560 lines
13 KiB
Go
560 lines
13 KiB
Go
// Package fitz provides wrapper for the [MuPDF](http://mupdf.com/) fitz library
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// that can extract pages from PDF and EPUB documents as images, text, html or svg.
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package fitz
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/*
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#include <mupdf/fitz.h>
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#include <stdlib.h>
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const char *fz_version = FZ_VERSION;
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fz_document *open_document(fz_context *ctx, const char *filename) {
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fz_document *doc;
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fz_try(ctx) {
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doc = fz_open_document(ctx, filename);
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}
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fz_catch(ctx) {
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return NULL;
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}
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return doc;
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}
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fz_document *open_document_with_stream(fz_context *ctx, const char *magic, fz_stream *stream) {
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fz_document *doc;
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fz_try(ctx) {
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doc = fz_open_document_with_stream(ctx, magic, stream);
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}
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fz_catch(ctx) {
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return NULL;
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}
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return doc;
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}
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*/
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import "C"
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import (
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"errors"
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"image"
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"io"
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"os"
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"path/filepath"
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"sync"
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"unsafe"
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)
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// Errors.
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var (
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ErrNoSuchFile = errors.New("fitz: no such file")
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ErrCreateContext = errors.New("fitz: cannot create context")
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ErrOpenDocument = errors.New("fitz: cannot open document")
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ErrOpenMemory = errors.New("fitz: cannot open memory")
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ErrPageMissing = errors.New("fitz: page missing")
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ErrCreatePixmap = errors.New("fitz: cannot create pixmap")
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ErrPixmapSamples = errors.New("fitz: cannot get pixmap samples")
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ErrNeedsPassword = errors.New("fitz: document needs password")
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ErrLoadOutline = errors.New("fitz: cannot load outline")
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)
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// Document represents fitz document.
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type Document struct {
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ctx *C.struct_fz_context
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data []byte // binds data to the Document lifecycle avoiding premature GC
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doc *C.struct_fz_document
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mtx sync.Mutex
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stream *C.fz_stream
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}
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// Outline type.
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type Outline struct {
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// Hierarchy level of the entry (starting from 1).
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Level int
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// Title of outline item.
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Title string
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// Destination in the document to be displayed when this outline item is activated.
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URI string
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// The page number of an internal link.
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Page int
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// Top.
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Top float64
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}
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// Link type.
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type Link struct {
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URI string
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}
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// New returns new fitz document.
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func New(filename string) (f *Document, err error) {
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f = &Document{}
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filename, err = filepath.Abs(filename)
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if err != nil {
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return
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}
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if _, e := os.Stat(filename); e != nil {
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err = ErrNoSuchFile
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return
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}
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f.ctx = (*C.struct_fz_context)(unsafe.Pointer(C.fz_new_context_imp(nil, nil, C.FZ_STORE_UNLIMITED, C.fz_version)))
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if f.ctx == nil {
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err = ErrCreateContext
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return
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}
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C.fz_register_document_handlers(f.ctx)
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cfilename := C.CString(filename)
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defer C.free(unsafe.Pointer(cfilename))
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f.doc = C.open_document(f.ctx, cfilename)
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if f.doc == nil {
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err = ErrOpenDocument
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return
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}
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ret := C.fz_needs_password(f.ctx, f.doc)
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v := int(ret) != 0
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if v {
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err = ErrNeedsPassword
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}
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return
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}
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// NewFromMemory returns new fitz document from byte slice.
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func NewFromMemory(b []byte) (f *Document, err error) {
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f = &Document{}
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f.ctx = (*C.struct_fz_context)(unsafe.Pointer(C.fz_new_context_imp(nil, nil, C.FZ_STORE_UNLIMITED, C.fz_version)))
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if f.ctx == nil {
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err = ErrCreateContext
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return
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}
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C.fz_register_document_handlers(f.ctx)
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stream := C.fz_open_memory(f.ctx, (*C.uchar)(&b[0]), C.size_t(len(b)))
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f.stream = C.fz_keep_stream(f.ctx, stream)
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if f.stream == nil {
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err = ErrOpenMemory
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return
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}
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magic := contentType(b)
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if magic == "" {
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err = ErrOpenMemory
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return
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}
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f.data = b
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cmagic := C.CString(magic)
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defer C.free(unsafe.Pointer(cmagic))
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f.doc = C.open_document_with_stream(f.ctx, cmagic, f.stream)
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if f.doc == nil {
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err = ErrOpenDocument
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}
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ret := C.fz_needs_password(f.ctx, f.doc)
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v := int(ret) != 0
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if v {
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err = ErrNeedsPassword
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}
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return
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}
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// NewFromReader returns new fitz document from io.Reader.
