terminal reports and responses. These are not intended to be used
as a general-purpose capabilities model.
+* Terminal Cache Management. This standard defines a means for
+ applications and terminals to communicate around cached multimedia
+ items, but terminals are free to implement whatever cache management
+ strategies they deem fit.
+
+* Reliable Transport. This standard defines a two-way
+ command/response protocol that may get out of order on unreliable
+ channels such as 3-wire RS232. Applictions that require reliable
+ transport on unreliable links may choose to use one of the many
+ successful standards available for this purpose.
+
Definitions
-
All Features - Detection
------------------------
Direct Multimedia - Summary
---------------------------
+Non-text data (multimedia) can be sent to the terminal for immediate
+display in a rectangular (single-layer) region of text Cells.
+Multimedia data is transmitted to the terminal using one of two wire
+formats described later in this document.
+
+Setting a Cell to multimedia is a destructive operation: the Cell's
+original text is lost. Multimedia pixels will not overlap rendered
+text in the same Cell. To achieve pixels overlaid on text, the layers
+feature can be used.
+
+Setting any part of a multi-Cell Tile to multimedia also "breaks up"
+the Tile into a range of single Cells. In other words, multimedia can
+only be carried by a Cell, not a Tile.
+
+The pixels of a multimedia Cell are assigned to the Cell's foreground;
+multimedia Cells have no background. If a terminal supports the
+layers feature, setting a multimedia Cell's foreground transparency to
+true/enabled causes that Cell to not be displayed at all; setting its
+background transparency to either true/enabled or false/disabled has
+no visible effect.
+
+The pixels of multimedia Cells can come from two sources:
+
+ 1. The application can generate pixels and send them to the terminal
+ for display at the current cursor position.
+
+ 2. The application can specify a source for the multimedia and the
+ terminal will generate the pixels for display at the current
+ cursor position.
+
Direct Multimedia - Required Support For Existing Sequences
Direct Multimedia - New Sequences
---------------------------------
+A terminal with direct multimedia feature must support the following
+new sequences:
+| Sequence | Command | Description |
+|--------------------------------------|-------------|-------------------------|
+| OSC 1 3 3 8 ; s i x e l : {data} BEL | SIXEL | Display sixel at (x, y) |
+| OSC 1 3 3 8 ; s i x e l : {data} ST | SIXEL | Display sixel at (x, y) |
+| OSC 1 3 3 8 ; F i l e = {data} BEL | DMDISPLAY | Display media at (x, y) |
+| OSC 1 3 3 8 ; F i l e = {data} ST | DMDISPLAY | Display media at (x, y) |
+| CSI ? 3 0 0 1 h | DECSET 3001 | Enable DMDISPLAY responses |
+| CSI ? 3 0 0 1 l | DECRST 3001 | Disable DMDISPLAY responses |
+| OSC 1 3 3 9 ; Pe ; {data} ST | DMRESP | Terminal response to DMDISPLAY |
+
+
+For the SIXEL command:
+
+* The {data} is a sixel sequence as described in the VT330/340
+ Programmer Reference Manual, Chapter 14, available online at:
+ http://vt100.net/docs/vt3xx-gp/chapter14.html . The {data} is the
+ "P1 ; P2 ; P3 ; q s..s" portion of the Device Control String, i.e. a
+ complete sixel sequence minus the leading DCS and trailing ST.
+
+* The sixel image is processed as shown below. Note that this
+ behavior is equivalent to Sixel Scrolling mode enabled.
+
+ - The sixel active position starts at the upper-left corner of the
+ text cursor position.
+
+ - The screen is scrolled up if the image overflows into the bottom
+ text row.
+
+ - Pixels that would be drawn to the right of the visible region on
+ screen are discarded.
+
+ - The cursor's final position is on the same column as the starting
+ cursor position, and on the row immediately below the image.
+
+
+For the DMDISPLAY command:
+
+* The {data} is a set of key-value pairs (each pair separated by
+ semicolon (';')), followed by a colon (':'), followed by a base-64
+ encoded string.
