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mirror of https://github.com/qpdf/qpdf.git synced 2024-05-29 00:10:54 +00:00
qpdf/libqpdf/QPDFPageObjectHelper.cc
Jay Berkenbilt e17585c2d2 Remove unreferenced: ignore names that are not Fonts or XObjects
Converted ResourceFinder to ParserCallbacks so we can better detect
the name that precedes various operators and use the operators to sort
the names into resource types. This enables us to be smarter about
detecting unreferenced resources in pages and also sets the stage for
reconciling differences in /DR across documents.
2021-03-03 17:05:49 -05:00

1311 lines
39 KiB
C++

#include <qpdf/QPDFPageObjectHelper.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QPDF.hh>
#include <qpdf/Pl_Concatenate.hh>
#include <qpdf/Pl_Buffer.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/QPDFExc.hh>
#include <qpdf/QPDFMatrix.hh>
#include <qpdf/QIntC.hh>
#include <qpdf/QPDFAcroFormDocumentHelper.hh>
#include <qpdf/ResourceFinder.hh>
class ContentProvider: public QPDFObjectHandle::StreamDataProvider
{
public:
ContentProvider(QPDFObjectHandle from_page) :
from_page(from_page)
{
}
virtual ~ContentProvider()
{
}
virtual void provideStreamData(int objid, int generation,
Pipeline* pipeline);
private:
QPDFObjectHandle from_page;
};
void
ContentProvider::provideStreamData(int, int, Pipeline* p)
{
Pl_Concatenate concat("concatenate", p);
std::string description = "contents from page object " +
QUtil::int_to_string(from_page.getObjectID()) + " " +
QUtil::int_to_string(from_page.getGeneration());
std::string all_description;
from_page.getKey("/Contents").pipeContentStreams(
&concat, description, all_description);
concat.manualFinish();
}
class InlineImageTracker: public QPDFObjectHandle::TokenFilter
{
public:
InlineImageTracker(QPDF*, size_t min_size, QPDFObjectHandle resources);
virtual ~InlineImageTracker()
{
}
virtual void handleToken(QPDFTokenizer::Token const&);
QPDFObjectHandle convertIIDict(QPDFObjectHandle odict);
QPDF* qpdf;
size_t min_size;
QPDFObjectHandle resources;
std::string dict_str;
std::string bi_str;
int min_suffix;
bool any_images;
enum { st_top, st_bi } state;
};
InlineImageTracker::InlineImageTracker(QPDF* qpdf, size_t min_size,
QPDFObjectHandle resources) :
qpdf(qpdf),
min_size(min_size),
resources(resources),
min_suffix(1),
any_images(false),
state(st_top)
{
}
QPDFObjectHandle
InlineImageTracker::convertIIDict(QPDFObjectHandle odict)
{
QPDFObjectHandle dict = QPDFObjectHandle::newDictionary();
dict.replaceKey("/Type", QPDFObjectHandle::newName("/XObject"));
dict.replaceKey("/Subtype", QPDFObjectHandle::newName("/Image"));
std::set<std::string> keys = odict.getKeys();
for (auto key: keys)
{
QPDFObjectHandle value = odict.getKey(key);
if (key == "/BPC")
{
key = "/BitsPerComponent";
}
else if (key == "/CS")
{
key = "/ColorSpace";
}
else if (key == "/D")
{
key = "/Decode";
}
else if (key == "/DP")
{
key = "/DecodeParms";
}
else if (key == "/F")
{
key = "/Filter";
}
else if (key == "/H")
{
key = "/Height";
}
else if (key == "/IM")
{
key = "/ImageMask";
}
else if (key == "/I")
{
key = "/Interpolate";
}
else if (key == "/W")
{
key = "/Width";
}
if (key == "/ColorSpace")
{
if (value.isName())
{
std::string name = value.getName();
if (name == "/G")
{
name = "/DeviceGray";
}
else if (name == "/RGB")
{
name = "/DeviceRGB";
}
else if (name == "/CMYK")
{
name = "/DeviceCMYK";
}
else if (name == "/I")
{
name = "/Indexed";
}
else
{
// This is a key in the page's /Resources ->
// /ColorSpace dictionary. We need to look it up
// and use its value as the color space for the
// image.