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func NewFromReader(r io.Reader) (f *Document, err error) {
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b, e := io.ReadAll(r)
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if e != nil {
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err = e
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return
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}
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f, err = NewFromMemory(b)
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return
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}
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// NumPage returns total number of pages in document.
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func (f *Document) NumPage() int {
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return int(C.fz_count_pages(f.ctx, f.doc))
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}
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// Image returns image for given page number.
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func (f *Document) Image(pageNumber int) (image.Image, error) {
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return f.ImageDPI(pageNumber, 300.0)
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}
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// ImageDPI returns image for given page number and DPI.
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func (f *Document) ImageDPI(pageNumber int, dpi float64) (image.Image, error) {
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f.mtx.Lock()
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defer f.mtx.Unlock()
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img := image.RGBA{}
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if pageNumber >= f.NumPage() {
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return nil, ErrPageMissing
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}
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page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
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defer C.fz_drop_page(f.ctx, page)
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var bounds C.fz_rect
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bounds = C.fz_bound_page(f.ctx, page)
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var ctm C.fz_matrix
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ctm = C.fz_scale(C.float(dpi/72), C.float(dpi/72))
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var bbox C.fz_irect
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bounds = C.fz_transform_rect(bounds, ctm)
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bbox = C.fz_round_rect(bounds)
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pixmap := C.fz_new_pixmap_with_bbox(f.ctx, C.fz_device_rgb(f.ctx), bbox, nil, 1)
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if pixmap == nil {
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return nil, ErrCreatePixmap
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}
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C.fz_clear_pixmap_with_value(f.ctx, pixmap, C.int(0xff))
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//defer C.fz_drop_pixmap(f.ctx, pixmap)
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device := C.fz_new_draw_device(f.ctx, ctm, pixmap)
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C.fz_enable_device_hints(f.ctx, device, C.FZ_NO_CACHE)
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defer C.fz_drop_device(f.ctx, device)
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drawMatrix := C.fz_identity
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C.fz_run_page(f.ctx, page, device, drawMatrix, nil)
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C.fz_close_device(f.ctx, device)
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pixels := C.fz_pixmap_samples(f.ctx, pixmap)
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if pixels == nil {
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return nil, ErrPixmapSamples
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}
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defer C.free(unsafe.Pointer(pixels))
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img.Pix = C.GoBytes(unsafe.Pointer(pixels), C.int(4*bbox.x1*bbox.y1))
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img.Rect = image.Rect(int(bbox.x0), int(bbox.y0), int(bbox.x1), int(bbox.y1))
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img.Stride = 4 * img.Rect.Max.X
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return &img, nil
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}
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// ImagePNG returns image for given page number as PNG bytes.
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func (f *Document) ImagePNG(pageNumber int, dpi float64) ([]byte, error) {
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f.mtx.Lock()
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defer f.mtx.Unlock()
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if pageNumber >= f.NumPage() {
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return nil, ErrPageMissing
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}
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page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
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defer C.fz_drop_page(f.ctx, page)
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var bounds C.fz_rect
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bounds = C.fz_bound_page(f.ctx, page)
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var ctm C.fz_matrix
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ctm = C.fz_scale(C.float(dpi/72), C.float(dpi/72))
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var bbox C.fz_irect
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bounds = C.fz_transform_rect(bounds, ctm)
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bbox = C.fz_round_rect(bounds)
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pixmap := C.fz_new_pixmap_with_bbox(f.ctx, C.fz_device_rgb(f.ctx), bbox, nil, 1)
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if pixmap == nil {
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return nil, ErrCreatePixmap
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}
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C.fz_clear_pixmap_with_value(f.ctx, pixmap, C.int(0xff))
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//defer C.fz_drop_pixmap(f.ctx, pixmap)
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device := C.fz_new_draw_device(f.ctx, ctm, pixmap)
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C.fz_enable_device_hints(f.ctx, device, C.FZ_NO_CACHE)
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defer C.fz_drop_device(f.ctx, device)
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drawMatrix := C.fz_identity
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C.fz_run_page(f.ctx, page, device, drawMatrix, nil)
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C.fz_close_device(f.ctx, device)
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buf := C.fz_new_buffer_from_pixmap_as_png(f.ctx, pixmap, C.fz_default_color_params)
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defer C.fz_drop_buffer(f.ctx, buf)
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size := C.fz_buffer_storage(f.ctx, buf, nil)
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str := C.GoStringN(C.fz_string_from_buffer(f.ctx, buf), C.int(size))
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return []byte(str), nil
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}
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// Links returns slice of links for given page number.
