Files
PDFPatcher/App/Processor/ImageExtractor.cs
T

766 lines
24 KiB
C#

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using FreeImageAPI;
using iTextSharp.text.pdf;
using PDFPatcher.Common;
using PDFPatcher.Model;
using PDFPatcher.Processor.Imaging;
namespace PDFPatcher.Processor
{
sealed class ImageExtractor
{
readonly PdfPageImageProcessor _parser;
int _totalImageCount;
int _imageCount;
int _activePage; // 在导出文件图片时,使用此属性命名文件
readonly string _fileMask;
int _pageRotation;
readonly ImageExtracterOptions _options;
readonly List<ImageInfo> _imageInfoList = new List<ImageInfo>();
readonly List<ImageDisposition> _imagePosList = new List<ImageDisposition>();
readonly HashSet<PdfObject> _exportedImages = new HashSet<PdfObject>();
readonly Stack<PdfObject> _visited = new Stack<PdfObject>();
internal List<ImageInfo> InfoList => _imageInfoList;
internal List<ImageDisposition> PosList => _imagePosList;
internal bool PrintImageLocation { get; set; }
public ImageExtractor(ImageExtracterOptions options) {
_fileMask = String.IsNullOrEmpty(options.FileMask) ? "0" : options.FileMask;
_options = options;
_parser = new PdfPageImageProcessor(_imagePosList, _imageInfoList);
}
internal void ExtractPageImages(PdfReader reader, int pageNum) {
if (pageNum < 1 || pageNum > reader.NumberOfPages) {
return;
}
_activePage = pageNum;
_parser.Reset();
_imageCount = 0;
_imageInfoList.Clear();
_imagePosList.Clear();
_visited.Clear();
var o = reader.GetPageNRelease(pageNum);
if (o == null) {
return;
}
// 收集页面字典引用的图片
var pp = o.Locate<PdfDictionary>(PdfName.RESOURCES, PdfName.XOBJECT);
if (pp != null) {
ExtractImageInstances(pp, false);
// 收集页面指令引用的图片
_parser.ProcessContent(reader.GetPageContent(pageNum), o.Locate<PdfDictionary>(PdfName.RESOURCES));
_imagePosList.Sort();
// 删除页面字典中没有在渲染指令中出现的图片
if (_options.ExtractOutOfPageImages == false) {
_imageInfoList.RemoveAll(IsOutOfPage);
}
}
pp = o.Locate<PdfDictionary>(PdfName.RESOURCES, PdfName.PATTERN);
if (pp != null) {
ExtractImageInstances(pp, true);
}
// 收集批注中的图片
if (_options.ExtractAnnotationImages) {
var an = o.Locate<PdfArray>(PdfName.ANNOTS);
if (an != null) {
foreach (var item in an.ArrayList) {
ExtractImageInstances(PdfReader.GetPdfObjectRelease(item) as PdfDictionary, true);
}
}
}
if (_imageInfoList.Count == 0) {
return;
}
_pageRotation = PdfHelper.GetPageRotation(o);
_imageInfoList.Sort((x, y) => {
var xi = _imagePosList.Find((info) => info.Image == x);
var yi = _imagePosList.Find((info) => info.Image == y);
if (xi == null) {
return yi == null ? 0 : -1;
}
else if (yi == null) {
return -1;
}
return xi.CompareTo(yi);
});
foreach (var item in _imageInfoList) {
try {
ExtractImage(item);
}
catch (FreeImageException ex) {
if (item.ReferenceCount > 0) {
Tracker.TraceMessage(Tracker.Category.Error, "在导出第 " + pageNum + " 页图片时遇到错误:" + ex.Message);
}
}
}
if (_options.MergeImages && _imagePosList.Count > 1) {
// 合并相同宽度、相同类型的图片
MergeImages();
}
}
bool IsOutOfPage(ImageInfo image) {
if (image.IsPageImage == false) {
return false;
}
var r = image.InlineImage.PdfRef;