QPDFObjectHandle colorspace =
resources.getKey("/ColorSpace");
if (colorspace.isDictionary() && colorspace.hasKey(name))
{
QTC::TC("qpdf", "QPDFPageObjectHelper colorspace lookup");
value = colorspace.getKey(name);
}
else
{
resources.warnIfPossible(
"unable to resolve colorspace " + name);
}
name.clear();
}
if (! name.empty())
{
value = QPDFObjectHandle::newName(name);
}
}
}
else if (key == "/Filter")
{
std::vector<QPDFObjectHandle> filters;
if (value.isName())
{
filters.push_back(value);
}
else if (value.isArray())
{
filters = value.getArrayAsVector();
}
for (auto& iter: filters)
{
std::string name;
if (iter.isName())
{
name = iter.getName();
}
if (name == "/AHx")
{
name = "/ASCIIHexDecode";
}
else if (name == "/A85")
{
name = "/ASCII85Decode";
}
else if (name == "/LZW")
{
name = "/LZWDecode";
}
else if (name == "/Fl")
{
name = "/FlateDecode";
}
else if (name == "/RL")
{
name = "/RunLengthDecode";
}
else if (name == "/CCF")
{
name = "/CCITTFaxDecode";
}
else if (name == "/DCT")
{
name = "/DCTDecode";
}
else
{
name.clear();
}
if (! name.empty())
{
iter = QPDFObjectHandle::newName(name);
}
}
if (value.isName() && (filters.size() == 1))
{
value = filters.at(0);
}
else if (value.isArray())
{
value = QPDFObjectHandle::newArray(filters);
}
}
dict.replaceKey(key, value);
}
return dict;
}
void
InlineImageTracker::handleToken(QPDFTokenizer::Token const& token)
{
if (state == st_bi)
{
if (token.getType() == QPDFTokenizer::tt_inline_image)
{
std::string image_data(token.getValue());
size_t len = image_data.length();
if (len >= this->min_size)
{
QTC::TC("qpdf", "QPDFPageObjectHelper externalize inline image");
Pl_Buffer b("image_data");
b.write(QUtil::unsigned_char_pointer(image_data), len);
b.finish();
QPDFObjectHandle dict =
convertIIDict(QPDFObjectHandle::parse(dict_str));
dict.replaceKey(
"/Length",
QPDFObjectHandle::newInteger(QIntC::to_longlong(len)));
std::string name = resources.getUniqueResourceName(
"/IIm", this->min_suffix);
QPDFObjectHandle image = QPDFObjectHandle::newStream(
this->qpdf, b.getBuffer());
image.replaceDict(dict);
resources.getKey("/XObject").replaceKey(name, image);
write(name);
write(" Do\n");
any_images = true;
}
else
{
QTC::TC("qpdf", "QPDFPageObjectHelper keep inline image");
write(bi_str);
writeToken(token);
state = st_top;
}
}
else if (token == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "ID"))
{
bi_str += token.getValue();
dict_str += " >>";
}
else if (token == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "EI"))
{
state = st_top;
}
else
{
bi_str += token.getRawValue();
dict_str += token.getRawValue();
}
}
else if (token == QPDFTokenizer::Token(QPDFTokenizer::tt_word, "BI"))
{
bi_str = token.getValue();
dict_str = "<< ";
state = st_bi;
}
else
{
writeToken(token);
}
}
QPDFPageObjectHelper::Members::~Members()
{
}
QPDFPageObjectHelper::Members::Members()
{
}
QPDFPageObjectHelper::QPDFPageObjectHelper(QPDFObjectHandle oh) :
QPDFObjectHelper(oh)
{
}
QPDFObjectHandle
QPDFPageObjectHelper::getAttribute(std::string const& name,
bool copy_if_shared)
{
QPDFObjectHandle result;
QPDFObjectHandle dict;
bool is_form_xobject = this->oh.isFormXObject();
bool inherited = false;
if (is_form_xobject)
{
dict = this->oh.getDict();
result = dict.getKey(name);
}
else
{
dict = this->oh;
bool inheritable = ((name == "/MediaBox") || (name == "/CropBox") ||
(name == "/Resources") || (name == "/Rotate"));
QPDFObjectHandle node = dict;
result = node.getKey(name);
std::set<QPDFObjGen> seen;
while (inheritable && result.isNull() && node.hasKey("/Parent"))
{
seen.insert(node.getObjGen());
node = node.getKey("/Parent");
