The graphics plane is used to represent all visible's except MPEG I-frames. The CI Application menu shall have a drawing area of 720x576 pixels. The graphics plane shall match the current video resolution and aspect ratio. Where high definition video is present then the graphics plane shall be scaled to match the current video resolution and aspect ratio.
The CI Plus Graphics plane shall be above the video(s) and any subtitling plane. Any intermediate planes separating the CI Plus graphics plane and video (and subtitle) plane may optionally be disabled or made transparent. i.e. in an application environment the application graphics plane may be visible if the CI Plus Application display includes transparency.
The minimum colour palette and colour space representation is defined by D-Book 5.0 [23], section 14. It is recommended that truecolour with a minimum of 16 bits is implemented.
12.4.1
LineArt and Dynamic LineArt
LineArt and Dynamic LineArt shall not be required by CIEngineProfile1, as defined in D-Book 5.0 [23], section 14.5.
12.4.2
PNG Bitmaps
PNG bitmaps shall conform to D-Book 5.0 [23], section 14.7.
12.4.3
MPEG Stills
MPEG stills or I-frames shall conform to D-Book 5.0 [23], section 14.8.
12.4.4
User Input
The User Input is defined in D-Book 5.0 [23], section 13.6. A CI Plus initiated application may start in any register group setting including Register Group 5.
12.4.5
High definition graphics model.
High definition receivers (i.e. ones that are capable of decoding and presenting HD resolution video) shall observe the Engine Graphics Model defined in clause 12.4 and 12.4.1 to 12.4.4 with the exceptions specified by the HDGraphicsPlaneExtension and HDVideoExtension as defined in ETSI MHEG [38] clause 12.11 and related clauses.
12.4.5.1
Discovery
CI Plus applications shall be able to determine the graphics capability of the receiver to which they are delivered. Hosts supporting the HD graphics model shall support the “HDExtension” (“HDE”) GetEngineSupport feature string as defined in ETSI MHEG [38] clause 11.4.1.
12.5
Engine Text
CIEngineProfile1 has full conformance with D-Book 5.0 [23], section 15. except as documented in the following sections. These replace sections 15.3.1 and 15.3.1.1 in D-Book 5.0.
The character repertoire of CIEngineProfile1 shall minimally be the character repertoire of UKEngineProfile1 when the resident font is used. The MHEG application may use other characters that are available in an alternative character set after first confirming the presence of the character set in rec://font/xxx, where xxx is the required character set.
CIEngineProfile1 has a font attribute class of "rec://font/CI1".
Downloaded fonts may have a wider character repertoire and all characters in a downloaded font shall be supported.
12.5.1
Downloadable Fonts
Receivers may optionally support downloadable fonts using the MHEG-5 Font class. Support is indicated by a positive response to DownloadableFont for the supported content hook. Only receiver fonts may be referenced by name, downloaded fonts shall be referenced as an MHEG-5 Font object. The receiver shall support all characters in a downloaded font and will not be limited to a country specific engine profile. The set of supported characters in any receiver embedded font file may be limited to a country specific set of characters.
A receiver supporting Downloadable fonts shall minimally reserve 256K bytes of memory for dynamically loaded fonts. Asian fonts, such as Chinese, require the receiver to reserve significantly more font resource memory. CI Plus enabled receivers deployed in these areas shall determine the CI Plus memory requirement based on the broadcast requirements of the local region.
Where downloadable fonts are supported by a Host then the Host is only required to support the download of a single font. A Host may optionally support more than one downloadable font.
12.5.1.1
OpenType Fonts
The CHook value of 10 is defined as being an OpenType® font meeting version 1.4 of the OpenType specification with TrueType™ outlines and as published on the following web sites:
<http://www.microsoft.com/typography/otspec/default.htm> <http://partners.adobe.com/asn/tech/type/opentype/index.jsp>
TrueType Collections are not supported in this profile. A font file is considered to contain a single font. This single font will be referenced as the default font style 'plain'. Where downloadable fonts are supported receivers are required to support the following tables:
tables related to TrueType outlines
For OpenType fonts, the following table defines the values to be used for the font metrics parameters referenced in D-Book 5.0 [23], section 15.5 "Text Rendering".
Table 12.7: OpenType font parameters
Parameter name Obtained from
metricsResolution, outlineResolution
unitsPerEm field, defined in the Font Header („head‟) table advanceWidth,
charSetWidth
advanceWidth values, defined in the Horizontal Metrics ('htmx') table. see note
xMin, yMin, yMax defined in the Font Header ('head') table Kern value, defined in the Kerning ('kern') table
Note: for monospaced fonts, only a single advance width may be defined.
12.5.1.2
Presentation
When a text object references a downloaded font the object shall be presented as defined in D-Book 5.0 [23] section 14.10, "Appearance of Visible objects during content retrieval" until successful download of the font or font download fails. Should the font download fail the receiver shall use the receivers default built-in font instead. When the receivers built-in font is used the text object shall be rendered using the rules for that font including the receivers defined Character repertoire.
12.5.1.3
Defensive Response
Font downloads may fail and applications may request invalid or unsupported features and characteristics. In order to handle these events in a predictable and robust manner receivers shall implement the following measures:
The receiver shall use its inbuilt font in place of the download font when: o The requested font is unavailable
o The content hook is unrecognised o The font attributes are invalid
When the receiver font is used then the text box shall be rendered as though the receiver font had been specified. The only supported font style is 'plain'. If any other font style is specified it shall be treated as 'plain'. If the requested font size is not supported by the font then the next smaller size shall be used. If the
required font is smaller than the smallest available, then the smallest available size shall be used.