foreach (var item in _imagePosList) {
var ir = item.Image.InlineImage?.PdfRef;
if (ir == null || (ir.Number == r.Number && ir.Generation == r.Generation)) {
return false;
}
}
return true;
}
void ExtractImageInstances(PdfDictionary source, bool recursive) {
if (source == null) {
return;
}
foreach (var item in source) {
if (PdfName.SMASK.Equals(item.Key)
|| PdfName.MASK.Equals(item.Key)
|| _options.AllowRedundantImages == false && _exportedImages.Contains(item.Value)
|| PdfReader.GetPdfObject(item.Value) is not PdfDictionary obj
|| _visited.Contains(item.Value)) {
continue;
}
_visited.Push(item.Value);
if (obj is not PRStream stream) {
goto NEXT;
}
PdfName subType = stream.GetAsName(PdfName.SUBTYPE);
if (PdfName.IMAGE.Equals(subType)) {
try {
_imageInfoList.Add(new ImageInfo(item.Value as PRIndirectReference, !recursive));
}
catch (NullReferenceException) {
Debug.WriteLine(item.Value);
}
continue;
}
if (PdfName.FORM.Equals(subType)) {
var fr = stream.Locate<PdfDictionary>(PdfName.RESOURCES, PdfName.XOBJECT);
if (fr == null) {
continue;
}
foreach (var fri in fr) {
if (_exportedImages.Contains(fri.Value)) {
continue;
}
stream = PdfReader.GetPdfObject(fri.Value) as PRStream;
if (stream != null) {
subType = stream.GetAsName(PdfName.SUBTYPE);
if (PdfName.IMAGE.Equals(subType)) {
_imageInfoList.Add(new ImageInfo(fri.Value as PRIndirectReference, false));
}
else if (recursive || PdfName.FORM.Equals(subType)) {
ExtractImageInstances(stream, true);
}
}
else if (recursive) {
ExtractImageInstances(stream, true);
}
}
}
NEXT:
if (recursive) {
ExtractImageInstances(obj, true);
}
_visited.Pop();
}
}
internal void ExtractImage(ImageInfo info) {
if (_options.AllowRedundantImages == false
&& _exportedImages.Add(info.InlineImage.PdfRef) == false) {
return;
}
if (_totalImageCount == 0 && Directory.Exists(_options.OutputPath) == false) {
Directory.CreateDirectory(_options.OutputPath);
}
var bytes = info.DecodeImage(_options);
if (bytes == null) {
return;
}
if (info.LastDecodeError != null) {
Tracker.TraceMessage(Tracker.Category.Error, info.LastDecodeError);
return;
}
var fileName = GetNewImageFileName();
if (info.ExtName == Constants.FileExtensions.Png
|| info.ExtName == Constants.FileExtensions.Tif
) {
SaveBitmap(info, bytes, fileName);
}
else {
SaveImageBytes(info, bytes, fileName);
}
if (info.Mask != null) {
using (var m = info.Mask) {
m.Palette.CreateGrayscalePalette();
m.Save($"{fileName}[mask]{(info.Mask.PixelFormat == PixelFormat.Format1bppIndexed ? Constants.FileExtensions.Tif : Constants.FileExtensions.Png)}");
}
}
_totalImageCount++;
}
void SaveImageBytes(ImageInfo info, byte[] bytes, string fileName) {
var vFlip = _options.VerticalFlipImages ^ info.VerticalFlip;
var n = fileName + info.ExtName;
if (PrintImageLocation) {
Tracker.TraceMessage(Tracker.Category.OutputFile, n);
Tracker.TraceMessage("导出图片:" + n);
}
if (info.ExtName == Constants.FileExtensions.Jp2) {
if (vFlip || _pageRotation != 0) {
try {
using (var ms = new MemoryStream(bytes))
using (var bmp = new FreeImageBitmap(ms)) {
RotateBitmap(bmp, _pageRotation, vFlip);
