Pngex
A library for generating PNG images.
installation
Installation
If available in Hex, the package can be installed
by adding pngex
to your list of dependencies in mix.exs
:
def deps do
[
{:pngex, "~> 0.1.0"}
]
end
Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/pngex.
generates-images
Generates images
pixel-data
Pixel data
Use binary, list of integers or list of tuples to express pixel data of the image.
Binary
type | example |
---|---|
:rgb | <<r0, g0, b0, r1, g1, b1, ...>> |
:rgba | <<r0, g0, b0, a0, r1, g1, b1, a1, ...>> |
:gray | <<c0, c1, ...> |
:gray_and_alpha | <<c0, a0, c1, a1, ...>> |
:indexed | <<c0, c1, ...> |
List of integers
type | example |
---|---|
:rgb | [r0, g0, b0, r1, g1, b1, ...] |
:rgba | [r0, g0, b0, a0, r1, g1, b1, a1, ...] |
:gray | [c0, c1, ...] |
:gray_and_alpha | [c0, a0, c1, a1, ...] |
:indexed | [c0, c1, ...] |
List of tuples
type | example |
---|---|
:rgb | [{r0, g0, b0}, {r1, g1, b1}, ...] |
:rgba | [{r0, g0, b0, a0}, {r1, g1, b1, a1}, ...] |
examples
Examples
RGB
Prepare bitmap image data
bitmap =
for n <- 0..65535 do
r = div(n, 256)
g = rem(n, 256)
b = 255 - max(r, g)
{r, g, b}
end
Generate PNG image
pngex =
Pngex.new()
|> Pngex.set_type(:rgb)
|> Pngex.set_depth(:depth8)
|> Pngex.set_size(256, 256)
image = Pngex.generate(pngex, bitmap)
File.write("rgb8_256x256.png", image)
or
image =
Pngex.new(
type: :rgb,
depth: :depth8,
width: 256,
height: 256
)
|> Pngex.generate(bitmap)
File.write("rgb8_256x256.png", image)
Indexed (Palette)
Prepare palette colors
palette = for n <- 0..255, do: {n, 255, 255 - n}
Prepare bitmap image data
bitmap = for n <- 0..65535, do: rem(n, 256)
Generate PNG image
image =
Pngex.new(
type: :indexed,
depth: :depth8,
width: 256,
height: 256,
palette: palette
)
|> Pngex.generate(bitmap)
File.write("indexed8_256x256.png", image)
Grayscale
Prepare bitmap image data
bitmap = for n <- 0..65535, do: rem(n, 256)
Generate PNG image
image =
Pngex.new(
type: :gray,
depth: :depth8,
width: 256,
height: 256
)
|> Pngex.generate(bitmap)
File.write("gray8_256x256.png", image)
avaiable-formats
Avaiable formats
color type \ depth | :depth1 | :depth2 | :depth4 | :depth8 | :depth16 |
---|---|---|---|---|---|
:indexed | ✓ | ✓ | ✓ | ✓ | |
:gray | ✓ | ✓ | ✓ | ✓ | ✓ |
:gray_and_alpha | ✓ | ✓ | |||
:rgb | ✓ | ✓ | |||
:rgba | ✓ | ✓ |