Hi mvg,
you can resize the ButtonPreview directly inside the composer inside ExtendedVirtualKeyboard::Keyboard.
The related characters can be resized inside ExtendedVirtualKeyboard::RelatedCharacters.generateButtons() there set the size after the creation of the button like:
btn.Bounds.size = <40,50>; // width and height in pixel
also adopt how the related characters component is positioned inside ExtendedVirtualKeyboard::RelatedCharacters.onButtonsChange e.g.:
// Check if there is a second row of characters. If true then position the related
// characters preview one row above
if ( String.length > buttonPerRow )
Bounds.origin.y = SourceButton.Bounds.y1 - 2 * /*height of button*/50 + KeyboardOriginY - Padding;
else
Bounds.origin.y = SourceButton.Bounds.y1 - /*height of button*/50 + KeyboardOriginY - Padding;
Regards,
Julian