info.CreatePaletteAndIccProfile(bmp);
try {
bmp.Save(n);
}
catch (FreeImageException) {
File.Delete(n);
bmp.Save(new FilePath(n).ChangeExtension(Constants.FileExtensions.Png));
}
SaveMaskedImage(info, bmp, fileName);
}
}
catch (FreeImageException ex) {
Tracker.TraceMessage(ex);
bytes.DumpBytes(n);
}
}
else {
using (FileStream f = new FileStream(n, FileMode.Create)) {
f.Write(bytes, 0, bytes.Length);
}
}
}
else if (PdfName.DEVICECMYK.Equals(info.ColorSpace)) {
using (var ms = new MemoryStream(bytes))
using (var bmp = new FreeImageBitmap(ms, FREE_IMAGE_LOAD_FLAGS.JPEG_CMYK | FREE_IMAGE_LOAD_FLAGS.TIFF_CMYK)) {
RotateBitmap(bmp, _pageRotation, vFlip);
if (bmp.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_24_BPP)) {
SwapRedBlue(bmp);
n = fileName + Constants.FileExtensions.Png;
bmp.Save(n, FREE_IMAGE_FORMAT.FIF_PNG);
}
else {
n = fileName + Constants.FileExtensions.Tif;
bmp.Save(n, FREE_IMAGE_FORMAT.FIF_TIFF, FREE_IMAGE_SAVE_FLAGS.TIFF_CMYK | FREE_IMAGE_SAVE_FLAGS.TIFF_DEFLATE);
}
SaveMaskedImage(info, bmp, fileName);
if (PrintImageLocation) {
Tracker.TraceMessage("导出图片:" + n);
}
}
}
else {
using (FileStream f = new FileStream(n, FileMode.Create)) {
f.Write(bytes, 0, bytes.Length);
}
if (info.ExtName == Constants.FileExtensions.Jpg) {
if (info.Mask != null) {
using (var bmp = new FreeImageBitmap(new MemoryStream(bytes), FREE_IMAGE_FORMAT.FIF_JPEG)) {
SaveMaskedImage(info, bmp, fileName);
}
}
if (vFlip) {
TransformJpeg(n, FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_FLIP_V);
}
if (_pageRotation != 0) {
TransformJpeg(n,
_pageRotation == 90 ? FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_ROTATE_90
: _pageRotation == 180 ? FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_ROTATE_180
: _pageRotation == 270 ? FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_ROTATE_270
: FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_NONE);
}
}
}
info.FileName = n;
}
static void SwapRedBlue(FreeImageBitmap bmp) {
var r = bmp.GetChannel(FREE_IMAGE_COLOR_CHANNEL.FICC_RED);
var b = bmp.GetChannel(FREE_IMAGE_COLOR_CHANNEL.FICC_BLUE);
bmp.SetChannel(b, FREE_IMAGE_COLOR_CHANNEL.FICC_RED);
bmp.SetChannel(r, FREE_IMAGE_COLOR_CHANNEL.FICC_BLUE);
}
static void TransformJpeg(string fileName, FREE_IMAGE_JPEG_OPERATION operation) {
var tmpName = fileName + Constants.FileExtensions.Tmp;
if (FreeImageBitmap.JPEGTransform(fileName, tmpName, operation, true)) {
File.Delete(fileName);
File.Move(tmpName, fileName);
return;
}
File.Delete(tmpName);
RotateFlipType type;
switch (operation) {
case FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_FLIP_H:
type = RotateFlipType.RotateNoneFlipX;
break;
case FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_FLIP_V:
type = RotateFlipType.RotateNoneFlipY;
break;
case FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_ROTATE_90:
type = RotateFlipType.Rotate270FlipNone;
break;
case FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_ROTATE_180:
type = RotateFlipType.Rotate180FlipNone;
break;
case FREE_IMAGE_JPEG_OPERATION.FIJPEG_OP_ROTATE_270:
