Starbase Functionality

Hardware Character Sets

When performing hardware generated text, this device driver will recognize the following character sets for the call designate_character_set. The device driver will then instruct the device to load that specific character set. If the designated character set is not supported, an error may or may not be reported according to the state of the buffer mode flag (see “Error Reporting and Buffer Mode ” in this section). You should check the device hardware manual to see if the device will support the designated character set. At this time the device driver does not support variable width characters.




	NOTE: Hardware character sets are not supported when the device is `gopen`ed with `INT_XFORM`.

Table 1-4 Hardware Character Sets

Font #	CHSET name	Description
0	`usascii`	ANSI ASCII
1	`9825`	9825 Character Set
2	`french`	French
2	`german`	German
3	`scandinavian`	Scandinavain
4	`spanish`	Spanish/Latin American
5	`special`	Special Symbols
6	`jisascii`	JIS ASCII
7	`hproman`	Roman Extensions
8	`katakana`	Katakana
9	`iso_irv`	ISO Inter. Ref. Vers.
30	`iso_swedish_1`	ISO Swedish
31	`iso_swedish_2`	ISO Swedish for Names
32	`iso_norway_v1`	ISO Norway, Version 1
33	`iso_german`	ISO German
34	`iso_french_v1`	ISO French, Version 1
35	`iso_united`	ISO United Kingdom
36	`iso_italian`	ISO Italian
37	`iso_spanish`	ISO Spanish
38	`iso_portugues` ^[1]	ISO Portuguese
39	`iso_norway_v2`	ISO Norway, Version 2
60	`iso_french_v2`	ISO French, Version 2
99	`iso_drafting`	Drafting Symbols
100	`kanji_v1`	Kanji, part 1
101	`kanji_v2`	Kanji, part 2
^[1]This is not a typographical error. The program recognizes this spelling.

Error Reporting and Buffer Mode

This device driver has two states for reporting errors depending on the buffer mode, as set by the procedure buffer_mode.

Buffering On
When buffering is enabled, the device driver will buffer all commands in an internal buffer before sending them to the device. All HP-GL errors generated by the device will be masked out. Regular Starbase errors will still be reported as normal.
Buffering Off
When buffering is disabled, the device driver will send each command to the device as it receives it. After each command is sent, the device driver will then inquire the device's status and report any HP-GL errors that occurred. This mode should only be used when debugging an application.

When the gopen mode is SPOOLED, the spooled file will mask out all HP-GL errors generated, regardless of the buffer mode.

Hardware Polygon Support

All Starbase polygon interiors and borders are drawn by using the device's hardware support for polygons. This will normally result in an increase in rendering speed and a decrease in the size of spooled files. Polygon hardware support conforms to Starbase specifications as defined in the Starbase Graphics Techniques manual. Hardware support is provided through the use of the HP-GL commands PM, FP, and EP. You cannot turn off hardware support of polygons.^[5]

The number of vertices supported is device dependent. For some devices, the default number of vertices supported can be modified by adjusting the size of the memory partitions through software control. There are two methods of changing the memory partition: through use of the HP-GL command GM and use of the HP-GL escape function "ESC.T". Users should refer to the device's programming manual on using these commands. The following table summarizes the default number of vertices supported and if that default can be changed using the HP-GL command GM or "ESC.T".

Table 1-5 Polygon Vertex Support

Device	# Vertices	GM	`ESC.T`
HP 7596A	219	yes	yes
HP 7595A	219	yes	yes
HP 7586B	218	no	yes
HP 7585B	218	no	yes
HP 7580B	218	no	yes
HP 7570A	93	yes	yes
HP 7550A	127	yes	yes
HP 7510A	495	yes	yes
HP C1600A	1500 ^[1]	no	no
HP C1601A	1500 *	no	no
HP 7575A	93	yes	yes
HP 7576A	93	yes	yes
^[1]The plotter has 16,900 bytes of available memory allocated to the downloadable character buffer as needed, the rest goes to the polygon buffer. For example, dividing 16,900 by 8 equals 2112.5. If you allow some extra for fill types, you can estimate that a polygon with up to 1500 points easily fits in the polygon buffer.

Hardware Rectangle Support

All Starbase rectangle interiors are drawn by using the device's hardware support for polygons. This will normally result in an increase in rendering speed and a decrease in the size of spooled files. Rectangle hardware support conforms to Starbase specifications as defined in the Starbase Graphics Techniques manual. Hardware support is provided through the use of the HP-GL commands PM, FP and EP. You cannot turn off hardware support of rectangles.^[6]

Hardware Text Support

Starbase text can be drawn by using the device's hardware support for text. This support is conditional on use of the Starbase procedure text_precision with a precision parameter of STRING_TEXT. This will normally result in an increase in rendering speed, a decrease in the size of spooled files, and an increase in text quality. Since this support is user selectable, not all of those devices supported through this device driver support all those features of Starbase text. Differences between device hardware generated text and Starbase software generated text are listed below:

Table 1-6 Hardware Text Support

Starbase Call	Parameter	Group 1	Group 2	Group 3
`text_precision`	`STRING_TEXT`	yes	yes	no
`text_path`	`PATH_LEFT`	no	no	no
`text_path`	`PATH_UP`	no	no	no
`text_path`	`PATH_DOWN`	yes	no	no
`text_font_index`	〈`index`〉 = 2	no	no	no
`text_alignment`	`TA_CONTINUOUS_HORIZONTAL`	no	no	no
`text_alignment`	`TA_CONTINUOUS_VERTICAL`	no	no	no
`text_alignment`	`TA_CAP`	no	no	no
`text_alignment`	`TA_BASE`	no	no	no
`text_line_path`	(all)	no	no	no

Group 1 = HP 7575A, HP 7576A.HP 7595A, HP 7596A.
Group 2 = HP 7586B, HP 7585B, HP 7580B, HP 7550A, HP 7510A, HP C1600A, and HP C1601A.
Group 3 = HP 7570A.

