pangowin32.c

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

/* Pango
 * pangowin32.c: Routines for handling Windows fonts
 *
 * Copyright (C) 1999 Red Hat Software
 * Copyright (C) 2000 Tor Lillqvist
 * Copyright (C) 2001 Alexander Larsson
 * Copyright (C) 2007 Novell, Inc.
 *
 * 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 <string.h>
#include <stdlib.h>
#include <glib.h>

#include "pango-impl-utils.h"
#include "pangowin32.h"
#include "pangowin32-private.h"

#define MAX_FREED_FONTS 16

#define CH_IS_UNIHAN_BMP(ch) ((ch) >= 0x3400 && (ch) <= 0x9FFF)
#define CH_IS_UNIHAN(ch) (CH_IS_UNIHAN_BMP (ch) || \
			  ((ch) >= 0x20000 && (ch) <= 0x2A6DF) ||	\
			  ((ch) >= 0x2F800 && (ch) <= 0x2FA1F))

HDC _pango_win32_hdc;
OSVERSIONINFO _pango_win32_os_version_info;
gboolean _pango_win32_debug = FALSE;

static void pango_win32_font_dispose    (GObject             *object);
static void pango_win32_font_finalize   (GObject             *object);

static gboolean pango_win32_font_real_select_font        (PangoFont *font,
							  HDC        hdc);
static void     pango_win32_font_real_done_font          (PangoFont *font);
static double   pango_win32_font_real_get_metrics_factor (PangoFont *font);

static PangoFontDescription *pango_win32_font_describe          (PangoFont        *font);
static PangoFontDescription *pango_win32_font_describe_absolute (PangoFont        *font);
static PangoCoverage        *pango_win32_font_get_coverage      (PangoFont        *font,
								 PangoLanguage    *lang);
static void                  pango_win32_font_calc_coverage     (PangoFont        *font,
								 PangoCoverage    *coverage,
								 PangoLanguage    *lang);
static PangoEngineShape     *pango_win32_font_find_shaper       (PangoFont        *font,
								 PangoLanguage    *lang,
								 guint32           ch);
static void                  pango_win32_font_get_glyph_extents (PangoFont        *font,
								 PangoGlyph        glyph,
								 PangoRectangle   *ink_rect,
								 PangoRectangle   *logical_rect);
static PangoFontMetrics *    pango_win32_font_get_metrics       (PangoFont        *font,
								 PangoLanguage    *lang);
static PangoFontMap *        pango_win32_font_get_font_map      (PangoFont        *font);

static gboolean pango_win32_font_real_select_font      (PangoFont *font,
							HDC        hdc);
static void     pango_win32_font_real_done_font        (PangoFont *font);
static double   pango_win32_font_real_get_metrics_factor (PangoFont *font);

static HFONT                 pango_win32_get_hfont              (PangoFont        *font);
static void                  pango_win32_get_item_properties    (PangoItem        *item,
								 PangoUnderline   *uline,
								 PangoAttrColor   *fg_color,
								 gboolean         *fg_set,
								 PangoAttrColor   *bg_color,
								 gboolean         *bg_set);

static HFONT
pango_win32_get_hfont (PangoFont *font)
{
  PangoWin32Font *win32font = (PangoWin32Font *)font;
  PangoWin32FontCache *cache;
  TEXTMETRIC tm;

  if (!win32font)
    return NULL;

  if (!win32font->hfont)
    {
      cache = pango_win32_font_map_get_font_cache (win32font->fontmap);

      win32font->hfont = pango_win32_font_cache_loadw (cache, &win32font->logfontw);
      if (!win32font->hfont)
	{
	  gchar *face_utf8 = g_utf16_to_utf8 (win32font->logfontw.lfFaceName,
					      -1, NULL, NULL, NULL);
	  g_warning ("Cannot load font '%s\n", face_utf8);
	  g_free (face_utf8);
	  return NULL;
	}