+
+* A key can be any alpha-numeric ASCII string ('0' - '9', 'A' - 'Z',
+ 'a' - 'z').
+
+* A value is any printable ASCII string not containing whitespace,
+ colon, or semicolon ('!' - '9', '<' - '~').
+
+* Any alpha-numeric key may be specified. A key that is not supported
+ by the terminal is ignored without error.
+
+* The multimedia pixels are processed as shown below.
+
+ - The pixel are drawn starting at the upper-left corner of the text
+ cursor position.
+
+ - If scrolling is specified as enabled, then:
+
+ a. The screen is scrolled up if the image overflows into the
+ bottom text row.
+
+ b. The cursor's final position is on the same column as the
+ starting cursor position, and on the row immediately below the
+ image.
+
+ - If scrolling is omitted or specified as disabled, then:
+
+ a. The screen is never scrolled.
+
+ b. Pixels that would be drawn below the visible region on screen
+ are discarded.
+
+ c. The cursor's final position is at the same column and row as
+ the starting cursor position, i.e. the cursor does not move at
+ all.
+
+ - Pixels that would be drawn to the right of the visible region on
+ screen are discarded.
+
+
+
+The keys for the key-value pairs that must be supported by the
+terminal are listed below:
+
+| Key | Default Value | Description |
+|--------------|---------------|----------------------------------------------|
+| width | 1 | Number of Cells or pixels wide to display in |
+| height | 1 | Number of Cells or pixels high to display in |
+| scale | "none" | Scale/zoom option, see below |
+| align | "nw" | Align image to edge option, see below |
+| type | "image/rgb" | mime-type describing data field |
+| url | "" | If set, a location containing the media data |
+
+A terminal may support additional keys. If a key is specified but not
+supported by the terminal, then it is ignored without error.
-Direct Multimedia - Error Handling
-----------------------------------
+The "width" and "height" values can take the following forms:
-Direct Multimedia - Cursor Position
------------------------------------
+| Value | Meaning |
+|-------------------------------|---------------------------|
+| N (a positive integer) | Number of Cells |
+| Npx (positive integer + "px") | Number of pixels |
+| N% (positive integer + "%") | Percent of screen width or height |
+| "auto" | Number of pixels as defined by the multimedia data |
-Direct Multimedia - Wire Format
--------------------------------
+The "scale" value can take the following values:
+
+| Value | Meaning |
+|------------|---------------------------------------------------------------|
+| "none" | No scaling along either axis. |
+| "scale" | Stretch image, preserving aspect ratio, to maximum size in the target area without cropping |
+| "stretch" | Stretch along both axes, distorting aspect ratio, to fill the target area |
+| "crop" | Stretch along both axes, preserving aspect ration, to completely fill the target area, cropping pixels that will not fit |
+
+
+
+The "align" value can take the following values:
+
+| Value | Meaning |
+|------------|-----------------------------------------------------------------|
+| "nw" | Media is placed at the top-left corner (northwest) |
+| "n" | Media is placed on the top and centered horizontally (north) |
+| "ne" | Media is placed at the top-right corner (northest) |
+| "w" | Media is placed on the left and centered vertically (west) |
+| "c" | Media is centered in the target area (center) |
+| "e" | Media is placed on the right and centered vertically (east) |
+| "sw" | Media is placed on the bottom-left corner (southwest) |
+| "s" | Media is placed on the bottom and centered horizontally (south) |
+| "se" | Media is placed on the bottom-right corner (southeast) |
+
+
+
+The "type" value is a mime-type string describing the format of the
+base64-encoded binary data. The terminal must support at mimunum these
+mime-types:
+
+| Type String | Description |
+|---------------|--------------------------------------------------------------|
+| "image/rgb" | Big-endian-encoded 24-bit red, green, blue values |
+| "image/rgba" | Big-endian-encoded 32-bit red, green, blue, alpha values |
+| "image/png" | PNG file data as described by (reference to PNG format) |
+
+A terminal may support additional types. An application can detect
+terminal support for a format by: enabling terminal responses (DECSET
+3001), sending a DMDISPLAY command, and examining the terminal's
+response sequence for success or error.
