Rendering a GtkPixbuf in a GtkDrawingArea with C - c

Question

So I am using C and I am trying to render a GtkPixbuf in a GtkDrawingArea. I have a GtkThread that should be in charge of forcing the draw every N seconds. I don't get any errors or warnings, but, my code still doesn't produce the intended results. Hence, I believe that I am missing something fundamental about how all this works.
My code is below:
#include <gtk.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define WIDTH 512
#define HEIGHT 512
#define CHANNELS 3
#define STEP (8*CHANNELS)
typedef struct pixbuf_data_s{
unsigned char* data;
GdkPixbuf *pixbuf;
GtkWidget *drawing;
} pixbuf_data_t;
GdkPixbuf* create_and_set_pixbuf(unsigned char* data){
GdkPixbuf *pixbuf;
pixbuf = gdk_pixbuf_new_from_data(data, GDK_COLORSPACE_RGB, FALSE, 8, WIDTH, HEIGHT, STEP/8, NULL, NULL);
return pixbuf;
}
void create_image_data(unsigned char* data){
int i,j,k;
unsigned char blue, red, green;
//===Create A Random RGB Combo===//
blue = (unsigned char)((rand()) % 255);
green = (unsigned char)((rand()) % 255);
red = (unsigned char)((rand()) % 255);
for(i=0;i<HEIGHT;i++){
for(j=0;j<WIDTH;j++){
for(k=0;k<CHANNELS;k++){
if (k == 0) data[i*STEP+j*CHANNELS+k] = red;
if (k == 1) data[i*STEP+j*CHANNELS+k] = green;
if (k == 2) data[i*STEP+j*CHANNELS+k] = blue;
}
}
}
return;
}
pixbuf_data_t* create_pixbuf_data(){
pixbuf_data_t* pixbuf_data = malloc(sizeof(pixbuf_data_t));
//===Create PixBuf Data===//
pixbuf_data->data = malloc( (WIDTH*HEIGHT*CHANNELS*STEP) * sizeof(unsigned char));
create_image_data(pixbuf_data->data);
pixbuf_data->pixbuf = gdk_pixbuf_new_from_data(pixbuf_data->data, GDK_COLORSPACE_RGB, FALSE, 8, WIDTH, HEIGHT, STEP/8, NULL, NULL);
return pixbuf_data;
}
void draw_callback(GtkWidget *widget, cairo_t *cr, gpointer ptr){
pixbuf_data_t *pixbuf;
pixbuf = (pixbuf_data_t*) ptr;
//===Redo Image===//
create_image_data(pixbuf->data);
//===Set Source===//
gdk_cairo_set_source_pixbuf(cr, pixbuf->pixbuf, 0, 0);
//===Fill===//
cairo_fill(cr);
return;
}
void *display_image_thread(gpointer in_data){
pixbuf_data_t* pixbuf;
pixbuf = g_object_get_data(G_OBJECT(in_data), "pixbuf");
while(1){
sleep(5);
gtk_widget_queue_draw(GTK_WIDGET(pixbuf->drawing));
}
return;
}
int main(int argc, char* argv[]){
GtkBuilder *builder;
GtkWidget *window;
GtkButton *button;
GtkImage *image;
GtkWidget *drawing_area;
GError *error = NULL;
GObject *object;
GThread *thread;
GdkPixbuf *pix_buf;
pixbuf_data_t* pixbuf_data;
//===Init Random Number Generator===//
srand(time(NULL));
//===Init GTK+===//
gtk_init(NULL, NULL);
//===Secure Glib and Gtk===/
if(!g_thread_supported()){
g_thread_init(NULL);
}
gdk_threads_init();
//===Obtain gtk's global lock===//
gdk_threads_enter();
//===Create new GtkBuilder object===//
builder = gtk_builder_new();
if(!gtk_builder_add_from_file( builder, "draw_glade.glade", &error )){
g_free(error);
exit(1);
}
//===Get main window pointer from UI===//
window = GTK_WIDGET( gtk_builder_get_object( builder, "main_window" ) );
g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
//===Get Buttons===//
button = GTK_BUTTON( gtk_builder_get_object(builder, "stop_button"));
gtk_button_set_label(button, "STOP");
button = GTK_BUTTON( gtk_builder_get_object(builder, "play_button"));
gtk_button_set_label(button, "PLAY");
button = GTK_BUTTON( gtk_builder_get_object(builder, "pause_button"));
gtk_button_set_label(button, "PAUSE");
button = GTK_BUTTON( gtk_builder_get_object(builder, "next_button"));
gtk_button_set_label(button, "NEXT");
//===Create Drawing Area and Callback===//
drawing_area = GTK_WIDGET(gtk_builder_get_object(builder, "main_drawing_area"));
pixbuf_data = create_pixbuf_data();
