!genFaPng.ps1

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# / ____/ /  /  __/ /  /  __/ /_/ (__  ) 
#/_/   /_/   \___/_/   \___/\__, /____/  
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# this script will automatically pull font awesome files from github via .net framework "WebClient"
# install fantastically handy ImageMagick tool from => http://www.imagemagick.org/script/binary-releases.php
#    and add it to your path
if (-not [bool](Get-Command "magick.exe" -ErrorAction SilentlyContinue)) { throw "Magick.exe not in path" }

# set the desired foreGround color (background will be set to transparent per magick.exe command line below)
$textColor="white"


cd (Split-Path -parent $PSCommandPath)

erase fa-*.png

#download font-awesome if not present (just delete ttf if you want to pull fresh copy)
if (-not (test-path fontawesome-webfont.ttf) -or -not (test-path font-awesome.css)) {
  #ignore SSL
  [System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}

  $webClient = New-Object Net.WebClient
  $webClient.DownloadFile("https://raw.githubusercontent.com/FortAwesome/Font-Awesome/master/fonts/fontawesome-webfont.ttf", "fontawesome-webfont.ttf")
  $webClient.DownloadFile("https://raw.githubusercontent.com/FortAwesome/Font-Awesome/master/css/font-awesome.css", "font-awesome.css")
  $webClient.Dispose()
}

#using readily provided css file as a convenient icon name to unicode lookup
if (-not (test-path fontawesome-webfont.ttf) -or -not (test-path font-awesome.css)) { throw "font-awesome download failed for some reason" }
[string]$faCSS = gc font-awesome.css

function CreateFAImages([string] $faIconName) {
  if (-not ($faIconName -like "fa-")) { $faIconName = "fa-" + $faIconName }
  if ($Matches) { $Matches.Clear() }
  $faCSS -match "\.$($faIconName):before.*?content:\s`"\\(.*?)`""
  if (-not $Matches[1]) { throw "$faIconName not found in css unicode lookup" }
  $faUnicode = [char][int]"0x$($Matches[1])"

  # i found these sizes in another xamarin sponsored project, not sure if they're "standard" yet
  CreateFAImage $faIconName $faUnicode 24x24
  CreateFAImage $faIconName@2x $faUnicode 48x48 
  CreateFAImage $faIconName@3x $faUnicode 72x72
}

function CreateFAImage([string]$faIconName, [string]$faUnicode, [string]$size) {
  # ***install fantastically handy ImageMagick tool from => http://www.imagemagick.org/script/binary-releases.php
  # main options docs: http://www.imagemagick.org/script/command-line-options.php#compose
  # ImageMagick basically works left to right applying the various options... parenthesis do work for nested flow... BUT MAKE SURE YOU LEAVE A SPACE INSIDE EACH PAREN OR IT'LL BOMB OUT SYNTAX CHECK
  #   if you're nesting operations, you'll probably have to "-levels merge" or "-flatten" them back together into single final image or else it'll output a file per each layer
  # options used:
  #   -pointsize - start with a nice big font to avoid pixelation on resize
  #   -trim - seemed to be required for these icon fonts... imagemagick docs mention automatic text "fit" logic but i always got a big whitespace gap under the icon character
  #   -resize is obvious but the annoying downside is that it somehow automatically trims in the horizontal direction... not sure what to make of that... so for now applying -extent after
  #   -gravity is a centering command, we can also do horizontal/vertical separately via "North", etc
  #     and then the -extent sets the outer "canvas" size

  magick -fill $textColor -background transparent -pointsize 500 -font "fontawesome-webfont.ttf" label:$faUnicode -trim -bordercolor none -border 5% -resize $size -gravity center -extent $size "$faIconName.png"
  # nugget: using powershell since i couldn't coax cmd.exe to generate the unicode character no matter what i tried from stack-o
}

@("bars", "camera") | % { CreateFAImages $_ }