pixie/README.md

👏 👏 👏 Check out video about the library: A full-featured 2D graphics library for Nim (NimConf 2021) 👏 👏 👏

Pixie - A full-featured 2D graphics library for Nim

Pixie is a 2D graphics library similar to Cairo and Skia written (almost) entirely in Nim.

This library is being actively developed and we'd be happy for you to use it.

nimble install pixie

Features:

• Typesetting and rasterizing text, including styled rich text via spans.
• Drawing paths, shapes and curves with even-odd and non-zero windings.
• Pixel-perfect AA quality.
• Supported file formats are PNG, BMP, JPG, SVG + more in development.
• Strokes with joins and caps.
• Shadows, glows and blurs.
• Complex masking: Subtract, Intersect, Exclude.
• Complex blends: Darken, Multiply, Color Dodge, Hue, Luminosity... etc.
• Many operations are SIMD accelerated.

Documentation

API reference: https://nimdocs.com/treeform/pixie/pixie.html

Image file formats

Format	Read	Write
PNG	✅	✅
JPEG	✅
BMP	✅	✅
QOI	✅	✅
GIF	✅
SVG	✅
PPM	✅	✅

Font file formats

Format	Read
TTF	✅
OTF	✅
SVG	✅

Joins and caps

Supported Caps:

• Butt
• Round
• Square

Supported Joins:

• Miter (with miter angle limit)
• Bevel
• Round

Blending & masking

Supported Blend Modes:

• Normal
• Darken
• Multiply
• ColorBurn
• Lighten
• Screen
• Color Dodge
• Overlay
• Soft Light
• Hard Light
• Difference
• Exclusion
• Hue
• Saturation
• Color
• Luminosity

Supported Mask Modes:

• Mask
• Overwrite
• Subtract Mask
• Intersect Mask
• Exclude Mask

SVG style paths:

Format	Supported	Description
M m	✅	move to
L l	✅	line to
h h	✅	horizontal line to
V v	✅	vertical line to
C c S s	✅	cublic to
Q q T t	✅	quadratic to
A a	✅	arc to
z	✅	close path

Pixie + GPU

To learn how to use Pixie for realtime graphics with GPU, check out Boxy.

Testing

nimble test

Examples

git clone https://github.com/treeform/pixie to run examples.

Text

nim c -r examples/text.nim

var font = readFont("examples/data/Roboto-Regular_1.ttf")
font.size = 20

let text = "Typesetting is the arrangement and composition of text in graphic design and publishing in both digital and traditional medias."

image.fillText(font.typeset(text, vec2(180, 180)), translate(vec2(10, 10)))

Text spans

nim c -r examples/text_spans.nim

let typeface = readTypeface("examples/data/Ubuntu-Regular_1.ttf")

proc newFont(typeface: Typeface, size: float32, color: Color): Font =
  result = newFont(typeface)
  result.size = size
  result.paint.color = color

let spans = @[
  newSpan("verb [with object] ",
    newFont(typeface, 12, color(0.78125, 0.78125, 0.78125, 1))),
  newSpan("strallow\n", newFont(typeface, 36, color(0, 0, 0, 1))),
  newSpan("\nstral·low\n", newFont(typeface, 13, color(0, 0.5, 0.953125, 1))),
  newSpan("\n1. free (something) from restrictive restrictions \"the regulations are intended to strallow changes in public policy\" ",
      newFont(typeface, 14, color(0.3125, 0.3125, 0.3125, 1)))
]

image.fillText(typeset(spans, vec2(180, 180)), translate(vec2(10, 10)))

Square

nim c -r examples/square.nim

let ctx = newContext(image)
ctx.fillStyle = rgba(255, 0, 0, 255)

let
  pos = vec2(50, 50)
  wh = vec2(100, 100)

ctx.fillRect(rect(pos, wh))

Line

nim c -r examples/line.nim

let ctx = newContext(image)
ctx.strokeStyle = "#FF5C00"
ctx.lineWidth = 10

let
  start = vec2(25, 25)
  stop = vec2(175, 175)

ctx.strokeSegment(segment(start, stop))

Rounded rectangle

nim c -r examples/rounded_rectangle.nim

let ctx = newContext(image)
ctx.fillStyle = rgba(0, 255, 0, 255)

let
  pos = vec2(50, 50)
  wh = vec2(100, 100)
  r = 25.0

ctx.fillRoundedRect(rect(pos, wh), r)

Heart

nim c -r examples/heart.nim

image.fillPath(
  """
    M 20 60
    A 40 40 90 0 1 100 60
    A 40 40 90 0 1 180 60
    Q 180 120 100 180
    Q 20 120 20 60
    z
  """,
  parseHtmlColor("#FC427B").rgba
)

Masking

nim c -r examples/masking.nim

let ctx = newContext(lines)
ctx.strokeStyle = "#F8D1DD"
ctx.lineWidth = 30

ctx.strokeSegment(segment(vec2(25, 25), vec2(175, 175)))
ctx.strokeSegment(segment(vec2(25, 175), vec2(175, 25)))

mask.fillPath(
  """
    M 20 60
    A 40 40 90 0 1 100 60
    A 40 40 90 0 1 180 60
    Q 180 120 100 180
    Q 20 120 20 60
    z
  """
)
lines.draw(mask)
image.draw(lines)

Gradient

nim c -r examples/gradient.nim

let paint = newPaint(pkGradientRadial)
paint.gradientHandlePositions = @[
  vec2(100, 100),
  vec2(200, 100),
  vec2(100, 200)
]
paint.gradientStops = @[
  ColorStop(color: color(1, 0, 0, 1), position: 0),
  ColorStop(color: color(1, 0, 0, 0.15625), position: 1.0),
]

image.fillPath(
  """
    M 20 60
    A 40 40 90 0 1 100 60
    A 40 40 90 0 1 180 60
    Q 180 120 100 180
    Q 20 120 20 60
    z
  """,
  paint
)

Image tiled

nim c -r examples/image_tiled.nim

let path = newPath()
path.polygon(
  vec2(100, 100),
  70,
  sides = 8
)

let paint = newPaint(pkImageTiled)
paint.image = readImage("examples/data/mandrill.png")
paint.imageMat = scale(vec2(0.08, 0.08))

image.fillPath(path, paint)

Shadow

nim c -r examples/shadow.nim

let path = newPath()
path.polygon(vec2(100, 100), 70, sides = 8)

let polygonImage = newImage(200, 200)
polygonImage.fillPath(path, rgba(255, 255, 255, 255))

let shadow = polygonImage.shadow(
  offset = vec2(2, 2),
  spread = 2,
  blur = 10,
  color = rgba(0, 0, 0, 200)
)

image.draw(shadow)
image.draw(polygonImage)

Blur

nim c -r examples/blur.nim

let path = newPath()
path.polygon(vec2(100, 100), 70, sides = 6)

let mask = newMask(200, 200)
mask.fillPath(path)

blur.blur(20)
blur.draw(mask, blendMode = bmMask)

image.draw(trees)
image.draw(blur)

Tiger

nim c -r examples/tiger.nim

let tiger = readImage("examples/data/tiger.svg")

image.draw(
  tiger,
  translate(vec2(100, 100)) *
  scale(vec2(0.2, 0.2)) *
  translate(vec2(-450, -450))
)