/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#+
#+     Glade / Gtk Programming
#+
#+     Copyright (C) 2019 by Kevin C. O'Kane
#+
#+     Kevin C. O'Kane
#+     kc.okane@gmail.com
#+     https://www.cs.uni.edu/~okane
#+     http://threadsafebooks.com/
#+
#+ This program is free software; you can redistribute it and/or modify
#+ it under the terms of the GNU General Public License as published by
#+ the Free Software Foundation; either version 2 of the License, or
#+ (at your option) any later version.
#+
#+ This program is distributed in the hope that it will be useful,
#+ but WITHOUT ANY WARRANTY; without even the implied warranty of
#+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#+ GNU General Public License for more details.
#+
#+ You should have received a copy of the GNU General Public License
#+ along with this program; if not, write to the Free Software
#+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#+
#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

#define _GNU_SOURCE

#include <stdlib.h>
#include <sys/types.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
#include <gtk/gtk.h>
#include <gtk/gtkx.h>
#include <math.h>
#include <time.h>
#include <ctype.h>
#include <time.h>
#include <sys/mman.h>

GtkWidget		*window;
GtkWidget		*fixed1;
GtkWidget		*draw1;
GtkWidget		*clear;
GtkWidget		*Red;
GtkWidget		*Green;
GtkWidget		*Blue;
GtkWidget		*White;
GtkBuilder		*builder; 

static void draw_brush (GtkWidget *widget, gdouble    x, gdouble    y);

struct Point {
	int x;
	int y;
	double red, green, blue;
	struct Point *next;
	} *p1, *p2, *start;

double red, green, blue;

void		on_destroy(); 

int main(int argc, char *argv[]) {

	p1 = p2 = start = NULL;

	red = green = blue = 0.0;

	gtk_init(&argc, &argv); // init Gtk

	builder = gtk_builder_new_from_file ("part1.glade");
 
	window = GTK_WIDGET(gtk_builder_get_object(builder, "window"));

	g_signal_connect(window, "destroy", G_CALLBACK(on_destroy), NULL);

        gtk_builder_connect_signals(builder, NULL);

	fixed1		= GTK_WIDGET(gtk_builder_get_object(builder, "fixed1"));
	draw1		= GTK_WIDGET(gtk_builder_get_object(builder, "draw1"));
	clear		= GTK_WIDGET(gtk_builder_get_object(builder, "clear"));
	Red		= GTK_WIDGET(gtk_builder_get_object(builder, "Red"));
	Green		= GTK_WIDGET(gtk_builder_get_object(builder, "Green"));
	Blue		= GTK_WIDGET(gtk_builder_get_object(builder, "Blue"));
	White		= GTK_WIDGET(gtk_builder_get_object(builder, "White"));

	g_object_unref(builder);

	gtk_widget_set_events(draw1, GDK_BUTTON_MOTION_MASK | GDK_BUTTON_PRESS_MASK);

	gtk_window_set_keep_above (GTK_WINDOW(window), TRUE);

	gtk_widget_show(window);

	gtk_main();

	return EXIT_SUCCESS;
	}

void	on_destroy() {
		gtk_main_quit();
		}

gboolean on_draw1_draw (GtkWidget *widget, cairo_t *cr, gpointer data) {

	guint width, height;

	width = gtk_widget_get_allocated_width (widget);
	height = gtk_widget_get_allocated_height (widget);

	cairo_set_line_width(cr, 1.0);
			
	if (start == NULL) return FALSE;

	int old_x = start->x;
	int old_y = start->y;

	p1 = start->next;

	while ( p1 != NULL ) {
		cairo_set_source_rgb(cr, p1->red, p1->green, p1->blue);

		cairo_move_to (cr, (double) old_x, (double) old_y);
		cairo_line_to (cr, (double) p1->x, (double) p1->y);
		cairo_stroke (cr);

		old_x = p1->x;
		old_y =  p1->y;
		p1 = p1 ->next;
		}

	return FALSE;
	}

gboolean on_draw1_button_press_event (GtkWidget *widget, GdkEventButton *event) {
	draw_brush (widget, event->x, event->y);
	return TRUE;
	}

void	on_clear_clicked(GtkWidget *b1) {
	p1 = start;
	while (p1) { p2 = p1 -> next; free(p1); p1 = p2; }
	start = NULL;
	gtk_widget_queue_draw (draw1);
	}

gboolean on_draw1_motion_notify_event (GtkWidget *widget, GdkEventMotion *event, gpointer data) {
	if (event->state & GDK_BUTTON1_MASK ) draw_brush (widget, event->x, event->y);
	return TRUE;
	}

static void draw_brush (GtkWidget *widget, gdouble x, gdouble y) {
	p1 = malloc (sizeof(struct Point));
	if (p1 == NULL) { printf("out of memory\n"); abort(); }
	p1->x = x;
	p1->y = y;
	p1->red = red;
	p1->green = green;
	p1->blue = blue;
	p1->next = start;
	start = p1;
	gtk_widget_queue_draw (draw1);
	}

void	on_Red_clicked(GtkWidget *b1) { red = 1.0;  green = 0.0; blue = 0.0; }

void	on_Green_clicked(GtkWidget *b1) { red = 0.0;  green = 1.0; blue = 0.0; }

void	on_Blue_clicked(GtkWidget *b1) { red = 0.0;  green = 0.0; blue = 1.0; }

void	on_White_clicked(GtkWidget *b1) { red = 1.0;  green = 1.0; blue = 1.0; }