Transparent text with rmagick?

ruby-talk
1

hi -

(this maybe more an imagemagick q that a ruby one, but here goes ..)

using rmagick / I have a small script for generating some type, but I
cannot get the type to come out as transparent png - it comes out just
on solid white .

does this have to be done with masks and compositing? there are a
number of methods that look like they should work (transparent_color
etc), but dont seem to...

is the library broken or am i doing something wrong?

tx,

/dc

···

---------
require 'rubygems'
require "RMagick"
include Magick

outfile = "output/matte.png"

drawObj = Magick::Draw.new
drawObj.font = './fonts/Ghoul.ttf'
drawObj.pointsize=30
drawObj.fill = '#44ff00'

buffer = Magick::Image.new(250,100)
drawObj.text(20,50, "hello world")
drawObj.matte(3,3,PaintMethod::ReplaceMethod)
drawObj.draw(buffer)
buffer.opacity = 1
buffer.transparent_color = '#000000'
buffer.matte = true
buffer.write(outfile)

system("open #{outfile}")

--
-------------------------------------------
      David "DC" Collier
mailto:dc@pikkle.com
      +81 (0)80 6521 9559
      skype: callto://d3ntaku
-------------------------------------------
      Pikkle 株式会社
      http://www.pikkle.com
-------------------------------------------

2

dc wrote:

hi -

(this maybe more an imagemagick q that a ruby one, but here goes ..)

using rmagick / I have a small script for generating some type, but I
cannot get the type to come out as transparent png - it comes out just
on solid white .

does this have to be done with masks and compositing? there are a
number of methods that look like they should work (transparent_color
etc), but dont seem to...

is the library broken or am i doing something wrong?

tx,

/dc

Set the background color to "none" when you create the image:

buffer = Magick::Image.new(250, 250) {self.background_color = 'none'}