Note - The correspondence between pel spacing, line spacing and resolution is: w 旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴쩡컴컴컴컴컴컴컴컴컴컴컴컴컴� � Pel spacing and line � Resolution in number � � spacing in BMU � of pels per 1200 BMU � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴� � 6 � 200 � � 5 � 240 � � 4 � 300 � � 3 � 400 � � 2 � 600 � � 1 � 1200 � 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴좔컴컴컴컴컴컴컴컴컴컴컴컴컴� 6.3 Logical presentation attributes 6.3.1image dimensions CATEGORY: Logical APPLICABILITY: Formatted processable content architecture class STRUCTURE: One of four parameters: a) "width controlled" with sub-parameters: - "minimum width", - "preferred height" b) "height controlled" with sub-parameters: - "minimum height:, - "preferred height" c) "area controlled" with sub-parameters: - "minimum width", - "preferred width", - "minimum height", - "preferred height", - "aspect ratio flag" d) "automatic" with no sub-parameters. PERMISSIBLE VALUES: "minimum width": non-negative integer, "preferred width": non-negative integer, "minimum height": non-negative integer, "preferred height": non-negative integer, "aspect ratio flag": 'fixed', 'variable' "automatic": 'null' DEFAULT VALUES: "automatic". DEFINITION: This attribute specifies the intended dimensions of the basic layout object that is to contain the clipped pel array. The values of "minimum width" and preferred width" specify, respectively, the lower limit and the upper limit of the allowed dimensions of the basic layout object in the direction of the pel path. The value of the "minimum width" shall not to be greater than the value of the "preferred width". The values of "minimum height" and "preferred height" specify, respectively, the lower limit and the upper limit of the dimensions of the basic layout object in the direction of the line progression. The value of the "minimum height" shall not to be greater than the value of the "preferred height". Fascicle VII.6 - Rec. T.417 1 If either or both of the values of the preferred parameters are specified, the corresponding dimensions of the basic layout object are required to be as close to these values as possible. If only the width is specified (case a), this attribute specifies that the height shall be such that the aspect ratio of the clipped pel array is maintained. If only the range of allowed heights is specified (case b), this attribute specifies that the width shall be such that the aspect ratio of the clipped pel array is maintained. If both the ranges of allowed widths and heights are specified (case c) the value of "aspect ratio flag" determines whether or not the aspect ratio of the clipped pel array shall be maintained during the determination of the dimensions of the basic layout object. If neither the range of allowed heights nor the range of allowed widths is specified (case d), this attribute specifies that the aspect ratio of the basic layout object shall be the same as the aspect ration of the clipped pel array, and also that the dimension of the basic layout object in the direction of the pel path shall be equal to the dimension of the available area in that direction. All parameters specifying a width or height are specified in SMUs. 6.3.2pel spacing CATEGORY: Logical APPLICABILITY: Formatted processable content architecture class STRUCTURE: Two parameters: "length" "pel spaces" or the value: 'null' PERMISSIBLE VALUES: "length": positive integer "pel spaces": positive integer DEFAULT VALUES: "length": 4 "pel spaces": 1 DEFINITION: This attribute specifies the method for determining the distance between successive pels along a line. The attribute consists of either 'null', or the two parameters "length" (with integer value m) and "pel spaces" (with integer value n). If the attribute takes a value of 'null' the scalable dimension content layout method is followed. If the attribute consists of the two parameters, the ratio of the integers m and n (m/n) specifies the spacing in SMUs between two successive pels, and the fixed dimension content layout method is followed. REMARKS: The scalable and fixed dimension content layout methods are described in Section 10. 