if (seen.count(node.getObjGen()))
{
break;
}
result = node.getKey(name);
if (! result.isNull())
{
QTC::TC("qpdf", "QPDFPageObjectHelper non-trivial inheritance");
inherited = true;
}
}
}
if (copy_if_shared && (inherited || result.isIndirect()))
{
QTC::TC("qpdf", "QPDFPageObjectHelper copy shared attribute",
is_form_xobject ? 0 : 1);
result = result.shallowCopy();
dict.replaceKey(name, result);
}
return result;
}
QPDFObjectHandle
QPDFPageObjectHelper::getTrimBox(bool copy_if_shared)
{
QPDFObjectHandle result = getAttribute("/TrimBox", copy_if_shared);
if (result.isNull())
{
result = getCropBox(copy_if_shared);
}
return result;
}
QPDFObjectHandle
QPDFPageObjectHelper::getCropBox(bool copy_if_shared)
{
QPDFObjectHandle result = getAttribute("/CropBox", copy_if_shared);
if (result.isNull())
{
result = getMediaBox();
}
return result;
}
QPDFObjectHandle
QPDFPageObjectHelper::getMediaBox(bool copy_if_shared)
{
return getAttribute("/MediaBox", copy_if_shared);
}
void
QPDFPageObjectHelper::forEachXObject(
bool recursive,
std::function<void(QPDFObjectHandle& obj,
QPDFObjectHandle& xobj_dict,
std::string const& key)> action,
std::function<bool(QPDFObjectHandle)> selector)
{
QTC::TC("qpdf", "QPDFPageObjectHelper::forEachXObject",
recursive
? (this->oh.isFormXObject() ? 0 : 1)
: (this->oh.isFormXObject() ? 2 : 3));
std::set<QPDFObjGen> seen;
std::list<QPDFPageObjectHelper> queue;
queue.push_back(*this);
while (! queue.empty())
{
QPDFPageObjectHelper ph = queue.front();
queue.pop_front();
QPDFObjGen og = ph.oh.getObjGen();
if (seen.count(og))
{
continue;
}
seen.insert(og);
QPDFObjectHandle resources = ph.getAttribute("/Resources", false);
if (resources.isDictionary() && resources.hasKey("/XObject"))
{
QPDFObjectHandle xobj_dict = resources.getKey("/XObject");
for (auto const& key: xobj_dict.getKeys())
{
QPDFObjectHandle obj = xobj_dict.getKey(key);
if ((! selector) || selector(obj))
{
action(obj, xobj_dict, key);
}
if (recursive && obj.isFormXObject())
{
queue.push_back(QPDFPageObjectHelper(obj));
}
}
}
}
}
void
QPDFPageObjectHelper::forEachImage(
bool recursive,
std::function<void(QPDFObjectHandle& obj,
QPDFObjectHandle& xobj_dict,
std::string const& key)> action)
{
forEachXObject(recursive, action,
[](QPDFObjectHandle obj) { return obj.isImage(); });
}
void
QPDFPageObjectHelper::forEachFormXObject(
bool recursive,
std::function<void(QPDFObjectHandle& obj,
QPDFObjectHandle& xobj_dict,
std::string const& key)> action)
{
forEachXObject(recursive, action,
[](QPDFObjectHandle obj) { return obj.isFormXObject(); });
}
std::map<std::string, QPDFObjectHandle>
QPDFPageObjectHelper::getPageImages()
{
return getImages();
}
std::map<std::string, QPDFObjectHandle>
QPDFPageObjectHelper::getImages()
{
std::map<std::string, QPDFObjectHandle> result;
forEachImage(false, [&result](QPDFObjectHandle& obj,
QPDFObjectHandle&,
std::string const& key) {
result[key] = obj;
});
return result;
}
std::map<std::string, QPDFObjectHandle>
QPDFPageObjectHelper::getFormXObjects()
{
std::map<std::string, QPDFObjectHandle> result;
forEachFormXObject(false, [&result](QPDFObjectHandle& obj,
QPDFObjectHandle&,
std::string const& key) {
result[key] = obj;
});
return result;
}
void
QPDFPageObjectHelper::externalizeInlineImages(size_t min_size)
{
externalizeInlineImages(min_size, false);
}
void
QPDFPageObjectHelper::externalizeInlineImages(size_t min_size, bool shallow)
{
if (shallow)
{
QPDFObjectHandle resources = getAttribute("/Resources", true);
// Calling mergeResources also ensures that /XObject becomes
// direct and is not shared with other pages.