+
+
+
+The "url" value is a
+
+
+
+Direct Multimedia - Terminal Responses / Error Handling
+-------------------------------------------------------
+
+If DMDISPLAY reponses are enabled, then a terminal will respond to the
+DMDISPLAY display with DMRESP. DMRESP responses must be sent in the
+same sequential order as the DMDISPLAY commands they are responses to:
+the terminal may not re-order responses.
+
+No provision is made for reliable delivery. On unreliable links
+(example: 3-wire RS232), the DMDISPLAY and DMRESP command/response
+sequence may get out of order.
+
+
+
+The format of DMRESP is:
+
+* Pe - a non-negative integer error code.
+
+* The {data} is a set of key-value pairs (each pair separated by
+ semicolon (';')).
+
+* A key can be any alpha-numeric ASCII string ('0' - '9', 'A' - 'Z',
+ 'a' - 'z').
+
+* A value is any printable ASCII string not containing whitespace,
+ colon, or semicolon ('!' - '9', '<' - '~').
+
+
+The Pe error codes are defined as:
+
+| Value | Meaning | {data} containts |
+|-------|------------------------------------|--------------------------|
+| 0 | No error occurred, i.e. success | nothing |
+| 1 | Unsupported "type" | "type" value that was incorrect |
+| 2 | Invalid value - no media displayed | "key" that was incorrect |
+| 3 | Unsupported key - media displayed | "key" that unsupported |
+| 4 | Insufficient memory | nothing |
+| 5 | Other error - no media displayed | nothing |
+| 6 | Other - media displayed | nothing |
+| 7 | Conflicting keys - no media displayed | nothing |
+
+Additional Pe error codes may be returned; any Pe value except 0, 3,
+and 6 must mean that the media was not displayed, and the cursor was
+not moved.
+
+If both "type" and "url" are set, no media is diaplyed, the cursor is
+not moved, and the DMRESP error code is 7.
Cached Multimedia - Summary
---------------------------
+Non-text data (multimedia) can be sent to the terminal for later
+display in a rectangular (single-layer) region of text Cells.
+Multimedia data is transmitted to the terminal using the CMCACHE
+command described below, and displayed on screen using the CMDISPLAY
+command. A single CMCACHE command can support many CMDISPLAY
+commands.
+
+Upon display, setting a Cell to multimedia is a destructive operation:
+the Cell's original text is lost. Multimedia pixels will not overlap
+rendered text in the same Cell. To achieve pixels overlaid on text,
+the layers feature can be used.
+
+Setting any part of a multi-Cell Tile to multimedia also "breaks up"
+the Tile into a range of single Cells. In other words, multimedia can
+only be carried by a Cell, not a Tile.
+
+The pixels of a multimedia Cell are assigned to the Cell's foreground;
+multimedia Cells have no background. If a terminal supports the
+layers feature, setting a multimedia Cell's foreground transparency to
+true/enabled causes that Cell to not be displayed at all; setting its
+background transparency to either true/enabled or false/disabled has
+no visible effect.
+
+The pixels of multimedia Cells can come from two sources:
+
+ 1. The application can generate pixels and send them to the terminal
+ for display at the current cursor position.
+
+ 2. The application can specify a source for the multimedia and the
+ terminal will generate the pixels for display at the current
+ cursor position.
+
+
+
+
+Cached Multimedia - Cache/Memory Management
+-------------------------------------------
-Pixel data that has scrolled off the displayed screen and into the
-scrollback buffer is required to be persistent even if the cache entry
-containing that image data has been evicted by the terminal or removed
-by the application.
