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1.2
date	2005.08.12.07.24.27;	author behdad;	state Exp;
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next	1.1;
commitid	75b042fc4e5b4567;

1.1
date	2004.11.11.19.45.53;	author pippin;	state Exp;
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desc
@@


1.2
log
@2005-08-12  Behdad Esfahbod  <behdad@@behdad.org>

        * hello.c, mouse_events.c: updated to latest cairo+gtk api.
	* README: noted the change from gtkcairo to cairo+gtk.
@
text
@/*  alpha blended rubber band using canvas, demonstrating mouse intercation
 *
 *  only things that are new compared to hello.c are commented
 */

#include <gtk/gtk.h>
#include <cairo.h>

#define DEFAULT_WIDTH  400
#define DEFAULT_HEIGHT 200

/* a structure keeping information about
 * the selection */
typedef struct
{
  gboolean active;   /* whether the selection is active or not */
  gdouble  x, y;
  gdouble  w, h;
}
SelectionInfo;

static void paint (GtkWidget      *widget,
		   GdkEventExpose *eev,
                   SelectionInfo  *sel_info);

/* forward definitions of handler for mouse events
 */
static gboolean event_press   (GtkWidget      *widget,
                               GdkEventButton *bev,
                               SelectionInfo  *sel_info);

static gboolean event_release (GtkWidget      *widget,
                               GdkEventButton *bev,
                               SelectionInfo  *sel_info);

static gboolean event_motion  (GtkWidget      *widget,
                               GdkEventMotion *mev,
                               SelectionInfo  *sel_info);

gint
main (gint    argc,
      gchar **argv)
{
  GtkWidget     *window;
  GtkWidget     *canvas;
  SelectionInfo  selection = {FALSE, 0, 0, 0, 0};

  gtk_init (&argc, &argv);

  window   = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  g_signal_connect (G_OBJECT (window), "delete-event",
                    G_CALLBACK (gtk_main_quit), NULL);

  canvas = gtk_drawing_area_new ();
  gtk_widget_set_size_request (canvas, DEFAULT_WIDTH, DEFAULT_HEIGHT);
  
  /* connect our drawing method to the "expose" signal
   * passing in a pointer to the selection structure as the user data
   */
  g_signal_connect (G_OBJECT (canvas), "expose-event",
                    G_CALLBACK (paint),
                    &selection
                  );

  /* add additional events the canvas widget will listen for
   */
  gtk_widget_add_events (canvas,
                    GDK_BUTTON1_MOTION_MASK |
                    GDK_BUTTON_PRESS_MASK   |
                    GDK_BUTTON_RELEASE_MASK);
  
  
  /* connect our rubber banding callbacks, like the paint callback
   * we pass the selection as userdata
   */
  g_signal_connect (G_OBJECT (canvas), "button_press_event",
                    G_CALLBACK (event_press),
                    &selection
                  );
  g_signal_connect (G_OBJECT (canvas), "button_release_event",
                    G_CALLBACK (event_release),
                    &selection
                  );
  g_signal_connect (G_OBJECT (canvas), "motion_notify_event",
                    G_CALLBACK (event_motion),
                    &selection
                  );

  gtk_container_add (GTK_CONTAINER (window), canvas);
  gtk_widget_show_all (window);
  gtk_main ();

  return 0;
}


/* function to draw the rectangular selection
 */
static void
paint_selection (cairo_t       *cr,
                 SelectionInfo *sel_info)
{
  if (!sel_info->active)
    return;

  cairo_save (cr);
    cairo_rectangle (cr, sel_info->x, sel_info->y,
                         sel_info->w, sel_info->h);

    cairo_set_source_rgba (cr, 0, 0, 1, 0.2);
    cairo_fill_preserve (cr);

    cairo_set_source_rgba (cr, 0, 0, 0, 0.5);
    cairo_stroke (cr);
  cairo_restore (cr);
}


static void
paint (GtkWidget      *widget,
       GdkEventExpose *eev,
       SelectionInfo  *sel_info)
{
  gint width, height;
  gint i;
  cairo_t *cr;

  width  = widget->allocation.width;
  height = widget->allocation.height;
  
  cr = gdk_cairo_create (widget->window);
  
    cairo_set_source_rgb (cr, 1,1,1);
    cairo_paint (cr);
    
    cairo_select_font_face (cr, "Sans", CAIRO_FONT_SLANT_NORMAL,
                                   CAIRO_FONT_WEIGHT_BOLD);
    cairo_save (cr);
      cairo_set_font_size (cr, 20);
      cairo_move_to (cr, 40, 60);
      cairo_set_source_rgb (cr, 0,0,0);
      cairo_show_text (cr, "Drag your mouse here");
    cairo_restore (cr);

    cairo_set_source_rgb (cr, 1,0,0);
    cairo_set_font_size (cr, 15);
    cairo_move_to (cr, 50, 100);
    cairo_show_text (cr, "(and see alpha blended selection)");

    cairo_set_source_rgb (cr, 0,0,1);

    cairo_move_to (cr, 0, 150);
    for (i=0; i< width/10; i++)
      {
        cairo_rel_line_to (cr, 5,  10);
        cairo_rel_line_to (cr, 5, -10);
      }

    cairo_stroke (cr);