resources.mergeResources(
QPDFObjectHandle::parse("<< /XObject << >> >>"));
InlineImageTracker iit(this->oh.getOwningQPDF(), min_size, resources);
Pl_Buffer b("new page content");
bool filtered = false;
try
{
filterContents(&iit, &b);
filtered = true;
}
catch (std::exception& e)
{
this->oh.warnIfPossible(
std::string("Unable to filter content stream: ") + e.what() +
"; not attempting to externalize inline images"
" from this stream");
}
if (filtered && iit.any_images)
{
if (this->oh.isFormXObject())
{
this->oh.replaceStreamData(
b.getBuffer(),
QPDFObjectHandle::newNull(),
QPDFObjectHandle::newNull());
}
else
{
this->oh.replaceKey(
"/Contents",
QPDFObjectHandle::newStream(
this->oh.getOwningQPDF(), b.getBuffer()));
}
}
}
else
{
externalizeInlineImages(min_size, true);
forEachFormXObject(
true,
[min_size](QPDFObjectHandle& obj,
QPDFObjectHandle&, std::string const&) {
QPDFPageObjectHelper(obj).externalizeInlineImages(
min_size, true);
});
}
}
std::vector<QPDFAnnotationObjectHelper>
QPDFPageObjectHelper::getAnnotations(std::string const& only_subtype)
{
std::vector<QPDFAnnotationObjectHelper> result;
QPDFObjectHandle annots = this->oh.getKey("/Annots");
if (annots.isArray())
{
int nannots = annots.getArrayNItems();
for (int i = 0; i < nannots; ++i)
{
QPDFObjectHandle annot = annots.getArrayItem(i);
if (only_subtype.empty() ||
(annot.isDictionary() &&
annot.getKey("/Subtype").isName() &&
(only_subtype == annot.getKey("/Subtype").getName())))
{
result.push_back(QPDFAnnotationObjectHelper(annot));
}
}
}
return result;
}
std::vector<QPDFObjectHandle>
QPDFPageObjectHelper::getPageContents()
{
return this->oh.getPageContents();
}
void
QPDFPageObjectHelper::addPageContents(QPDFObjectHandle contents, bool first)
{
this->oh.addPageContents(contents, first);
}
void
QPDFPageObjectHelper::rotatePage(int angle, bool relative)
{
this->oh.rotatePage(angle, relative);
}
void
QPDFPageObjectHelper::coalesceContentStreams()
{
this->oh.coalesceContentStreams();
}
void
QPDFPageObjectHelper::parsePageContents(
QPDFObjectHandle::ParserCallbacks* callbacks)
{
parseContents(callbacks);
}
void
QPDFPageObjectHelper::parseContents(
QPDFObjectHandle::ParserCallbacks* callbacks)
{
if (this->oh.isFormXObject())
{
this->oh.parseAsContents(callbacks);
}
else
{
this->oh.parsePageContents(callbacks);
}
}
void
QPDFPageObjectHelper::filterPageContents(
QPDFObjectHandle::TokenFilter* filter,
Pipeline* next)
{
return filterContents(filter, next);
}
void
QPDFPageObjectHelper::filterContents(
QPDFObjectHandle::TokenFilter* filter,
Pipeline* next)
{
if (this->oh.isFormXObject())
{
this->oh.filterAsContents(filter, next);
}
else
{
this->oh.filterPageContents(filter, next);
}
}
void
QPDFPageObjectHelper::pipePageContents(Pipeline* p)
{
pipeContents(p);
}
void
QPDFPageObjectHelper::pipeContents(Pipeline* p)
{
if (this->oh.isFormXObject())
{
this->oh.pipeStreamData(p, 0, qpdf_dl_specialized);
}
else
{
this->oh.pipePageContents(p);
}
}
void
QPDFPageObjectHelper::addContentTokenFilter(
PointerHolder<QPDFObjectHandle::TokenFilter> token_filter)
{
if (this->oh.isFormXObject())
{
this->oh.addTokenFilter(token_filter);
}
else
{
this->oh.addContentTokenFilter(token_filter);
}
}
bool
QPDFPageObjectHelper::removeUnreferencedResourcesHelper(
QPDFPageObjectHelper ph, std::set<std::string>& unresolved)
{
bool is_page = (! ph.oh.isFormXObject());
if (! is_page)
{
QTC::TC("qpdf", "QPDFPageObjectHelper filter form xobject");
}
ResourceFinder rf;
try
{
ph.parseContents(&rf);
}
catch (std::exception& e)
{
ph.oh.warnIfPossible(
std::string("Unable to parse content stream: ") + e.what() +
"; not attempting to remove unreferenced objects"
" from this object");
return false;
}
if (rf.sawBad())
{
QTC::TC("qpdf", "QPDFPageObjectHelper bad token finding names");
ph.oh.warnIfPossible(
"Bad token found while scanning content stream; "
"not attempting to remove unreferenced objects from this object");
return false;
}
// We will walk through /Font and /XObject dictionaries, removing
// any resources that are not referenced. We must make copies of
// resource dictionaries down into the dictionaries are mutating
// to prevent mutating one dictionary from having the side effect
// of mutating the one it was copied from.
