[cairo] Pango Cairo Rendering Text with Misc Fonts

Tue May 20 07:50:32 PDT 2008

Based on my results, either I am doing something wrong or the default 
pango-cairo fonts being used are the cairo toy fonts.  Specifiying any 
available font results in only a small subset of rendered font faces.  
Given that I am using (forced to based on environment) an older release 
(pango-cairo 1.14) should I be able to programatically select freetype 
fonts vs. cairo toy fonts?

-----Original Message-----
From: robertk54 at aol.com
To: cairo at cairographics.org
Sent: Wed, 14 May 2008 11:35 am
Subject: Pango Cairo Rendering Text with Misc Fonts

I switched to a Linux prototype and have a simple test app which 
renders text on top of an ARGB surface and saves to a .png file. I am 
still having some issues with rendering text when selecting 
international fonts. It's almost as if Cairo is using the toy fonts but 
some fonts render good. The version of Pango I am currently using is 
older and does not support Gravity so I am not trying to render 
vertical text. 

Fonts I tried, all render in english and are not very different from 
each other so I do not think they are all good . . . 

Century Schoolbook L 
Courier 
Drugulin CLM 
East Syriac Adiabene 
Frank Ruehl CLM 
KacstDecorative 
KacstQura 
Kochi Mincho 
Lohit Punjabi 
Lohit Tamil 
Miriam Mono CLM 
Mukti Narrow 
Serto Batnan 
Serto Jerusalem Outline 
ZYSong18030 

Most of my current test app . . . 

<< 
#include <unistd.h> 
#include <stdio.h> 

#include <pango/pangocairo.h> 

#define FOURCIF_WIDTH 704 
#define FOURCIF_HEIGHT 476 

#if !defined(CAIRO_HAS_FT_FONT) 
#error !CAIRO_HAS_FT_FONT 
#endif 

static cairo_t *m_pCairo=NULL; 
static cairo_surface_t *m_pSurface=NULL; 
static cairo_surface_t *m_pSurfaceSample=NULL;static double 
m_dXPosStart=0.0; 
static double m_dYPosStart=0.0; 
static double m_dXPos=0.0; 
static double m_dYPos=0.0; 
static char *m_pUtf8=NULL; 
static char *m_pColor=NULL; 
static char *m_pFont=NULL; 
static PangoLayout *m_pPangoLayout=NULL; 
static PangoFontMap *m_pPangoFontMap=NULL; 
static double m_size=12.0; 
static double m_r=1.0, m_g=0.0, m_b=0.0, m_a=1.0; 
static double m_dTransparency = 0.0; 
static int m_iNumFonts; 

void ListFonts (void); 
void ParseParameters (int argc, char *argv[]); 
void SetFont ( const char *font); 
void SetRGB (unsigned char r, unsigned char g, unsigned char b, 
unsigned char a); 
void HTML40ToRGB(char *HTML40, unsigned char *R, unsigned char *G, 
unsigned char *B); 
void AddText (const char *utf8); 

int main(int argc, char *argv[]) 
{ 
  // Default initial color blue 
  unsigned char R = 0; 
  unsigned char G = 0; 
  unsigned char B = 255; 
  unsigned char A = 255; 
  double dNorm; 

  m_pSurface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 
FOURCIF_WIDTH, FOURCIF_HEIGHT); 
  m_pCairo = cairo_create (m_pSurface); 
  cairo_set_source_rgba (m_pCairo, R, G, B, A); 
  cairo_paint (m_pCairo); 
  m_pSurfaceSample = cairo_image_surface_create_from_png 
("sample.png"); 
  cairo_set_source_surface (m_pCairo, m_pSurfaceSample, 
FOURCIF_WIDTH*0.21, 0); 
  cairo_paint (m_pCairo); 
  m_pPangoFontMap = pango_cairo_font_map_get_default (); 
  m_pPangoLayout = pango_cairo_create_layout (m_pCairo); 

