Change label size per screen size xamarin forms

Question

I'm using xamarin.forms to do an app and I perceived that to use the same size to letter to ios devices is not working: on 7 plus it works well, but on iphone 5 it's a Big letter for the size of the screen... Do someone know a way to do letter with scallable size, or change the size for a specific device or type of screen size? Thank you very much.

Answer 1

You can refer following samples:

1. Estimate font-size for visual consistency - (docs | github)

   // Resolution in device-independent units per inch.
   double resolution = 160;
   
   // Do some numeric point sizes.
   int[] ptSizes = { 4, 6, 8, 10, 12 };
   
   // Select numeric point size you need from ptSize[] array 
   double ptSize = 4;
   
   // this is your new visually consistent font-size.
   var fontSize = resolution * ptSize / 72; 
   

2. Fitting text to available size - (docs | github)

   double lineHeight = Device.OnPlatform(1.2, 1.2, 1.3);//TODO: Change this to Device.RuntimePlatform
   double charWidth = 0.5;
   
   int charCount = text.Length;
   
   var view = this.Parent;
   // Because:
   //   lineCount = view.Height / (lineHeight * fontSize)
   //   charsPerLine = view.Width / (charWidth * fontSize)
   //   charCount = lineCount * charsPerLine
   // Hence, solving for fontSize:
   int fontSize = (int)Math.Sqrt(view.Width * view.Height /
                       (charCount * lineHeight * charWidth));