Page Class

class metlinkpid.Page(animate: metlinkpid.PageAnimate, delay: int, text: str)

A Page object represents one “screen” of information in a DisplayMessage.

Each Page object holds the text to be displayed, how the text animates on entry, and how long the page should “pause” between completion of the animation and display of the next page.

Page objects are not typically constructed directly. Instead, they usually come to exist through construction of DisplayMessage objects.

Parameters

• animate – the type of animation to take place on page entry, given as a PageAnimate constant.

• delay – the length of time (in approximately quarter-seconds) to delay display of the next page after animation completes, given as an int between 0 and 255 inclusive.

• text –

  the text to display on the page. All ASCII letters & numbers, the ASCII space character, and these other printable ASCII characters can be used freely:

     (+)  (0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(B)(C)(D)(E)(F)
  
  (0x20)      !     #  $     &  '  (  )  *  +  ,  -  .  /
  (0x30)                                 :  ;  <  =  >  ?
  (0x50)                                       \
  

  as well as some Unicode characters:

       (+)  (0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(B)(C)(D)(E)(F)
  
  (0x00B0)                        ·
  (0x2020)         •
  (0x2500)   ─  ━
  (0x2580)                           █
  (0x2590)               ▔
  

  Notably, some printable ASCII characters cannot be used:

     (+)  (0)(1)(2)(3)(4)(5)(6)(7)(8)(9)(A)(B)(C)(D)(E)(F)
  
  (0x20)         "        %
  (0x40)   @
  (0x50)                                    [     ]  ^  _
  (0x60)   `
  (0x70)                                    {  |  }  ~  
  

  Some of these unusable characters are instead utilised for other purposes:

  • Use ~ to right-justify the remaining text on the line.

  • Use _ to advance to the next line of the display.

  A few more of these characters are utilised by the various Page & DisplayMessage string methods to enable compact, easily-typed, pure-string representations containing all attributes.

Raises

ValueError – if the text contains unusable characters, or if a valid PageAnimate value is not given, or if the delay is outside the permissible range.

Page.from_str() Class Method

classmethod Page.from_str(string: str, default_animate: metlinkpid.PageAnimate = <PageAnimate.NONE: 'N'>, default_delay: int = 20) → metlinkpid.Page

Construct a Page object from a string representation.

Parameters

• string –

  a string in one of the following formats:

  • <text>

  • ^<text>

  • <animate>^<text>

  • <delay>^<text>

  • <animate><delay>^<text>

  where:

  • <animate> is the string value of the desired Animate value (e.g. N for Animate.NONE);

  • <delay> is the desired delay value; and

  • <text> is the desired text value.

  For reference, such a string can also be obtained by converting an existing Page object to a string using str():

  >>> str(Page(animate=PageAnimate.VSCROLL, delay=40, text='12:34 FUNKYTOWN~5_Limited Express'))
  'V40^12:34 FUNKYTOWN~5_Limited Express'
  

• default_animate – the animate value to use if one is not provided in the string. Defaults to PageAnimate.NONE.

• default_delay – the delay value to use if one is not provided in the string. Defaults to 20.

Raises

ValueError – if the text contains unusable characters, or if a valid Animate value is not given, or if the delay is outside the permissible range.

__str__() Method

Page.__str__() → str

The string representation of this object.

Passing this string to Page.from_str() will yield an equivalent Page object to this one.

Page.from_bytes() Class Method

classmethod Page.from_bytes(bytes_in: bytes) → metlinkpid.Page

Construct a Page object from a raw byte representation.

Typically used by DisplayMessage.from_bytes() when attempting to construct a DisplayMessage from bytes.

Parameters

bytes_in – the bytes relating to one page.

Raises

ValueError – if the bytes could not be understood.

to_bytes() Method

Page.to_bytes() → bytes

The raw byte representation of the Page as understood by the display.

Used by DisplayMessage.to_bytes() when preparing to send() a complete DisplayMessage to the display.