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

#include <cairo.h>
#include <glib-object.h>
#include <pango/pango.h>
#include <pango/pangocairo.h>

void draw_text(cairo_t *, const char *);

static const int MARGIN = 20;
static const int WIDTH = 800;
static const int HEIGHT = 1131;
static const char * FONT = "Serif 34";


int main(int argc, const char ** argv)
{
	if (1 >= argc)
	{
		dprintf(2, "Usage: %s OUTPUT [TEXT]\n", argv[0]);
		return 1;
	}
	const char * filename = argv[1];
	const char * text = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";
	if (3 == argc)
		text = argv[2];
	cairo_surface_t * surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, WIDTH, HEIGHT);
	cairo_t * ctx = cairo_create(surface);
	cairo_scale(ctx, 1, 1);
	cairo_set_source_rgb(ctx, 1., 1., 1.);
	cairo_paint(ctx);
	cairo_set_source_rgb(ctx, 0., 0., 0.);
	draw_text(ctx, text);
	cairo_destroy(ctx);
	cairo_status_t status = cairo_surface_write_to_png(surface, filename);
	cairo_surface_destroy(surface);
	if (CAIRO_STATUS_SUCCESS != status)
	{
		dprintf(2, "Could not save output to %s\n", filename);
		return 1;
	}
}


void draw_text(cairo_t * ctx, const char * text)
{
	cairo_translate(ctx, MARGIN, MARGIN);
	PangoLayout * layout = pango_cairo_create_layout(ctx);
	PangoFontDescription * desc = pango_font_description_from_string(FONT);
	pango_layout_set_font_description(layout, desc);
	pango_font_description_free(desc);
	pango_layout_set_text(layout, text, -1);
	pango_layout_set_wrap(layout, PANGO_WRAP_WORD);
	pango_layout_set_width(layout, (WIDTH - 2 * MARGIN) * PANGO_SCALE);
	pango_cairo_update_layout(ctx, layout);
	pango_cairo_show_layout(ctx, layout);
	g_object_unref(layout);
}