Image

local Image = Quark.Image

local minimap = Image.FromHeights(256, 256, heights:View("f32"), {
    Colors = { { 0, "#1f4e8c" }, { 0.35, "#e0d090" }, { 0.5, "#3c8c3c" }, { 0.8, "#806040" }, { 1, "#ffffff" } },
})
for _, character in ipairs(Character.GetAll()) do
    local location = character:GetLocation()
    minimap:DrawCircle(math.floor(location.X / 100), math.floor(location.Y / 100), 3, "#ff0000")
end

server:Get("/minimap.webp", function(_, response)
    response:Send(minimap:Encode("webp"), "image/webp")
end)

Images in memory: decode and encode PNG, JPEG, WebP and BMP, draw, transform and build images from height maps or tile maps, for example minimaps on a web page, generated thumbnails or screenshots received from clients.

Pixels are addressed with x and y starting at the index base of the package (0 by default), the origin is the top left corner. Images are limited to 16384 pixels per side and 64 million pixels.

Colors

Colors are hex texts ("#rgb", "#rgba", "#rrggbb", "#rrggbbaa"), lists of 0 to 255 values ({ 255, 128, 0, 255 }, alpha optional) or tables and nanos world Color values with R, G, B and A from 0 to 1. Pixels are read as r, g, b, a from 0 to 255.

Creating images

Function
Image.New(width, height, color?)	image filled with a color, transparent by default
Image.Decode(data, callback?)	image from PNG, JPEG, WebP or BMP data, or nil, message. The format is detected
Image.FromHeights(width, height, values, options?)	colors a height map, a list or buffer view of width * height numbers row by row
Image.FromIndexed(width, height, data, palette)	one color per value, for tile maps. data is a string, buffer, list or buffer view, palette maps values to colors
Image.IsImage(value)

FromHeights options are Min and Max (the smallest and largest value by default) and Colors, a list of { position, color } from 0 to 1 that the heights are interpolated between (black to white by default).

local map = Quark.ProcGen.Dungeon(64, 64)
local Tile = Quark.ProcGen.Tile
local picture = Image.FromIndexed(64, 64, map:GetTiles(), {
    [Tile.Wall] = "#202020", [Tile.Floor] = "#c8c8c8", [Tile.Corridor] = "#909090", [Tile.Door] = "#a05000",
}):Resize(512, 512, "Nearest")

Drawing

Method
:GetPixel(x, y), :SetPixel(x, y, color)
:Fill(color)	replace every pixel
:FillRect(x, y, width, height, color)	rectangle, blended with transparent colors
:DrawLine(x1, y1, x2, y2, color, thickness?)
:DrawCircle(x, y, radius, color, filled?)	filled (true) or outline
:DrawImage(image, x, y, options?)	draws another image on top, with transparency and the option Opacity (1)

Drawing outside of the image is clipped.

Transforming

These return a new image and keep the original:

Method
:Resize(width, height, filter?)	filter Nearest (sharp pixels), Linear (default), Cubic or Lanczos (best quality, slowest)
:Crop(x, y, width, height)	part of the image, cut at the borders
:Rotate(degrees)	90, 180 or 270 degrees clockwise
:Flip(direction?)	Horizontal (default) or Vertical
:Blur(sigma)	Gaussian blur
:Grayscale(), :Clone()

Encoding

:Encode(format?, options?, callback?) returns the image as png (default), jpeg, webp or bmp. JPEG takes the option Quality from 1 to 100 (85) and drops transparency. WebP is encoded lossless, which suits generated images like minimaps: they are usually smaller than PNG and keep every pixel exact. With a callback encoding runs on a worker thread, which is recommended for large images. :GetSize() returns width and height, :GetBytes() the raw RGBA pixels.

Format	Content type
png	image/png
jpeg	image/jpeg
webp	image/webp
bmp	image/bmp