[Fontconfig] Font weights?

[Dave Pawson]

On 17 September 2011 14:34, Behdad Esfahbod <behdad at behdad.org> wrote:
> 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?

So from the figures below, mapping backwards
<40 : 75
<50 : 245
<75 : 365
<80 : 420
<100: 500
<180: 600
<200: 700
<205: 800
else  900

Thanks for that.

  Shame there are no standards in this area.

DaveP



>
> 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
>



-- 
Dave Pawson
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