Vertical Text Rendering with OpenType Color Emoji

emoji.c

#include <stdio.h>
#include <math.h>
#include <pango/pangocairo.h>

int main ()
{
  cairo_t *cr;
  cairo_status_t status;
  cairo_surface_t *surface;

  PangoLayout *layout;
  PangoFontDescription *desc;
  PangoContext *context;

  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 800, 300);
  cr = cairo_create (surface);
  cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
  cairo_paint (cr);

  cairo_translate (cr, 50, 100);

  layout = pango_cairo_create_layout (cr);
  pango_layout_set_text (layout, "麦酒(beer) 🍺🍻🍺🍻😂", -1);
  desc = pango_font_description_from_string ("Noto Sans CJK JP Regular 40");
  pango_layout_set_font_description (layout, desc);
  pango_font_description_free (desc);

  context = pango_layout_get_context (layout);
  pango_context_set_base_gravity (context, PANGO_GRAVITY_EAST);

  cairo_set_source_rgb (cr, 0, 0, 0);

  pango_cairo_update_layout (cr, layout);
  pango_cairo_show_layout (cr, layout);

  g_object_unref (layout);
  cairo_destroy (cr);

  status = cairo_surface_write_to_png (surface, "output.png");
  cairo_surface_destroy (surface);

  return 0;
}