QPDFObjectHandle resources = ph.getAttribute("/Resources", true);
std::vector<QPDFObjectHandle> rdicts;
std::set<std::string> known_names;
std::vector<std::string> to_filter = {"/Font", "/XObject"};
if (resources.isDictionary())
{
for (auto const& iter: to_filter)
{
QPDFObjectHandle dict = resources.getKey(iter);
if (dict.isDictionary())
{
dict = dict.shallowCopy();
resources.replaceKey(iter, dict);
rdicts.push_back(dict);
auto keys = dict.getKeys();
known_names.insert(keys.begin(), keys.end());
}
}
}
std::set<std::string> local_unresolved;
auto names_by_rtype = rf.getNamesByResourceType();
for (auto const& i1: to_filter)
{
for (auto const& n_iter: names_by_rtype[i1])
{
std::string const& name = n_iter.first;
if (! known_names.count(name))
{
unresolved.insert(name);
local_unresolved.insert(name);
}
}
}
// Older versions of the PDF spec allowed form XObjects to omit
// their resources dictionaries, in which case names were resolved
// from the containing page. This behavior seems to be widely
// supported by viewers. If a form XObjects has a resources
// dictionary and has some unresolved names, some viewers fail to
// resolve them, and others allow them to be inherited from the
// page or from another form XObjects that contains them. Since
// this behavior is inconsistent across viewers, we consider an
// unresolved name when a resources dictionary is present to be
// reason not to remove unreferenced resources. An unresolved name
// in the absence of a resource dictionary is not considered a
// problem. For form XObjects, we just accumulate a list of
// unresolved names, and for page objects, we avoid removing any
// such names found in nested form XObjects.
if ((! local_unresolved.empty()) && resources.isDictionary())
{
// It's not worth issuing a warning for this case. From qpdf
// 10.3, we are hopefully only looking at names that are
// referencing fonts and XObjects, but until we're certain
// that we know the meaning of every name in a content stream,
// we don't want to give warnings that might be false
// positives. Also, this can happen in legitimate cases with
// older PDFs, and there's nothing to be done about it, so
// there's no good reason to issue a warning. The only sad
// thing is that it was a false positive that alerted me to a
// logic error in the code, and any future such errors would
// now be hidden.
QTC::TC("qpdf", "QPDFPageObjectHelper unresolved names");
return false;
}
for (auto& dict: rdicts)
{
for (auto const& key: dict.getKeys())
{
if (is_page && unresolved.count(key))
{
// This name is referenced by some nested form
// xobject, so don't remove it.
QTC::TC("qpdf", "QPDFPageObjectHelper resolving unresolved");
}
else if (! rf.getNames().count(key))
{
dict.removeKey(key);
}
}
}
return true;
}
void
QPDFPageObjectHelper::removeUnreferencedResources()
{
// Accumulate a list of unresolved names across all nested form
// XObjects.
std::set<std::string> unresolved;
bool any_failures = false;
forEachFormXObject(
true,
[&any_failures, &unresolved](
QPDFObjectHandle& obj, QPDFObjectHandle&, std::string const&)
{
if (! removeUnreferencedResourcesHelper(
QPDFPageObjectHelper(obj), unresolved))
{
any_failures = true;
}
});
if (this->oh.isFormXObject() || (! any_failures))
{
removeUnreferencedResourcesHelper(*this, unresolved);
}
}
QPDFPageObjectHelper
QPDFPageObjectHelper::shallowCopyPage()
{
QPDF* qpdf = this->oh.getOwningQPDF();
if (! qpdf)
{
throw std::runtime_error(
"QPDFPageObjectHelper::shallowCopyPage"
" called with a direct object");
}
QPDFObjectHandle new_page = this->oh.shallowCopy();
return QPDFPageObjectHelper(qpdf->makeIndirectObject(new_page));
}
QPDFObjectHandle::Matrix
QPDFPageObjectHelper::getMatrixForTransformations(bool invert)
{
QPDFObjectHandle::Matrix matrix(1, 0, 0, 1, 0, 0);
QPDFObjectHandle bbox = getTrimBox(false);
if (! bbox.isRectangle())
{
return matrix;
}
QPDFObjectHandle rotate_obj = getAttribute("/Rotate", false);
QPDFObjectHandle scale_obj = getAttribute("/UserUnit", false);
if (! (rotate_obj.isNull() && scale_obj.isNull()))
{
QPDFObjectHandle::Rectangle rect = bbox.getArrayAsRectangle();
double width = rect.urx - rect.llx;
double height = rect.ury - rect.lly;
double scale = (scale_obj.isNumber()
