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::DissolveCompositeOp)
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
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
···
On Thu, 3 Aug 2006, Timothy Hunter wrote:
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?
--
we can never obtain peace in the outer world until we make peace with
ourselves.
- h.h. the 14th dali lama
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@noaa.gov wrote:
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
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
···
Le 2 août 2006 à 23:38, ara.t.howard@noaa.gov 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
--
I bought me an illusion An' I put it on the wall
I left it fill my head with dreams And I had to have them all
But oh the taste is never so sweet As what you'b believe it is...
Well I guess it never is (Guns n' Roses, Locomotive)
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
···
On Thu, 3 Aug 2006, Timothy Hunter wrote:
ara.t.howard@noaa.gov wrote:
--
we can never obtain peace in the outer world until we make peace with
ourselves.
- h.h. the 14th dali lama