BitmapData.fromRenderTextureQuad(RenderTextureQuad renderTextureQuad)

Source 

BitmapData.fromRenderTextureQuad(RenderTextureQuad renderTextureQuad)
    : this.renderTextureQuad = renderTextureQuad,
      this.width = renderTextureQuad.targetWidth,
      this.height = renderTextureQuad.targetHeight;