Function calculateDimensions

scripts/tmux/tmux-viewer/gif-exporter.ts:53–86

* Calculate canvas dimensions based on terminal size and font metrics

(
  sessionData: SessionData,
  options: GifExportOptions
)

 * Calculate canvas dimensions based on terminal size and font metrics
 */
function calculateDimensions(
  sessionData: SessionData,
  options: GifExportOptions
): { width: number; height: number; charWidth: number; lineHeight: number } {
  const fontSize = options.fontSize ?? 14
  // Approximate character dimensions for monospace font
  const charWidth = fontSize * 0.6
  const lineHeight = fontSize * 1.2

  // Get terminal dimensions from session info or first capture
  let termWidth = 80
  let termHeight = 24

  if (sessionData.sessionInfo.dimensions) {
    termWidth =
      typeof sessionData.sessionInfo.dimensions.width === 'number'
        ? sessionData.sessionInfo.dimensions.width
        : 80
    termHeight =
      typeof sessionData.sessionInfo.dimensions.height === 'number'
        ? sessionData.sessionInfo.dimensions.height
        : 24
  }

  // Calculate canvas size with padding
  const padding = 20
  const labelHeight = options.showLabel !== false ? 30 : 0

  const width = options.width ?? Math.ceil(termWidth * charWidth + padding * 2)
  const height =
    options.height ?? Math.ceil(termHeight * lineHeight + padding * 2 + labelHeight)

  return { width, height, charWidth, lineHeight }
}

/**
 * Render a single capture frame to the canvas