6.3.3spacing ratio CATEGORY: Logical APPLICABILITY: Formatted processable content architecture class 2 Fascicle VII.6 - Rec. T.417 STRUCTURE: Two parameters: "line spacing value" "pel spacing value" PERMISSIBLE VALUES: "line spacing value": positive integer "pel spacing value": positive integer Fascicle VII.6 - Rec. T.417 3 DEFAULT VALUES: "line spacing value": 1 "pel spacing value": 1 DEFINITION: This attribute specifies the ratio between the line spacing and the pel spacing of the image represented by the content portion. This ratio is to be observed by the raster graphics content layout process (defined in Section 10) in determining the block size, and by the imaging process (defined in Section 11) to avoid image distortion. The value of this attribute consists of two parameters, the "line spacing value" and the "pel spacing value", the ratio of which equals the ratio of the line spacing to be pel spacing. REMARKS: The attribute "spacing ratio" one has an effect when the value of the parameter "aspect ratio flag" in the attribute "image dimensions" is set to 'fixed'. 6.4 Content architecture class attributes 6.4.1Content architecture class The value of the attribute "content architecture class" of a basic component description that conforms to this Recommendation is an ASN.1 object identifier with one of the following values: { 2 8 2 7 0 } for the formatted content architecture class; { 2 8 2 7 2 } for the formatted processable content architecture class. 6.4.2Content type The formatted content architecture class can be specified by the attribute "content type" with the value 1. Note - Use of the attribute "content type" as an alternative to use of the content architec- ture class attribute "content architecture class" is permitted only for compatibility with Recommendation T.73 (1984). 7 Definition of raster graphics content portion attributes According to Recommendation T.412, content portion attributes consist of four categories: - identification attributes; - common coding attributes; - coding attributes; - content information attributes. The identification attributes are completely defined in Recommendation T.412. The common coding attributes are described in Recommendation T.412; attribute values that are specific to raster graphics content architectures are specified in  7.1. Coding attributes are defined in  7.2 and the format of the content information, i.e. the possible values of content information attributes, is specified in  7.3. 7.1 Common coding attributes 7.1.1type of coding CLASSIFICATION: Defaultable 4 Fascicle VII.6 - Rec. T.417 APPLICABILITY: Formatted and formatted processable content architecture class STRUCTURE: ASN.1 object identifier or non-negative integer Fascicle VII.6 - Rec. T.417 5 PERMISSIBLE VALUES: ASN.1 object identifier: { 2 8 3 7 0 } for 'Rec. T.6 encoding', { 2 8 3 7 1 } for 'Rec. T.4 one dimensional encoding', { 2 8 3 7 2 } for 'Rec. T.4 two dimensional encoding', { 2 8 3 7 3 } for 'bitmap encoding' non-negative integer: 0 for 'Rec. T.6 encoding; DEFAULT VALUE: 'Rec. T.6 encoding' DEFINITION: For the raster graphics content architectures, the possible values of this attribute are: - 'Rec. T.6 encoding', according to the two dimensional encoding scheme defined in Recommendation T.6; - 'Rec. T.4 one dimensional encoding', according to the one dimensional encoding scheme defined in Recommendation T.4; - 'Rec. T.4 two dimensional encoding', according to the two dimensional encoding scheme defined in Recommendation T.4; - 'bitmap encoding'. An explanation of these coding schemes is given in Section 9. The value of the attribute "type of coding" of a content portion description, that conforms to this Recommendation, is an ASN.1 object identifier or an integer. REMARKS: For bitmap encoding, the relationship between the order of the pels and the order of the bits within an octet is such that the first pel in the order of bits is allocated to the most significant bit of an octet. 7.2 Coding attributes These attributes provide information required for encoding and decoding the content information, as well as other information that is intrinsic to the content portion and required by the content layout and imaging processes. 