type = RotateFlipType.Rotate90FlipNone;
break;
default:
Tracker.TraceMessage(Tracker.Category.Error, "无损翻转 JPG 图片失败:" + fileName);
return;
}
using (var bmp = new FreeImageBitmap(fileName)) {
bmp.RotateFlip(type);
if (bmp.UniqueColors < 256) {
bmp.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_08_BPP);
}
bmp.Save(new FilePath(fileName).ChangeExtension(Constants.FileExtensions.Png));
}
File.Delete(fileName);
}
void SaveBitmap(ImageInfo info, byte[] bytes, string fileName) {
var vFlip = _options.VerticalFlipImages ^ info.VerticalFlip;
var ext = info.ExtName;
if (info.PixelFormat == PixelFormat.Format1bppIndexed) {
ext = _options.MonoPng == false ? Constants.FileExtensions.Tif : Constants.FileExtensions.Png;
}
var n = fileName + ext;
if (PrintImageLocation) {
Tracker.TraceMessage(Tracker.Category.OutputFile, n);
Tracker.TraceMessage("导出图片:" + n);
}
if (PdfName.DEVICECMYK.Equals(info.ColorSpace)) {
// TODO: 转换字节数组的 CMYK 为 RGB 后加载到 FreeImageBitmap
//info.PixelFormat = PixelFormat.Undefined;
using (var bmp = new FreeImageBitmap(
//info.Width,
//info.Height,
//GetStride (info, bytes, vFlip),
//PixelFormat.Format32bppArgb, bytes
new MemoryStream(bytes), FREE_IMAGE_LOAD_FLAGS.JPEG_CMYK
)) {
if (info.ICCProfile != null) {
bmp.CreateICCProfile(info.ICCProfile);
}
RotateBitmap(bmp, _pageRotation, false);
if (bmp.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_24_BPP)) {
SwapRedBlue(bmp);
n = fileName + Constants.FileExtensions.Png;
bmp.Save(n, FREE_IMAGE_FORMAT.FIF_PNG);
}
else {
bmp.Save(n,
FREE_IMAGE_FORMAT.FIF_TIFF,
FREE_IMAGE_SAVE_FLAGS.TIFF_CMYK | FREE_IMAGE_SAVE_FLAGS.TIFF_DEFLATE);
}
SaveMaskedImage(info, bmp, fileName);
}
}
else {
using (var bmp = CreateFreeImageBitmap(info, ref bytes, vFlip, true)) {
if (ext == Constants.FileExtensions.Png
&& _options.InvertBlackAndWhiteImages
&& info.PixelFormat == PixelFormat.Format1bppIndexed
&& bmp.Palette.Length == 2) {
bmp.SwapPaletteIndices(0, 1);
}
RotateBitmap(bmp, _pageRotation, false);
if (ext == Constants.FileExtensions.Tif) {
TiffHelper.Save(bmp, n);
}
else {
try {
bmp.Save(n, FREE_IMAGE_FORMAT.FIF_PNG);
}
catch (FreeImageException ex) when (ex.Message == "Unable to save bitmap") {
using (var b = bmp.ToBitmap()) {
b.Save(n, ImageFormat.Png);
}
}
catch (System.Runtime.InteropServices.SEHException) {
Tracker.TraceMessage(Tracker.Category.Error, "保存图片时出现错误,请联系程序开发者:" + n);
}
SaveMaskedImage(info, bmp, fileName);
}
}
}
info.FileName = n;
}
static void RotateBitmap(FreeImageBitmap bitmap, int rotation, bool vflip) {
if (rotation == 0 && vflip == false) {
return;
}
RotateFlipType r;
switch (rotation) {
case 0: r = RotateFlipType.RotateNoneFlipY; break;
case 90: r = vflip ? RotateFlipType.Rotate270FlipY : RotateFlipType.Rotate270FlipNone; break;
case 180: r = vflip ? RotateFlipType.Rotate180FlipY : RotateFlipType.Rotate180FlipNone; break;
case 270: r = vflip ? RotateFlipType.Rotate90FlipY : RotateFlipType.Rotate90FlipNone; break;
default: return;
}
bitmap.RotateFlip(r);
}
internal static FreeImageBitmap CreateFreeImageBitmap(ImageInfo info, ref byte[] bytes, bool vFlip, bool loadPaletteAndIccp) {
