I’d like to combine Wx (Wx::Image) with Rmagick/ImageMagick processing.
Other than saving to disk constantly, how would I pass an
Rmagick/ImageMagick image (e.g. RMagick:Image) to and from a Wx Image
(e.g. Wx:Image)?
Pito S. wrote:
I’d like to combine Wx (Wx::Image) with Rmagick/ImageMagick processing.
Other than saving to disk constantly, how would I pass an
Rmagick/ImageMagick image (e.g. RMagick:Image) to and from a Wx Image
(e.g. Wx:Image)?
If the image data from RMagick can be put into a string, you can use
StringIO + Wx::Image.read and Wx::Image#write to exchange image data in
a recognised format (PNG, TIF etc) in memory. See also
Wx::Image#set_data for low-level access to raw image data (see the
images/maths_drawing.rb for an example of using this).
a
Hi,
On Mon, Jun 1, 2009 at 9:17 PM, Alex F. [email protected] wrote:
recognised format (PNG, TIF etc) in memory. See also Wx::Image#set_data for
low-level access to raw image data (see the images/maths_drawing.rb for an
example of using this).
I’m just about to add an RMagick sample to wxRuby.
The following code snippet allows direct exchange between RMagick and
wxRuby :
magick_image = Magick::ImageList.new(img_file)
some magick conversion
wx_image = Wx::Image.new(magick_image.columns, magick_image.rows)
wx_image.set_data(magick_image.to_blob { self.format = “RGB” }
The only problem is transparency.
If img_file is a PNG file with transparent areas, those transparent
areas are lost (i.e. displaying a Wx::Bitmap corresponding to the
Wx::Image shows black areas instead of transparent areas).
At the moment, the only way I found to keep the transparency is to
save the magick_image into a PNG file and read it into a Wx::Image,
but this is not what you’re looking for.
Cheers.
Chauk-Mean.
I dunno, in RMagick, is the format “RGBA” available? If it is, that
should
allow for transparencies to be retained. Just a thought, don’t have
RMagick
to test.
Chauk-Mean P. wrote:
The only problem is transparency.
If img_file is a PNG file with transparent areas, those transparent
areas are lost (i.e. displaying a Wx::Bitmap corresponding to the
Wx::Image shows black areas instead of transparent areas).At the moment, the only way I found to keep the transparency is to
save the magick_image into a PNG file and read it into a Wx::Image,
but this is not what you’re looking for.
Does Wx::Image#set_alpha help here? it works like set_data but for the
alpha channel.
a
On Wed, Jun 3, 2009 at 1:07 PM, Alex F. [email protected] wrote:
Does Wx::Image#set_alpha help here? it works like set_data but for the alpha
channel.
Following Mario’s suggestion, I tried “RGBA” format which is available
in RMagick.
I extracted the image and the alpha raw data.
But when I tried to use set_alpha with the alpha raw data, an
exception is raised :
alpha_raw_string = apha_raw_data.pack(“C*”)
image.set_alpha(alpha_raw_string)
It seems that there is a SWIG problem.
Cheers.
Chauk-Mean.
On Thu, Jun 4, 2009 at 2:54 AM, Mario S. [email protected] wrote:
Following Mario’s suggestion, I tried “RGBA” format which is available
in RMagick.
I extracted the image and the alpha raw data.I just want to clarify, that you separated the RGB and the A values from
each pixel byte section (As I call it) in the blob that is returned from
RMagick, and tried applying it via image.set_data, and image.set_alpha,
Yes. Here is the detailed code I’m using :
wx_image = Wx::Image.new(magick_image.columns, magick_image.rows)
rgba_data = magick_image.to_blob {
self.format = “RGBA”
}
rgba_array = rgba_data.unpack(“C*”)
separate the RGB image and the alpha data
i = 0
image_array, alpha_array = rgba_array.partition do |val|
i += 1
if i % 4 != 0
true
else
false
end
end
image_data = image_array.pack(“C*”)
alpha_data = alpha_array.pack(“C*”)
wx_image.data = image_data
wx_image.set_alpha(alpha_data)
The set_alpha method raises the following exception :
rmagic_bitmap_image.rb:109:in `set_alpha’: Wrong arguments for
overloaded method ‘wxImage.SetAlpha’. (ArgumentError)
Possible C/C++ prototypes are:
void wxImage.SetAlpha(unsigned char *alpha, bool static_data)
void wxImage.SetAlpha(int x, int y, unsigned char alpha)
Chauk-Mean.