7.2.1compression CLASSIFICATION: Defaultable APPLICABILITY: Formatted and formatted processable content architecture class PERMISSIBLE VALUES: 'Compressed', 'uncompressed' DEFAULT VALUE: 'Compressed' DEFINITION: This attribute indicates if the code extension technique for uncompressed mode is present in the content portion. This attribute can have one of two values: - 'compressed' indicates that the code extension technique for uncompressed mode is not used.; - 'uncompressed' indicates that the code extension technique for uncompressed mode may be used. Note - Basic mode (compressed) encoding is used initially for coding all such content portions. The occurrence of the code extension technique for uncompressed mode coding results in subsequent content being coded in uncompressed mode. REMARKS: This attribute is only applicable if the value of the attribute "type of coding" is 6 Fascicle VII.6 - Rec. T.417 'Rec. T.6 encoding' or 'Rec. T.4 two dimensional encoding'. Fascicle VII.6 - Rec. T.417 7 7.2.2number of lines CLASSIFICATION: Non-mandatory APPLICABILITY: Formatted processable content architecture class PERMISSIBLE VALUES: Positive integer DEFINITION: This attribute specifies the number of lines of pels within a content portion. REMARKS: This attribute takes effect during the content layout process. 7.2.3number of pels per line CLASSIFICATION: Defaultable for components of the formatted content architecture class; Mandatory for components of the formatted processable content architecture class. APPLICABILITY: Formatted and formatted processable content architecture classes PERMISSIBLE VALUES: Non-negative integer DEFAULT VALUE: The default value for components of the formatted content architecture class depends upon the "pel transmission density" as specified in Table 3/T.417. No default value is specified for components of the formatted processable content architecture class. TABLE 3/T.417 Default value of the presentation attribute "number of pels per line" w 旼컴컴컴컴컴컴컴컴컴컴컫컴컴컴컴컴컴컴컴컴컴컴컴컴� � Pel transmission � Default number of � � density (BMU) � pels per line � 쳐컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴� � 1 � 10 368 � � 2 � 5 184 � � 3 � 3 456 � � 4 � 2 592 � � 5 � 2 074 � � 6 � 1 728 � 읕컴컴컴컴컴컴컴컴컴컴컨컴컴컴컴컴컴컴컴컴컴컴컴컴� DEFINITION: This attribute specifies the number of pels in each line within a content portion. 7.2.4number of discarded pels CLASSIFICATION: Defaultable APPLICABILITY: Formatted content architecture class PERMISSIBLE VALUES: Non-negative integer DEFAULT VALUE: If the number of pels per line exceeds the line length, then the default value is half the excess number of discarded pels, otherwise it is 0. 8 Fascicle VII.6 - Rec. T.417 DEFINITION: This attribute specifies the number of pels that are to be ignored at the beginning of each line within a content portion. The positioning of each line is started from the next pel in the line. 7.3 Content information attributes 7.3.1content information For raster graphics content architectures, the value of this attribute is an octet string representing a pel array encoded according to the value of the attribute "type of coding". 7.4 Interactions with document architecture attributes The layout directives "indivisibility" and "concatenation" are not taken into account during the layout of raster graphics content associated with a basic logical component. 8 Formal definitions of raster graphics content architecture dependent data types 8.1 Introduction This section contains formal definitions in ASN.1 notation (defined in Recommendation X.208) of the data types corresponding to presentation and coding attributes that are applicable to raster graphics content architectures. These data types are: - the data type to represent raster graphics content architecture specific presentation attributes in basic layout components, presentation styles and default value lists; - the data type to represent raster graphics content architecture specific coding attributes in content portions; - the data type to represent non-basic values of raster graphics content architecture presentation attributes in the document profile; - the data type to represent non-basic values of raster graphics content architecture coding attributes in the document profile; - the data type to represent non-standard default values of raster graphics content architecture presentation and coding attributes in the document profile. 8.2 Representation of presentation attributes The data type "Raster-Graphics-Attributes" contains a set of subordinate data types that specify the raster graphics presentation attributes. Some of these subordinate data types are elementary but others are structured and are themselves made up of subordinate data types. The format of these data types is given below. The subset of subordinate data types that may occur within a particular instance of the data type "Raster-Graphics-Attributes" depends upon the particular raster graphics content architecture level that is specified. Fascicle VII.6 - Rec. T.417 9