I'm struggling to attach a Vips:Image object to an ActiveStorage object.
I use Vips to compress a PNG image. I'm then looking to save this compressed PNG version into a second ActiveStorage attachment. The code is failing when attempting to attach. All I get is: Process finished with exit code -1073741819 (0xC0000005)
# compress the image and save the compressed version of the file as a PNG
# both img and img_to_compress are active storage attachments
def compress_charlie(img, img_to_compress)
# load the image as a Vips Image object
vips_img = Vips::Image.new_from_buffer (URI.open(img.url) { |f| f.read }), ''
# do compression, etc ... not bothering to show this code as it has no impact on the issue I have
# save the compressed png
img_to_compress.attach(
io: StringIO.new(vips_img .write_to_buffer('.png')),
filename: img.filename
)
end
Any help is appreciated, Charlie
Ruby 3.1 Rails 7.0.1
You're decompressing and recompressing twice. How about (untested):
def convert_to_png(img, img_to_compress)
# load the image as a Vips Image object
vips_img = Vips::Image.new_from_buffer (URI.open(img.url) { |f| f.read }), ''
# save as a PNG string
png = StringIO.new(vips_img.write_to_buffer('.png')),
img_to_compress.attach(io: png, filename: img.filename)
end
pngsave_buffer gives you a String with binary encoding, you don't need to save a second time. Try this test program:
require "vips"
x = Vips::Image.new_from_file ARGV[0]
y = x.pngsave_buffer
puts "y.class = #{y.class}"
I see:
$ ./pngsave.rb ~/pics/k2.jpg
y.class = String
If the image is already a PNG you'll be wasting a lot of time, of course. You could add something to detect the format and skip the conversion.