On Thu, Jun 4, 2009 at 6:45 AM, Chauk-Mean P.
[email protected]wrote:
wx_image.data = image_data
wx_image.set_alpha(alpha_data)
Alright, this may be a mistake in the Documentation, but try doing:
wx_image.set_alpha(alpha_data, false)
Something tells me that SWIG isn’t taking into consideration the default
param for static_data.
On Wed, Jun 3, 2009 at 5:39 PM, Chauk-Mean P.
[email protected]wrote:
but this is not what you’re looking for.
Does Wx::Image#set_alpha help here? it works like set_data but for the
alpha
channel.Following Mario’s suggestion, I tried “RGBA” format which is available
in RMagick.
I extracted the image and the alpha raw data.
I just want to clarify, that you separated the RGB and the A values from
each pixel byte section (As I call it) in the blob that is returned from
RMagick, and tried applying it via image.set_data, and image.set_alpha,
or
did you just tried to do the entire image data blob set through
image.set_alpha?
I just want to make sure, there’s no confusion about the order that is
going
on, with this.
Hi Mario,
On Thu, Jun 4, 2009 at 9:37 PM, Mario S.[email protected] wrote:
Alright, this may be a mistake in the Documentation, but try doing:
wx_image.set_alpha(alpha_data, false)
I’ve already tried that with the true value 
and it didn’t work.
Something tells me that SWIG isn’t taking into consideration the default
param for static_data.
Yes, there is a SWIG problem here. I don’t know what but this can be
revealed simply with the following code (there is no need to have
RMagick) :
require ‘wx’
wx_image = Wx::Image.new(2,2)
image_data = [0,0,0,64,64,64,128,128,128,255,255,255].pack(“C*”)
alpha_data = [0,255,0,255].pack(“C*”)
unique_alpha_data = [255].pack(“C”)
wx_image.set_data(image_data)
#Following call works :
wx_image.set_alpha()
#Following calls do not work :
#wx_image.set_alpha(alpha_data)
#wx_image.set_alpha(alpha_data, false)
#wx_image.set_alpha(0,0,unique_alpha_data)
I’m not sufficiently comfortable with SWIG to fix such kind of issue.
Cheers.
Chauk-Mean.
Hi all,
On Thu, Jun 4, 2009 at 11:57 PM, Chauk-Mean P.[email protected]
wrote:
#wx_image.set_alpha(alpha_data, false)
#wx_image.set_alpha(0,0,unique_alpha_data)I’m not sufficiently comfortable with SWIG to fix such kind of issue.
I’ve finally been able to fix this SWIG issue which seems to be caused
by :
- the use of a typemap for the first form of the SetAlpha C++ method
- and by the fact that this SetAlpha C++ method has an overloaded method
I’ve just hidden the overloaded method in the SWIG header for the
Image class and now everything works.
Maybe Alex will be able to provide a complete fix to this issue
without having to hide the overloaded method.
I’ve also found a way to get directly the alpha raw data from a RMagick
image.
So here is the code to convert seamlessly a RMagick image to a wxRuby
image :
wx_img = Wx::Image.new(magick_img.columns, magick_img.rows)
Set the image data
wx_img.data = magick_img.to_blob { self.format = “RGB” }
Set the alpha (transparency) if any
if magick_img.alpha?
wx_img.alpha = magick_img.to_blob { self.format = “A” }
end
I’ve just committed the fix and a complete sample
(samples/drawing/rmagic_bitmap_image.rb) in subversion.
Cheers.
Chauk-Mean.