Delphi - Set Font Property of a Component in Firemonkey/FMX

In order to set the font property of a component in FMX there are two ways you can do it:

1) In design time. By dropping a component onto the form and then changing its properties in the Object Inspector you can alter the properties of the font (font fmaily, size, color etc).

2) At run time. If, for example, you have a project which drops a series of labels onto a form when a button is clicked then you'll need to handle the changing of the font in your code.

 Option 1 is pretty straight forward but it's worth noting that if you make this change, you can view the effect this has had by saving your project and then opening up the .fmx file in notedpad and looking to see what has changed. In my project, i added a label to my form and changed the Text Settings > Font Color to be 'crimson'. In my .fmx file i can see that there are now two new lines:

    object Label1: TLabel
      Position.X = 120.000000000000000000
      Position.Y = 352.000000000000000000
      TextSettings.FontColor = claCrimson
      StyledSettings = [Family, Size, Style]
      Text = 'Label1'
    end 

This shows us what the impact was of changing the font color. The first change is to be expected since the property we changed was the FontColor. The second change is important, however, since it shows us what other change delphi made under the covers - namely that delphi altered the StyledSettings. The styled settings tell delphi whether to pull down the projects style settings (i.e. those which may be applied through a stylebook) for a given setting. Thus if you go back to design time and drop down the StyledSettings option, you'll see that 'FontColor' is currently unchecked. If you check the box against it, the font in the label will cease to be red.  

Thus, if you're creating new components at run time and need to alter some property of the font style, you'll need to include two lines - one to set the font setting and one to uncheck the relevant setting in StyledSettings:

MyLabel.TextSettings.FontColor := TAlphaColor($FF009900);
MyLabel.StyledSettings := [TStyledSetting.Family, TStyledSetting.Size, TStyledSetting.Style];