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.
On 23/02/2015 23:05, Glus Xof wrote:
2015-02-23 22:21 GMT+01:00 Markus Kolb <markus kolb+gtkmm tower-net de
<mailto:markus.kolb+gtkmm@tower-net.de>>:
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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