      SelectObject (_pango_win32_hdc, win32font->hfont);
      GetTextMetrics (_pango_win32_hdc, &tm);

      win32font->tm_overhang = tm.tmOverhang;
      win32font->tm_descent = tm.tmDescent;
      win32font->tm_ascent = tm.tmAscent;
    }

  return win32font->hfont;
}

/**
 * pango_win32_get_context:
 *
 * Retrieves a #PangoContext appropriate for rendering with Windows fonts.
  *
 * Return value: the new #PangoContext
 **/
PangoContext *
pango_win32_get_context (void)
{
  PangoContext *result;

  result = pango_context_new ();
  pango_context_set_font_map (result, pango_win32_font_map_for_display ());

  return result;
}

G_DEFINE_TYPE (PangoWin32Font, _pango_win32_font, PANGO_TYPE_FONT)

static void
_pango_win32_font_init (PangoWin32Font *win32font)
{
  win32font->size = -1;

  win32font->metrics_by_lang = NULL;

  win32font->glyph_info = g_hash_table_new_full (NULL, NULL, NULL, g_free);
}

/**
 * pango_win32_get_dc:
 *
 * Obtains a handle to the Windows device context that is used by Pango.
 *
 * Return value: A handle to the Windows device context that is used by Pango.
 **/
HDC
pango_win32_get_dc (void)
{
  if (_pango_win32_hdc == NULL)
    {
      _pango_win32_hdc = CreateDC ("DISPLAY", NULL, NULL, NULL);
      memset (&_pango_win32_os_version_info, 0,
	      sizeof (_pango_win32_os_version_info));
      _pango_win32_os_version_info.dwOSVersionInfoSize =
	sizeof (OSVERSIONINFO);
      GetVersionEx (&_pango_win32_os_version_info);

      /* Also do some generic pangowin32 initialisations... this function
       * is a suitable place for those as it is called from a couple
       * of class_init functions.
       */
#ifdef PANGO_WIN32_DEBUGGING
      if (getenv ("PANGO_WIN32_DEBUG") != NULL)
	_pango_win32_debug = TRUE;
#endif
    }

  return _pango_win32_hdc;
}

/**
 * pango_win32_get_debug_flag:
 *
 * Returns whether debugging is turned on.
 *
 * Return value: %TRUE if debugging is turned on.
 *
 * Since: 1.2
 */
gboolean
pango_win32_get_debug_flag (void)
{
  return _pango_win32_debug;
}

static void
_pango_win32_font_class_init (PangoWin32FontClass *class)
{
  GObjectClass *object_class = G_OBJECT_CLASS (class);
  PangoFontClass *font_class = PANGO_FONT_CLASS (class);

  object_class->finalize = pango_win32_font_finalize;
  object_class->dispose = pango_win32_font_dispose;

  font_class->describe = pango_win32_font_describe;
  font_class->describe_absolute = pango_win32_font_describe_absolute;
  font_class->get_coverage = pango_win32_font_get_coverage;
  font_class->find_shaper = pango_win32_font_find_shaper;
  font_class->get_glyph_extents = pango_win32_font_get_glyph_extents;
  font_class->get_metrics = pango_win32_font_get_metrics;
  font_class->get_font_map = pango_win32_font_get_font_map;

  class->select_font = pango_win32_font_real_select_font;
  class->done_font = pango_win32_font_real_done_font;
  class->get_metrics_factor = pango_win32_font_real_get_metrics_factor;

  pango_win32_get_dc ();
}

/**
 * pango_win32_render:
 * @hdc:     the device context
 * @font:    the font in which to draw the string
 * @glyphs:  the glyph string to draw
 * @x:       the x position of start of string (in pixels)
 * @y:       the y position of baseline (in pixels)
 *
 * Render a #PangoGlyphString onto a Windows DC
 */
void
pango_win32_render (HDC               hdc,
		    PangoFont        *font,
		    PangoGlyphString *glyphs,
		    int               x,
		    int               y)
{
  HFONT hfont, old_hfont = NULL;
  int i, j, num_valid_glyphs;
  guint16 *glyph_indexes;
  gint *dX;
  gint this_x;
  gint start_x_offset, x_offset, next_x_offset, cur_y_offset; /* in Pango units */

  g_return_if_fail (glyphs != NULL);