if (info.ExtName != Constants.FileExtensions.Jpg && info.ExtName != Constants.FileExtensions.Jp2) {
info.ConvertDecodedBytes(ref bytes);
}
FreeImageBitmap bmp;
if (PdfName.DEVICECMYK.Equals(info.ColorSpace)) {
bmp = new FreeImageBitmap(new MemoryStream(bytes), FREE_IMAGE_LOAD_FLAGS.TIFF_CMYK);
}
else if (info.ExtName == Constants.FileExtensions.Jp2 || info.ExtName == Constants.FileExtensions.Jpg) {
bmp = new FreeImageBitmap(new MemoryStream(bytes));
}
else {
bmp = new FreeImageBitmap(info.Width, info.Height, GetStride(info, bytes, vFlip), info.PixelFormat, bytes);
}
if (loadPaletteAndIccp
|| info.ColorSpace == PdfName.DEVICEGRAY && info.PaletteColorSpace == null) {
info.CreatePaletteAndIccProfile(bmp);
}
return bmp;
}
static int GetStride(ImageInfo info, byte[] bytes, bool vFlip) {
if (PdfName.COLORSPACE.Equals(info.ColorSpace)) {
return vFlip ? -(info.Width << 2) : (info.Width << 2);
}
var components = bytes.Length / info.Width / info.Height;
var stride = components > 0
? info.Width * components
: (info.Width + 8 / info.BitsPerComponent - 1) / (8 / info.BitsPerComponent);
return vFlip ? -stride : stride;
}
string GetNewImageFileName() {
_imageCount++;
return String.Concat(
FileHelper.CombinePath(_options.OutputPath, _activePage.ToString(_fileMask)),
_imageCount > 1 ? "[" + _imageCount + "]" : null);
}
void MergeImages() {
var l = _imagePosList.Count;
for (int i = 0; i < l; i++) {
var imageI = _imagePosList[i];
// 由于在导出图像时仅为 PNG 和 TIF 指定 ImageInfo 的 PixelFormat,因此合并过程中仅处理这两类文件
if (imageI.Image.ReferenceCount < 1 // 图像已处理
|| imageI.Image.PixelFormat == PixelFormat.Undefined // 不属于可合并的类型
|| l - i < 2 // 是最后一张图片
) {
continue;
}
var imageParts = new ImageInfo[l - i];
var w = imageI.Image.Width;
var h = 0;
var i2 = 0;
for (int j = i; j < l; j++) {
var imageJ = _imagePosList[j];
if (imageJ.Image.ReferenceCount < 1 // 图像已处理
|| imageJ.Image.Width != w // 宽度不相符
|| Math.Abs(Math.Round(imageJ.X - imageI.X)) > 1 // 位置相差超过 1 点
) {
continue;
}
imageParts[i2] = imageJ.Image;
h += imageJ.Image.Height;
_imagePosList[j].Image.ReferenceCount--; // 避免重复处理
i2++;
}
if (i2 == 0) { // 没有符合合并条件的图片
continue;
}
if (i2 == 1) {
_imagePosList[i].Image.ReferenceCount++;
continue;
}
if (i2 < imageParts.Length) {
Array.Resize(ref imageParts, i2);
}
if (PrintImageLocation) {
Tracker.TraceMessage("合并图片:" + String.Join("、", Array.ConvertAll<ImageInfo, string>(imageParts, p => Path.GetFileName(p.FileName))));
}
var ext = Path.GetExtension(imageI.Image.FileName).ToLowerInvariant();
if (imageI.Image.PixelFormat == PixelFormat.Format1bppIndexed) {
ext = Constants.FileExtensions.Tif;
}
var f = GetNewImageFileName();
using (FreeImageBitmap bmp = new FreeImageBitmap(w, h, imageI.Image.PixelFormat)) {
var mi = new ImageMerger(bmp);
foreach (var part in imageParts) {
using (var bmp2 = FreeImageBitmap.FromFile(part.FileName)) {
mi.MergeImage(bmp2);
}
}
mi.TryReduceColor();
if (ext == Constants.FileExtensions.Jpg && _options.MergeJpgToPng) {
ext = Constants.FileExtensions.Png;
}
