Documentation
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Overview ¶
Package render provides PDF-to-image rendering via go-pdfium. Used by ONNX layout detection and OCR fallback to produce page images.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrRendererNotInitialized = errors.New("renderer not initialized") ErrInvalidPage = errors.New("invalid page number") ErrRenderFailed = errors.New("failed to render page") ErrPDFNotLoaded = errors.New("PDF not loaded") )
Common errors for the render package.
Functions ¶
func ClosePdfiumPool ¶
func ClosePdfiumPool()
ClosePdfiumPool closes the global pdfium pool. Call this at program exit to cleanly release resources.
Types ¶
type NewRendererOptions ¶
type NewRendererOptions struct {
// PoolSize is the number of renderer instances to pool.
// go-pdfium benefits from pooling for concurrent rendering.
PoolSize int
}
NewRendererOptions holds options for creating a new renderer.
func DefaultRendererOptions ¶
func DefaultRendererOptions() *NewRendererOptions
DefaultRendererOptions returns the default renderer options.
type PageRenderer ¶
type PageRenderer interface {
// RenderPage renders a specific page to an image.
// pageIndex is 0-based.
// dpi controls the resolution (72 = 1:1, 150 = 2x, etc.)
RenderPage(pageIndex int, dpi float64) (image.Image, error)
// PageCount returns the total number of pages in the document.
PageCount() int
// PageSize returns the size of a page in PDF points (1/72 inch).
// pageIndex is 0-based.
PageSize(pageIndex int) (width, height float64, err error)
// Close releases all resources.
Close() error
}
PageRenderer renders PDF pages to images. This interface abstracts the PDF rendering implementation, allowing for different backends (go-pdfium, poppler, etc.).
func DefaultRendererFactory ¶
func DefaultRendererFactory(pdfPath string) (PageRenderer, error)
DefaultRendererFactory creates a PdfiumRenderer. This is the default factory for PageRenderer creation.
type PdfiumRenderer ¶
type PdfiumRenderer struct {
// contains filtered or unexported fields
}
PdfiumRenderer implements PageRenderer using go-pdfium WebAssembly backend.
func NewPdfiumRenderer ¶
func NewPdfiumRenderer(pdfPath string, config *RenderConfig) (*PdfiumRenderer, error)
NewPdfiumRenderer creates a new renderer for the given PDF file. Uses go-pdfium with WebAssembly/Wazero backend for cross-platform compatibility.
func (*PdfiumRenderer) PageCount ¶
func (r *PdfiumRenderer) PageCount() int
PageCount returns the total number of pages in the document.
func (*PdfiumRenderer) PageSize ¶
func (r *PdfiumRenderer) PageSize(pageIndex int) (width, height float64, err error)
PageSize returns the size of a page in PDF points (1/72 inch). pageIndex is 0-based.
func (*PdfiumRenderer) RenderPage ¶
RenderPage renders a specific page to an image. pageIndex is 0-based.
type RenderConfig ¶
type RenderConfig struct {
// DPI for rendering (default: 150 for good ONNX input quality)
DPI float64
// MaxDimension limits the maximum width or height of rendered images.
// 0 means no limit. This helps manage memory for large pages.
MaxDimension int
// BackgroundColor for transparent pages (default: white)
BackgroundColor [3]uint8
}
RenderConfig holds configuration for page rendering.
func DefaultRenderConfig ¶
func DefaultRenderConfig() *RenderConfig
DefaultRenderConfig returns the default rendering configuration.
func RenderConfigForONNX ¶
func RenderConfigForONNX() *RenderConfig
RenderConfigForONNX returns configuration optimized for ONNX model input. Uses 150 DPI which typically produces images around 1200x1500 pixels for standard letter/A4 pages, suitable for the 1024x1024 YOLO input.
type RendererFactory ¶
type RendererFactory func(pdfPath string) (PageRenderer, error)
RendererFactory creates PageRenderer instances. This is a function type for dependency injection.
func RendererFactoryWithConfig ¶
func RendererFactoryWithConfig(config *RenderConfig) RendererFactory
RendererFactoryWithConfig creates a factory with specific config.
Source Files