Re: Is the API of JavaFX pixel-based?

From: (Stefan Ram)
3 Feb 2015 15:16:18 GMT
Jeff Higgins <jeff@invalid.invalid> writes:

Can you point to the specific tutorial you mention?

  I refer to code like:

Scene s = new Scene( r, 360, 120, Color.rgb( 0, 0, 0, 0 ));

  . It is not obvious how the author arrived at those
  values ?360? and ?120?.

  The Scene contains some text fields stacked one above
  the other. What I would prefer instead would be a call

Scene s = new Scene( r, Color.rgb( 0, 0, 0, 0 ));

  The textfields would have a default font that is
  readable (but not excessively high as in a heading).
  Symbolic constants are Ok, like ?PARAGRAPH_FONT?,

  The pixel height of that default font depends on the
  run-time environment and does not have to be known
  to the programmer. Then, the height of the textfield
  would be adjusted to the height of this font, while
  the width is given by the programmer in ?m?s (?10?
  means, wide as 10 ?m? letters in that font).

  The width and height of all the containers and,
  ultimatively of the scene, is calculated bottom-up
  from those values. They are not known to the
  programmer, because they are calculated as late
  as run time.

  In programming, we were taught early to avoid
  ?magic constants? in source code (such as ?360?
  above). More so, in my opinion, we should especially
  avoid ?magic pixel values? in source code. A good program
  will not set a fixed pixel height for a font, but
  adjust to the font height that is natural (readable)
  on a device and will only be known as late as at run time.

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