Pen Selection

If a program specifies a pen number that is larger then the number of pens the device has, the device driver will perform a MOD calculation to define the actual pen to be used. If the mod calculation returns a value of zero, then the largest pen number will be used instead.

If pen number 0 is selected, then a device dependent action will occur and you should consult your device hardware manual. In general, pen 0 will cause most devices to not select any pen at all when performing any drawing operation.

Roll Paper, Autoloading and Rasterizing

The device driver will attempt to set the paper size and perform a page feed using the HP-GL commands PS and PG when the Starbase procedure gclose is called. This will cause those devices using roll paper or having autoloading capabilities to feed the current drawing out. For those devices that accept HP-GL commands and then rasterize the data for output, this will cause the rasterization to occur and the drawing to be ejected. Devices supporting this functionality are shown below:

HP 7596A
HP 7586B
HP 7550A
HP 7510A
HP C1600A
HP C1601A

New Device Support

This driver uses a subset of the HP-GL command language. When attempting to use this device driver with unsupported devices, that device should support those HP-GL commands as required below:

Table 1-7 HP-GL Command Support

`CM`*	`DF`	`DI`*	`DS`Q
`DV`*	`EP`**	`ES`*	`FP`**
`IM`	`IN`	`IP`	`IV`*
`LB`*	`LO`*	`LT`**	`OE`
`OF`	`OI`	`OP`	`PA`**
`D`**	`PG`***	`PM`**	`PS`***
`PT`**	`PU`**	`SC`	`SR`*
`SL`*	`SP`**	`VS`

*: This command is only required for hardware text. If Starbase software generated text is used, the device does not need to support this command.
**: This command is used for generating polygons, rectangles and lines. The device must implement this command for correctly displaying primitives.
***: This command is used for support of roll paper, autoloading and rasterizing devices.

Exceptions to Standard Starbase Support

Commands Not Supported (no-ops)

The following commands are not supported. If one of these commands is used, it is ignored.

 alpha_transparency                display_enable
 await_retrace                     double_buffer
 backface_control                  drawing_mode
 background_color                  file_to_bitmap
 background_color_index            file_to_dcbitmap
 bank_switch                       file_to_intbitmap
 bf_alpha_transparency             fill_dither
 bf_control                        hidden_surface
 bf_fill_color                     intbitmap_print
 bf_interior_style                 intbitmap_to_file
 bf_perimeter_color                intblock_move
 bf_perimeter_repeat_length        intblock_read
 bf_perimeter_type                 intblock_write
 bf_surface_coefficients           interior_style (INT_OUTLINE)
 bf_surface_model                  interior_style (INT_POINT)
 bf_texture_index                  intline_width
 bitmap_print                      light_ambient
 bitmap_to_file                    light_attenuation
 block_move                        light_model
 block_read                        light_source
 block_write                       light_switch
 clear_control                     line_endpoint
 contour_enable                    line_filter
 dbuffer_switch                    pattern_define
 dcbitmap_print                    perimeter_filter
 dcbitmap_to_file                  set_capping_planes
 dcblock_move                      set_model_clip_indicator
 dcblock_read                      set_model_clip_volume
 dcblock_write                     shade_mode
 define_contour_table              shade_range
 define_raster_echo                surface_coefficients
 define_texture                    surface_model
 define_trimming_curve             texture_index
 deformation_mode                  texture_viewport
 depth_cue                         texture_window
 depth_cue_color                   viewpoint
 depth_cue_range                   write_enable
 depth_cue-range                    zbuffer_switch

Commands Conditionally Supported

The following commands are supported under the listed conditions:

clear_view_surface

Indicates a new page on devices with automatic paper feeders.^[7]

define_color_table

updates software color table only (an operator must physically change the pens).

hatch_spacing

care should be taken to specify spacings greater than or equal to one pen width.

interior_style

only the INT_SOLID, INT_HATCH, and INT_HOLLOW styles are supported.

with_data

The following routines are called with_data routines because they contain with_data in their routine names. These with_data routines are supported by the CADPLT graphics devices.

partial_polygon_with_data3d
polygon_with_data3d
polyhedron_with_data
polyline_with_data3d
polymarker_with_data3d
quadrilateral_mesh_with_data
triangle_strip_with_data

For detailed information on these routines, read the Starbase Reference. In some cases, you will be able to find the routines under their own name, but in other cases, you will need to use the first part of the routine name to locate these routines (e.g., polyline_with_data3d is described on the man page for polyline(3G)).

vertex_format

the 〈use〉 parameter must be zero, any extra coordinates supplied will be ignored.

^[5]The present exception to this is for polygons drawn with the interior_style parameter INT_HATCH. At this time, hatching is performed only through software.

^[6]The present exception to this is for polygons drawn with the interior_style parameter INT_HATCH. At this time, hatching is performed only through software.

^[7]Some plotters will only eject the paper if it has been plotted on.