+
+
+Cached Multimedia - Scrollback
+------------------------------
Cached Multimedia - New Sequences
---------------------------------
+A terminal with cached multimedia feature must support the following new
+sequences:
+
+| Sequence | Command | Description |
+|--------------------------------------|-----------|-------------------------|
+| OSC 1 3 4 0 ; F i l e = {data} BEL | CMCACHE | Display media at (x, y) |
+| OSC 1 3 4 1 ; Pi ; {data} ST | CMDISPLAY | Display media at (x, y) |
+| OSC 1 3 4 2 ; Pi ; Pe ; {data} ST | CMCRESP | Terminal response to CMCACHE |
+| OSC 1 3 4 3 ; Pi ; Pe ; {data} ST | CMDRESP | Terminal response to CMDISPLAY |
+
+
+
+
+Cached Multimedia - CMCACHE
+---------------------------
+
+For the CMCACHE command:
+
+* The {data} is a set of key-value pairs (each pair separated by
+ semicolon (';')).
+
+* A key can be any alpha-numeric ASCII string ('0' - '9', 'A' - 'Z',
+ 'a' - 'z').
+
+* A value is any printable ASCII string not containing whitespace,
+ colon, or semicolon ('!' - '9', '<' - '~').
+
+The keys for the key-value pairs that must be supported by the
+terminal are listed below:
+
+| Key | Default Value | Description |
+|--------------|---------------|----------------------------------------------|
+| type | "image/rgb" | mime-type describing data field |
+| url | "" | If set, a location containing the media data |
+
+
+The "type" value is a mime-type string describing the format of the
+base64-encoded binary data. The terminal must support at mimunum these
+mime-types:
+
+| Type String | Description |
+|---------------|--------------------------------------------------------------|
+| "image/rgb" | Big-endian-encoded 24-bit red, green, blue values |
+| "image/rgba" | Big-endian-encoded 32-bit red, green, blue, alpha values |
+| "image/png" | PNG file data as described by (reference to PNG format) |
+
+A terminal may support additional types. An application can detect
+terminal support for a format by: sending a CMCACHE command, and
+examining the terminal's CMCRESP sequence for success or error.
+
+
+
+Cached Multimedia - CMDISPLAY
+-----------------------------
+
+For the CMDISPLAY command:
+
+* Pi - a non-negative integer media ID that was returned by a CMCRESP
+ response to a previous CMCACHE command.
+
+* The {data} is a set of key-value pairs (each pair separated by
+ semicolon (';')), followed by a colon (':'), followed by a base-64
+ encoded string.
+
+* A key can be any alpha-numeric ASCII string ('0' - '9', 'A' - 'Z',
+ 'a' - 'z').
+
+* A value is any printable ASCII string not containing whitespace,
+ colon, or semicolon ('!' - '9', '<' - '~').
+
+* Any alpha-numeric key may be specified. A key that is not supported
+ by the terminal is ignored without error.
+
+* The multimedia pixels are processed as shown below.
+
+ - The pixel are drawn starting at the upper-left corner of the text
+ cursor position.
+
+ - The screen is never scrolled.
+
+ - The cursor's final position is at the same column and row as the
+ starting cursor position, i.e. the cursor does not move at all.
+
+ - Pixels that would be drawn below the visible region on screen are
+ discarded.
+
+ - Pixels that would be drawn to the right of the visible region on
+ screen are discarded.
+
+
+
+The keys for the key-value pairs that must be supported by the
+terminal are listed below:
+
+| Key | Default Value | Description |
+|--------------|---------------|----------------------------------------------|
+| width | 1 | number of Cells or pixels wide to display in |
+| height | 1 | number of Cells or pixels high to display in |
+| scale | "none" | scale/zoom option, see below |
+| align | "nw" | align image to edge option, see below |
+
+A terminal may support additional keys. If a key is specified but not
+supported by the terminal, then it is ignored without error.
