par-term-render

GPU-accelerated rendering engine for the par-term terminal emulator.

This crate provides the full rendering pipeline: cell-based GPU rendering with a glyph atlas, inline graphics (Sixel, iTerm2, Kitty), custom GLSL post-processing shaders (Shadertoy/Ghostty compatible), scrollbar rendering with mark overlays, and background image support. All rendering is performed via wgpu.

What This Crate Provides

• CellRenderer — main renderer for terminal cells; manages the glyph atlas, instance buffers, and per-frame draw call generation
• PaneViewport — viewport parameters for a single terminal pane
• Renderer — top-level compositor: manages split-pane layouts, dividers, pane titles, and orchestrates three-phase draw calls (backgrounds → text → cursor overlays)
• RendererParams — per-frame parameters passed to the renderer
• CustomShaderRenderer — GLSL-to-WGSL transpilation and post-processing pipeline
• GraphicsRenderer — inline graphics rendering (Sixel, iTerm2, Kitty protocol)
• Scrollbar — scrollbar rendering with scrollback mark overlays
• RenderError — error type for GPU initialization and render failures

Rendering Architecture

The renderer uses three render phases per frame, enforced by emit_three_phase_draw_calls():

1. Backgrounds — cell background quads (cell_bg.wgsl)
2. Text — glyph instances from the atlas (cell_text.wgsl)
3. Cursor overlays — beam, underline, and hollow cursor shapes

This ordering is mandatory: cursor overlays must render after text, or beam/underline cursors are hidden under glyph quads.

GPU Pipelines

Workspace Position

Layer 3 in the dependency graph. Depends on par-term-config (Layer 1) and par-term-fonts (Layer 2). Used directly by the root par-term crate.

Related Documentation

• Custom Shaders — background and cursor shader documentation
• Shader Gallery — included shader reference
• GPU Compositor — render layer details
• Architecture Overview — workspace structure
• Crate Structure — dependency layers