RMagick::Image.from_blob method don't work - ruby

Question

I using Ruby, Sinatra and RMagick
I wont take browser icon (.svg file), add to icon text - version of browser - and return new .svg as respond to user
I wont open .svg as string, add some lines with my text and save this as new .svg file using RMagick.
but method to_blob and from_blob doesn't work correct
# myapp.rb
require 'sinatra'
require 'rmagick'
get '/test/:browser' do
img = Magick::Image::read("icons/default/#{params[:browser]}.svg")[0]
str = img.to_blob
"<textarea name='image' cols='100' rows='100'>#{str}</textarea>"
end
documentation from https://rmagick.github.io/image3.html#to_blob
img.to_blob [ { optional arguments } ]-> string
Description: Creates a Binary Large OBject, a direct-to-memory version
of the image.
chrome.svg:
<svg xmlns="http://www.w3.org/2000/svg" viewBox="15.5 15.5 224.5 224.5">
<defs>
<radialGradient cy="0" cx="0.5" id="r">
<stop stop-color="#f06b59"/>
<stop offset="1" stop-color="#df2227"/>
</radialGradient>
<radialGradient r="0.76" cy="0.3" cx="0.65" id="g">
<stop offset="0.65" stop-color="#4cb749"/>
<stop offset="1" stop-color="#388b41"/>
</radialGradient>
<radialGradient r="0.8" cy="0.25" cx="0.36" id="y">
<stop offset="0.6" stop-color="#FCD209"/>
<stop offset="0.7" stop-color="#f7c616"/>
<stop offset="1" stop-color="#bc821e"/>
</radialGradient>
<radialGradient r="1" cy="0" cx="0.5" spreadMethod="pad" id="cf">
<stop offset="0.1" stop-color="#7FB3DF"/>
<stop offset="0.9" stop-color="#0F5B94"/>
</radialGradient>
<radialGradient id="cb" r="1" cy="0" cx="0.5">
<stop offset="0" stop-color="#F6F0EE"/>
<stop offset="1" stop-color="#ddd"/>
</radialGradient>
</defs>
<path d="m198,148a70,70 0 0 0 -140,0l20,0a50,50 0 0 1 100,0" fill-opacity="0.1"/>
<circle r="45" cx="127.5" cy="127.6" fill="url(#cf)" stroke="url(#cb)" stroke-width="9" />
<path d="m228,78a112,112 0 0 0 -193,-13l45,78a50,50 0 0 1 47,-65" fill="url(#r)"/>
<path d="m35,65a112,112 0 0 0 84,174l47,-80a50,50 0 0 1 -86,-16" fill="url(#g)"/>
<path d="m119,239a112,112 0 0 0 109,-161l-101,0a50,50 0 0 1 39,81" fill="url(#y)"/>
<path d="m35,65l45,78a50,50 0 0 1 2,-34l-45,-47" opacity="0.075"/>
<path d="m119,239l47,-80a50,50 0 0 1 -29,17l-20,63" opacity="0.05"/>
<path d="m228,78l-101,0a50,50 0 0 1 39,19l64,-16" opacity="0.05"/>
</svg>
But to_blob return this:
<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20010904//EN"
"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
<svg width="225" height="225">
<circle cx="0" cy="0" r="1" fill="white"/>
<circle cx="1" cy="0" r="1" fill="white"/>
<circle cx="2" cy="0" r="1" fill="white"/>
==============================
about 50 000 such lines here
if this save to file, size of file will be about 3 MB
==============================
<circle cx="220" cy="224" r="1" fill="white"/>
<circle cx="221" cy="224" r="1" fill="white"/>
<circle cx="222" cy="224" r="1" fill="white"/>
<circle cx="223" cy="224" r="1" fill="white"/>
<circle cx="224" cy="224" r="1" fill="white"/>
</svg>
What I doing wrong?
Or, if you have another idea how to do this task - please, share.

Answer 1

get '/test/:browser' do
image = File.open('icons/default/chrome.svg')
blob = image.read
"<textarea name='image' cols='100' rows='100'>#{blob}</textarea>"
end
This is what i need.
First open file, then use read method.
In this case all work correct and .to_blob not needed