GdkPixbufLoader            package:RGtk2            R Documentation

_G_d_k_P_i_x_b_u_f_L_o_a_d_e_r

_D_e_s_c_r_i_p_t_i_o_n:

     Application-driven progressive image loading.

_M_e_t_h_o_d_s _a_n_d _F_u_n_c_t_i_o_n_s:

     'gdkPixbufLoaderNew()'
      'gdkPixbufLoaderNewWithType(image.type, .errwarn = TRUE)'
      'gdkPixbufLoaderNewWithMimeType(mime.type, .errwarn = TRUE)'
      'gdkPixbufLoaderGetFormat(object)'
      'gdkPixbufLoaderWrite(object, buf, .errwarn = TRUE)'
      'gdkPixbufLoaderSetSize(object, width, height)'
      'gdkPixbufLoaderGetPixbuf(object)'
      'gdkPixbufLoaderGetAnimation(object)'
      'gdkPixbufLoaderClose(object, .errwarn = TRUE)'
      'gdkPixbufLoader(image.type, mime.type, .errwarn = TRUE)'

_H_i_e_r_a_r_c_h_y:

     GObject
        +----GdkPixbufLoader 

_D_e_t_a_i_l_e_d _D_e_s_c_r_i_p_t_i_o_n:

     'GdkPixbufLoader' provides a way for applications to drive the
     process of loading an image, by letting them send the image data
     directly to the loader instead of having the loader read the data
     from a file.  Applications can use this functionality instead of
     'gdkPixbufNewFromFile' or 'gdkPixbufAnimationNewFromFile'  when
     they need to parse image data in small chunks.  For example, it
     should be used when reading an image from a (potentially) slow
     network connection, or when loading an extremely large file.

     To use 'GdkPixbufLoader' to load an image, just create a new one,
     and call 'gdkPixbufLoaderWrite' to send the data to it.  When
     done, 'gdkPixbufLoaderClose' should be called to end the stream
     and finalize everything.  The loader will emit three important
     signals throughout the process.  The first, "size_prepared", will
     be called as soon as the image has enough information to determine
     the size of the image to be used. If you want to scale the image
     while loading it, you can call 'gdkPixbufLoaderSetSize' in
     response to this signal. The second signal, "area_prepared", will
     be called as soon as the pixbuf of the desired has been 
     allocated.  You can obtain it by calling
     'gdkPixbufLoaderGetPixbuf'.  If you want to use it, simply ref it.
       In addition, no actual information will be passed in yet, so the
     pixbuf can be safely filled with any temporary graphics (or an
     initial color) as needed.  You can also call
     'gdkPixbufLoaderGetPixbuf' later and get the same pixbuf.

     The last signal, "area_updated" gets called every time a region is
     updated.  This way you can update a partially completed image. 
     Note that you do not know anything about the completeness of an
     image from the area updated.  For example, in an interlaced image,
     you need to make several passes before the image is done loading.

_L_o_a_d_i_n_g _a_n _a_n_i_m_a_t_i_o_n:

     Loading an animation is almost as easy as loading an image.  Once
     the first "area_prepared" signal has been emitted, you can call
     'gdkPixbufLoaderGetAnimation' to get the 'GdkPixbufAnimation'
     struct and 'gdkPixbufAnimationGetIter' to get an
     'GdkPixbufAnimationIter' for displaying it.

_S_t_r_u_c_t_u_r_e_s:


     '_G_d_k_P_i_x_b_u_f_L_o_a_d_e_r' The 'GdkPixbufLoader' struct contains only
          private fields. 


_C_o_n_v_e_n_i_e_n_t _C_o_n_s_t_r_u_c_t_i_o_n:

     'gdkPixbufLoader' is the result of collapsing the constructors of
     'GdkPixbufLoader' ('gdkPixbufLoaderNew',
     'gdkPixbufLoaderNewWithType', 'gdkPixbufLoaderNewWithMimeType')
     and accepts a subset of its arguments matching the required
     arguments of one of its delegate constructors.

_S_i_g_n_a_l_s:


     '_a_r_e_a-_p_r_e_p_a_r_e_d(_l_o_a_d_e_r, _u_s_e_r._d_a_t_a)' This signal is emitted when the
          pixbuf loader has allocated the  pixbuf in the desired size. 
          After this signal is emitted,  applications can call
          'gdkPixbufLoaderGetPixbuf' to fetch  the partially-loaded
          pixbuf.  

          '_l_o_a_d_e_r' ['GdkPixbufLoader']  the object which received the
               signal.

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_a_r_e_a-_u_p_d_a_t_e_d(_l_o_a_d_e_r, _x, _y, _w_i_d_t_h, _h_e_i_g_h_t, _u_s_e_r._d_a_t_a)' This signal
          is emitted when a significant area of the image being loaded
          has been updated.  Normally it means that a complete scanline
          has been read in, but it could be a different area as well. 
          Applications can use this signal to know when to repaint
          areas of an image that is being loaded.  

          '_l_o_a_d_e_r' ['GdkPixbufLoader']  the object which received the
               signal.

          '_x' [integer]  X offset of upper-left corner of the updated
               area.

          '_y' [integer]  Y offset of upper-left corner of the updated
               area.

          '_w_i_d_t_h' [integer]  Width of updated area.

          '_h_e_i_g_h_t' [integer]  Height of updated area.

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_c_l_o_s_e_d(_l_o_a_d_e_r, _u_s_e_r._d_a_t_a)' This signal is emitted when
          'gdkPixbufLoaderClose' is called. It can be used by different
          parts of an application to receive notification when an image
          loader is closed by the code that drives it.  

          '_l_o_a_d_e_r' ['GdkPixbufLoader']  the object which received the
               signal.

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_s_i_z_e-_p_r_e_p_a_r_e_d(_l_o_a_d_e_r, _w_i_d_t_h, _h_e_i_g_h_t, _u_s_e_r._d_a_t_a)' This signal is
          emitted when the pixbuf loader has been fed the initial
          amount of data that is required to figure out the size of the
          image that it will create.  Applications can call  
          'gdkPixbufLoaderSetSize' in response to this signal to set
          the desired size to which the image should be scaled.  

          '_l_o_a_d_e_r' ['GdkPixbufLoader']  the object which received the
               signal.

          '_w_i_d_t_h' [integer]  the original width of the image

          '_h_e_i_g_h_t' [integer]  the original height of the image

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


_A_u_t_h_o_r(_s):

     Derived by RGtkGen from GTK+ documentation

_R_e_f_e_r_e_n_c_e_s:

     <URL:
     http://developer.gnome.org/doc/API/2.0/gdk-pixbuf/GdkPixbufLoader.html>

