2015-02-24 8:12 GMT+01:00 Yann LEYDIER <[email protected]>:
> According to this : http://www.cplusplus.com/
> reference/string/basic_string/basic_string/
>
> "If the resulting string length would exceed the max_size, a length_error
> exception is thrown."
>
> Your image is to big to fit in a std::string.
>
Thanks for your remark...
I write the following test code,
std::cout
<< "Length : " << ref_orig->get_byte_length() << std::endl
<< "Max Size : " << image_pixels.max_size() << std::endl;
And after, I obtained,
Length : 750000
Max Size : 4611686018427387897
I don't know if both values are expressed according the same magnitude...
if so, I suppose the problem would be another...
Glus
>
> On 23/02/2015 23:05, Glus Xof wrote:
>
>>
>>
>> 2015-02-23 22:21 GMT+01:00 Markus Kolb <[email protected]
>> <mailto:[email protected]>>:
>>
>> Am 2015-02-23 21:40, schrieb Glus Xof:
>>
>> Hi guys,
>>
>> Before anything, I admit that probably my question is not an
>> specifically
>> Gtkmm question... but nevertheless I think you may know how
>> Gdk::Pixbuf is
>> done...
>>
>> Having the following,
>>
>> Glib::RefPtr<Gdk::Pixbuf> ref_orig = Gdk::Pixbuf::create_from_file
>> ("./file.png");
>>
>> I'm trying to temporary store (because I need so) the image data
>> into a
>> std::string object. It seems that get_pixels() could solve the
>> problem,
>> getting a pointer of type guint8.
>>
>>
>> Seems that gdkmm is not up-to-date here.
>> gdk uses a guchar*. But this shouldn't be a problem.
>>
>>
>> So, I wrote as follows,
>>
>> std::string image_pixels (reinterpret_cast<const char
>> *>(ref_orig->get_pixels()), ref_orig->get_rowstride());
>>
>>
>> I think this does not what you expect.
>>
>> https://developer.gnome.org/__gdk-pixbuf/stable/gdk-pixbuf-_
>> _The-GdkPixbuf-Structure.html#__gdk-pixbuf-get-rowstride
>> <https://developer.gnome.org/gdk-pixbuf/stable/gdk-pixbuf-
>> The-GdkPixbuf-Structure.html#gdk-pixbuf-get-rowstride>
>>
>> See also the part below the description headline.
>>
>> Maybe you should use gsize Gdk::Pixbuf::get_byte_length()
>> because
>> https://developer.gnome.org/__gdk-pixbuf/stable/gdk-pixbuf-_
>> _The-GdkPixbuf-Structure.html#__gdk-pixbuf-get-pixels-with-__length
>> <https://developer.gnome.org/gdk-pixbuf/stable/gdk-pixbuf-
>> The-GdkPixbuf-Structure.html#gdk-pixbuf-get-pixels-with-length>
>> is missing.
>>
>> I hope it will help you.
>>
>> But think about the std::string. Big ? ;-)
>>
>>
>> According to Yann & Markus' comments, I remake my code as follows,
>>
>> Glib::RefPtr<Gdk::Pixbuf> ref_orig = Gdk::Pixbuf::create_from_file
>> ("./file.png");
>>
>> // Glib::ustring::c_str() or data() allows me to get an std::string
>> object...
>>
>> Glib::ustring image_pixels (
>> reinterpret_cast<const char *>(ref_orig->get_pixels()),
>> ref_orig->get_byte_length());
>>
>> Glib::RefPtr<Gdk::Pixbuf> ref_dest =
>> Gdk::Pixbuf::create_from_data (
>> reinterpret_cast<const guint8*>(image_pixels.data()),
>> Gdk::COLORSPACE_RGB,
>> ref_orig->get_has_alpha(), ref_orig->get_bits_per_sample(),
>> ref_orig->get_width(), ref_orig->get_height(),
>> ref_orig->get_rowstride());
>>
>> But, at runtime I get a lenght error exception,
>>
>> terminate called after throwing an instance of 'std::length_error'
>> what(): basic_string::_S_create
>>
>> Could help ?
>>
>> Glus
>>
>>
>>
>>
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>>
>>
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