else if (bmp.PixelFormat == PixelFormat.Format1bppIndexed) {
if (_options.MonoPng == false) {
ext = Constants.FileExtensions.Tif;
}
else {
ext = Constants.FileExtensions.Png;
}
}
f += ext;
if (PrintImageLocation) {
Tracker.TraceMessage(Tracker.Category.OutputFile, f);
Tracker.TraceMessage("保存合并后的图片:" + f);
}
if (ext == Constants.FileExtensions.Tif) {
TiffHelper.Save(bmp, f);
}
else {
bmp.Save(f);
}
var mii = new ImageInfo { FileName = f, ReferenceCount = 1, Height = h, Width = w };
_imageInfoList.Add(mii);
_imagePosList.Add(new ImageDisposition(_imagePosList[i].Ctm, mii));
}
}
DeleteIntermediateFiles();
_imageInfoList.Sort((ImageInfo x, ImageInfo y) => string.Compare(x.FileName, y.FileName, StringComparison.OrdinalIgnoreCase));
_totalImageCount -= _imageCount;
_imageCount = 0;
var newFileNames = new List<string>();
foreach (var item in _imageInfoList) {
if (item.FileName != null && item.InlineImage == null) {
string n;
do {
n = GetNewImageFileName() + Path.GetExtension(item.FileName);
} while (_imagePosList.Exists((i) => i.Image.FileName == n) || newFileNames.Contains(n));
if (PrintImageLocation) {
Tracker.TraceMessage(String.Concat("重命名合并后的文件 ", item.FileName, " 为 ", n));
Tracker.TraceMessage(Tracker.Category.OutputFile, n);
}
newFileNames.Add(n);
File.Delete(n);
File.Move(item.FileName, n);
item.FileName = n;
}
}
_totalImageCount += _imageCount;
}
void DeleteIntermediateFiles() {
foreach (var item in _imageInfoList) {
if (item.ReferenceCount < 1) {
File.Delete(item.FileName);
item.FileName = null;
}
}
}
static void SaveMaskedImage(ImageInfo info, FreeImageBitmap bmp, string fileName) {
if (info.Mask != null
&& info.Mask.Size == bmp.Size
&& (bmp.PixelFormat == PixelFormat.Format32bppArgb
|| bmp.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_32_BPP))) {
var m = (FreeImageBitmap)info.Mask.Clone();
if ((m.PixelFormat == PixelFormat.Format8bppIndexed || m.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_08_BPP | FREE_IMAGE_COLOR_DEPTH.FICD_FORCE_GREYSCALE))
&& bmp.SetChannel(m, FREE_IMAGE_COLOR_CHANNEL.FICC_ALPHA)) {
bmp.Save($"{fileName}[merged]{Constants.FileExtensions.Png}");
}
}
}
sealed class ImageMerger
{
readonly FreeImageBitmap _Image;
ColorType _ColorType;
RGBQUAD[] _Colors;
int _Height;
public ImageMerger(FreeImageBitmap image) {
_Image = image;
if (image.HasPalette == false) {
_ColorType = ColorType.FullColor;
}
}
public void MergeImage(FreeImageBitmap bmp) {
if (_Height == 0) {
PasteFirstImage(bmp);
return;
}
if (_ColorType == ColorType.FullColor) {
PasteIntoFullColor(bmp);
return;
}
if (bmp.HasPalette == false) {
ExpandColorSpaceAndPaste(bmp);
return;
}
var p = bmp.Palette.ToArray();
if (p.SequenceEqual(_Colors)) {
PasteAndIncrementHeight(bmp);
return;
}
switch (_ColorType) {
case ColorType.BlackAndWhite:
if (p[0].Color == Color.White
&& p[1].Color == Color.Black
&& bmp.Invert()) {
PasteAndIncrementHeight(bmp);
return;
}
break;
case ColorType.WhiteAndBlack:
if (p[0].Color == Color.Black
&& p[1].Color == Color.White
&& bmp.Invert()) {
PasteAndIncrementHeight(bmp);
return;
}
break;
}
TryExpandColorDepth(_Image);
