directvt/vtm v2026.04.16

on GitHub

Known Issues

• References to deleted images from the scrollback are not removed. (fixed in cb895a7)
• There is no way to do image inheritance and composition.

Changes

• This release is not compatible with previous releases.
• AnyPlex Protocol, (tracked in #902):
  • Change the way images are displayed. See the updated specification.

Attributes

Rendering & Interaction

• Normalized Source Viewport: The source document is first projected onto a virtual canvas of size 1.0 by 1.0. A rectangular fragment (crop) is then extracted from this canvas using normalized coordinates u, v (top-left) and uw, vh (size), where 1.0 equals the full canvas dimension. Negative values for uw or vh cause the extracted fragment to be flipped along the respective axis.
• Target Rectangular Area: The grid footprint is explicitly defined by the unique attributes W and H. The range of affected cell indices starts at the current cursor position and spans [0 .. W-1] horizontally and [0 .. H-1] vertically. If W or H is 0, no cells are modified, and the object is only registered in the cache.
• Pixel-wise Precision:
  • Content Positioning: The image fragment is scaled according to fit and aligned within the Clipping Box (w x h) using the a attribute.
  • Box Positioning: This Clipping Box is then aligned within the Grid Container (W x H) using the same a attribute.
  • Offsets: Shared x and y values are applied as final pixel offsets from the resulting position.
  • Final Cut: The Grid Container acts as a strict physical mask; any pixels falling outside the W x H cell area are not rendered.
• Persistence: Metadata (Object Reference + Unique attributes) is stored per-cell to survive scrollback and ensure logical linking for rectangular reflow, using only an implementation-defined minimum of data to minimize memory overhead.
• Cursor Position: Anchored at the top-left; moves to the cell immediately following the bottom-right corner of the Grid Container (W x H) after output.
• Destructivity:
  • If the gc attribute is not empty, the provided grapheme cluster is written to every cell in the target area, replacing existing text and SGR attributes.
  • If gc is empty, the output is non-destructive; existing text and SGR attributes remain visually intact.
  • Subsequent text written over the area does not destroy the underlying object. Metadata remains in the cell until explicitly replaced.
• Selection & Highlighting: When a cell is selected (e.g., mouse selection or SGR 7), the frontend applies a 0.5 opacity mask to the object's pixels within that specific cell to ensure the selection remains visible.
• Searchability: Any text contained within the document (e.g., <text> in SVG) is rendered as part of the graphic and is not indexed for terminal text search.
• Layering & Transparency: Supports per-pixel alpha. The o(ontop) attribute determines Z-order:
  • 0: [Cell BG] -> [Object] -> [Text]
  • 1: [Cell BG] -> [Text] -> [Object]
  • The cell's background color always remains at the bottom. The terminal cursor is always drawn on top. Alpha blending should be performed in linear color space.
• Foreground Color & Security: The underlying cell SGR foreground color maps to currentColor (for SVG). All external references (e.g., http://...) are ignored for security purposes.

Example

• https://commons.wikimedia.org/wiki/File:Ghostscript_Tiger.svg
• anyplex_test.ps1:

  "`e[H`e]app; gc='' id=tiger w=20 h=20 W=50 H=12 $(cat Ghostscript_Tiger.svg) f=h`a"
  while ($true)
  {
    for ($i = 0; $i -lt 40; $i++)
    {
        "`e[H`e]app;gc='' id=tiger x={0:N3} uw=$i f=n`a" -f (($i - 40) / 30)
        Start-Sleep -Milliseconds 10
    }
    for ($i = 39; $i -gt 0; $i--)
    {
        "`e[H`e]app;gc='' id=tiger x={0:N3} uw=$i f=h`a" -f ($i / 30)
        Start-Sleep -Milliseconds 10
    }
    for ($i = 0; $i -lt 40; $i++)
    {
        "`e[H`e]app;gc='' id=tiger x={0:N3} uw=0 f=n`a" -f ((-$i) / 30)
        Start-Sleep -Milliseconds 10
    }
  }