  /* paint the selection */
  paint_selection (cr, sel_info);
    
  cairo_destroy (cr);
}


static gboolean
event_press (GtkWidget      *widget,
             GdkEventButton *bev,
             SelectionInfo  *sel_info)
{
  sel_info->active = TRUE;

  sel_info->x = bev->x;
  sel_info->y = bev->y;
  sel_info->w = 0;
  sel_info->h = 0;

  /* tell the canvas widget that it needs to redraw itself */
  gtk_widget_queue_draw (widget);

  return TRUE;
}


static gboolean
event_motion (GtkWidget      *widget,
              GdkEventMotion *mev,
              SelectionInfo  *sel_info)
{
  sel_info->w = mev->x - sel_info->x;
  sel_info->h = mev->y - sel_info->y;

  /* tell the canvas widget that it needs to redraw itself */
  gtk_widget_queue_draw (widget);
  return TRUE;
}

static gboolean
event_release (GtkWidget      *widget,
               GdkEventButton *bev,
               SelectionInfo  *sel_info)
{
  sel_info->active = FALSE;

  /* tell the canvas widget that it needs to redraw itself */
  gtk_widget_queue_draw (widget);
  return TRUE;
}
@


1.1
log
@added mouse event example
@
text
@d1 1
a1 1
/*  alpha blended rubber band using gtkcairo, demonstrating mouse intercation
d7 1
a7 1
#include <gtkcairo.h>
d22 3
a24 3
static void paint (GtkWidget     *widget,
                   cairo_t       *cr,
                   SelectionInfo *sel_info);
d45 1
a45 1
  GtkWidget     *gtkcairo;
d54 2
a55 2
  gtkcairo = gtk_cairo_new ();
  gtk_widget_set_size_request (gtkcairo, DEFAULT_WIDTH, DEFAULT_HEIGHT);
d57 1
a57 1
  /* connect our drawing method to the "paint" signal
d60 1
a60 1
  g_signal_connect (G_OBJECT (gtkcairo), "paint",
d65 1
a65 1
  /* add additional events the gtkcairo widget will listen for
d67 1
a67 1
  gtk_widget_add_events (gtkcairo,
d76 1
a76 1
  g_signal_connect (G_OBJECT (gtkcairo), "button_press_event",
d80 1
a80 1
  g_signal_connect (G_OBJECT (gtkcairo), "button_release_event",
d84 1
a84 1
  g_signal_connect (G_OBJECT (gtkcairo), "motion_notify_event",
d89 1
a89 1
  gtk_container_add (GTK_CONTAINER (window), gtkcairo);
d105 1
a108 5
    cairo_save (cr);
      cairo_set_rgb_color (cr, 0, 0, 1);
      cairo_set_alpha (cr, 0.2);
      cairo_fill (cr);
    cairo_restore (cr);
d110 4
a113 2
    cairo_set_rgb_color (cr, 0, 0, 0);
    cairo_set_alpha (cr, 0.5);
d120 3
a122 3
paint (GtkWidget     *widget,
       cairo_t       *cr,
       SelectionInfo *sel_info)
d126 1
d131 1
a131 1
  cairo_save (cr);
d133 2
a134 3
    cairo_rectangle (cr, 0, 0, width, height);
    cairo_set_rgb_color (cr, 1,1,1);
    cairo_fill (cr);
d136 1
a136 1
    cairo_select_font (cr, "Sans", CAIRO_FONT_SLANT_NORMAL,
d139 1
a139 1
      cairo_scale_font (cr, 20);
d141 1
a141 1
      cairo_set_rgb_color (cr, 0,0,0);
d145 2
a146 2
    cairo_set_rgb_color (cr, 1,0,0);
    cairo_scale_font (cr, 15);
d150 1
a150 1
    cairo_set_rgb_color (cr, 0,0,1);
d164 1
a164 1
  cairo_restore (cr);
d180 1
a180 1
  /* tell the gtkcairo widget that it needs to redraw itself */
d195 1
a195 1
  /* tell the gtkcairo widget that it needs to redraw itself */
d207 1
a207 1
  /* tell the gtkcairo widget that it needs to redraw itself */
@