sec-progressbars.html

gtk 开发手册和参考文档。 包括gtk glib gdk等

><LI
><P
> %v - value</P
></LI
><LI
><P
> %l - lower range value</P
></LI
><LI
><P
> %u - upper range value</P
></LI
></UL
><P
>The displaying of this text string can be toggled using:</P
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><PRE
CLASS="PROGRAMLISTING"
>void gtk_progress_set_show_text( GtkProgress *progress,
                                 gint         show_text );</PRE
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><P
>The <TT
CLASS="LITERAL"
>show_text</TT
> argument is a boolean TRUE/FALSE value. The
appearance of the text can be modified further using:</P
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><PRE
CLASS="PROGRAMLISTING"
>void gtk_progress_set_text_alignment( GtkProgress   *progress,
                                      gfloat         x_align,
                                      gfloat         y_align );</PRE
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><P
>The <TT
CLASS="LITERAL"
>x_align</TT
> and <TT
CLASS="LITERAL"
>y_align</TT
> arguments take values between 0.0
and 1.0. Their values indicate the position of the text string within
the trough. Values of 0.0 for both would place the string in the top
left hand corner; values of 0.5 (the default) centres the text, and
values of 1.0 places the text in the lower right hand corner.</P
><P
>The current text setting of a progress object can be retrieved using
the current or a specified adjustment value using the following two
functions. The character string returned by these functions should be
freed by the application (using the g_free() function). These
functions return the formatted string that would be displayed within
the trough.</P
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><PRE
CLASS="PROGRAMLISTING"
>gchar *gtk_progress_get_current_text( GtkProgress   *progress );

gchar *gtk_progress_get_text_from_value( GtkProgress *progress,
                                         gfloat       value );</PRE
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><P
>There is yet another way to change the range and value of a progress
object using the following function:</P
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><TD
><PRE
CLASS="PROGRAMLISTING"
>void gtk_progress_configure( GtkProgress  *progress,
                             gfloat        value,
                             gfloat        min,
                             gfloat        max );</PRE
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></TR
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><P
>This function provides quite a simple interface to the range and value
of a progress object.</P
><P
>The remaining functions can be used to get and set the current value
of a progess object in various types and formats:</P
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><PRE
CLASS="PROGRAMLISTING"
>void gtk_progress_set_percentage( GtkProgress *progress,
                                  gfloat       percentage );

void gtk_progress_set_value( GtkProgress *progress,
                             gfloat       value );

gfloat gtk_progress_get_value( GtkProgress *progress );

gfloat gtk_progress_get_current_percentage( GtkProgress *progress );

gfloat gtk_progress_get_percentage_from_value( GtkProgress *progress,
                                               gfloat       value );</PRE
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><P
>These functions are pretty self explanatory. The last function uses
the the adjustment of the specified progess object to compute the
percentage value of the given range value.</P
><P
>Progress Bars are usually used with timeouts or other such functions
(see section on <A
HREF="ch-timeouts.html"
>Timeouts, I/O and Idle Functions</A
>) to give
the illusion of multitasking. All will employ the
gtk_progress_bar_update function in the same manner.</P
><P
>Here is an example of the progress bar, updated using timeouts. This
code also shows you how to reset the Progress Bar.</P
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><PRE
CLASS="PROGRAMLISTING"
>/* example-start progressbar progressbar.c */

#include &#60;gtk/gtk.h&#62;

typedef struct _ProgressData {
    GtkWidget *window;
    GtkWidget *pbar;
    int timer;
} ProgressData;

/* Update the value of the progress bar so that we get
 * some movement */
gint progress_timeout( gpointer data )
{
    gfloat new_val;
    GtkAdjustment *adj;

    /* Calculate the value of the progress bar using the
     * value range set in the adjustment object */

    new_val = gtk_progress_get_value( GTK_PROGRESS(data) ) + 1;

    adj = GTK_PROGRESS (data)-&#62;adjustment;
    if (new_val &#62; adj-&#62;upper)
      new_val = adj-&#62;lower;

    /* Set the new value */
    gtk_progress_set_value (GTK_PROGRESS (data), new_val);

    /* As this is a timeout function, return TRUE so that it
     * continues to get called */
    return(TRUE);
} 

/* Callback that toggles the text display within the progress
 * bar trough */
void toggle_show_text( GtkWidget    *widget,
		       ProgressData *pdata )
{
    gtk_progress_set_show_text (GTK_PROGRESS (pdata-&#62;pbar),
                                GTK_TOGGLE_BUTTON (widget)-&#62;active);
}

/* Callback that toggles the activity mode of the progress
 * bar */
void toggle_activity_mode( GtkWidget    *widget,
			   ProgressData *pdata )
{
    gtk_progress_set_activity_mode (GTK_PROGRESS (pdata-&#62;pbar),
                                    GTK_TOGGLE_BUTTON (widget)-&#62;active);
}

/* Callback that toggles the continuous mode of the progress
 * bar */
void set_continuous_mode( GtkWidget    *widget,
			  ProgressData *pdata )
{
    gtk_progress_bar_set_bar_style (GTK_PROGRESS_BAR (pdata-&#62;pbar),
                                    GTK_PROGRESS_CONTINUOUS);
}

/* Callback that toggles the discrete mode of the progress
 * bar */
void set_discrete_mode( GtkWidget    *widget,
			ProgressData *pdata )
{
    gtk_progress_bar_set_bar_style (GTK_PROGRESS_BAR (pdata-&#62;pbar),
                                    GTK_PROGRESS_DISCRETE);
}
 
