libraryextensions/image/lib/Image.xtl

Image.xtl -- the facade of the image extension: PNG and JPEG files as Float arrays from 0 to 1, and back. Gray is h by w, color h by w by 3 (red, green, blue); alpha is dropped. Import: "im:" u_se< "Image" Files are named by paths under the working directory (or XETAL_IMAGE_ROOT), relative, with no .. Run with xetal-x (xetal-x --ext DIR puts this directory on XETAL_PATH). Each signature line is written out by the binding macro (lib/Ffi.xtlm).

source · imports ffi: lib/Ffi.xtlm

ˡr̲ead : Char -> Float

function · line 13

im:r_ead "photo.png": the picture as it is (gray or color).

"r_ead : text -> floats"         ᶠᶠⁱb̲ind< "image/read"

ᶠᶠⁱb̲ind< expands to

ˡr̲ead ← { a →
  pa ← a ⎕N̲PUT "ext:image/read?text"
  v ← n̲umbers ⎕N̲GET "ext:image/read"
  (f̲loor n̲umbers ⎕N̲GET "ext:image/read?shape") r̲eshape v
}

Used in: c

ˡg̲ray : Char -> Float

function · line 15

im:g_ray "photo.jpg": the picture in gray (its luminance), h by w.

"g_ray : text -> floats"         ᶠᶠⁱb̲ind< "image/gray"

ᶠᶠⁱb̲ind< expands to

ˡg̲ray ← { a →
  pa ← a ⎕N̲PUT "ext:image/gray?text"
  v ← n̲umbers ⎕N̲GET "ext:image/gray"
  (f̲loor n̲umbers ⎕N̲GET "ext:image/gray?shape") r̲eshape v
}

Used in: p

ˡs̲ize : Char -> Int

function · line 17

im:s_ize "photo.jpg": height and width, without reading the pixels.

"s_ize : text -> ints"           ᶠᶠⁱb̲ind< "image/size"

ᶠᶠⁱb̲ind< expands to

ˡs̲ize ← { a →
  pa ← a ⎕N̲PUT "ext:image/size?text"
  v ← f̲loor n̲umbers ⎕N̲GET "ext:image/size"
  (f̲loor n̲umbers ⎕N̲GET "ext:image/size?shape") r̲eshape v
}

Used in: extensions/image/demos/photo-lab.xtl:20

ˡw̲rite! : Num a => Char -> a -> Int

function · line 20

"out.png" im:w_rite! a: the array as a PNG (or a JPEG, by the name), values clamped to 0..1; how many pixels.

"w_rite! : text float -> int"    ᶠᶠⁱb̲ind< "image/write"

ᶠᶠⁱb̲ind< expands to

ˡw̲rite! ← { a b →
  pa ← a ⎕N̲PUT "ext:image/write?text"
  pb ← (f̲ormat r̲avel f̲loat b) ⎕N̲PUT "ext:image/write?float=" c̲at f̲ormat s̲hape b
  f̲loor f̲irst n̲umbers ⎕N̲GET "ext:image/write"
}

Used in: n

ˡr̲esize : (Num a, Num b) => a -> b -> Float

function · line 22

(h c_at w) im:r_esize a: resampled to h by w (Lanczos), gray or color.

"r_esize : float float -> floats" ᶠᶠⁱb̲ind< "image/resize"

ᶠᶠⁱb̲ind< expands to

ˡr̲esize ← { a b →
  pa ← (f̲ormat r̲avel f̲loat a) ⎕N̲PUT "ext:image/resize?float=" c̲at f̲ormat s̲hape a
  pb ← (f̲ormat r̲avel f̲loat b) ⎕N̲PUT "ext:image/resize?float=" c̲at f̲ormat s̲hape b
  v ← n̲umbers ⎕N̲GET "ext:image/resize"
  (f̲loor n̲umbers ⎕N̲GET "ext:image/resize?shape") r̲eshape v
}

Used in: p, c

ˡpackage : Char

value · line 25

The native package behind these functions.

ˡpackage ← "image"