viewer-win32.c

Pango is a library for layout and rendering of text, with an emphasis on internationalization. Pang

/* Pango
 * viewer-win32.c: Example program to view a UTF-8 encoding file
 *                 using Pango to render result.
 *
 * Copyright (C) 1999 Red Hat Software
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
#include <config.h>
#include <gtk/gtk.h>
#include <gdk/win32/gdkwin32.h>

#include <pango/pango.h>
#include <pango/pangowin32.h>

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define BUFSIZE 1024

typedef struct _Paragraph Paragraph;

/* Structure representing a paragraph
 */
struct _Paragraph {
  char *text;
  int length;
  int height;   /* Height, in pixels */
  PangoLayout *layout;
};

GList *paragraphs;

static PangoFontDescription *font_description;
static Paragraph *highlight_para;
static int highlight_offset;

GtkWidget *styles_combo;

static GtkWidget *message_label;
GtkWidget *layout;

PangoContext *context;

static void fill_styles_combo (GtkWidget *combo);

/* Read an entire file into a string
 */
static char *
read_file(char *name)
{
  GString *inbuf;
  FILE *file;
  char *text;
  char buffer[BUFSIZE];

  file = fopen (name, "r");
  if (!file)
    {
      fprintf (stderr, "%s: Cannot open %s\n", g_get_prgname (), name);
      return NULL;
    }

  inbuf = g_string_new (NULL);
  while (1)
    {
      char *bp = fgets (buffer, BUFSIZE-1, file);
      if (ferror (file))
	{
	  fprintf (stderr, "%s: Error reading %s\n", g_get_prgname (), name);
	  g_string_free (inbuf, TRUE);
	  return NULL;
	}
      else if (bp == NULL)
	break;

      g_string_append (inbuf, buffer);
    }

  fclose (file);

  text = inbuf->str;
  g_string_free (inbuf, FALSE);

  return text;
}

/* Take a UTF8 string and break it into paragraphs on \n characters
 */
static GList *
split_paragraphs (char *text)
{
  char *p = text;
  char *next;
  gunichar wc;
  GList *result = NULL;
  char *last_para = text;

  while (*p)
    {
      wc = g_utf8_get_char (p);
      next = g_utf8_next_char (p);
      if (wc == (gunichar)-1)
	{
	  fprintf (stderr, "%s: Invalid character in input\n", g_get_prgname ());
	  g_list_foreach (result, (GFunc)g_free, NULL);
	  return NULL;
	}
      if (!*p || !wc || wc == '\n')
	{
	  Paragraph *para = g_new (Paragraph, 1);
	  para->text = last_para;
	  para->length = p - last_para;
	  para->layout = pango_layout_new (context);
	  pango_layout_set_text (para->layout, para->text, para->length);
	  para->height = 0;

	  last_para = next;

	  result = g_list_prepend (result, para);
	}
      if (!wc) /* incomplete character at end */
	break;
      p = next;
    }

  return g_list_reverse (result);
}

/* Given an x-y position, return the paragraph and offset
 * within the paragraph of the click.
 */
gboolean
xy_to_cp (int width, int x, int y, Paragraph **para_return, int *index)
{
  GList *para_list;
  int height = 0;

  *para_return = NULL;

  para_list = paragraphs;
  while (para_list && height < y)
    {
      Paragraph *para = para_list->data;

      if (height + para->height >= y)
	{
	  gboolean result = pango_layout_xy_to_index (para->layout,
						      x * PANGO_SCALE,
						      (y - height) * PANGO_SCALE,
						      index, NULL);
	  if (result && para_return)
	    *para_return = para;

	  return result;
	}

      height += para->height;
      para_list = para_list->next;
    }

  return FALSE;
}

/* Given a paragraph and offset in that paragraph, find the
 * bounding rectangle for the character at the offset.
 */
void
char_bounds (Paragraph *para, int index, int width, PangoRectangle *rect)
{
  GList *para_list;

  int height = 0;

  para_list = paragraphs;
  while (para_list)
    {
      Paragraph *cur_para = para_list->data;

      if (cur_para == para)
	{
	  PangoRectangle pos;

	  pango_layout_index_to_pos (cur_para->layout, index, &pos);

	  rect->x = PANGO_PIXELS (MIN (pos.x, pos.x + pos.width));
	  rect->width = PANGO_PIXELS (ABS (pos.width));
	  rect->y = height + PANGO_PIXELS (pos.y);
	  rect->height = PANGO_PIXELS (pos.height);
	}

      height += cur_para->height;
      para_list = para_list->next;
    }
}

/* XOR a rectangle over a given character
 */
void
xor_char (GtkWidget *layout, GdkRectangle *clip_rect,
	  Paragraph *para, int offset)
{
  static GdkGC *gc;
  PangoRectangle rect;		/* GdkRectangle in 1.2 is too limited
				 */
  if (!gc)
    {
      GdkGCValues values;
      values.foreground = layout->style->white.pixel ?
	layout->style->white : layout->style->black;
      values.function = GDK_XOR;
      gc = gdk_gc_new_with_values (GTK_LAYOUT (layout)->bin_window,
				   &values,
				   GDK_GC_FOREGROUND | GDK_GC_FUNCTION);
    }

  gdk_gc_set_clip_rectangle (gc, clip_rect);

  char_bounds (para, offset, layout->allocation.width, &rect);

  rect.y -= GTK_LAYOUT (layout)->yoffset;

  if ((rect.y + rect.height >= 0) && (rect.y < layout->allocation.height))
    gdk_draw_rectangle (GTK_LAYOUT (layout)->bin_window, gc, TRUE,
			rect.x, rect.y, rect.width, rect.height);
}