+
+
+
+The "width" and "height" values can take the following forms:
+
+| Value | Meaning |
+|-------------------------------|---------------------------|
+| N (a positive integer) | Number of Cells |
+| Npx (positive integer + "px") | Number of pixels |
+| N% (positive integer + "%") | Percent of screen width or height |
+| "auto" | Number of pixels as defined by the multimedia data |
+
+
+
+The "scale" value can take the following values:
+
+| Value | Meaning |
+|------------|---------------------------------------------------------------|
+| "none" | No scaling along either axis. |
+| "scale" | Stretch image, preserving aspect ratio, to maximum size in the target area without cropping |
+| "stretch" | Stretch along both axes, distorting aspect ratio, to fill the target area |
+| "crop" | Stretch along both axes, preserving aspect ration, to completely fill the target area, cropping pixels that will not fit |
+
+
+
+The "align" value can take the following values:
+
+| Value | Meaning |
+|------------|-----------------------------------------------------------------|
+| "nw" | Media is placed at the top-left corner (northwest) |
+| "n" | Media is placed on the top and centered horizontally (north) |
+| "ne" | Media is placed at the top-right corner (northest) |
+| "w" | Media is placed on the left and centered vertically (west) |
+| "c" | Media is centered in the target area (center) |
+| "e" | Media is placed on the right and centered vertically (east) |
+| "sw" | Media is placed on the bottom-left corner (southwest) |
+| "s" | Media is placed on the bottom and centered horizontally (south) |
+| "se" | Media is placed on the bottom-right corner (southeast) |
+
Cached Multimedia - Error Handling
----------------------------------
+A terminal will always respond to the CMCACHE command with CMCRESP,
+and to the CMDISPLAY command with CMDRESP. Responses must be sent in
+the same sequential order as the CMCACHE/CMDISPLAY commands they are
+responses to: the terminal may not re-order responses.
+No provision is made for reliable delivery. On unreliable links
+(example: 3-wire RS232), the command/response sequence may get out of
+order.
-Cached Multimedia - Cursor Position
------------------------------------
+Cached Multimedia - Error Handling - CMCRESP
+--------------------------------------------
-Cached Multimedia - Scrollback
-------------------------------
+The format of CMCRESP is:
+
+* Pi - a non-negative integer media ID. The terminal will generate a
+ new ID for every image successfully loaded into the cache. The
+ application must use this ID for CMDISPLAY commands.
+
+* Pe - a non-negative integer error code.
+
+* The {data} is a set of key-value pairs (each pair separated by
+ semicolon (';')).
+
+* A key can be any alpha-numeric ASCII string ('0' - '9', 'A' - 'Z',
+ 'a' - 'z').
+* A value is any printable ASCII string not containing whitespace,
+ colon, or semicolon ('!' - '9', '<' - '~').
-Cached Multimedia - Wire Format
--------------------------------
+The Pe error codes are defined as:
+
+| Value | Meaning | {data} containts |
+|-------|------------------------------------|--------------------------|
+| 0 | No error occurred, i.e. success | nothing |
+| 1 | Unsupported "type" | "type" value that was incorrect |
+| 2 | Invalid value - no media stored | "key" that was incorrect |
+| 3 | Unsupported key - media stored | "key" that unsupported |
+| 4 | Insufficient memory - no media stored | nothing |
+| 5 | Other error - no media stored | nothing |
+| 6 | Other - media stored | nothing |
+| 7 | Conflicting keys - no media stored | nothing |
+
+Additional Pe error codes may be returned; any Pe value except 0, 3,
+and 6 must mean that the media was not stored in the cache.
+
+If both "type" and "url" are set, no media is diaplyed, the cursor is
+not moved, and the CMCRESP error code is 7.
+
+
+
+Cached Multimedia - Error Handling - CMDRESP
+--------------------------------------------
+
+The format of CMDRESP is:
+
+* Pi - a non-negative integer media ID.
+
+* Pe - a non-negative integer error code.
+
+* The {data} is a set of key-value pairs (each pair separated by
+ semicolon (';')).
+
+* A key can be any alpha-numeric ASCII string ('0' - '9', 'A' - 'Z',
+ 'a' - 'z').
