func extract(pd *pdfread.PdfReaderT, page int, t *TiffBuilder, next bool) {
pg := pd.Pages()[page-1]
mbox := util.StringArray(pd.Arr(pd.Att("/MediaBox", pg)))
fmt.Println("Page", page)
fmt.Println(" MediaBox", mbox)
resources := pd.Dic(pd.Att("/Resources", pg))
if xo := pd.Dic(resources["/XObject"]); xo != nil {
for name, ref := range xo {
dic, data := pd.Stream(ref)
printdic(dic, name, " ")
if string(dic["/Subtype"]) != "/Image" {
continue
}
switch string(dic["/Filter"]) {
case "/CCITTFaxDecode": // TIFF
if string(dic["/ColorSpace"]) != "/DeviceGray" {
log.Fatal("cannot convert /CCITTFaxDecode ", string(pd.Obj(dic["/ColorSpace"])))
}
dparms := pd.Dic(dic["/DecodeParms"])
width := pd.Num(dparms["/Columns"])
height := pd.Num(dparms["/Rows"])
k := pd.Num(dparms["/K"])
bpc := pd.Num(dic["/BitsPerComponent"])
if k >= 0 {
// can't do this right now
log.Fatal("can't do encoding with K=", k)
}
t.AddLong(TAG_IMAGE_WIDTH, uint32(width))
t.AddLong(TAG_IMAGE_LENGTH, uint32(height))
t.AddShort(TAG_BITS_PER_SAMPLE, uint16(bpc))
t.AddShort(TAG_COMPRESSION, 4) // CCITT Group 4
t.AddShort(TAG_PHOTOMETRIC_INTERPRETATION, 0) // white is zero
t.AddLong(TAG_STRIP_OFFSETS, 0)
//t.AddShort(TAG_ORIENTATION, 1)
//t.AddShort(TAG_SAMPLES_PER_PIXEL, 1)
t.AddLong(TAG_ROWS_PER_STRIP, uint32(height))
t.AddLong(TAG_STRIP_BYTE_COUNTS, uint32(len(data)))
//t.AddRational(TAG_X_RESOLUTION, 300, 1) // 300 dpi (300/1)
//t.AddRational(TAG_Y_RESOLUTION, 300, 1) // 300 dpi (300/1)
//t.AddShort(TAG_RESOLUTION_UNIT, 2) // pixels/inch
t.WriteIFD(data, next)
case "/DCTDecode": // JPEG
/*
width := pd.Num(dic["/Width"])
height := pd.Num(dic["/Height"])
bpc := pd.Num(dic["/BitsPerComponent"])
*/
f, err := os.Create("test.jpg")
if err != nil {
log.Fatal(err)
}
f.Write(data)
f.Close()
case "/FlateDecode": // compressed bitmap
data = fancy.ReadAndClose(zlib.NewReader(fancy.SliceReader(data)))
width := pd.Num(dic["/Width"])
height := pd.Num(dic["/Height"])
bpc := pd.Num(dic["/BitsPerComponent"])
if bpc != 8 {
log.Fatal("cannot convert /FlateDecode bpc:", bpc)
}
if string(dic["/ColorSpace"]) != "/DeviceRGB" {
log.Fatal("cannot convert /FlateDecode ", string(pd.Obj(dic["/ColorSpace"])))
}
ima := image.NewRGBA(image.Rect(0, 0, width, height))
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
ima.Set(x, y, color.RGBA{R: data[0], G: data[1], B: data[2], A: 255})
data = data[3:]
}
}
f, err := os.Create("test.png")
if err != nil {
log.Fatal(err)
}
png.Encode(f, ima)
f.Close()
default:
log.Fatal("cannot decode ", string(dic["/Filter"]))
}
}
}
}