? scale_obj.getNumericValue()
: 1.0);
int rotate = (rotate_obj.isInteger()
? rotate_obj.getIntValueAsInt()
: 0);
if (invert)
{
if (scale == 0.0)
{
return matrix;
}
scale = 1.0 / scale;
rotate = 360 - rotate;
}
// Ignore invalid rotation angle
switch (rotate)
{
case 90:
matrix = QPDFObjectHandle::Matrix(
0, -scale, scale, 0, 0, width * scale);
break;
case 180:
matrix = QPDFObjectHandle::Matrix(
-scale, 0, 0, -scale, width * scale, height * scale);
break;
case 270:
matrix = QPDFObjectHandle::Matrix(
0, scale, -scale, 0, height * scale, 0);
break;
default:
matrix = QPDFObjectHandle::Matrix(
scale, 0, 0, scale, 0, 0);
break;
}
}
return matrix;
}
QPDFObjectHandle
QPDFPageObjectHelper::getFormXObjectForPage(bool handle_transformations)
{
QPDF* qpdf = this->oh.getOwningQPDF();
if (! qpdf)
{
throw std::runtime_error(
"QPDFPageObjectHelper::getFormXObjectForPage"
" called with a direct object");
}
QPDFObjectHandle result = QPDFObjectHandle::newStream(qpdf);
QPDFObjectHandle newdict = result.getDict();
newdict.replaceKey("/Type", QPDFObjectHandle::newName("/XObject"));
newdict.replaceKey("/Subtype", QPDFObjectHandle::newName("/Form"));
newdict.replaceKey("/Resources",
getAttribute("/Resources", false).shallowCopy());
newdict.replaceKey("/Group",
getAttribute("/Group", false).shallowCopy());
QPDFObjectHandle bbox = getTrimBox(false).shallowCopy();
if (! bbox.isRectangle())
{
this->oh.warnIfPossible(
"bounding box is invalid; form"
" XObject created from page will not work");
}
newdict.replaceKey("/BBox", bbox);
PointerHolder<QPDFObjectHandle::StreamDataProvider> provider =
new ContentProvider(this->oh);
result.replaceStreamData(
provider, QPDFObjectHandle::newNull(), QPDFObjectHandle::newNull());
QPDFObjectHandle rotate_obj = getAttribute("/Rotate", false);
QPDFObjectHandle scale_obj = getAttribute("/UserUnit", false);
if (handle_transformations &&
(! (rotate_obj.isNull() && scale_obj.isNull())))
{
newdict.replaceKey("/Matrix",
QPDFObjectHandle::newArray(
getMatrixForTransformations()));
}
return result;
}
QPDFMatrix
QPDFPageObjectHelper::getMatrixForFormXObjectPlacement(
QPDFObjectHandle fo, QPDFObjectHandle::Rectangle rect,
bool invert_transformations,
bool allow_shrink, bool allow_expand)
{
// Calculate the transformation matrix that will place the given
// form XObject fully inside the given rectangle, center and
// shrinking or expanding as needed if requested.
// When rendering a form XObject, the transformation in the
// graphics state (cm) is applied first (of course -- when it is
// applied, the PDF interpreter doesn't even know we're going to
// be drawing a form XObject yet), and then the object's matrix
// (M) is applied. The resulting matrix, when applied to the form
// XObject's bounding box, will generate a new rectangle. We want
// to create a transformation matrix that make the form XObject's
// bounding box land in exactly the right spot.
QPDFObjectHandle fdict = fo.getDict();
QPDFObjectHandle bbox_obj = fdict.getKey("/BBox");
if (! bbox_obj.isRectangle())
{
return QPDFMatrix();
}
QPDFMatrix wmatrix; // work matrix
QPDFMatrix tmatrix; // "to" matrix
QPDFMatrix fmatrix; // "from" matrix
if (invert_transformations)
{
// tmatrix inverts scaling and rotation of the destination
// page. Applying this matrix allows the overlaid form
// XObject's to be absolute rather than relative to properties
// of the destination page. tmatrix is part of the computed
// transformation matrix.
tmatrix = QPDFMatrix(getMatrixForTransformations(true));
wmatrix.concat(tmatrix);
}
if (fdict.getKey("/Matrix").isMatrix())
{
// fmatrix is the transformation matrix that is applied to the
// form XObject itself. We need this for calculations, but we
// don't explicitly use it in the final result because the PDF
// rendering system automatically applies this last before
// drawing the form XObject.
fmatrix = QPDFMatrix(fdict.getKey("/Matrix").getArrayAsMatrix());
wmatrix.concat(fmatrix);
}
// The current wmatrix handles transformation from the form
// xobject and, if requested, the destination page. Next, we have
// to adjust this for scale and position.
// Step 1: figure out what scale factor we need to make the form
// XObject's bounding box fit within the destination rectangle.
