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qpdf/libqpdf/QPDFAnnotationObjectHelper.cc

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Implement helper class for interactive forms
2018-06-19 13:26:41 +00:00
#include <qpdf/QPDFAnnotationObjectHelper.hh>
#include <qpdf/QTC.hh>
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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#include <qpdf/QPDFMatrix.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/QPDF.hh>
#include <qpdf/QPDFNameTreeObjectHelper.hh>
Implement helper class for interactive forms
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QPDFAnnotationObjectHelper::Members::~Members()
{
}
QPDFAnnotationObjectHelper::Members::Members()
{
}
QPDFAnnotationObjectHelper::QPDFAnnotationObjectHelper(QPDFObjectHandle oh) :
QPDFObjectHelper(oh)
{
}
std::string
QPDFAnnotationObjectHelper::getSubtype()
{
return this->oh.getKey("/Subtype").getName();
}
QPDFObjectHandle::Rectangle
QPDFAnnotationObjectHelper::getRect()
{
return this->oh.getKey("/Rect").getArrayAsRectangle();
}
QPDFObjectHandle
QPDFAnnotationObjectHelper::getAppearanceDictionary()
{
return this->oh.getKey("/AP");
}
std::string
QPDFAnnotationObjectHelper::getAppearanceState()
{
if (this->oh.getKey("/AS").isName())
{
QTC::TC("qpdf", "QPDFAnnotationObjectHelper AS present");
return this->oh.getKey("/AS").getName();
}
QTC::TC("qpdf", "QPDFAnnotationObjectHelper AS absent");
return "";
}
Add form fields to json output Also add some additional methods for detecting form field types to assist in the json creation and for later use.
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int
QPDFAnnotationObjectHelper::getFlags()
{
QPDFObjectHandle flags_obj = this->oh.getKey("/F");
Fix sign and conversion warnings (major) This makes all integer type conversions that have potential data loss explicit with calls that do range checks and raise an exception. After this commit, qpdf builds with no warnings when -Wsign-conversion -Wconversion is used with gcc or clang or when -W3 -Wd4800 is used with MSVC. This significantly reduces the likelihood of potential crashes from bogus integer values. There are some parts of the code that take int when they should take size_t or an offset. Such places would make qpdf not support files with more than 2^31 of something that usually wouldn't be so large. In the event that such a file shows up and is valid, at least qpdf would raise an error in the right spot so the issue could be legitimately addressed rather than failing in some weird way because of a silent overflow condition.
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return flags_obj.isInteger() ? flags_obj.getIntValueAsInt() : 0;
Add form fields to json output Also add some additional methods for detecting form field types to assist in the json creation and for later use.
2019-01-02 02:27:18 +00:00
}
Implement helper class for interactive forms
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QPDFObjectHandle
QPDFAnnotationObjectHelper::getAppearanceStream(
std::string const& which,
std::string const& state)
{
QPDFObjectHandle ap = getAppearanceDictionary();
std::string desired_state = state.empty() ? getAppearanceState() : state;
if (ap.isDictionary())
{
QPDFObjectHandle ap_sub = ap.getKey(which);
if (ap_sub.isStream() && desired_state.empty())
{
QTC::TC("qpdf", "QPDFAnnotationObjectHelper AP stream");
return ap_sub;
}
if (ap_sub.isDictionary() && (! desired_state.empty()))
{
QTC::TC("qpdf", "QPDFAnnotationObjectHelper AP dictionary");
QPDFObjectHandle ap_sub_val = ap_sub.getKey(desired_state);
if (ap_sub_val.isStream())
{
QTC::TC("qpdf", "QPDFAnnotationObjectHelper AN sub stream");
return ap_sub_val;
}
}
}
QTC::TC("qpdf", "QPDFAnnotationObjectHelper AN null");
return QPDFObjectHandle::newNull();
}
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
2018-12-24 22:54:48 +00:00
std::string
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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QPDFAnnotationObjectHelper::getPageContentForAppearance(
Honor flags when flattening annotations
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std::string const& name, int rotate,
int required_flags, int forbidden_flags)
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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{
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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if (! getAppearanceStream("/N").isStream())
{
return "";
}
// The appearance matrix computed by this method is the
// transformation matrix that needs to be in effect when drawing
// this annotation's appearance stream on the page. The algorithm
// for computing the appearance matrix described in section 12.5.5
// of the ISO-32000 PDF spec is similar but not identical to what
// we are doing here.
