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normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual The ’font-weight’ property selects the weight of the font. The values ’100’ to ’900’ form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor. The keyword ’normal’ is synonymous with ’400’, and ’bold’ is synonymous with ’700’. Keywords other than ’normal’ and ’bold’ have been shown to be often confused with font names and a numerical scale was therefore chosen for the 9-value list. p { font-weight: normal } /* 400 */ h1 { font-weight: 700 } /* bold */ The ’bolder’ and ’lighter’ values select font weights that are relative to the weight inherited from the parent: strong { font-weight: bolder } Child elements inherit the resultant weight, not the keyword value. Fonts (the font data) typically have one or more properties whose values are names that are descriptive of the "weight" of a font. There is no accepted, universal meaning to these weight names. Their primary role is to distinguish faces of differing darkness within a single font family. Usage across font families is quite variant; for example a font that you might think of as being bold might be described as being Regular, Roman, Book, Medium, Semi- or DemiBold, Bold, or Black, depending on how black the "normal" face of the font is within the design. Because there is no standard usage of names, the weight property values in CSS 2.1 are given on a numerical scale in which the value ’400’ (or ’normal’) corresponds to the "normal" text face for that family. The weight name associated with that face will typically be Book, Regular, Roman, Normal or sometimes Medium. The association of other weights within a family to the numerical weight values is intended only to preserve the ordering of darkness within that family. However, the following heuristics tell how the assignment is done in typical cases: 195 2 Aug 2002 21:33 Fonts If the font family already uses a numerical scale with nine values (like e.g. OpenType does), the font weights should be mapped directly. If there is both a face labeled Medium and one labeled Book, Regular, Roman or Normal, then the Medium is normally assigned to the ’500’. The font labeled "Bold" will often correspond to the weight value ’700’. If there are fewer then 9 weights in the family, the default algorithm for filling the "holes" is as follows. If ’500’ is unassigned, it will be assigned the same font as ’400’. If any of the values ’600’, ’700’, ’800’ or ’900’ remains unassigned, they are assigned to the same face as the next darker assigned keyword, if any, or the next lighter one otherwise. If any of ’300’, ’200’ or ’100’ remains unassigned, it is assigned to the next lighter assigned keyword, if any, or the next darker otherwise. The following two examples show typical mappings. Assume four weights in the "Rattlesnake" family, from lightest to darkest: Regular, Medium, Bold, Heavy. First example of font-weight mapping Available faces Assignments "Rattlesnake Regular" 400 "Rattlesnake Medium" 500 "Rattlesnake Bold" 700 "Rattlesnake Heavy" 800 Filling the holes 100, 200, 300 600 900 Assume six weights in the "Ice Prawn" family: Book, Medium, Bold, Heavy, Black, ExtraBlack. Note that in this instance the user agent has decided not to assign a numeric value to "Ice Prawn ExtraBlack". Second example of font-weight mapping Available faces Assignments Filling the holes "Ice Prawn Book" 400 "Ice Prawn Medium" 500 "Ice Prawn Bold" 700 "Ice Prawn Heavy" 800 "Ice Prawn Black" 900 "Ice Prawn ExtraBlack" (none) 100, 200, 300 600 2 Aug 2002 21:33 196 Fonts Since the intent of the relative keywords ’bolder’ and ’lighter’ is to darken or lighten the face within the family and because a family may not have faces aligned with all the symbolic weight values, the matching of ’bolder’ is to the next darker face avail- able on the client within the family and the matching of ’lighter’ is to the next lighter face within the family. To be precise, the meaning of the relative keywords ’bolder’ and ’lighter’ is as follows: ’bolder’ selects the next weight that is assigned to a font that is darker than the [ Pobierz całość w formacie PDF ] |