/* Clean up allocated memory and remove the timer */
void destroy_progress( GtkWidget     *widget,
		       ProgressData *pdata)
{
    gtk_timeout_remove (pdata-&#62;timer);
    pdata-&#62;timer = 0;
    pdata-&#62;window = NULL;
    g_free(pdata);
    gtk_main_quit();
}

int main( int   argc,
          char *argv[])
{
    ProgressData *pdata;
    GtkWidget *align;
    GtkWidget *separator;
    GtkWidget *table;
    GtkAdjustment *adj;
    GtkWidget *button;
    GtkWidget *check;
    GtkWidget *vbox;

    gtk_init (&#38;argc, &#38;argv);

    /* Allocate memory for the data that is passwd to the callbacks */
    pdata = g_malloc( sizeof(ProgressData) );
  
    pdata-&#62;window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_policy (GTK_WINDOW (pdata-&#62;window), FALSE, FALSE, TRUE);

    gtk_signal_connect (GTK_OBJECT (pdata-&#62;window), "destroy",
	                GTK_SIGNAL_FUNC (destroy_progress),
                        pdata);
    gtk_window_set_title (GTK_WINDOW (pdata-&#62;window), "GtkProgressBar");
    gtk_container_set_border_width (GTK_CONTAINER (pdata-&#62;window), 0);

    vbox = gtk_vbox_new (FALSE, 5);
    gtk_container_set_border_width (GTK_CONTAINER (vbox), 10);
    gtk_container_add (GTK_CONTAINER (pdata-&#62;window), vbox);
    gtk_widget_show(vbox);
  
    /* Create a centering alignment object */
    align = gtk_alignment_new (0.5, 0.5, 0, 0);
    gtk_box_pack_start (GTK_BOX (vbox), align, FALSE, FALSE, 5);
    gtk_widget_show(align);

    /* Create a Adjusment object to hold the range of the
     * progress bar */
    adj = (GtkAdjustment *) gtk_adjustment_new (0, 1, 150, 0, 0, 0);

    /* Create the GtkProgressBar using the adjustment */
    pdata-&#62;pbar = gtk_progress_bar_new_with_adjustment (adj);

    /* Set the format of the string that can be displayed in the
     * trough of the progress bar:
     * %p - percentage
     * %v - value
     * %l - lower range value
     * %u - upper range value */
    gtk_progress_set_format_string (GTK_PROGRESS (pdata-&#62;pbar),
	                            "%v from [%l-%u] (=%p%%)");
    gtk_container_add (GTK_CONTAINER (align), pdata-&#62;pbar);
    gtk_widget_show(pdata-&#62;pbar);

    /* Add a timer callback to update the value of the progress bar */
    pdata-&#62;timer = gtk_timeout_add (100, progress_timeout, pdata-&#62;pbar);

    separator = gtk_hseparator_new ();
    gtk_box_pack_start (GTK_BOX (vbox), separator, FALSE, FALSE, 0);
    gtk_widget_show(separator);

    /* rows, columns, homogeneous */
    table = gtk_table_new (2, 3, FALSE);
    gtk_box_pack_start (GTK_BOX (vbox), table, FALSE, TRUE, 0);
    gtk_widget_show(table);

    /* Add a check button to select displaying of the trough text */
    check = gtk_check_button_new_with_label ("Show text");
    gtk_table_attach (GTK_TABLE (table), check, 0, 1, 0, 1,
                      GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
                      5, 5);
    gtk_signal_connect (GTK_OBJECT (check), "clicked",
                        GTK_SIGNAL_FUNC (toggle_show_text),
                        pdata);
    gtk_widget_show(check);

    /* Add a check button to toggle activity mode */
    check = gtk_check_button_new_with_label ("Activity mode");
    gtk_table_attach (GTK_TABLE (table), check, 0, 1, 1, 2,
                      GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
                      5, 5);
    gtk_signal_connect (GTK_OBJECT (check), "clicked",
                        GTK_SIGNAL_FUNC (toggle_activity_mode),
                        pdata);
    gtk_widget_show(check);

    separator = gtk_vseparator_new ();
    gtk_table_attach (GTK_TABLE (table), separator, 1, 2, 0, 2,
                      GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
                      5, 5);
    gtk_widget_show(separator);

    /* Add a radio button to select continuous display mode */
    button = gtk_radio_button_new_with_label (NULL, "Continuous");
    gtk_table_attach (GTK_TABLE (table), button, 2, 3, 0, 1,
                      GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
                      5, 5);
    gtk_signal_connect (GTK_OBJECT (button), "clicked",
                        GTK_SIGNAL_FUNC (set_continuous_mode),
                        pdata);
    gtk_widget_show (button);

    /* Add a radio button to select discrete display mode */
    button = gtk_radio_button_new_with_label(
               gtk_radio_button_group (GTK_RADIO_BUTTON (button)),
               "Discrete");
    gtk_table_attach (GTK_TABLE (table), button, 2, 3, 1, 2,
                      GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL,
                      5, 5);
    gtk_signal_connect (GTK_OBJECT (button), "clicked",
                        GTK_SIGNAL_FUNC (set_discrete_mode),
                        pdata);
    gtk_widget_show (button);

    separator = gtk_hseparator_new ();
    gtk_box_pack_start (GTK_BOX (vbox), separator, FALSE, FALSE, 0);
    gtk_widget_show(separator);

    /* Add a button to exit the program */
    button = gtk_button_new_with_label ("close");
    gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
                               (GtkSignalFunc) gtk_widget_destroy,
                               GTK_OBJECT (pdata-&#62;window));
    gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

    /* This makes it so the button is the default. */
    GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);

    /* This grabs this button to be the default button. Simply hitting
     * the "Enter" key will cause this button to activate. */
    gtk_widget_grab_default (button);
    gtk_widget_show(button);

    gtk_widget_show (pdata-&#62;window);

    gtk_main ();
    
    return(0);
}
/* example-end */</PRE
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