okk.moe
🖨️ esc/pos implementation in gleam
docs: width warning
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src/escpos/image.gleam
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src/escpos/image.gleam
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//// Module to parse/dither PBM/PGM image to be printed on monochrome
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//// Module to parse and dither PBM/PGM images to be printed on monochrome
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//// printers.
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//// There are printers that can print grayscale or even color, if
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//// you want to do that, you'll need to implement that yourself
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//// and/or leverage the `protocol` module directly.
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////
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//// 80mm printers usually have a maximum of 640 dots width.
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//// There is no validation so please check your image beforehand.
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////
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//// Thank you jak for the pgm reading and bayer dithering
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//// Thank you jak for the pgm reading and bayer dithering 💕
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import gleam/float
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import gleam/int
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use #(width, rest) <- result.try(parse_number(rest, 0))
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use #(height, rest) <- result.try(parse_number(rest, 0))
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case rest {
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<<"255\n", pixels:bytes>> -> Ok(GrayscaleImage(width:, height:, pixels:))
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<<"255\n", pixels:bytes>> ->
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Ok(GrayscaleImage(width:, height:, pixels:))
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_ -> Error(ParseError)
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}
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}
···
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}
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}
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fn dither_map(image: GrayscaleImage, fun: fn(Int, Int, Int) -> Int) -> PrintableImage {
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fn dither_map(
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image: GrayscaleImage,
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fun: fn(Int, Int, Int) -> Int,
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) -> PrintableImage {
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let pixels =
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dither_loop(image.pixels, image.width, 0, 0, <<>>, fun)
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|> byte_align_rows(image.width)