/*
 * Copyright © 2004 David Reveman, Peter Nilsson
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without
 * fee, provided that the above copyright notice appear in all copies
 * and that both that copyright notice and this permission notice
 * appear in supporting documentation, and that the names of
 * David Reveman and Peter Nilsson not be used in advertising or
 * publicity pertaining to distribution of the software without
 * specific, written prior permission. David Reveman and Peter Nilsson
 * makes no representations about the suitability of this software for
 * any purpose. It is provided "as is" without express or implied warranty.
 *
 * DAVID REVEMAN AND PETER NILSSON DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DAVID REVEMAN AND
 * PETER NILSSON BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
 * OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 *
 * Authors: David Reveman <c99drn@cs.umu.se>
 *          Peter Nilsson <c99pnn@cs.umu.se>
 */

#include <cairo.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

static float font_scale1, font_scale2,
	     font_rotate1, font_rotate2,
	     font_alpha1, font_alpha2,
	     font_speed1, font_speed2,
	     font_x1, font_y1,
	     font_x2, font_y2;

static cairo_surface_t *bg_surface;
static int bg_width, bg_height;

void
text_setup (cairo_surface_t *target, int w, int h)
{
    cairo_surface_t *image;
    cairo_t *cr;

    image = cairo_image_surface_create_from_png ("orion.png");
    if (cairo_surface_status (image)) {
	printf ("error reading orion.png: %s\n",
		cairo_status_to_string (cairo_surface_status (image)));
	exit(1);
    }

    bg_width = cairo_image_surface_get_width (image);
    bg_height = cairo_image_surface_get_height (image);
    bg_surface = cairo_surface_create_similar (target,
	    CAIRO_CONTENT_COLOR_ALPHA,
	    bg_width, bg_height);

    cr = cairo_create (bg_surface);
    cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
    cairo_set_source_surface (cr, image, 0.0, 0.0);
    cairo_paint (cr);
    cairo_destroy (cr);

    cairo_surface_destroy (image);

    drand48 ();
    drand48 ();

    font_rotate1 = (float) (drand48 () * 3.14);
    font_rotate2 = (float) (drand48 () * 3.14);
    font_scale1 =  (float) (drand48 () * 250.0);
    font_scale2 =  (float) (drand48 () * 250.0);
    font_speed1 = (float) (drand48 () + 0.5);
    font_speed2 = (float) (drand48 () + 0.5);
    font_alpha1 = 0.0;
    font_alpha2 = 0.0;
    font_x1 =  200.0 + (float) (drand48 () * (w - 200.0));
    font_y1 =  100.0 + (float) (drand48 () * (h - 100.0));
    font_x2 =  200.0 + (float) (drand48 () * (w - 200.0));
    font_y2 =  100.0 + (float) (drand48 () * (h - 100.0));
}

static void
text_path_render_text1 (cairo_t *cr)
{
    cairo_save (cr);
    cairo_set_source_rgba (cr, 1.0, 0.0, 0.0, font_alpha1);

    cairo_set_font_size (cr, font_scale1);

    cairo_move_to (cr, font_x1 - font_scale1, font_y1);
    cairo_rotate(cr, font_rotate1);
    cairo_text_path (cr, "CAIRO");
    cairo_fill_preserve (cr);
    cairo_set_source_rgba (cr, 0.0, 1.0, 0.0, font_alpha1);
    cairo_stroke (cr);
    cairo_restore (cr);
}

static void
text_path_render_text2 (cairo_t *cr)
{
    cairo_save (cr);
    cairo_set_source_rgba (cr, 0.0, 0.0, 1.0, font_alpha2);
    cairo_set_font_size (cr, font_scale2);
    cairo_move_to (cr, font_x2 - font_scale2, font_y2);
    cairo_rotate(cr, font_rotate2);
    cairo_text_path (cr, "GEARS");
    cairo_fill_preserve (cr);
    cairo_set_source_rgba (cr, 0.0, 1.0, 0.0, font_alpha2);
    cairo_stroke (cr);
    cairo_restore (cr);
}

void
text_render (cairo_t *cr, int w, int h)
{
    double scale_x, scale_y;

    cairo_select_font_face (cr,
	    "arial",
	    CAIRO_FONT_SLANT_NORMAL,
	    CAIRO_FONT_WEIGHT_BOLD);
    cairo_set_font_size (cr, 1.0);

    cairo_save (cr);

    cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
    cairo_move_to (cr, 0, 0);

    scale_x = ((double) w) / (double) bg_width;
    scale_y = ((double) h) / (double) bg_height;

    cairo_scale (cr, scale_x, scale_y);

    cairo_set_source_surface (cr, bg_surface, 0.0, 0.0);
    cairo_paint (cr);

    cairo_set_operator (cr, CAIRO_OPERATOR_OVER);

    if (font_scale1 < font_scale2) {
	text_path_render_text1 (cr);
	text_path_render_text2 (cr);
    } else {
	text_path_render_text2 (cr);
	text_path_render_text1 (cr);
    }

    if (font_scale1 > 250) {
	font_scale1 = (float) (drand48 () * 50.0);
	font_x1 =  ((float) (drand48 () * (w - 400.0))) + 200.0;
	font_y1 =  ((float) (drand48 () * (h - 200.0))) + 100.0;
	font_rotate1 = (float) (drand48 () * 3.14);
	font_speed1 = (float) (drand48 () * 10.0);
	font_alpha1 = 0;
    }

    if (font_scale2 > 250) {
	font_scale2 = (float) (drand48 () * 50.0);
	font_x2 =  ((float) (drand48 () * (w - 400.0))) + 200.0;
	font_y2 =  ((float) (drand48 () * (h - 200.0))) + 100.0;
	font_rotate2 = (float) (drand48 () * 3.14);
	font_speed2 = (float) (drand48 () * 10.0);
	font_alpha2 = 0;
    }

    font_scale1 > 150? font_scale1 += 2: font_scale1++;
    font_scale2 > 150? font_scale2 += 2: font_scale2++;
    font_scale1 < 175?  (font_alpha1 += 0.01): (font_alpha1 -= 0.05);
    font_scale2 < 175?  (font_alpha2 += 0.01): (font_alpha2 -= 0.05);
    font_scale1 += font_speed1;
    font_scale2 += font_speed2;

    cairo_restore (cr);
}