Class screen

Screen class subset of cairo drawing functions.

see https://www.cairographics.org/tutorial/

Methods

screen:update_default () copy buffer to screen.
screen:ping () restart screen saver timer
screen:update_low_battery () low battery screen update
screen:aa (state) enable/disable anti-aliasing.
screen:clear () clear.
screen:level (value) set level (color/brightness).
screen:line_width (w) set line width.
screen:line_cap (style) set line cap style.
screen:line_join (style) set line join style.
screen:miter_limit (limit) set miter limit.
screen:move (x, y) move drawing position.
screen:move_rel (x, y) move drawing position relative to current position.
screen:line (x, y) draw line to specified point.
screen:line_rel (x, y) draw line to specified point relative to current position.
screen:arc (x, y, r, angle1, angle2) draw arc.
screen:circle (x, y, r) draw circle.
screen:rect (x, y, w, h) draw rectangle.
screen:curve (x1, y1, x2, y2, x3, y3) draw curve (cubic Bézier spline).
screen:curve_rel (x1, y1, x2, y2, x3, y3) draw curve (cubic Bézier spline) relative coordinates.
screen:close () close current path.
screen:stroke () stroke current path.
screen:fill () fill current path.
screen:text (str) draw text (left aligned).
screen:text_rotate (x, y, str, degrees) draw text (left aligned) and rotated.
screen:text_right (str) draw text, right aligned.
screen:text_center (str) draw text, center aligned.
screen:text_center_rotate (x, y, str, degrees) draw text, center aligned, and rotated.
screen:text_extents (str) calculate width of text.
screen:font_face (index) select font face.
screen:font_size (size) set font size.
screen:pixel (x, y) draw single pixel (requires integer x/y, fill afterwards).
screen:display_png (filename, x, y) display png.
screen:peek (x, y, w, h) get a rectangle of screen content.
screen:poke (x, y, w, h, s) set a rectangle of screen content.
screen:rotate (number) rotate
screen:translate (x, y) move origin position
screen:save () save
screen:blend_mode (index) change screen blending mode.


Methods

screen:update_default ()
copy buffer to screen.
screen:ping ()
restart screen saver timer
screen:update_low_battery ()
low battery screen update
screen:aa (state)
enable/disable anti-aliasing.

Parameters:

  • state on(1) or off(0)
screen:clear ()
clear.
screen:level (value)
set level (color/brightness).

Parameters:

  • value number 0-15 (0=off, 15=white)
screen:line_width (w)
set line width.

Parameters:

  • w number line width (in pixels, floats permitted)
screen:line_cap (style)
set line cap style.

Parameters:

  • style line cap style string ("butt", "round" or "square"). default is "butt".
screen:line_join (style)
set line join style.

Parameters:

  • style line join style string ("miter", "round" or "bevel"). default is "miter"
screen:miter_limit (limit)
set miter limit.

Parameters:

  • limit if the current line join style is set to "miter", the miter limit is used to determine whether the lines should be joined with a bevel instead of a miter. if the length of the miter divided by the line width is greater than the miter limit, the style is converted to a bevel. default value 10.
screen:move (x, y)
move drawing position.

Parameters:

  • x number position x
  • y number position y
screen:move_rel (x, y)
move drawing position relative to current position.

Parameters:

  • x number relative position x
  • y number relative position y
screen:line (x, y)
draw line to specified point.

Parameters:

  • x number destination x
  • y number destination y
screen:line_rel (x, y)
draw line to specified point relative to current position.

Parameters:

  • x number relative destination x
  • y number relative destination y
screen:arc (x, y, r, angle1, angle2)
draw arc.

Parameters:

  • x number circle center x
  • y number circle center y
  • r number radius
  • angle1 number start angle
  • angle2 number end angle
screen:circle (x, y, r)
draw circle.

Parameters:

  • x number origin x
  • y number origin y
  • r number radius
screen:rect (x, y, w, h)
draw rectangle.

Parameters:

  • x number x position
  • y number y position
  • w number width
  • h number height
screen:curve (x1, y1, x2, y2, x3, y3)
draw curve (cubic Bézier spline).

Parameters:

  • x1 number destination x
  • y1 number destination y
  • x2 number handle 1 x
  • y2 number handle 1 y
  • x3 number handle 2 x
  • y3 number handle 2 y
screen:curve_rel (x1, y1, x2, y2, x3, y3)
draw curve (cubic Bézier spline) relative coordinates.

