#include <cairo.h>

#include <gtk/gtk.h>

#include <math.h>

static void draw_aligned_text(cairo_t *cr, const char *font, double x, double y,

			       double fontsize, const char *text, int alignment)

{

#define CENTERED 0

#define LEFT_JUSTIFIED 1

#define RIGHT_JUSTIFIED 2

	double factor, direction;

	cairo_text_extents_t extents;

	switch (alignment) {

		case CENTERED:

			direction = -1.0;

			factor = 0.5;

			break;

		case RIGHT_JUSTIFIED:

			direction = -1.0;

			factor = 1.0;

			break;

		case LEFT_JUSTIFIED:

		default:

			direction = 1.0;

			factor = 0.0;

			break;

	}

	cairo_select_font_face(cr, font, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);

	cairo_set_font_size(cr, fontsize);

	cairo_text_extents(cr, text, &extents);

	x = x + direction * (factor * extents.width  + extents.x_bearing);

	y = y - (extents.height / 2 + extents.y_bearing);

	cairo_move_to(cr, x, y);

	cairo_show_text(cr, text);

}

void draw_centered_text(cairo_t *cr, const char *font, double x, double y,

			       double fontsize, const char *text)

{

	draw_aligned_text(cr, font, x, y, fontsize, text, CENTERED);

}

void draw_right_justified_text(cairo_t *cr, const char *font,

				double x, double y,

				double fontsize, const char *text)

{

	draw_aligned_text(cr, font, x, y, fontsize, text, RIGHT_JUSTIFIED);

}

void draw_left_justified_text(cairo_t *cr, const char *font,

				double x, double y,

				double fontsize, const char *text)

{

	draw_aligned_text(cr, font, x, y, fontsize, text, LEFT_JUSTIFIED);

}

void draw_vertical_centered_text(cairo_t *cr, const char *font, double x,

					double y, double fontsize,

					const char *text)

{

	double sx, sy;

	cairo_text_extents_t extents;

	cairo_select_font_face(cr, font, CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);

	cairo_set_font_size(cr, fontsize);

	cairo_text_extents(cr, text, &extents);

	sx = x;

	sy = y;

	y = y + (extents.width / 2.0 + extents.x_bearing);

	x = x - (extents.height / 2.0 + extents.y_bearing);

	cairo_move_to(cr, x, y);

	cairo_save(cr);

	cairo_translate(cr, -sx, -sy);

	cairo_rotate(cr, -90.0 * M_PI / 180.0);

	cairo_translate(cr, sx, sy);

	cairo_show_text(cr, text);

	cairo_restore(cr);

}