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func (f *Document) Links(pageNumber int) ([]Link, error) {
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f.mtx.Lock()
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defer f.mtx.Unlock()
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if pageNumber >= f.NumPage() {
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return nil, ErrPageMissing
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}
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page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
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defer C.fz_drop_page(f.ctx, page)
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links := C.fz_load_links(f.ctx, page)
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defer C.fz_drop_link(f.ctx, links)
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linkCount := 0
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for currLink := links; currLink != nil; currLink = currLink.next {
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linkCount++
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}
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if linkCount == 0 {
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return nil, nil
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}
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gLinks := make([]Link, linkCount)
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currLink := links
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for i := 0; i < linkCount; i++ {
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gLinks[i] = Link{
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URI: C.GoString(currLink.uri),
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}
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currLink = currLink.next
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}
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return gLinks, nil
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}
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// Text returns text for given page number.
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func (f *Document) Text(pageNumber int) (string, error) {
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f.mtx.Lock()
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defer f.mtx.Unlock()
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if pageNumber >= f.NumPage() {
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return "", ErrPageMissing
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}
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page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
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defer C.fz_drop_page(f.ctx, page)
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var bounds C.fz_rect
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bounds = C.fz_bound_page(f.ctx, page)
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var ctm C.fz_matrix
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ctm = C.fz_scale(C.float(72.0/72), C.float(72.0/72))
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text := C.fz_new_stext_page(f.ctx, bounds)
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defer C.fz_drop_stext_page(f.ctx, text)
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var opts C.fz_stext_options
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opts.flags = 0
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device := C.fz_new_stext_device(f.ctx, text, &opts)
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C.fz_enable_device_hints(f.ctx, device, C.FZ_NO_CACHE)
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defer C.fz_drop_device(f.ctx, device)
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var cookie C.fz_cookie
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C.fz_run_page(f.ctx, page, device, ctm, &cookie)
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C.fz_close_device(f.ctx, device)
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buf := C.fz_new_buffer_from_stext_page(f.ctx, text)
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defer C.fz_drop_buffer(f.ctx, buf)
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str := C.GoString(C.fz_string_from_buffer(f.ctx, buf))
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return str, nil
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}
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// HTML returns html for given page number.
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func (f *Document) HTML(pageNumber int, header bool) (string, error) {
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f.mtx.Lock()
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defer f.mtx.Unlock()
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if pageNumber >= f.NumPage() {
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return "", ErrPageMissing
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}
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page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
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defer C.fz_drop_page(f.ctx, page)
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var bounds C.fz_rect
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bounds = C.fz_bound_page(f.ctx, page)
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var ctm C.fz_matrix
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ctm = C.fz_scale(C.float(72.0/72), C.float(72.0/72))
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text := C.fz_new_stext_page(f.ctx, bounds)
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defer C.fz_drop_stext_page(f.ctx, text)
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var opts C.fz_stext_options
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opts.flags = C.FZ_STEXT_PRESERVE_IMAGES
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device := C.fz_new_stext_device(f.ctx, text, &opts)
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C.fz_enable_device_hints(f.ctx, device, C.FZ_NO_CACHE)
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defer C.fz_drop_device(f.ctx, device)
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var cookie C.fz_cookie
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C.fz_run_page(f.ctx, page, device, ctm, &cookie)
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C.fz_close_device(f.ctx, device)
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buf := C.fz_new_buffer(f.ctx, 1024)
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defer C.fz_drop_buffer(f.ctx, buf)
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out := C.fz_new_output_with_buffer(f.ctx, buf)
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defer C.fz_drop_output(f.ctx, out)
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if header {
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C.fz_print_stext_header_as_html(f.ctx, out)
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}
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C.fz_print_stext_page_as_html(f.ctx, out, text, C.int(pageNumber))
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if header {
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C.fz_print_stext_trailer_as_html(f.ctx, out)
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}
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str := C.GoString(C.fz_string_from_buffer(f.ctx, buf))
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return str, nil
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}
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// SVG returns svg document for given page number.