// When rendering an appearance stream associated with an
// annotation, there are four relevant components:
//
// * The appearance stream's bounding box (/BBox)
// * The appearance stream's matrix (/Matrix)
// * The annotation's rectangle (/Rect)
// * In the case of form fields with the NoRotate flag, the
// page's rotation
// When rendering a form xobject in isolation, just drawn with a
// /Do operator, the is no form field, so page rotation is not
// relevant, and there is no annotation, so /Rect is not relevant,
// so only /BBox and /Matrix are relevant. The effect of these are
// as follows:
// * /BBox is treated as a clipping region
// * /Matrix is applied as a transformation prior to rendering the
// appearance stream.
// There is no relationship between /BBox and /Matrix in this
// case.
// When rendering a form xobject in the context of an annotation,
// things are a little different. In particular, a matrix is
// established such that /BBox, when transformed by /Matrix, would
// fit completely inside of /Rect. /BBox is no longer a clipping
// region. To illustrate the difference, consider a /Matrix of
// [2 0 0 2 0 0], which is scaling by a factor of two along both
// axes. If the appearance stream drew a rectangle equal to /BBox,
// in the case of the form xobject in isolation, this matrix would
// cause only the lower-left quadrant of the rectangle to be
// visible since the scaling would cause the rest of it to fall
// outside of the clipping region. In the case of the form xobject
// displayed in the context of an annotation, such a matrix would
// have no effect at all because it would be applied to the
// bounding box first, and then when the resulting enclosing
// quadrilateral was transformed to fit into /Rect, the effect of
// the scaling would be undone.
// Our job is to create a transformation matrix that compensates
// for these differences so that the appearance stream of an
// annotation can be drawn as a regular form xobject.
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
2018-12-24 22:54:48 +00:00
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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// To do this, we perform the following steps, which overlap
// significantly with the algorithm in 12.5.5:
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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// 1. Transform the four corners of /BBox by applying /Matrix to
// them, creating an arbitrarily transformed quadrilateral.
// 2. Find the minimum upright rectangle that encompasses the
// resulting quadrilateral. This is the "transformed appearance
// box", T.
// 3. Compute matrix A that maps the lower left and upper right
// corners of T to the annotation's /Rect. This can be done by
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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// scaling so that the sizes match and translating so that the
// scaled T exactly overlaps /Rect.
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
2018-12-24 22:54:48 +00:00
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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// If the annotation's /F flag has bit 4 set, this means that
// annotation is to be rotated about its upper left corner to
// counteract any rotation of the page so it remains upright. To
// achieve this effect, we do the following extra steps:
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
2018-12-24 22:54:48 +00:00
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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// 1. Perform the rotation on /BBox box prior to transforming it
// with /Matrix (by replacing matrix with concatenation of
// matrix onto the rotation)
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
2018-12-24 22:54:48 +00:00
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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// 2. Rotate the destination rectangle by the specified amount
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
2018-12-24 22:54:48 +00:00
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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// 3. Apply the rotation to A as computed above to get the final
// appearance matrix.
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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QPDFObjectHandle rect_obj = this->oh.getKey("/Rect");
QPDFObjectHandle as = getAppearanceStream("/N").getDict();
QPDFObjectHandle bbox_obj = as.getKey("/BBox");
QPDFObjectHandle matrix_obj = as.getKey("/Matrix");
Add form fields to json output Also add some additional methods for detecting form field types to assist in the json creation and for later use.
2019-01-02 02:27:18 +00:00
int flags = getFlags();
Honor flags when flattening annotations
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if (flags & forbidden_flags)
{
QTC::TC("qpdf", "QPDFAnnotationObjectHelper forbidden flags");
return "";
}
if ((flags & required_flags) != required_flags)
{
QTC::TC("qpdf", "QPDFAnnotationObjectHelper missing required flags");
return "";
}
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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if (! (bbox_obj.isRectangle() && rect_obj.isRectangle()))
{
return "";
}
QPDFMatrix matrix;
if (matrix_obj.isMatrix())
{
Annotation flattening including form fields Flatten annotations by integrating their appearance streams into the content stream of the containing page. In the case of form fields, only flatten if /NeedAppearance is false (or equivalently absent). If flattening form fields, also remove /AcroForm from the document catalog.
