std/image

Images: PNG read and written, resized, and made into the icons each system wants. An Image is RGBA, 8 bits a channel, not premultiplied, rows from the top; img.pixels holds them, and img.get(x, y) and img.set(x, y, r, g, b, a) read and write one. PNG's deflate is std/compress's, so a program that imports std/image links with zlib.

import "std/image"

Image logo = read_png("logo.png")?
write_png("logo-32.png", resize(logo, 32, 32))?
write_bytes("app.ico", encode_ico(icon_sizes(logo, ICO_SIZES)))
write_bytes("app.icns", encode_icns(icon_sizes(logo, ICNS_SIZES)))

Function	Result
`decode_png(data)`, `read_png(path)`	the image of a PNG in any of its forms: grayscale, RGB, palette, with alpha or a transparent color, 1 to 16 bits, interlaced or not; an `ERROR` of kind `"invalid_image"` for data that is not PNG, a chunk whose CRC is wrong, or pixels that are not what the header says, and of kind `"too_large"` past `IMAGE_MAX_PIXELS`
`encode_png(img, level)`, `write_png(path, img)`	RGBA PNG, each row with the filter that makes it smallest
`new_image(width, height)`	a transparent image
`resize(img, width, height, filter)`	the image at a new size, with one of `RESIZE_FILTERS`: `"lanczos"` (the default), `"bicubic"`, `"bilinear"`, or `"box"`; colors are weighted by alpha, so transparent pixels leave no fringe
`square(img)`	the image centered on a transparent square
`icon_sizes(img, sizes)`	the image, square, at each size: `ICO_SIZES`, `ICNS_SIZES`, or `HICOLOR_SIZES`
`encode_ico(images)`, `decode_ico(data)`	a Windows icon of PNG images; reading takes the 24-bit and 32-bit bitmaps of older icons too
`encode_icns(images)`, `decode_icns(data)`	a macOS icon, each size as PNG, with the Retina types of twice the size