GTK/DFB中的WaitCursor

GTK/DFB中的WaitCursor

转载时请注明出处和作者联系方式
作者联系方式：李先静 <xianjimli at hotmail dot com>

虽然我们实现了单实例应用程序，即在应用程序第二次运行时自动激活第一个实例，并将参数传递给第一个运行实例。但如果在桌面连续点击应用程序的起动图标，会让应用程序起动过过程变得更慢，为了避免这种情况出现，有必要实现类似WaitCursor机制。GTK+-2.6/DFB中没有实现WaitCursor，新版本中好像也没有，只好自己动手了：

• 在gdkwindow.h文件中增加两个函数：

gint gdk_window_begin_wait_cursor(GdkWindow *window); gint gdk_window_end_wait_cursor(GdkWindow *window);

• 在_GdkWindowObject结构中增加waitcursor的信息。

struct { gint ref; gint elapsed; gint timeout_id; }wait_cursor;

• 在gdkwindow-directfb.c中实现这两个函数，很简单，就是实现一个定时器，每隔一段时间更新一下Cursor。

gint gdk_window_begin_wait_cursor(GdkWindow *window) { GdkWindowObject *private = GDK_WINDOW_OBJECT (window); g_return_val_if_fail(private != NULL, 0); private->wait_cursor.ref++; if(private->wait_cursor.ref == 1 && update_wait_cursor(window)) { private->wait_cursor.elapsed = 0; private->wait_cursor.timeout_id = g_timeout_add(250, update_wait_cursor, window); #ifndef LINUX_I386 gdk_directfb_display->layer->EnableCursor(gdk_directfb_display->layer, 1); #endif } return private->wait_cursor.ref; } gint gdk_window_end_wait_cursor(GdkWindow *window) { GdkWindowObject *private = GDK_WINDOW_OBJECT (window); if(private == NULL || private->wait_cursor.ref <=0) { return 0; } private->wait_cursor.ref--; #ifndef LINUX_I386 gdk_directfb_display->layer->EnableCursor(gdk_directfb_display->layer, private->wait_cursor.ref != 0); #endif return private->wait_cursor.ref; } static gboolean update_wait_cursor(gpointer user_data) { GdkWindow *window = user_data; GdkWindowObject *private = GDK_WINDOW_OBJECT (window); g_return_val_if_fail(private != NULL, FALSE); int cursor_type = GDK_WAIT_BEGIN + (private->wait_cursor.elapsed)%(GDK_WAIT_END - GDK_WAIT_BEGIN + 1); GdkCursor* cursor = gdk_cursor_new_for_display (gdk_display_get_default(), cursor_type); gdk_window_set_cursor(window, cursor); gdk_cursor_unref(cursor); private->wait_cursor.elapsed++; if(private->wait_cursor.ref <= 0) { private->wait_cursor.elapsed = 0; private->wait_cursor.timeout_id = 0; gdk_window_set_cursor(window, NULL); } return private->wait_cursor.ref > 0; }
在gdkcursor-directfb.c中加载Cursor图片，Cursor图片与主题关联：
static GdkCursor * gdk_cursor_load_wait_cursor(GdkDisplay *display, GdkCursorType cursor_type) { GdkCursor* cursor = NULL; if(cursor_type >= GDK_WAIT_BEGIN && cursor_type <= GDK_WAIT_END) { int index = 0; GValue value = {0}; char* theme = NULL; char filename[260] = {0}; GObject* setting = g_object_get_data (G_OBJECT (gdk_screen_get_default()), "gtk-settings"); g_return_val_if_fail(setting != NULL, NULL); g_value_init(&value, G_TYPE_STRING); g_object_get_property (setting, "gtk-icon-theme-name", &value); theme = g_value_get_string(&value); index = cursor_type-GDK_WAIT_BEGIN + 1; snprintf(filename, sizeof(filename), WAITCURSOR, theme, index); if((cursor = gdk_cursor_new_from_name(display, filename)) == NULL) { snprintf(filename, sizeof(filename), WAITCURSOR, "hicolor", index); cursor = gdk_cursor_new_from_name(display, filename); g_debug("load %p %s", cursor, filename); } g_value_reset(&value); } return cursor; }

• 要注意的是gdk_cursor_new_from_pixbuf有点问题，pixbuf中的格式居然是GBRA而不是代码中要求的ARGB，要修改一下这个函数，否则无法实现透明效果。

• 为了避免enable/disable时闪现一下传统的cursor，修改gdk_cursor_new_for_display,让alpha=0，让传统cursor全透明。

• 出现WaitCursor时，丢弃按键和笔点事件，修改gdk_event_translate：

if(private->wait_cursor.ref > 0) { switch (dfbevent->type) { case DWET_BUTTONDOWN: case DWET_BUTTONUP: case DWET_MOTION: case DWET_KEYDOWN: case DWET_KEYUP: return NULL; default:break; } }
在手机上和PC上有点不问，手机上平时不能显示cursor，而且waitcursor的位置要居中，所以还要修改DirectFB:

• 在dfb_layer_context_create_window中禁止cursor，把以前的dfb_windowstack_cursor_enable(core, stack, true )改为dfb_windowstack_cursor_enable( core, stack, false )
  

• 在wm_update_cursor里让位置居中：

#ifndef LINUX_I386 if(context->stack->cursor.enabled && (flags & CCUF_POSITION)) { stack->cursor.hot.x = stack->cursor.x - (context->width/2 - stack->cursor.size.w); stack->cursor.hot.y = stack->cursor.y - (context->height/2 - stack->cursor.size.h); } #endif
测试了一下，基本功能正常。

～～end～～