#ifdef PANGO_WIN32_DEBUGGING
  if (_pango_win32_debug)
    {
      PING (("num_glyphs:%d", glyphs->num_glyphs));
      for (i = 0; i < glyphs->num_glyphs; i++)
	{
	  g_print (" %d:%d", glyphs->glyphs[i].glyph, glyphs->glyphs[i].geometry.width);
	  if (glyphs->glyphs[i].geometry.x_offset != 0 ||
	      glyphs->glyphs[i].geometry.y_offset != 0)
	    g_print (":%d,%d", glyphs->glyphs[i].geometry.x_offset,
		     glyphs->glyphs[i].geometry.y_offset);
	}
      g_print ("\n");
    }
#endif

  if (glyphs->num_glyphs == 0)
    return;

  hfont = pango_win32_get_hfont (font);
  if (!hfont)
    return;

  old_hfont = SelectObject (hdc, hfont);

  glyph_indexes = g_new (guint16, glyphs->num_glyphs);
  dX = g_new (INT, glyphs->num_glyphs);

  /* Render glyphs using one ExtTextOutW() call for each run of glyphs
   * that have the same y offset. The big majoroty of glyphs will have
   * y offset of zero, so in general, the whole glyph string will be
   * rendered by one call to ExtTextOutW().
   *
   * In order to minimize buildup of rounding errors, we keep track of
   * where the glyphs should be rendered in Pango units, and round
   * to pixels separately for each glyph,
   */

  i = 0;

  /* Outer loop through all glyphs in string */
  while (i < glyphs->num_glyphs)
    {
      cur_y_offset = glyphs->glyphs[i].geometry.y_offset;
      num_valid_glyphs = 0;
      x_offset = 0;
      start_x_offset = glyphs->glyphs[i].geometry.x_offset;
      this_x = PANGO_PIXELS (start_x_offset);

      /* Inner loop through glyphs with the same y offset, or code
       * point zero (just spacing).
       */
      while (i < glyphs->num_glyphs &&
	     (glyphs->glyphs[i].glyph == PANGO_GLYPH_EMPTY ||
	      cur_y_offset == glyphs->glyphs[i].geometry.y_offset))
	{
	  if (glyphs->glyphs[i].glyph == PANGO_GLYPH_EMPTY)
	    {
	      /* PANGO_GLYPH_EMPTY glyphs should not be rendered, but their
	       * indicated width (set up by PangoLayout) should be taken
	       * into account.
	       */

	      /* If the string starts with spacing, must shift the
	       * starting point for the glyphs actually rendered.  For
	       * spacing in the middle of the glyph string, add to the dX
	       * of the previous glyph to be rendered.
	       */
	      if (num_valid_glyphs == 0)
		start_x_offset += glyphs->glyphs[i].geometry.width;
	      else
		{
		  x_offset += glyphs->glyphs[i].geometry.width;
		  dX[num_valid_glyphs-1] = PANGO_PIXELS (x_offset) - this_x;
		}
	    }
	  else
	    {
	      if (glyphs->glyphs[i].glyph & PANGO_GLYPH_UNKNOWN_FLAG)
		{
		  /* Glyph index is actually the char value that doesn't
		   * have any glyph (ORed with the flag). We should really
		   * do the same that pango_xft_real_render() does: render
		   * a box with the char value in hex inside it in a tiny
		   * font. Later. For now, use the TrueType invalid glyph
		   * at 0.
		   */
		  glyph_indexes[num_valid_glyphs] = 0;
		}
	      else
		glyph_indexes[num_valid_glyphs] = glyphs->glyphs[i].glyph;

	      x_offset += glyphs->glyphs[i].geometry.width;

	      /* If the next glyph has an X offset, take that into consideration now */
	      if (i < glyphs->num_glyphs - 1)
		next_x_offset = glyphs->glyphs[i+1].geometry.x_offset;
	      else
		next_x_offset = 0;

	      dX[num_valid_glyphs] = PANGO_PIXELS (x_offset + next_x_offset) - this_x;

