Welcome to Fractal Forums

#include <gtk/gtk.h>
#include <math.h>
#include <jpeglib.h>
#include <setjmp.h>
#include <stdio.h>

#define IMAGE_WIDTH	800
#define IMAGE_HEIGHT 800

guchar *rgbbuf;

gboolean on_darea_expose(GtkWidget *widget, GdkEventExpose *event, gpointer user_data);

struct sFractal
{
	double amin;
	double amax;
	double bmin;
	double bmax;
	int N;
	double da;
	double db;
};

struct sParam
{
	int start;
	int index;
	sFractal fractal;
};

int CalculateIterations(double &a, double &b, int &N)
{
	double x = a;
	double y = b;

	int i;

	for (i = 0; i < N; i++)
	{
		double tempx = x * x - y * y + a;
		y = 2.0 * x * y + b;
		x = tempx;
		double r = x * x + y * y;
		if (r > 4) break;
	}

	return i;
}

//function for saving JPG file using jpeglib
void SaveJPEG(char *filename, int quality, int width, int height, JSAMPLE *image)
{
	struct jpeg_compress_struct cinfo;
	struct jpeg_error_mgr jerr;
	FILE * outfile;
	JSAMPROW row_pointer[1];
	int row_stride;

	cinfo.err = jpeg_std_error(&jerr);
	jpeg_create_compress(&cinfo);

	if ((outfile = fopen(filename, "wb")) == NULL)
	{
		fprintf(stderr, "can't open %s\n", filename);
		return;
	}
	jpeg_stdio_dest(&cinfo, outfile);

	cinfo.image_width = width;
	cinfo.image_height = height;
	cinfo.input_components = 3; /* # of color components per pixel */
	cinfo.in_color_space = JCS_RGB; /* colorspace of input image */

	jpeg_set_defaults(&cinfo);
	jpeg_set_quality(&cinfo, quality, TRUE);

	jpeg_start_compress(&cinfo, TRUE);

	row_stride = width * 3; /* JSAMPLEs per row in image_buffer */

	while (cinfo.next_scanline < cinfo.image_height)
	{
		row_pointer[0] = &image[cinfo.next_scanline * row_stride];
		(void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
	}

	jpeg_finish_compress(&cinfo);
	fclose(outfile);
	jpeg_destroy_compress(&cinfo);
}

//********************************** MAIN ******************************* 
int main(int argc, char *argv[])
{
	//gtk widgets
	GtkWidget *window, *darea, *box;

	//allocation memory for graphics
	rgbbuf = new guchar[IMAGE_WIDTH * IMAGE_HEIGHT * 3];

	//main window
	gtk_init(&argc, &argv);
	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);
	g_signal_connect(G_OBJECT(window), "delete_event", G_CALLBACK(gtk_main_quit), NULL);

	//,ain box in window
	box = gtk_vbox_new(FALSE, 0);
	gtk_container_set_border_width(GTK_CONTAINER(box), 5);

	//drawing area
	darea = gtk_drawing_area_new();
	gtk_widget_set_size_request(darea, IMAGE_WIDTH, IMAGE_HEIGHT);
	gtk_signal_connect(GTK_OBJECT(darea), "expose-event", GTK_SIGNAL_FUNC(on_darea_expose), NULL);

	//putting darea to box
	gtk_box_pack_start(GTK_BOX(box), darea, FALSE, FALSE, 0);

	//putting box to window
	gtk_container_add(GTK_CONTAINER(window), box);

	gtk_widget_show_all(window);

	//main parameters of fractal
	sFractal fractal;

	fractal.amin = -2.2;
	fractal.amax = 0.8;
	fractal.bmin = -1.5;
	fractal.bmax = 1.5;
	fractal.N = 32;

	fractal.da = (fractal.amax - fractal.amin) / IMAGE_WIDTH;
	fractal.db = (fractal.bmax - fractal.bmin) / IMAGE_HEIGHT;

	//rendering

	for (int x = 0; x < IMAGE_WIDTH; x++)
	{
		for (int y = 0; y < IMAGE_HEIGHT; y++)
		{
			double a = fractal.amin + x * fractal.da;
			double b = fractal.bmin + y * fractal.db;

			int L = CalculateIterations(a, b, fractal.N);

			int brightness = 255.0 * ((double) L / fractal.N);

			int address = (x + y * IMAGE_WIDTH) * 3;
			rgbbuf[address] = brightness * 1.0; // red
			rgbbuf[address + 1] = brightness * 0.9; //green
			rgbbuf[address + 2] = brightness * 0.5; //blue
		}
	}

	//end of rendering

	//draw offscreen image in window
	gdk_draw_rgb_image(darea->window, darea->style->fg_gc[GTK_STATE_NORMAL], 0, 0, IMAGE_WIDTH, IMAGE_HEIGHT, GDK_RGB_DITHER_NONE, rgbbuf, IMAGE_WIDTH * 3);

	//saving image in JPG file
	SaveJPEG("/media/Dane/Roboczy2/test.jpg", 90, IMAGE_WIDTH, IMAGE_HEIGHT, (JSAMPLE*) rgbbuf);

	//wait for refreshing interface (it is necessary when fractal is rendering in animation loop)
	while (gtk_events_pending())
		gtk_main_iteration();

	printf("End of rendering");
	gtk_main();
	return 0;
}

//This function refreshes graphinc when window is exposured
gboolean on_darea_expose(GtkWidget *widget, GdkEventExpose *event, gpointer user_data)
{
	gdk_draw_rgb_image(widget->window, widget->style->fg_gc[GTK_STATE_NORMAL], 0, 0, IMAGE_WIDTH, IMAGE_HEIGHT, GDK_RGB_DITHER_MAX, rgbbuf, IMAGE_WIDTH * 3);
	return TRUE;
}