#include <math.h>
#include <string.h>

#include <gdk/gdk.h>
#include <gdk/gdkx.h>
#include <X11/Xlib.h>

/* for test program */
#include <gtk/gtk.h>

/* a test of server side rotated text */

#define IROUND(x) (int)((x) > 0 ? (x) + .5 : (x) - .5)

void
gdk_draw_rotated_text(GdkDrawable *drawable,
		      const gchar *xlfdtemplate, guint points,
		      GdkGC *gc,
		      gint x,
		      gint y,
		      gdouble angle, /* in radians */
		      const gchar *text,
		      guint text_length)
{
  gdouble matrix[4];
  gchar *smatrix, *xlfd;
  GdkFont *font;
  XFontStruct *fontinfo;
  gdouble offset;
  guint i;

  g_return_if_fail(drawable != NULL);
  g_return_if_fail(xlfdtemplate != NULL);
  g_return_if_fail(gc != NULL);
  g_return_if_fail(text != NULL);

  /* build up rotated font XLFD */
  matrix[0] = matrix[3] = points * cos(angle);
  matrix[1] = points * sin(angle);
  matrix[2] = -matrix[1];

  smatrix = g_strdup_printf("[%g %g %g %g]", matrix[0], matrix[1],
			    matrix[2], matrix[3]);
  for (i = 0; smatrix[i] != '\0'; i++)
    if (smatrix[i] == '-')
      smatrix[i] = '~';
  xlfd = g_strdup_printf(xlfdtemplate, smatrix);
  g_free(smatrix);
  font = gdk_font_load(xlfd);
  g_free(xlfd);

  g_return_if_fail(font != NULL);

  fontinfo = GDK_FONT_XFONT(font);

  /* draw rotated text */
  offset = 0.0;
  for (i = 0; i < text_length; i++) {
    int charno = (unsigned char)text[i];
    int char_metric_offset = charno - fontinfo->min_char_or_byte2;

    gdk_draw_text(drawable, font, gc,
		  IROUND((double)x + offset * matrix[0] / 1000.0),
		  IROUND((double)y - offset * matrix[1] / 1000.0),
		  &text[i], 1);

    offset += (double)(fontinfo->per_char ?
		       fontinfo->per_char[char_metric_offset].attributes :
		       fontinfo->min_bounds.attributes);
  }
}

void
gdk_draw_rotated_string(GdkDrawable *drawable,
			const gchar *xlfdtemplate, guint points,
			GdkGC *gc,
			gint x,
			gint y,
			gdouble angle, /* in radians */
			const gchar *string)
{
  gdk_draw_rotated_text(drawable, xlfdtemplate, points, gc, x, y, angle,
			string, strlen(string));
}

static gint
expose_event(GtkWidget *drawing_area, GdkEventExpose *event)
{
  GdkDrawable *drw = drawing_area->window;

  if (!drw)
    return;

  gdk_window_clear(drw);
  gdk_draw_rotated_text(drw,
		"-*-times-medium-r-normal-*-%s-*-*-*-p-*-iso8859-1", 48,
		drawing_area->style->text_gc[GTK_WIDGET_STATE(drawing_area)],
		50, 40, 0, "Hello World", 11);
  gdk_draw_rotated_text(drw,
		"-*-times-medium-r-normal-*-%s-*-*-*-p-*-iso8859-1", 36,
		drawing_area->style->text_gc[GTK_WIDGET_STATE(drawing_area)],
		36, 65, -M_PI/6.0, "Hello World", 11);
  gdk_draw_rotated_text(drw,
		"-*-times-medium-r-normal-*-%s-*-*-*-p-*-iso8859-1", 24,
		drawing_area->style->text_gc[GTK_WIDGET_STATE(drawing_area)],
		20, 73, -M_PI/3.0, "Hello World", 11);
  gdk_draw_rotated_text(drw,
		"-*-times-medium-r-normal-*-%s-*-*-*-p-*-iso8859-1", 18,
		drawing_area->style->text_gc[GTK_WIDGET_STATE(drawing_area)],
		5, 75, -M_PI/2.0, "Hello World", 11);
}

gint
main(int argc, char **argv)
{
  GtkWidget *window;
  GtkWidget *da;

  gtk_init(&argc, &argv);

  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_signal_connect(GTK_OBJECT(window), "destroy",
		     GTK_SIGNAL_FUNC(gtk_main_quit), NULL);

  da = gtk_drawing_area_new();
  gtk_drawing_area_size(GTK_DRAWING_AREA(da), 300, 200);
  gtk_signal_connect(GTK_OBJECT(da), "expose_event",
		     GTK_SIGNAL_FUNC(expose_event), NULL);

  gtk_container_add(GTK_CONTAINER(window), da);
  gtk_widget_show_all(window);

  gtk_main();

  return 0;
}