问题描述
这是我以前的,我试图将鼠标悬停在GtkDrawingArea上时将鼠标光标设置为十字线.我正在尝试将 ebassi 的答案应用于以下代码来自zetcode.到目前为止,我已经得到:
This follows from my previous question, I am trying to set the mouse cursor to cross hair when hovering over a GtkDrawingArea. I am trying to apply the answer from ebassi to the following code from zetcode. So far I have got:
#include <cairo.h>
#include <gtk/gtk.h>
static void do_drawing(cairo_t *);
struct {
int count;
double coordx[100];
double coordy[100];
} glob;
static gboolean on_draw_event(GtkWidget *widget, cairo_t *cr,
gpointer user_data)
{
do_drawing(cr);
return FALSE;
}
static void do_drawing(cairo_t *cr)
{
cairo_set_source_rgb(cr, 0, 0, 0);
cairo_set_line_width(cr, 0.5);
int i, j;
for (i = 0; i <= glob.count - 1; i++ ) {
for (j = 0; j <= glob.count - 1; j++ ) {
cairo_move_to(cr, glob.coordx[i], glob.coordy[i]);
cairo_line_to(cr, glob.coordx[j], glob.coordy[j]);
}
}
glob.count = 0;
cairo_stroke(cr);
}
static gboolean
on_crossing (GtkWidget *darea, GdkEventCrossing *event)
{
switch (gdk_event_get_event_type (event))
{
case GDK_ENTER_NOTIFY:
printf("Yey!");
break;
case GDK_LEAVE_NOTIFY:
printf("Whooo!");
break;
}
}
static gboolean clicked(GtkWidget *widget, GdkEventButton *event,
gpointer user_data)
{
if (event->button == 1) {
glob.coordx[glob.count] = event->x;
glob.coordy[glob.count++] = event->y;
}
if (event->button == 3) {
gtk_widget_queue_draw(widget);
}
return TRUE;
}
int main(int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *darea;
glob.count = 0;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
darea = gtk_drawing_area_new();
gtk_container_add(GTK_CONTAINER(window), darea);
gtk_widget_set_has_window (GTK_WIDGET (darea), TRUE);
int crossing_mask = GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK;
gtk_widget_add_events (GTK_WIDGET (darea), crossing_mask);
gtk_widget_add_events(window, GDK_BUTTON_PRESS_MASK);
g_signal_connect (darea, "enter-notify-event", G_CALLBACK (on_crossing), NULL);
g_signal_connect (darea, "leave-notify-event", G_CALLBACK (on_crossing), NULL);
g_signal_connect(G_OBJECT(darea), "draw",
G_CALLBACK(on_draw_event), NULL);
g_signal_connect(window, "destroy",
G_CALLBACK(gtk_main_quit), NULL);
g_signal_connect(window, "button-press-event",
G_CALLBACK(clicked), NULL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 400, 300);
gtk_window_set_title(GTK_WINDOW(window), "Lines");
gtk_widget_show_all(window);
gtk_main();
return 0;
}
但是,它没有编译,gcc 5.3.0会告诉错误:
However, it is not compiling, gcc 5.3.0 tells the error:
undefined reference to `gdk_event_get_event_type'
我在做什么错了?
我正在使用MinGW在Win10机器上工作.我尚未尝试在GNU/Linux系统中进行编译.
I am working on a Win10 machine, using MinGW. I have not tried yet to compile this in a GNU/Linux system.
推荐答案
未定义的引用"表示您使用的GTK +版本没有 gdk_event_get_event_type()
.该功能是在GTK + 3.10中引入的,如文档所指定; 3.10.0已在 2013年9月中发布,因此表示您的版本比该版本至少早4年,并且不受支持.
"Undefined reference" means that you're using a version of GTK+ that does not have gdk_event_get_event_type()
. That function was introduced in GTK+ 3.10, as the documentation specifies; 3.10.0 was released in September 2013, so it means you have a version that is at least 4 years older than that, and very much unsupported.
在我撰写此答案时,最新版本的GTK +为 3.22.12 ,于2017年4月发布.
The latest version of GTK+ is, at the time I'm writing this answer, 3.22.12, released in April 2017.
请按照 GTK +网站上的说明有关如何在以下位置安装GTK + Windows.
Please, follow the instructions on the GTK+ website on how to install GTK+ on Windows.
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