TryExpandColorDepth(bmp);
PasteAndIncrementHeight(bmp);
_Colors = null;
_ColorType = ColorType.FullColor;
}
public bool TryReduceColor() {
if (_ColorType != ColorType.FullColor) {
return false;
}
var c = _Image.UniqueColors;
if (c > 256) {
return false;
}
if (c < 3) {
if (_Image.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_01_BPP)) {
_ColorType = ColorType.BlackAndWhite;
return true;
}
return false;
}
if (_Image.ConvertColorDepth(c < 17 ? FREE_IMAGE_COLOR_DEPTH.FICD_04_BPP : FREE_IMAGE_COLOR_DEPTH.FICD_08_BPP)) {
_ColorType = ColorType.IndexedColor;
return true;
}
return false;
}
void PasteFirstImage(FreeImageBitmap bmp) {
if (bmp.HasPalette) {
_Colors = new RGBQUAD[bmp.ColorsUsed];
_Image.Palette.AsArray = bmp.Palette.AsArray;
bmp.Palette.CopyTo(_Colors, 0);
_ColorType = GetWhiteBlackType(_Colors);
}
_Image.Paste(bmp, 0, 0, Int32.MaxValue);
_Height = bmp.Height;
}
static ColorType GetWhiteBlackType(RGBQUAD[] colors) {
var c0 = colors[0].Color;
var c1 = colors[1].Color;
return c0 == Color.Black && c1 == Color.White ? ColorType.BlackAndWhite
: c0 == Color.White && c1 == Color.Black ? ColorType.WhiteAndBlack
: ColorType.IndexedColor;
}
void PasteIntoFullColor(FreeImageBitmap bmp) {
if (bmp.HasPalette) {
TryExpandColorDepth(bmp);
}
PasteAndIncrementHeight(bmp);
}
static void TryExpandColorDepth(FreeImageBitmap bmp) {
if (bmp.ConvertColorDepth(FREE_IMAGE_COLOR_DEPTH.FICD_24_BPP) == false) {
throw new InvalidOperationException("合并图片失败:无法转换图片颜色");
}
}
void PasteAndIncrementHeight(FreeImageBitmap bmp) {
if (_Image.Paste(bmp, 0, _Height, Int32.MaxValue) == false) {
throw new InvalidOperationException("合并图片失败:粘贴操作出错");
}
_Height += bmp.Height;
}
void ExpandColorSpaceAndPaste(FreeImageBitmap bmp) {
TryExpandColorDepth(_Image);
PasteIntoFullColor(bmp);
}
}
enum ColorType
{
Undefined,
BlackAndWhite,
WhiteAndBlack,
IndexedColor,
FullColor,
}
sealed class PdfPageImageProcessor : PdfContentStreamProcessor
{
readonly List<ImageDisposition> _posList;
readonly List<ImageInfo> _infoList;
public PdfPageImageProcessor(List<ImageDisposition> posList, List<ImageInfo> infoList) {
PopulateOperators();
_posList = posList;
_infoList = infoList;
}
protected override void InvokeOperator(PdfLiteral oper, List<PdfObject> operands) {
base.InvokeOperator(oper, operands);
switch (oper.ToString()) {
case "Do":
var xobjects = Resource.GetAsDict(PdfName.XOBJECT);
var r = xobjects.GetAsIndirectObject(operands[0] as PdfName);
var info = _infoList.Find(
i => i.InlineImage.PdfRef != null
&& i.InlineImage.PdfRef.Number == r.Number
&& i.InlineImage.PdfRef.Generation == r.Generation);
if (info != null) {
info.ReferenceCount++;
_posList.Add(new ImageDisposition(CurrentGraphicState.TransMatrix, info));
}
else {
Trace.WriteLine(String.Concat("Image ", r, " not found."));
}
break;
case "BI":
info = new ImageInfo(new PdfImageData(operands[0] as PdfDictionary, ((PdfImageData)operands[0]).RawBytes));
info.ReferenceCount++;
_infoList.Add(info);
_posList.Add(new ImageDisposition(CurrentGraphicState.TransMatrix, info));
break;
}
}
}
}
}