Can't convert String into Integer (TypeError)

[Timothy Hunter]

Okay, I'm stumped. I've been looking at this program off-and-on for 3
days now and I can't understand why it's failing like it does. It's
*supposed* to fail, but not the way it does.

The Image#dissolve method takes 2 arguments, an Image object and a
percentage. The percentage argument can be specified either as a number
between 0.0 and 1.0, or as a string in the form "NNN%", like "50%" for
example. In this test I'm passing "1x0%" as the percentage, which is
clearly incorrect. I expect dissolve to raise an ArgumentError exception
with the message "expected percentage, got `1x0%'". What actually
happens is that I get

/Users/timothyhunter/Temporary/bug.rb:22:in `raise': can't convert
String into Integer (TypeError)
from /Users/timothyhunter/Temporary/bug.rb:22:in `dissolve'
from /Users/timothyhunter/Temporary/bug.rb:43

Line 22 is the "raise" statement.

What am I missing?

require 'RMagick'

module Magick
class Image

# Similar to `composite self -dissolve pct overlay'
# Returns composited result
def dissolve(overlay, pct)
begin
# Clamp to 0 <= pct <= 1
pct = [1.0, Float(pct)].min
pct = [0.0, pct].max
# Convert to 0 <= pct <= 100
pct = (pct * 100.0).to_i
rescue
m = pct.to_s.match(/\A(\d+)%\z/)
if m
# Clamp to 0 <= pct <= 100
pct = [100, m[1].to_i].min
pct = [0, pct].max
else
raise ArgumentError, "expected percentage, got `#{pct}'"
end
end

temp = overlay.geometry
begin
overlay.geometry = pct.to_s
res = composite(overlay, 0, 0, Magick:issolveCompositeOp)
ensure
overlay.geometry = temp
end
return res
end

end
end

# composite Flower_Hat.jpg -dissolve 90 Violin.jpg
bgnd = Magick::Image.read('Flower_Hat.jpg').first
overlay = Magick::Image.read('Violin.jpg').first

bgnd.dissolve(overlay, '1x0%').display

 

[ara.t.howard]

Okay, I'm stumped. I've been looking at this program off-and-on for 3 days
now and I can't understand why it's failing like it does. It's *supposed* to
fail, but not the way it does.

The Image#dissolve method takes 2 arguments, an Image object and a
percentage. The percentage argument can be specified either as a number
between 0.0 and 1.0, or as a string in the form "NNN%", like "50%" for
example. In this test I'm passing "1x0%" as the percentage, which is clearly
incorrect. I expect dissolve to raise an ArgumentError exception with the
message "expected percentage, got `1x0%'". What actually happens is that I
get

/Users/timothyhunter/Temporary/bug.rb:22:in `raise': can't convert String
into Integer (TypeError)
from /Users/timothyhunter/Temporary/bug.rb:22:in `dissolve'
from /Users/timothyhunter/Temporary/bug.rb:43

Line 22 is the "raise" statement.

What am I missing?

jib:~ > ruby -r RMagick -e' p Magick::Image.instance_methods.grep(/raise/) '
["raise"]


btw, seems like you could get away with something like:

pct = Float(pct) rescue (Float(pct.to_s.delete('%'))/100)
r = 0.0 .. 1.0
pct = [r.min, pct].max
pct = [r.max, pct].min

cheers.

-a

 

[Timothy Hunter]

jib:~ > ruby -r RMagick -e' p
Magick::Image.instance_methods.grep(/raise/) '
["raise"]


btw, seems like you could get away with something like:

pct = Float(pct) rescue (Float(pct.to_s.delete('%'))/100)
r = 0.0 .. 1.0
pct = [r.min, pct].max
pct = [r.max, pct].min

cheers.

-a

Arg! I should spend more time coding in Ruby and less in C. Thanks, Ara!

"1%0%".delete('%') => "10". Might be a bit too tolerent, don't you think?

I had the clamping down to 1 line but when I looked at it the next day I
couldn't tell if it was correct or not :-(

 

[ara.t.howard]

jib:~ > ruby -r RMagick -e' p
Magick::Image.instance_methods.grep(/raise/) '
["raise"]


btw, seems like you could get away with something like:

pct = Float(pct) rescue (Float(pct.to_s.delete('%'))/100)
r = 0.0 .. 1.0
pct = [r.min, pct].max
pct = [r.max, pct].min

cheers.

-a

Arg! I should spend more time coding in Ruby and less in C. Thanks, Ara!

yeah - i have the opposite issue ;-)

"1%0%".delete('%') => "10". Might be a bit too tolerent, don't you think?

dunno. you could do pct.sub(/%$/,'') too. lately i've found that parameter
checking just comes back to haunt me - though i do it heavily in certain
situations. just food for thought.

I had the clamping down to 1 line but when I looked at it the next day I
couldn't tell if it was correct or not :-(

indeed - i tend even to avoid method chaining in production code for that
reason - it makes logs less than useful for pinpointng errors

cheers.

-a

 

[F. Senault]

Le 2 août 2006 à 23:38, (e-mail address removed) a écrit :

btw, seems like you could get away with something like:

pct = Float(pct) rescue (Float(pct.to_s.delete('%'))/100)
r = 0.0 .. 1.0
pct = [r.min, pct].max
pct = [r.max, pct].min

BTW, another fun way to write the three last lines would be :

[0.0, pct, 1.0].sort[1]

But it doesn't convey the meaning well...

Fred