求助：如何解决子widget刷新覆盖父widget中内容？

allon_ren · 发表于 2014-11-24 10:44:42

我想实现拖动GtkPaned控件中的手柄不进行实时更新，而是有一条虚线表明拖动位置，鼠标弹起时再更新的效果，现在大部分问题都解决了，但是在paned中加入滚动窗口控件显示图片时，图片区域绘制的虚线被刷掉了，应该是子widget刷新时覆盖了父widget的内容，不知道怎么解决！
以下是代码：

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

gboolean bleftdown = FALSE;

gint oldx = 0;
gint oldy = 0;

void Sort(gint *a, gint *b)
{
int c = 0;
if(*a > *b)
{
      c  = *a;
      *a = *b;
      *b = c;
}

return;
}

void RrawRect(GtkWidget* widget,unsigned long R,unsigned long G,
            unsigned long B,gint x1, gint y1, gint x2, gint y2)
{
GdkColor color;
GdkGCValues vals;
GdkGC *gc = NULL;
GdkColormap *cmap = NULL;

static gint8 dash_list[] = {1,1};

Sort(&x1, &x2);
Sort(&y1, &y2);

cmap = gdk_colormap_get_system();
gc = gdk_gc_new(widget->window);

color.red = R;// 0x00;
color.green = G;// 0xFFFF;
color.blue  = B;//0x0;

vals.foreground = color;
vals.line_style = GDK_LINE_ON_OFF_DASH;
gdk_gc_set_values(gc, &vals, GDK_GC_FOREGROUND|GDK_GC_LINE_STYLE);
gdk_gc_set_dashes(gc, 0, dash_list, sizeof(dash_list));

if (gdk_color_alloc(cmap, &color) == 0)
{
      g_error("can't allocate color/n");
}
gdk_gc_set_rgb_fg_color(gc, &color);
gdk_draw_rectangle(widget->window,gc,FALSE,x1, y1, x2-x1, y2-y1);

gdk_gc_destroy(gc);

return;
}

void  Redraw(GtkWidget *widget, gint x1, gint y1, gint x2, gint y2)
{
GdkRectangle rect;

Sort(&x1, &x2);
Sort(&y1, &y2);

rect.x = x1;
rect.y = y1;
rect.width = x2- x1+1;
rect.height =y2 -y1+1;

gtk_widget_draw(widget, &rect);

return;
}

gboolean  button_release(GtkWidget *widget, GdkEventButton *event,gpointer user_data)
{
if(event->button == 1 ) // left button
{
      if (bleftdown && event->type == GDK_BUTTON_RELEASE)
      {
         bleftdown =  FALSE;
         RrawRect(widget, 0x400F, 0x400F, 0x400F,
                  oldx , widget->allocation.y,
                  oldx+4 , widget->allocation.y + widget->allocation.height-1);

         int x = 0, y = 0;
         gtk_widget_get_pointer(widget, &x, &y);
         gtk_paned_set_position(GTK_PANED(widget),x);
   }
}

return FALSE;
}

gboolean  button_press(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
if(event->button == 1 ) // left button
{
      if (event->type == GDK_BUTTON_PRESS)
      {
         int x = 0, y = 0;
         gtk_widget_get_pointer(widget, &x, &y);

         RrawRect(widget,  0x400F, 0x400F, 0x400F,
                  x , widget->allocation.y,
                  x+4 , widget->allocation.y + widget->allocation.height-1);
         Redraw(widget,
               oldx, widget->allocation.y,
               oldx+4, widget->allocation.y + widget->allocation.height-1);

         bleftdown =  TRUE;
         oldx = x;
         oldy = y;
      }
}

return TRUE;
}

gboolean  motion_notify(GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
{

if (bleftdown)
{
      printf("dragging\n");
      int x = 0, y = 0;
      gtk_widget_get_pointer(widget, &x, &y);

      Redraw(widget,oldx, widget->allocation.y, oldx+4,
            widget->allocation.y + widget->allocation.height-1);
      RrawRect(widget,  0x400F, 0x400F, 0x400F,
            x, widget->allocation.y,
            x+4 , widget->allocation.y + widget->allocation.height-1);

      oldx = x ;
      oldy = event->y;
}

return TRUE;
}

gboolean expose_event(GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
{
if (bleftdown)
{
      int x = 0, y = 0;
      gtk_widget_get_pointer(widget, &x, &y);

      Redraw(widget,oldx, widget->allocation.y, oldx+4,
            widget->allocation.y + widget->allocation.height-1);
      RrawRect(widget,  0x400F, 0x400F, 0x400F,
            x, widget->allocation.y,
            x+4 , widget->allocation.y + widget->allocation.height-1);

      oldx = x ;
}

return FALSE;

}

gint close_application( GtkWidget *widget,
                     GdkEvent  *event,
                     gpointer data )
{
gtk_main_quit();
return(FALSE);
}

int main (int argc, char *argv[])
{
GtkWidget *win = NULL;
GtkWidget *label = NULL;
GtkWidget *image = NULL;
GdkPixbuf *pixbuf = NULL;
GtkWidget *paned = NULL;
GtkWidget *scrollw = NULL;
GtkWidget *fixed = NULL;
GtkWidget *eventbox = NULL;

/* Initialize GTK+ */
gtk_init (&argc, &argv);

/* Create the main window */
win = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_container_set_border_width (GTK_CONTAINER (win), 8);
gtk_widget_set_usize(win, 500, 400);
gtk_window_set_title (GTK_WINDOW (win), "Drawing Rectangle on Image");
gtk_window_set_position (GTK_WINDOW (win), GTK_WIN_POS_CENTER);
gtk_widget_realize (win);

pixbuf = gdk_pixbuf_new_from_file ("/home/allon/pics/cairo.jpg", NULL);
image = gtk_image_new_from_pixbuf (pixbuf);

eventbox = gtk_event_box_new();
gtk_container_add(GTK_CONTAINER(eventbox), image);

fixed = gtk_fixed_new();
scrollw = gtk_scrolled_window_new(NULL, NULL);
gtk_scrolled_window_add_with_viewport(GTK_SCROLLED_WINDOW(scrollw), eventbox);
gtk_widget_add_events(scrollw, GDK_EXPOSURE_MASK);

label = gtk_label_new("add to paned");

gtk_rc_parse_string("style 'my_style' {\n"
                     "GtkPaned::handle-size = 6\n"
                     " }\n"
                     "widget '*' style 'my_style'");
paned = gtk_hpaned_new();
gtk_paned_add1(GTK_PANED(paned), label);
gtk_paned_add2(GTK_PANED(paned), scrollw);

g_signal_connect (G_OBJECT (win), "delete_event",
                  G_CALLBACK (close_application), NULL);

gtk_widget_add_events(paned,
                        GDK_POINTER_MOTION_MASK
                     | GDK_BUTTON_PRESS_MASK
                     | GDK_BUTTON_RELEASE_MASK
                     | GDK_POINTER_MOTION_HINT_MASK);

g_signal_connect (eventbox , "motion-notify-event", G_CALLBACK(expose_event), NULL);
g_signal_connect (paned , "button-press-event", G_CALLBACK(button_press), NULL);
g_signal_connect (paned , "button-release-event", G_CALLBACK(button_release), NULL);
g_signal_connect (paned , "motion-notify-event", G_CALLBACK(motion_notify), NULL);

gtk_container_add (GTK_CONTAINER (win), paned );
gtk_widget_show_all(win);
gtk_main ();

return 0;
}

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