Function getCanvasDimensions

src/core/GPUContext.ts:45–77

Gets display dimensions - clientWidth/Height for HTMLCanvasElement, width/height for OffscreenCanvas.

(canvas: SupportedCanvas)

/** Gets display dimensions - clientWidth/Height for HTMLCanvasElement, width/height for OffscreenCanvas. */
function getCanvasDimensions(canvas: SupportedCanvas): { width: number; height: number } {
  if (isHTMLCanvasElement(canvas)) {
    // Prefer clientWidth/clientHeight (CSS pixels) for HTMLCanvasElement as they reflect actual display size
    // Fall back to canvas.width/height (device pixels) if client dimensions are 0 or invalid
    const width = canvas.clientWidth || canvas.width || 0;
    const height = canvas.clientHeight || canvas.height || 0;
    
    // Validate dimensions are finite and non-negative
    // Note: 0 dimensions are allowed here - they'll be clamped to 1 during GPUContext initialization
    if (!Number.isFinite(width) || !Number.isFinite(height)) {
      throw new Error(
        `GPUContext: Invalid canvas dimensions detected: width=${canvas.clientWidth || canvas.width}, ` +
        `height=${canvas.clientHeight || canvas.height}. ` +
        `Canvas must have finite dimensions. Ensure canvas is properly sized before initialization.`
      );
    }
    
    return { width, height };
  }
  // OffscreenCanvas: dimensions already set by main thread (device pixels)
  const width = canvas.width;
  const height = canvas.height;
  
  // Validate OffscreenCanvas dimensions
  if (!Number.isFinite(width) || !Number.isFinite(height)) {
    throw new Error(
      `GPUContext: Invalid OffscreenCanvas dimensions: width=${width}, height=${height}. ` +
      `OffscreenCanvas must be initialized with finite dimensions before GPUContext creation.`
    );
  }
  
  return { width, height };
}

/**
 * Creates a new GPUContext state with initial values.