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QTC::TC("qpdf", "QPDFAnnotationObjectHelper explicit matrix");
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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matrix = QPDFMatrix(matrix_obj.getArrayAsMatrix());
}
else
{
Annotation flattening including form fields Flatten annotations by integrating their appearance streams into the content stream of the containing page. In the case of form fields, only flatten if /NeedAppearance is false (or equivalently absent). If flattening form fields, also remove /AcroForm from the document catalog.
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QTC::TC("qpdf", "QPDFAnnotationObjectHelper default matrix");
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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}
QPDFObjectHandle::Rectangle rect = rect_obj.getArrayAsRectangle();
Honor flags when flattening annotations
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bool do_rotate = (rotate && (flags & an_no_rotate));
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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if (do_rotate)
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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{
// If the the annotation flags include the NoRotate bit and
// the page is rotated, we have to rotate the annotation about
// its upper left corner by the same amount in the opposite
// direction so that it will remain upright in absolute
// coordinates. Since the semantics of /Rotate for a page are
// to rotate the page, while the effect of rotating using a
// transformation matrix is to rotate the coordinate system,
// the opposite directionality is explicit in the code.
QPDFMatrix mr;
mr.rotatex90(rotate);
mr.concat(matrix);
matrix = mr;
double rect_w = rect.urx - rect.llx;
double rect_h = rect.ury - rect.lly;
switch (rotate)
{
case 90:
Annotation flattening including form fields Flatten annotations by integrating their appearance streams into the content stream of the containing page. In the case of form fields, only flatten if /NeedAppearance is false (or equivalently absent). If flattening form fields, also remove /AcroForm from the document catalog.
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QTC::TC("qpdf", "QPDFAnnotationObjectHelper rotate 90");
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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rect = QPDFObjectHandle::Rectangle(
rect.llx,
rect.ury,
rect.llx + rect_h,
rect.ury + rect_w);
break;
case 180:
Annotation flattening including form fields Flatten annotations by integrating their appearance streams into the content stream of the containing page. In the case of form fields, only flatten if /NeedAppearance is false (or equivalently absent). If flattening form fields, also remove /AcroForm from the document catalog.
2019-01-01 04:08:57 +00:00
QTC::TC("qpdf", "QPDFAnnotationObjectHelper rotate 180");
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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rect = QPDFObjectHandle::Rectangle(
rect.llx - rect_w,
rect.ury,
rect.llx,
rect.ury + rect_h);
break;
case 270:
Annotation flattening including form fields Flatten annotations by integrating their appearance streams into the content stream of the containing page. In the case of form fields, only flatten if /NeedAppearance is false (or equivalently absent). If flattening form fields, also remove /AcroForm from the document catalog.
2019-01-01 04:08:57 +00:00
QTC::TC("qpdf", "QPDFAnnotationObjectHelper rotate 270");
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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rect = QPDFObjectHandle::Rectangle(
rect.llx - rect_h,
rect.ury - rect_w,
rect.llx,
rect.ury);
break;
default:
// ignore
break;
}
}
// Transform bounding box by matrix to get T
QPDFObjectHandle::Rectangle bbox = bbox_obj.getArrayAsRectangle();
Move rectangle transformation into QPDFMatrix
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QPDFObjectHandle::Rectangle T = matrix.transformRectangle(bbox);
if ((T.urx == T.llx) || (T.ury == T.lly))
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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{
// avoid division by zero
return "";
}
// Compute a matrix to transform the appearance box to the rectangle
QPDFMatrix AA;
AA.translate(rect.llx, rect.lly);
Move rectangle transformation into QPDFMatrix
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AA.scale((rect.urx - rect.llx) / (T.urx - T.llx),
(rect.ury - rect.lly) / (T.ury - T.lly));
AA.translate(-T.llx, -T.lly);
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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if (do_rotate)
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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{
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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AA.rotatex90(rotate);
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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}
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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as.replaceKey("/Subtype", QPDFObjectHandle::newName("/Form"));
return (
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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"q\n" +
Switch annotation flattening to use the form xobjects Instead of directly putting the contents of the annotation appearance streams into the page's content stream, add commands to render the form xobjects directly. This is a more robust way to do it than the original solution as it works properly with patterns and avoids problems with resource name clashes between the pages and the form xobjects.
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AA.unparse() + " cm\n" +
name + " Do\n" +
"Q\n");
Add matrix and annotation appearance stream handling Generate page content fragment for rendering appearance streams including all matrix calculation.
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}
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