+
+* A value is any printable ASCII string not containing whitespace,
+ colon, or semicolon ('!' - '9', '<' - '~').
+
+
+The Pe error codes are defined as:
+
+| Value | Meaning | {data} containts |
+|-------|-------------------------------------|--------------------------|
+| 0 | No error occurred, i.e. success | nothing |
+| 1 | RESERVED FOR FUTURE USE | RESERVED FOR FUTURE USE |
+| 2 | Invalid value - no media displayed | "key" that was incorrect |
+| 3 | Unsupported key - media displayed | "key" that unsupported |
+| 4 | Insufficient memory - no media displayed | nothing |
+| 5 | Other error - no media displayed | nothing |
+| 6 | Other - media displayed | nothing |
+
+Additional Pe error codes may be returned; any Pe value except 0, 3,
+and 6 must mean that the media was not displayed.
* If it attempts to set Z to a value greater than the number of
layers, then Z is set to the number of layers.
-New sequences are provided to set and query Z, Y, X, to set and query
-the screen cube size, and control visibility of Cells in-front-of
+New sequences are provided to set and query Z, Y, X; to set and query
+the screen cube size; and control visibility of Cells in-front-of
other Cells.
-Operations that act on more than one Cell are defined such to act on
-all layers simultaneously by default.
+Operations that can act on more than one Cell are defined such to act
+on all layers simultaneously by default; most of these operations can
+also be set to act only on the current layer.
| Sequence | Command | Description |
|-------------------|-------------|----------------------------------------|
| CSI ? z ; y ; x H | CUPZ | Move cursor to (x, y, z) |
-| CSI ? z ; y ; x H | SLA | Set layer alpha |
-| CSI ? 3 0 0 1 h | DECSET 3001 | Enable Manupulate Single Layer (MSL) |
-| CSI ? 3 0 0 1 l | DECRST 3001 | Disable Manupulate Single Layer (MSL) |
+| CSI 2 2 5 ; 1 ; Pa t | SLA | Set layer alpha |
+| CSI ? 3 0 0 2 h | DECSET 3002 | Enable Manupulate Single Layer (MSL) |
+| CSI ? 3 0 0 2 l | DECRST 3002 | Disable Manupulate Single Layer (MSL) |
| CSI ? l ; h ; w t | RSZCUBE | Resize cube to (layers, height, width) |
Default parameters and ranges are listed below:
| CUPZ | 3 / x | 1 | 1 | # columns |
| SLA | 1 / alpha | 255 | 0 | 255 |
| RSZCUBE | 1 / l | 1 | 1 | varies |
-| RSZCUBE | 2 / h | 80 | 1 | varies |
-| RSZCUBE | 3 / w | 24 | 1 | varies |
+| RSZCUBE | 2 / h | 24 | 1 | varies |
+| RSZCUBE | 3 / w | 80 | 1 | varies |
The terminal must also support the following new queries:
| CSI ? 1 0 0 n | CSI ? z ; y ; x n | Report cursor Z, Y, X position |
| CSI ? 1 8 t | CSI ? 8 ; l ; h ; w t | Report the text area cube layers, height, width |
-
The terminal must support the following new Set Graphics Rendition
(SGR) character attributes commands:
| SGR Parameter | Description |
|---------------|---------------------------------------------|
-| 230 | Set text foreground color to transparent |
-| 239 | Set text foreground color to solid (opaque) |
-| 240 | Set text background color to transparent |
-| 249 | Set text background color to solid (opaque) |
-
+| 2 3 0 | Set text foreground color to transparent |
+| 2 3 9 | Set text foreground color to solid (opaque) |
+| 2 4 0 | Set text background color to transparent |
+| 2 4 9 | Set text background color to solid (opaque) |
| CSI $ x | DECFRA | Only current layer affected if MSL=on |
| CSI $ z | DECERA | Only current layer affected if MSL=on |
+(( TODO: add many more to the above table... ))
+
The VT52 sub-mode commands:
| Sequence | Command | Additional behavior |