pixbuf_data->drawing = drawing_area;
g_signal_connect(pixbuf_data->drawing, "draw", G_CALLBACK(draw_callback), pixbuf_data);
//===Create new thread===//
object = g_object_new(G_TYPE_OBJECT, NULL);
g_object_set_data(G_OBJECT(object), "pixbuf", (gpointer) pixbuf_data);
thread = g_thread_new(NULL, display_image_thread, (gpointer)object);
if(!thread){
printf("Bad Thread!\n");
exit(1);
}
//===Connect signals===//
gtk_builder_connect_signals(builder, NULL);
//==Show window===//
gtk_widget_show(window);
//===Gtk Main Callback===//
gtk_main();
//===Release gtk's global lock===//
gdk_threads_leave();
//===Destroy builder===//
g_object_unref(G_OBJECT(builder));
return 0;
}
The glade file is:
<?xml version="1.0" encoding="UTF-8"?>
<interface>
<!-- interface-requires gtk+ 3.0 -->
<object class="GtkWindow" id="main_window">
<property name="can_focus">False</property>
<property name="default_width">800</property>
<property name="default_height">600</property>
<child>
<object class="GtkBox" id="right_vbox">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="orientation">vertical</property>
<child>
<object class="GtkDrawingArea" id="main_drawing_area">
<property name="width_request">512</property>
<property name="height_request">512</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
</object>
<packing>
<property name="expand">True</property>
<property name="fill">True</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkBox" id="play_button_box">
<property name="visible">True</property>
<property name="can_focus">False</property>
<child>
<object class="GtkButton" id="stop_button">
<property name="label" translatable="yes">button</property>
<property name="use_action_appearance">False</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<property name="use_action_appearance">False</property>
</object>
<packing>
<property name="expand">True</property>
<property name="fill">True</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkButton" id="play_button">
<property name="label" translatable="yes">button</property>
<property name="use_action_appearance">False</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<property name="use_action_appearance">False</property>
</object>
<packing>
<property name="expand">True</property>
<property name="fill">True</property>
<property name="position">1</property>
</packing>
</child>
<child>
<object class="GtkButton" id="pause_button">
<property name="label" translatable="yes">button</property>
<property name="use_action_appearance">False</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<property name="use_action_appearance">False</property>
</object>
<packing>
<property name="expand">True</property>
<property name="fill">True</property>
<property name="position">2</property>
</packing>
</child>
<child>
<object class="GtkButton" id="next_button">
<property name="label" translatable="yes">button</property>
<property name="use_action_appearance">False</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<property name="use_action_appearance">False</property>
</object>
<packing>
<property name="expand">True</property>
<property name="fill">True</property>
<property name="position">3</property>
</packing>
</child>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">1</property>
</packing>
</child>
</object>
</child>
</object>
</interface>
So what am I missing?
Sources I've used:
C/GTK+3 draw event for multiple widgets
https://developer.gnome.org/gtk3/stable/GtkDrawingArea.html
https://developer.gnome.org/gdk3/stable/gdk3-Cairo-Interaction.html#gdk-cairo-set-source-pixbuf
https://developer.gnome.org/gtk3/stable/GtkWidget.html#gtk-widget-queue-draw
https://developer.gnome.org/gtk3/stable/GtkWidget.html#GtkWidget-draw