Open image file on Windows

[icm7216]

In Windows environment IO class has two modes, that is in text mode and binary mode.
Image files must be loaded in binary mode.

Before applying the patch.

Image files are not displayed in the IRuby on Windows.

After applying the patch.

Image file is displayed.

[zverok]

Well, probably #binread is appropriate for binary mime types on all platforms?..

[icm7216]

Only Windows platform uses #binread.

if RUBY_PLATFORM =~ /mswin(?!ce)|mingw|cygwin/

[icm7216]

I added mime types check, that apply only 'image/png' and 'image/jpeg' on windows platform.

[kojix2]

Thank you @icm7216
I agree with this change.
What do you think? @mrkn

[mrkn]

OMG! I didn't know the feature for displaying an IO object!

I think this feature is evil. We must drop it.
And we should provide the alternative feature to displaying the content of a file as an image.

[kojix2]

Yes. It should be so.
But, you know It is hard to create and maintain image classes for Ruby.
https://github.com/mrkn/IMF

[mrkn]

@kojix2 we don't need such a thing just for displaying a file as an image.
It can be done by providing a new method that takes a path of the file, reads the contents, and calls IRuby.display with an appropriate mime type.
If such a method is provided as IRuby.display_file, we can do:

IRuby.display_file(io.path)

instead of just displaying an IO.

[kojix2]

@mrkn I get the point.

What about the following example?

IRuby.display(file: "foo.png")

like ruby-gnome2

require 'gtk3'
GdkPixbuf::Pixbuf.new(file: "logo-32x32.png")

It does not mean that I recommend writing that way.
I just want to hear your opinion about other possibilities.

[mrkn]

@kojix2 I want to make a method simple as possible.

[kojix2]

@icm7216
Thank you very much for the great pull request.
This allowed us to find problems with IRuby