Parameters:

  • x1 number relative destination x
  • y1 number relative destination y
  • x2 number handle 1 x
  • y2 number handle 1 y
  • x3 number handle 2 x
  • y3 number handle 2 y
screen:close ()
close current path.
screen:stroke ()
stroke current path. uses currently selected color.
screen:fill ()
fill current path. uses currently selected color.
screen:text (str)
draw text (left aligned). uses currently selected font.

Parameters:

screen:text_rotate (x, y, str, degrees)
draw text (left aligned) and rotated. uses currently selected font.

Parameters:

  • x number x position
  • y number y position
  • str string : text to write
  • degrees number : degrees to rotate
screen:text_right (str)
draw text, right aligned. uses currently selected font

Parameters:

screen:text_center (str)
draw text, center aligned. uses currently selected font.

Parameters:

screen:text_center_rotate (x, y, str, degrees)
draw text, center aligned, and rotated. uses currently selected font.

Parameters:

  • x number x position
  • y number y position
  • str string : text to write
  • degrees number : degress to rotate
screen:text_extents (str)
calculate width of text. uses currently selected font.

Parameters:

  • str string : text to calculate width of
screen:font_face (index)
select font face.

Parameters:

  • index font face (see list)

    1 04B_03 (norns default)

    2 ALEPH

    3 Roboto Thin

    4 Roboto Light

    5 Roboto Regular

    6 Roboto Medium

    7 Roboto Bold

    8 Roboto Black

    9 Roboto Thin Italic

    10 Roboto Light Italic

    11 Roboto Italic

    12 Roboto Medium Italic

    13 Roboto Bold Italic

    14 Roboto Black Italic

screen:font_size (size)
set font size.

Parameters:

  • size number in pixel height.
screen:pixel (x, y)
draw single pixel (requires integer x/y, fill afterwards).

Parameters:

  • x number position
  • y number position
screen:display_png (filename, x, y)
display png.

Parameters:

  • filename
  • x number x position
  • y number y position
screen:peek (x, y, w, h)
get a rectangle of screen content. returned buffer contains one byte (valued 0 - 15) per pixel, i.e. w * h bytes

Parameters:

  • x number x position
  • y number y position
  • w number width, default 1
  • h number height, default 1
screen:poke (x, y, w, h, s)
set a rectangle of screen content. expected buffer contains one byte (valued 0 - 15) per pixel, i.e. w * h bytes

Parameters:

  • x number x position
  • y number y position
  • w number width
  • h number height
  • s string screen content to set
screen:rotate (number)
rotate

Parameters:

  • number radians
screen:translate (x, y)
move origin position

Parameters:

  • x number position x
  • y number position y
screen:save ()
save
screen:blend_mode (index)
change screen blending mode.

Parameters:

  • index number/string blending mode (see list), strings are case-insensitive, include '_' between words

    more info at https://www.cairographics.org/operators/

    there are other operators available, see the above link or use tab.print(screen.BLEND_MODES) in the REPL for the full list.

    0 Over (default)

    1 XOR: clears any overlapping pixels.

    2 Add: adds together the alpha (brightness) of overlapping pixels.

    3 Multiply: multiplies the colors of overlapping pixels, the result is always darker than the two inputs.

    4 Screen: the colors of overlapping pixels are complemented, multiplied, then their product is complimented. the result is always lighter than the two inputs.

    5 Overlay: multiplies colors if destination pixel level is >= 8, screens colors if destination pixel level is < 8.

    6 Darken: keeps the darker value of overlapping pixels.

    7 Lighten: keeps the lighter value of overlapping pixels.

    8 Color_Dodge: brightens pixels being drawn over.

    9 Color_Burn: darkens pixels being drawn over.

    10 Hard_Light: multiplies colors if source pixel level is >= 8, screens colors if source pixel level is < 8.

    11 Soft_Light: uses Darken or Lighten depending on the color of the source pixel.

    12 Difference: the result is the absolute value of the difference of the destination and source pixels.

    13 Exclusion: similar to Difference, but has lower contrast.

Usage:

  • -- number vs. string input
screen.blend_mode(0)
screen.blend_mode('over')
  • -- case-insensitivity
screen.blend_mode('hard_light')
screen.blend_mode('hArD_lIgHt')
screen.blend_mode('HARD_LIGHT')
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