Method onRender

packages/@ant/ink/src/core/ink.tsx:506–883

()

  }

  onRender() {
    if (this.isUnmounted || this.isPaused) {
      return;
    }
    // Entering a render cancels any pending drain tick — this render will
    // handle the drain (and re-schedule below if needed). Prevents a
    // wheel-event-triggered render AND a drain-timer render both firing.
    if (this.drainTimer !== null) {
      clearTimeout(this.drainTimer);
      this.drainTimer = null;
    }

    // Flush deferred interaction-time update before rendering so we call
    // Date.now() at most once per frame instead of once per keypress.
    // Done before the render to avoid dirtying state that would trigger
    // an extra React re-render cycle.
    this.options.onBeforeRender?.();

    const renderStart = performance.now();
    const terminalWidth = this.options.stdout.columns || 80;
    const terminalRows = this.options.stdout.rows || 24;

    const frame = this.renderer({
      frontFrame: this.frontFrame,
      backFrame: this.backFrame,
      isTTY: this.options.stdout.isTTY,
      terminalWidth,
      terminalRows,
      altScreen: this.altScreenActive,
      prevFrameContaminated: this.prevFrameContaminated,
    });
    const rendererMs = performance.now() - renderStart;

    // Sticky/auto-follow scrolled the ScrollBox this frame. Translate the
    // selection by the same delta so the highlight stays anchored to the
    // TEXT (native terminal behavior — the selection walks up the screen
    // as content scrolls, eventually clipping at the top). frontFrame
    // still holds the PREVIOUS frame's screen (swap is at ~500 below), so
    // captureScrolledRows reads the rows that are about to scroll out
    // before they're overwritten — the text stays copyable until the
    // selection scrolls entirely off. During drag, focus tracks the mouse
    // (screen-local) so only anchor shifts — selection grows toward the
    // mouse as the anchor walks up. After release, both ends are text-
    // anchored and move as a block.
    const follow = consumeFollowScroll();
    if (
      follow &&
      this.selection.anchor &&
      // Only translate if the selection is ON scrollbox content. Selections
      // in the footer/prompt/StickyPromptHeader are on static text — the
      // scroll doesn't move what's under them. Without this guard, a
      // footer selection would be shifted by -delta then clamped to
      // viewportBottom, teleporting it into the scrollbox. Mirror the
      // bounds check the deleted check() in ScrollKeybindingHandler had.
      this.selection.anchor.row >= follow.viewportTop &&
      this.selection.anchor.row <= follow.viewportBottom
    ) {
      const { delta, viewportTop, viewportBottom } = follow;