  ParseParameters (argc, argv); 

  dNorm = m_dTransparency; 
  dNorm = (dNorm < 0.0) ? 0.0 : dNorm; 
  dNorm = (dNorm > 1.0) ? 1.0 : dNorm; 
  A = (unsigned char) ((1.0 - dNorm) * 255.0) & 0xff; 

  HTML40ToRGB (m_pColor, &R, &G, &B); 
  SetRGB (R, G, B, A); 
  SetFont (m_pFont); 

  AddText (m_pUtf8); 

  g_object_unref (m_pPangoLayout); 
  // Write the ARGB surface to a .PNG file so we can view it. 
  cairo_surface_write_to_png (m_pSurface, "utf8test-pango.png"); 
  return 0; 
} 

void ListFonts () 
{ 
  PangoFontMap *pPangoFontMap; 
  PangoFontFamily **pPangoFontFamily; 
  PangoFontFace **pPangoFontFace; 
  int n_faces; 
  int n_families; 
  int i; 
  int j; 

  m_iNumFonts = 0; 
  pPangoFontMap = pango_cairo_font_map_get_default (); 
  pango_font_map_list_families (pPangoFontMap, &pPangoFontFamily, 
&n_families); 
  // Determine the font string and insert into (alpabetically sorted) 
combo list. 
  for (i=0; i<n_families; i++) 
  { 
  pango_font_family_list_faces (pPangoFontFamily[i], &pPangoFontFace, 
&n_faces); 
  printf ("%s :: [", pango_font_family_get_name (pPangoFontFamily[i])); 
  for (j=0; j<n_faces; j++) 
  { 
  printf ("%s", pango_font_face_get_face_name (pPangoFontFace[j])); 
  if (j+1 < n_faces) printf (", "); 
  m_iNumFonts++; 
  } 
  printf ("]\n"); 
  } 
  g_free (pPangoFontFace); 
  g_free (pPangoFontFamily); 
} 

void AddText (const char *utf8) 
{ 
  PangoAttrList* pPangoAttrList; 
  gchar *text; 
  // Get the layout's current attribute list 
  pPangoAttrList = pango_layout_get_attributes (m_pPangoLayout); 

/////////////////////////////////////////////////////////////////////////

/ 
  // Would be nice to extend the markup language for dynamic 
attributes. 
  // These would need to be processed and stripped here, prior to the 
pango_parse_markup call. 

/////////////////////////////////////////////////////////////////////////

/ 
  // Update the attribute list from the markup text. 
  pango_parse_markup (utf8, -1, 0, &pPangoAttrList, &text, NULL, NULL); 
  pango_layout_set_attributes (m_pPangoLayout, pPangoAttrList); 
  pango_attr_list_unref (pPangoAttrList); 
  pango_layout_set_text (m_pPangoLayout, text, -1); 
  // Set the color and position of the cairo context. 
  cairo_set_source_rgba (m_pCairo, m_r, m_g, m_b, m_a); 
  cairo_save (m_pCairo); 
  cairo_move_to (m_pCairo, m_dXPos+m_dXPosStart, m_dYPos+m_dYPosStart); 
  // Let the pango layout know of the context changes above. 
  pango_layout_context_changed (m_pPangoLayout); 
  pango_cairo_update_layout (m_pCairo, m_pPangoLayout); 
  pango_cairo_show_layout (m_pCairo, m_pPangoLayout); 
  cairo_restore (m_pCairo); 
}; 

void SetFont (const char *font) 
{ 
  PangoFontDescription* pPangoFontDescription=NULL; 
  double dSize; 

  pPangoFontDescription = pango_font_description_from_string (font); 
  dSize = m_size * cairo_image_surface_get_height (m_pSurface) / 100.0 
* PANGO_SCALE; 
  pango_font_description_set_absolute_size (pPangoFontDescription, 
dSize); 
  pango_layout_set_font_description (m_pPangoLayout, 
pPangoFontDescription); 
  printf ("%s : %s : %d : %d\n", font, pango_font_description_to_string 
(pPangoFontDescription), (int) m_size, (int) dSize); 
  pango_font_description_free (pPangoFontDescription); 
  pPangoFontDescription = NULL; 
}; 
>> 