	      /* Prepare for next glyph */
	      this_x += dX[num_valid_glyphs];
	      num_valid_glyphs++;
	    }
	  i++;
	}
#ifdef PANGO_WIN32_DEBUGGING
      if (_pango_win32_debug)
	{
	  g_print ("ExtTextOutW at %d,%d deltas:",
		   x + PANGO_PIXELS (start_x_offset),
		   y + PANGO_PIXELS (cur_y_offset));
	  for (j = 0; j < num_valid_glyphs; j++)
	    g_print (" %d", dX[j]);
	  g_print ("\n");
	}
#endif

      ExtTextOutW (hdc,
		   x + PANGO_PIXELS (start_x_offset),
		   y + PANGO_PIXELS (cur_y_offset),
		   ETO_GLYPH_INDEX,
		   NULL,
		   glyph_indexes, num_valid_glyphs,
		   dX);
      x += this_x;
    }


  SelectObject (hdc, old_hfont); /* restore */
  g_free (glyph_indexes);
  g_free (dX);
}

/**
 * pango_win32_render_transformed:
 * @hdc:     a windows device context
 * @matrix:  a #PangoMatrix, or %NULL to use an identity transformation
 * @font:    the font in which to draw the string
 * @glyphs:  the glyph string to draw
 * @x:       the x position of the start of the string (in Pango
 *           units in user space coordinates)
 * @y:       the y position of the baseline (in Pango units
 *           in user space coordinates)
 *
 * Renders a #PangoGlyphString onto a windows DC, possibly
 * transforming the layed-out coordinates through a transformation
 * matrix. Note that the transformation matrix for @font is not
 * changed, so to produce correct rendering results, the @font
 * must have been loaded using a #PangoContext with an identical
 * transformation matrix to that passed in to this function.
 **/
void
pango_win32_render_transformed (HDC                hdc,
				const PangoMatrix *matrix,
				PangoFont         *font,
				PangoGlyphString  *glyphs,
				int                x,
				int                y)
{
  XFORM xForm;
  XFORM xFormPrev = {1.0, 0.0, 0.0, 1.0, 0.0, 0.0};
  int   mode = GetGraphicsMode (hdc);

  if (!SetGraphicsMode (hdc, GM_ADVANCED))
    g_warning ("SetGraphicsMode() failed");
  else if (!GetWorldTransform (hdc, &xFormPrev))
    g_warning ("GetWorldTransform() failed");
  else if (matrix)
    {
      xForm.eM11 = matrix->xx;
      xForm.eM12 = matrix->yx;
      xForm.eM21 = matrix->xy;
      xForm.eM22 = matrix->yy;
      xForm.eDx = matrix->x0;
      xForm.eDy = matrix->y0;
      if (!SetWorldTransform (hdc, &xForm))
	g_warning ("GetWorldTransform() failed");
    }

  pango_win32_render (hdc, font, glyphs, x/PANGO_SCALE, y/PANGO_SCALE);

  /* restore */
  SetWorldTransform (hdc, &xFormPrev);
  SetGraphicsMode (hdc, mode);
}

static void
pango_win32_font_get_glyph_extents (PangoFont      *font,
				    PangoGlyph      glyph,
				    PangoRectangle *ink_rect,
				    PangoRectangle *logical_rect)
{
  PangoWin32Font *win32font = (PangoWin32Font *)font;
  guint16 glyph_index = glyph;
  GLYPHMETRICS gm;
  guint32 res;
  HFONT hfont;
  MAT2 m = {{0,1}, {0,0}, {0,0}, {0,1}};
  PangoWin32GlyphInfo *info;

  if (glyph == PANGO_GLYPH_EMPTY)
    {
      if (ink_rect)
	ink_rect->x = ink_rect->width = ink_rect->y = ink_rect->height = 0;
      if (logical_rect)
	logical_rect->x = logical_rect->width = logical_rect->y = logical_rect->height = 0;
      return;
    }

  if (glyph & PANGO_GLYPH_UNKNOWN_FLAG)
    glyph_index = glyph = 0;

  info = g_hash_table_lookup (win32font->glyph_info, GUINT_TO_POINTER (glyph));

  if (!info)
    {