基于gtk的imshow:用gtk读取并显示图像

gtk实现imshow，最naive的做法是用gtk的组件去读取图像，然后show出来；后续再考虑用GTK显示用别的方式例如stb image读取的图像。先前基于GDI实现imshow时也是这一思路，先能show出来给自己一点信心。

官方代码

gtk官方文档提供了这个例子，并且show出来的图像和原图大小一致。

#include <gtk/gtk.h>

static void activate (GtkApplication *app, gpointer user_data)
{
    GtkWidget *window;
    GtkWidget *image;

    /*Create a window with a title and a default size*/
    window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), "Welcome to GNOME");
    //gtk_window_set_default_size (GTK_WINDOW (window), 300, 300);

    const char* im_pth = "/home/zz/work/libfc/imgs/Lena.png";
    image = gtk_image_new_from_file (im_pth);

    gtk_container_add (GTK_CONTAINER (window), GTK_WIDGET (image));

    gtk_widget_show_all (GTK_WIDGET (window));
}

int main (int argc, char **argv)
{
    GtkApplication *app;
    int status;

    app = gtk_application_new ("org.gtk.example",G_APPLICATION_FLAGS_NONE);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
    status = g_application_run (G_APPLICATION (app), argc, argv);
    g_object_unref (app);
    return status;
}

效果：

简单封装

从imshow的用户来讲，ta只需要传入图片路径、图片标题，就应该得到显示结果。因此可以把上述代码进行封装。使用了全局变量my_window，这是因为回调函数无法传入额外的参数，并且后续要给窗口绑定更多的参数。

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

typedef struct MyWindow {
    const char* im_pth;
    const char* title;
} MyWindow;

MyWindow my_window;

static void activate (GtkApplication *app, gpointer user_data)
{
    GtkWidget *window;
    GtkWidget *image;

    /*Create a window with a title and a default size*/
    window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), my_window.title);
    //gtk_window_set_default_size (GTK_WINDOW (window), 300, 300);

    image = gtk_image_new_from_file (my_window.im_pth);

    gtk_container_add (GTK_CONTAINER (window), GTK_WIDGET (image));

    gtk_widget_show_all (GTK_WIDGET (window));
}

void show_image_gtk_temp()
{
    GtkApplication *app;
    int status;

    app = gtk_application_new ("org.gtk.example",G_APPLICATION_FLAGS_NONE);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
    status = g_application_run (G_APPLICATION (app), 0, NULL);
    g_object_unref (app);
}

void gtk_show_image_v1(const char* im_pth, const char* title) {

    my_window.im_pth = im_pth;
    my_window.title = title;

    show_image_gtk_temp();
}

int main() {
    const char* im_pth = "/home/zz/work/libfc/imgs/fruits.jpg";
    const char* title = "fruit";
    gtk_show_image_v1(im_pth, title);

    return 0;
}

参考

https://developer.gnome.org/gnome-devel-demos/stable/image.c.html.en

Platform Demos in C