// Transform bounding box
QPDFObjectHandle::Rectangle bbox = bbox_obj.getArrayAsRectangle();
QPDFObjectHandle::Rectangle T = wmatrix.transformRectangle(bbox);
// Calculate a scale factor, if needed. Shrink or expand if needed
// and allowed.
if ((T.urx == T.llx) || (T.ury == T.lly))
{
// avoid division by zero
return QPDFMatrix();
}
double rect_w = rect.urx - rect.llx;
double rect_h = rect.ury - rect.lly;
double t_w = T.urx - T.llx;
double t_h = T.ury - T.lly;
double xscale = rect_w / t_w;
double yscale = rect_h / t_h;
double scale = (xscale < yscale ? xscale : yscale);
if (scale > 1.0)
{
if (! allow_expand)
{
scale = 1.0;
}
}
else if (scale < 1.0)
{
if (! allow_shrink)
{
scale = 1.0;
}
}
// Step 2: figure out what translation is required to get the
// rectangle to the right spot: centered within the destination.
wmatrix = QPDFMatrix();
wmatrix.scale(scale, scale);
wmatrix.concat(tmatrix);
wmatrix.concat(fmatrix);
T = wmatrix.transformRectangle(bbox);
double t_cx = (T.llx + T.urx) / 2.0;
double t_cy = (T.lly + T.ury) / 2.0;
double r_cx = (rect.llx + rect.urx) / 2.0;
double r_cy = (rect.lly + rect.ury) / 2.0;
double tx = r_cx - t_cx;
double ty = r_cy - t_cy;
// Now we can calculate the final matrix. The final matrix does
// not include fmatrix because that is applied automatically by
// the PDF interpreter.
QPDFMatrix cm;
cm.translate(tx, ty);
cm.scale(scale, scale);
cm.concat(tmatrix);
return cm;
}
std::string
QPDFPageObjectHelper::placeFormXObject(
QPDFObjectHandle fo, std::string const& name,
QPDFObjectHandle::Rectangle rect,
bool invert_transformations,
bool allow_shrink, bool allow_expand)
{
QPDFMatrix cm;
return placeFormXObject(
fo, name, rect, cm, invert_transformations,
allow_shrink, allow_expand);
}
std::string
QPDFPageObjectHelper::placeFormXObject(
QPDFObjectHandle fo, std::string const& name,
QPDFObjectHandle::Rectangle rect,
QPDFMatrix& cm,
bool invert_transformations,
bool allow_shrink,
bool allow_expand)
{
cm = getMatrixForFormXObjectPlacement(
fo, rect, invert_transformations, allow_shrink, allow_expand);
return (
"q\n" +
cm.unparse() + " cm\n" +
name + " Do\n" +
"Q\n");
}
void
QPDFPageObjectHelper::flattenRotation()
{
flattenRotation(nullptr);
}
void
QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
{
QPDF* qpdf = this->oh.getOwningQPDF();
if (! qpdf)
{
throw std::runtime_error(
"QPDFPageObjectHelper::flattenRotation"
" called with a direct object");
}
auto rotate_oh = this->oh.getKey("/Rotate");
int rotate = 0;
if (rotate_oh.isInteger())
{
rotate = rotate_oh.getIntValueAsInt();
}
if (! ((rotate == 90) || (rotate == 180) || (rotate == 270)))
{
return;
}
auto mediabox = this->oh.getKey("/MediaBox");
if (! mediabox.isRectangle())
{
return;
}
auto media_rect = mediabox.getArrayAsRectangle();
std::vector<std::string> boxes = {
"/MediaBox", "/CropBox", "/BleedBox", "/TrimBox", "/ArtBox",
};
for (auto const& boxkey: boxes)
{
auto box = this->oh.getKey(boxkey);
if (! box.isRectangle())
{
continue;
}
auto rect = box.getArrayAsRectangle();
decltype(rect) new_rect;
// How far are the edges of our rectangle from the edges
// of the media box?
auto left_x = rect.llx - media_rect.llx;
auto right_x = media_rect.urx - rect.urx;
auto bottom_y = rect.lly - media_rect.lly;
auto top_y = media_rect.ury - rect.ury;
// Rotating the page 180 degrees does not change
// /MediaBox. Rotating 90 or 270 degrees reverses llx and
// lly and also reverse urx and ury. For all the other
// boxes, we want the corners to be the correct distance
// away from the corners of the mediabox.
switch (rotate)
{
case 90:
new_rect.llx = media_rect.lly + bottom_y;
new_rect.urx = media_rect.ury - top_y;
new_rect.lly = media_rect.llx + right_x;
new_rect.ury = media_rect.urx - left_x;
break;
case 180:
new_rect.llx = media_rect.llx + right_x;
new_rect.urx = media_rect.urx - left_x;
new_rect.lly = media_rect.lly + top_y;
new_rect.ury = media_rect.ury - bottom_y;
break;
case 270:
new_rect.llx = media_rect.lly + top_y;
new_rect.urx = media_rect.ury - bottom_y;
new_rect.lly = media_rect.llx + left_x;
new_rect.ury = media_rect.urx - right_x;
break;
default:
// ignore
break;
}
this->oh.replaceKey(
boxkey, QPDFObjectHandle::newFromRectangle(new_rect));
}
// When we rotate the page, pivot about the point 0, 0 and then
// translate so the page is visible with the origin point being
// the same offset from the lower left corner of the media box.