/* Handle a size allocation by re-laying-out each paragraph to
 * the new width, setting the new size for the layout and
 * then queing a redraw
 */
void
size_allocate (GtkWidget *layout, GtkAllocation *allocation)
{
  GList *tmp_list;
  guint height = 0;
  PangoDirection base_dir = pango_context_get_base_dir (context);

  tmp_list = paragraphs;
  while (tmp_list)
    {
      Paragraph *para = tmp_list->data;
      PangoRectangle logical_rect;

      tmp_list = tmp_list->next;

      pango_layout_set_alignment (para->layout,
				  base_dir == PANGO_DIRECTION_LTR ? PANGO_ALIGN_LEFT : PANGO_ALIGN_RIGHT);
      pango_layout_set_width (para->layout, layout->allocation.width * PANGO_SCALE);

      pango_layout_get_extents (para->layout, NULL, &logical_rect);
      para->height = PANGO_PIXELS (logical_rect.height);

      height += para->height;
    }

  gtk_layout_set_size (GTK_LAYOUT (layout), allocation->width, height);

  if (GTK_LAYOUT (layout)->yoffset + allocation->height > height)
    gtk_adjustment_set_value (GTK_LAYOUT (layout)->vadjustment, (float)(height - allocation->height));
}

/* Handle a draw/expose by finding the paragraphs that intersect
 * the region and reexposing them.
 */
void
draw (GtkWidget *layout, GdkRectangle *area)
{
  GList *tmp_list;
  guint height = 0;
  HDC hdc;
  const GdkGCValuesMask mask = GDK_GC_FOREGROUND|GDK_GC_BACKGROUND|GDK_GC_FONT;

  gdk_draw_rectangle (GTK_LAYOUT (layout)->bin_window,
		      layout->style->base_gc[layout->state],
		      TRUE,
		      area->x, area->y,
		      area->width, area->height);

  gdk_gc_set_clip_rectangle (layout->style->text_gc[layout->state], area);

  hdc = gdk_win32_hdc_get (GTK_LAYOUT (layout)->bin_window,
			   layout->style->text_gc[GTK_STATE_NORMAL],
			   mask);
  tmp_list = paragraphs;
  while (tmp_list &&
	 height < area->y + area->height + GTK_LAYOUT (layout)->yoffset)
    {
      Paragraph *para = tmp_list->data;
      tmp_list = tmp_list->next;

      if (height + para->height >= GTK_LAYOUT (layout)->yoffset + area->y)
	pango_win32_render_layout (hdc, para->layout,
				   0, height - GTK_LAYOUT (layout)->yoffset);
      height += para->height;
    }

  gdk_win32_hdc_release (GTK_LAYOUT (layout)->bin_window,
			 layout->style->text_gc[GTK_STATE_NORMAL],
			 mask);
  gdk_gc_set_clip_rectangle (layout->style->text_gc[layout->state], NULL);

  if (highlight_para)
    xor_char (layout, area, highlight_para, highlight_offset);
}

gboolean
expose (GtkWidget *layout, GdkEventExpose *event)
{
  if (event->window == GTK_LAYOUT (layout)->bin_window)
    draw (layout, &event->area);

  return TRUE;
}

void
button_press (GtkWidget *layout, GdkEventButton *event)
{
  Paragraph *para = NULL;
  int offset;
  gchar *message;

  xy_to_cp (layout->allocation.width,
	    event->x, event->y + GTK_LAYOUT (layout)->yoffset,
	    &para, &offset);

  if (highlight_para)
    xor_char (layout, NULL, highlight_para, highlight_offset);

  highlight_para = para;
  highlight_offset = offset;

  if (para)
    {
      gunichar wc;

      wc = g_utf8_get_char (para->text + offset);
      message = g_strdup_printf ("Current char: U%04x", wc);

      xor_char (layout, NULL, highlight_para, highlight_offset);
    }
  else
    message = g_strdup_printf ("Current char:");

  gtk_label_set_text (GTK_LABEL (message_label), message);
  g_free (message);
}

static void
checkbutton_toggled (GtkWidget *widget, gpointer data)
{
  GList *para_list;

  pango_context_set_base_dir (context, GTK_TOGGLE_BUTTON (widget)->active ? PANGO_DIRECTION_RTL : PANGO_DIRECTION_LTR);

  para_list = paragraphs;
  while (para_list)
    {
      Paragraph *para = para_list->data;