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Cairo LuaJit FFI

FFI bindings to Cairo graphics

Installation

LuaRocks

sudo luarocks --lua-version 5.1 install rocks/cairo-luajit-ffi-0.1.0-1.rockspec

Dependencies

For Debian or Ubuntu

sudo apt-get install libcairo2-dev

For Fedora

sudo yum install cairo-devel

For openSUSE

zypper install cairo-devel

Documentation

https://www.cairographics.org/manual/ Methods have undergone minimal changes, but it's better to refer to cairo-ffi.lua, the examples, and test/all_test.lua.

Constants

All cairo enum constants are available through cairo.consts:

local consts = require('cairo-luajit-ffi').consts

local format = consts.CAIRO_FORMAT_ARGB32

Minimal Example

local cairo = require('cairo-luajit-ffi')
local consts = cairo.consts

local WIDTH = 512
local HEIGHT = 512

local surface = cairo.image_surface_create(consts.CAIRO_FORMAT_ARGB32, WIDTH, HEIGHT)
local cr = cairo.create(surface)

cairo.set_source_rgb(cr, 1, 1, 1)
cairo.paint(cr)

-- Fill circle
cairo.set_source_rgb(cr, 0, 0.7, 0.7)
cairo.arc(cr, WIDTH/2, HEIGHT/2, 128, 0, 2 * math.pi)
cairo.fill(cr)

cairo.surface_write_to_png(surface, 'circle-test.png')
cairo.destroy(cr)
cairo.surface_destroy(surface)

Extensions

The ext/ modules return objects with :writePng(filename), :pngString() and :destroy() methods.

Captcha:

local captcha = require('cairo-luajit-ffi.ext.captcha')

math.randomseed(os.time())

local c = captcha.new({ length = 6 })
print(c.text)
c:writePng(c.text..'.png')
c:destroy()

Histogram:

local histogram = require('cairo-luajit-ffi.ext.histogram')

local h = histogram.new({
  values = { 1, 5, 3, 8 },
  descriptions = { 'a', 'b', 'c', 'd' },
})
h:writePng('histogram.png')
h:destroy()

Identicon (deterministic avatar from a string):

local identicon = require('cairo-luajit-ffi.ext.identicon')

local icon = identicon.new({ seed = 'user@example.com' })
icon:writePng('avatar.png')
icon:destroy()

Placeholder image:

local placeholder = require('cairo-luajit-ffi.ext.placeholder')

local p = placeholder.new({ width = 300, height = 150 })
p:writePng('placeholder.png')
p:destroy()

Badge (shields.io style):

local badge = require('cairo-luajit-ffi.ext.badge')

local b = badge.new({ label = 'build', value = 'passing' })
b:writePng('badge.png')
b:destroy()

Progress ring:

local progress = require('cairo-luajit-ffi.ext.progress')

local p = progress.new({ percent = 42 })
p:writePng('progress.png')
p:destroy()