height)  
                        newHeight = 250;  
  
                    var newImage = new Bitmap(newWidth, newHeight);  
  
                    using var a = Graphics.FromImage(newImage);  
                a.DrawImage(image, 0, 0, newImage.Width, newImage.Height);  
  
                newImage.Save(filepath);

when i try to calculate in Asp net core, It always returns 0;

Answer

Looks like a problem of doing integer math. Might try doing using single precision variables.

Answer

Hi @osyris ,

               int newWidth = 250;

                  int newHeight = 200;  
   
              int OldWidth = image.Width;  
              int OldHeight = image.Height;  
   
                  if (image.Width > image.Height)  
                      newHeight = (newWidth / OldWidth) * OldHeight; // returns 0;  
                  else if (image.Width < image.Height)  
                      newWidth = (newHeight / OldHeight) * OldWidth; returns 0;  
                  else if (image.Width == image.Height)  
                      newHeight = 250;

If you set a break point to the above code, you can see that issue relates the integer division, the result is 0.

To solve this issue, you can try to change the number from the int type to decimal type or use the float type. Code like this:

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Best regards,
Dillion

Asp net core Dividing does not work

2 answers