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func (f *Document) SVG(pageNumber int) (string, error) {
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f.mtx.Lock()
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defer f.mtx.Unlock()
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if pageNumber >= f.NumPage() {
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return "", ErrPageMissing
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}
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page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
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defer C.fz_drop_page(f.ctx, page)
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var bounds C.fz_rect
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bounds = C.fz_bound_page(f.ctx, page)
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var ctm C.fz_matrix
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ctm = C.fz_scale(C.float(72.0/72), C.float(72.0/72))
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bounds = C.fz_transform_rect(bounds, ctm)
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buf := C.fz_new_buffer(f.ctx, 1024)
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defer C.fz_drop_buffer(f.ctx, buf)
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out := C.fz_new_output_with_buffer(f.ctx, buf)
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defer C.fz_drop_output(f.ctx, out)
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device := C.fz_new_svg_device(f.ctx, out, bounds.x1-bounds.x0, bounds.y1-bounds.y0, C.FZ_SVG_TEXT_AS_PATH, 1)
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C.fz_enable_device_hints(f.ctx, device, C.FZ_NO_CACHE)
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defer C.fz_drop_device(f.ctx, device)
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var cookie C.fz_cookie
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C.fz_run_page(f.ctx, page, device, ctm, &cookie)
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C.fz_close_device(f.ctx, device)
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str := C.GoString(C.fz_string_from_buffer(f.ctx, buf))
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return str, nil
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}
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// ToC returns the table of contents (also known as outline).
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func (f *Document) ToC() ([]Outline, error) {
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data := make([]Outline, 0)
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outline := C.fz_load_outline(f.ctx, f.doc)
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if outline == nil {
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return nil, ErrLoadOutline
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}
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defer C.fz_drop_outline(f.ctx, outline)
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var walk func(outline *C.fz_outline, level int)
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walk = func(outline *C.fz_outline, level int) {
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for outline != nil {
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res := Outline{}
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res.Level = level
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res.Title = C.GoString(outline.title)
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res.URI = C.GoString(outline.uri)
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res.Page = int(outline.page.page)
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res.Top = float64(outline.y)
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data = append(data, res)
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if outline.down != nil {
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walk(outline.down, level+1)
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}
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outline = outline.next
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}
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}
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walk(outline, 1)
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return data, nil
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}
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// Metadata returns the map with standard metadata.
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func (f *Document) Metadata() map[string]string {
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data := make(map[string]string)
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lookup := func(key string) string {
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ckey := C.CString(key)
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defer C.free(unsafe.Pointer(ckey))
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buf := make([]byte, 256)
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C.fz_lookup_metadata(f.ctx, f.doc, ckey, (*C.char)(unsafe.Pointer(&buf[0])), C.int(len(buf)))
|
|
|
|
return string(buf)
|
|
}
|
|
|
|
data["format"] = lookup("format")
|
|
data["encryption"] = lookup("encryption")
|
|
data["title"] = lookup("info:Title")
|
|
data["author"] = lookup("info:Author")
|
|
data["subject"] = lookup("info:Subject")
|
|
data["keywords"] = lookup("info:Keywords")
|
|
data["creator"] = lookup("info:Creator")
|
|
data["producer"] = lookup("info:Producer")
|
|
data["creationDate"] = lookup("info:CreationDate")
|
|
data["modDate"] = lookup("info:modDate")
|
|
|
|
return data
|
|
}
|
|
|
|
// Bound gives the Bounds of a given Page in the document.
|
|
func (f *Document) Bound(pageNumber int) (image.Rectangle, error) {
|
|
f.mtx.Lock()
|
|
defer f.mtx.Unlock()
|
|
|
|
if pageNumber >= f.NumPage() {
|
|
return image.Rectangle{}, ErrPageMissing
|
|
}
|
|
|
|
page := C.fz_load_page(f.ctx, f.doc, C.int(pageNumber))
|
|
defer C.fz_drop_page(f.ctx, page)
|
|
|
|
var bounds C.fz_rect
|
|
bounds = C.fz_bound_page(f.ctx, page)
|
|
return image.Rect(int(bounds.x0), int(bounds.y0), int(bounds.x1), int(bounds.y1)), nil
|
|
}
|
|
|
|
// Close closes the underlying fitz document.
|
|
func (f *Document) Close() error {
|
|
if f.stream != nil {
|
|
C.fz_drop_stream(f.ctx, f.stream)
|
|
}
|
|
|
|
C.fz_drop_document(f.ctx, f.doc)
|
|
C.fz_drop_context(f.ctx)
|
|
|
|
f.data = nil
|
|
|
|
return nil
|
|
}
|