// These calculations have been verified empirically with various
// PDF readers.
QPDFMatrix cm(0, 0, 0, 0, 0, 0);
switch (rotate)
{
case 90:
cm.b = -1;
cm.c = 1;
cm.f = media_rect.urx + media_rect.llx;
break;
case 180:
cm.a = -1;
cm.d = -1;
cm.e = media_rect.urx + media_rect.llx;
cm.f = media_rect.ury + media_rect.lly;
break;
case 270:
cm.b = 1;
cm.c = -1;
cm.e = media_rect.ury + media_rect.lly;
break;
default:
break;
}
std::string cm_str =
std::string("q\n") + cm.unparse() + " cm\n";
this->oh.addPageContents(
QPDFObjectHandle::newStream(qpdf, cm_str), true);
this->oh.addPageContents(
QPDFObjectHandle::newStream(qpdf, "\nQ\n"), false);
this->oh.removeKey("/Rotate");
QPDFObjectHandle rotate_obj = getAttribute("/Rotate", false);
if (! rotate_obj.isNull())
{
QTC::TC("qpdf", "QPDFPageObjectHelper flatten inherit rotate");
this->oh.replaceKey("/Rotate", QPDFObjectHandle::newInteger(0));
}
QPDFObjectHandle annots = this->oh.getKey("/Annots");
if (annots.isArray())
{
std::vector<QPDFObjectHandle> new_annots;
std::vector<QPDFObjectHandle> new_fields;
std::set<QPDFObjGen> old_fields;
PointerHolder<QPDFAcroFormDocumentHelper> afdhph;
if (! afdh)
{
afdhph = new QPDFAcroFormDocumentHelper(*qpdf);
afdh = afdhph.getPointer();
}
afdh->transformAnnotations(
annots, new_annots, new_fields, old_fields, cm);
afdh->removeFormFields(old_fields);
for (auto const& f: new_fields)
{
afdh->addFormField(QPDFFormFieldObjectHelper(f));
}
this->oh.replaceKey("/Annots", QPDFObjectHandle::newArray(new_annots));
}
}
void
QPDFPageObjectHelper::copyAnnotations(
QPDFPageObjectHelper from_page, QPDFMatrix const& cm,
QPDFAcroFormDocumentHelper* afdh,
QPDFAcroFormDocumentHelper* from_afdh)
{
auto old_annots = from_page.getObjectHandle().getKey("/Annots");
if (! old_annots.isArray())
{
return;
}
QPDF* from_qpdf = from_page.getObjectHandle().getOwningQPDF();
if (! from_qpdf)
{
throw std::runtime_error(
"QPDFPageObjectHelper::copyAnnotations:"
" from page is a direct object");
}
QPDF* this_qpdf = this->oh.getOwningQPDF();
if (! this_qpdf)
{
throw std::runtime_error(
"QPDFPageObjectHelper::copyAnnotations:"
" this page is a direct object");
}
std::vector<QPDFObjectHandle> new_annots;
std::vector<QPDFObjectHandle> new_fields;
std::set<QPDFObjGen> old_fields;
PointerHolder<QPDFAcroFormDocumentHelper> afdhph;
PointerHolder<QPDFAcroFormDocumentHelper> from_afdhph;
if (! afdh)
{
afdhph = new QPDFAcroFormDocumentHelper(*this_qpdf);
afdh = afdhph.getPointer();
}
if (this_qpdf == from_qpdf)
{
from_afdh = afdh;
}
else if (from_afdh)
{
if (from_afdh->getQPDF().getUniqueId() != from_qpdf->getUniqueId())
{
throw std::logic_error(
"QPDFAcroFormDocumentHelper::copyAnnotations: from_afdh"
" is not from the same QPDF as from_page");
}
}
else
{
from_afdhph = new QPDFAcroFormDocumentHelper(*from_qpdf);
from_afdh = from_afdhph.getPointer();
}
afdh->transformAnnotations(
old_annots, new_annots, new_fields, old_fields, cm,
from_qpdf, from_afdh);
for (auto const& f: new_fields)
{
afdh->addFormField(QPDFFormFieldObjectHelper(f));
}
auto annots = this->oh.getKey("/Annots");
if (! annots.isArray())
{
annots = QPDFObjectHandle::newArray();
this->oh.replaceKey("/Annots", annots);
}
for (auto const& annot: new_annots)
{
annots.appendItem(annot);
}
}