[Fontconfig] Font weights?

[Behdad Esfahbod]

On 09/17/11 08:00, Dave Pawson wrote:
> W3c css has
> http://www.w3.org/TR/css3-fonts/#font-weight-prop
> 
> 100 - Thin
> 200 - Extra Light (Ultra Light)
> 300 - Light
> 400 - Normal
> 500 - Medium
> 600 - Semi Bold (Demi Bold)
> 700 - Bold
> 800 - Extra Bold (Ultra Bold)
> 900 - Black (Heavy)
> 
> fontconfig has
> 
> #define FC_WEIGHT_THIN		    0
> #define FC_WEIGHT_EXTRALIGHT	    40
> #define FC_WEIGHT_ULTRALIGHT	    FC_WEIGHT_EXTRALIGHT
> #define FC_WEIGHT_LIGHT		    50
> #define FC_WEIGHT_BOOK		    75
> #define FC_WEIGHT_REGULAR	    80
> #define FC_WEIGHT_NORMAL	    FC_WEIGHT_REGULAR
> #define FC_WEIGHT_MEDIUM	    100
> #define FC_WEIGHT_DEMIBOLD	    180
> #define FC_WEIGHT_SEMIBOLD	    FC_WEIGHT_DEMIBOLD
> #define FC_WEIGHT_BOLD		    200
> #define FC_WEIGHT_EXTRABOLD	    205
> #define FC_WEIGHT_ULTRABOLD	    FC_WEIGHT_EXTRABOLD
> #define FC_WEIGHT_BLACK		    210
> #define FC_WEIGHT_HEAVY		    FC_WEIGHT_BLACK
> #define FC_WEIGHT_EXTRABLACK	    215
> #define FC_WEIGHT_ULTRABLACK	    FC_WEIGHT_EXTRABLACK
> 
> Is there any clear relationship between them please?

This is how Pango maps them:


static int
pango_fc_convert_weight_to_fc (PangoWeight pango_weight)
{
  if (pango_weight <= (PANGO_WEIGHT_THIN + PANGO_WEIGHT_ULTRALIGHT) / 2)
    return FC_WEIGHT_THIN;
  else if (pango_weight <= (PANGO_WEIGHT_ULTRALIGHT + PANGO_WEIGHT_LIGHT) / 2)
    return FC_WEIGHT_ULTRALIGHT;
  else if (pango_weight <= (PANGO_WEIGHT_LIGHT + PANGO_WEIGHT_BOOK) / 2)
    return FC_WEIGHT_LIGHT;
  else if (pango_weight <= (PANGO_WEIGHT_BOOK + PANGO_WEIGHT_NORMAL) / 2)
    return FC_WEIGHT_BOOK;
  else if (pango_weight <= (PANGO_WEIGHT_NORMAL + PANGO_WEIGHT_MEDIUM) / 2)
    return FC_WEIGHT_NORMAL;
  else if (pango_weight <= (PANGO_WEIGHT_MEDIUM + PANGO_WEIGHT_SEMIBOLD) / 2)
    return FC_WEIGHT_MEDIUM;
  else if (pango_weight <= (PANGO_WEIGHT_SEMIBOLD + PANGO_WEIGHT_BOLD) / 2)
    return FC_WEIGHT_DEMIBOLD;
  else if (pango_weight <= (PANGO_WEIGHT_BOLD + PANGO_WEIGHT_ULTRABOLD) / 2)
    return FC_WEIGHT_BOLD;
  else if (pango_weight <= (PANGO_WEIGHT_ULTRABOLD + PANGO_WEIGHT_HEAVY) / 2)
    return FC_WEIGHT_ULTRABOLD;
  else if (pango_weight <= (PANGO_WEIGHT_HEAVY + PANGO_WEIGHT_ULTRAHEAVY) / 2)
    return FC_WEIGHT_BLACK;
  else
    return FC_WEIGHT_EXTRABLACK;
}

where:

typedef enum {
  PANGO_WEIGHT_THIN = 100,
  PANGO_WEIGHT_ULTRALIGHT = 200,
  PANGO_WEIGHT_LIGHT = 300,
  PANGO_WEIGHT_BOOK = 380,
  PANGO_WEIGHT_NORMAL = 400,
  PANGO_WEIGHT_MEDIUM = 500,
  PANGO_WEIGHT_SEMIBOLD = 600,
  PANGO_WEIGHT_BOLD = 700,
  PANGO_WEIGHT_ULTRABOLD = 800,
  PANGO_WEIGHT_HEAVY = 900,
  PANGO_WEIGHT_ULTRAHEAVY = 1000
} PangoWeight;


behdad

> TIA