Add QPDFObjectHandle::Rectangle type

Provide a convenient way of accessing rectangles.

ChangeLog

@@ -1,3 +1,10 @@
+2018-06-19  Jay Berkenbilt  <ejb@ql.org>
+
+	* New QPDFObject::Rectangle class will convert to and from arrays
+	of four numerical values. Rectangles are used in various places
+	within the PDF file format and are called out as a specific data
+	type in the PDF specification.
+
 2018-05-12  Jay Berkenbilt  <ejb@ql.org>
 
 	* In newline before endstream mode, an extra newline was not

include/qpdf/QPDFObjectHandle.hh

@@ -172,6 +172,31 @@ class QPDFObjectHandle
         void terminateParsing();
     };
 
+    // Convenience object for rectangles
+    class Rectangle
+    {
+      public:
+        Rectangle() :
+            llx(0.0),
+            lly(0.0),
+            urx(0.0),
+            ury(0.0)
+        {
+        }
+        Rectangle(double llx, double lly,
+                  double urx, double ury) :
+            llx(llx),
+            lly(lly),
+            urx(urx),
+            ury(ury)
+        {
+        }
+
+        double llx;
+        double lly;
+        double urx;
+        double ury;
+    };
 
     QPDF_DLL
     QPDFObjectHandle();
@@ -344,11 +369,18 @@ class QPDFObjectHandle
     static QPDFObjectHandle newArray(
 	std::vector<QPDFObjectHandle> const& items);
     QPDF_DLL
+    static QPDFObjectHandle newArray(Rectangle const&);
+    QPDF_DLL
     static QPDFObjectHandle newDictionary();
     QPDF_DLL
     static QPDFObjectHandle newDictionary(
 	std::map<std::string, QPDFObjectHandle> const& items);
 
+    // Create an array from a rectangle. Equivalent to the rectangle
+    // form of newArray.
+    QPDF_DLL
+    static QPDFObjectHandle newFromRectangle(Rectangle const&);
+
     // Create a new stream and associate it with the given qpdf
     // object.  A subsequent call must be made to replaceStreamData()
     // to provide data for the stream.  The stream's dictionary may be
@@ -465,6 +497,12 @@ class QPDFObjectHandle
     QPDFObjectHandle getArrayItem(int n);
     QPDF_DLL
     std::vector<QPDFObjectHandle> getArrayAsVector();
+    QPDF_DLL
+    bool isRectangle();
+    // If the array an array of four numeric values, return as a
+    // rectangle. Otherwise, return the rectangle [0, 0, 0, 0]
+    QPDF_DLL
+    Rectangle getArrayAsRectangle();
 
     // Methods for dictionary objects
     QPDF_DLL
@@ -739,6 +777,15 @@ class QPDFObjectHandle
     QPDF_DLL
     void coalesceContentStreams();
 
+    // Issue a warning about this object if possible. If the object
+    // has a description, a warning will be issued. Otherwise, if
+    // throw_if_no_description is true, throw an exception. Otherwise
+    // do nothing. Objects read normally from the file have
+    // descriptions. See comments on setObjectDescription for
+    // additional details.
+    void warnIfPossible(std::string const& warning,
+                        bool throw_if_no_description = false);
+
     // Initializers for objects.  This Factory class gives the QPDF
     // class specific permission to call factory methods without
     // making it a friend of the whole QPDFObjectHandle class.

libqpdf/QPDFObjectHandle.cc

@@ -554,6 +554,42 @@ QPDFObjectHandle::getArrayItem(int n)
     return result;
 }
 
+bool
+QPDFObjectHandle::isRectangle()
+{
+    if (! isArray())
+    {
+        return false;
+    }
+    if (getArrayNItems() != 4)
+    {
+        return false;
+    }
+    for (size_t i = 0; i < 4; ++i)
+    {
+        if (! getArrayItem(i).isNumber())
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+
+QPDFObjectHandle::Rectangle
+QPDFObjectHandle::getArrayAsRectangle()
+{
+    Rectangle result;
+    if (isRectangle())
+    {
+        result = Rectangle(getArrayItem(0).getNumericValue(),
+                           getArrayItem(1).getNumericValue(),
+                           getArrayItem(2).getNumericValue(),
+                           getArrayItem(3).getNumericValue());
+    }
+    return result;
+}
+
 std::vector<QPDFObjectHandle>
 QPDFObjectHandle::getArrayAsVector()
 {
@@ -1833,6 +1869,23 @@ QPDFObjectHandle::newArray(std::vector<QPDFObjectHandle> const& items)
     return QPDFObjectHandle(new QPDF_Array(items));
 }
 
+QPDFObjectHandle
+QPDFObjectHandle::newArray(Rectangle const& rect)
+{
+    std::vector<QPDFObjectHandle> items;
+    items.push_back(newReal(rect.llx));
+    items.push_back(newReal(rect.lly));
+    items.push_back(newReal(rect.urx));
+    items.push_back(newReal(rect.ury));
+    return newArray(items);
+}
+
+QPDFObjectHandle
+QPDFObjectHandle::newFromRectangle(Rectangle const& rect)
+{
+    return newArray(rect);
+}
+
 QPDFObjectHandle
 QPDFObjectHandle::newDictionary()
 {
@@ -2103,7 +2156,8 @@ QPDFObjectHandle::typeWarning(char const* expected_type,
 }
 
 void
-QPDFObjectHandle::objectWarning(std::string const& warning)
+QPDFObjectHandle::warnIfPossible(std::string const& warning,
+                                 bool throw_if_no_description)
 {
     QPDF* context = 0;
     std::string description;
@@ -2115,12 +2169,18 @@ QPDFObjectHandle::objectWarning(std::string const& warning)
                  "", description, 0,
                  warning));
     }
-    else
+    else if (throw_if_no_description)
     {
         throw std::logic_error(warning);
     }
 }
 
+void
+QPDFObjectHandle::objectWarning(std::string const& warning)
+{
+    warnIfPossible(warning, true);
+}
+
 void
 QPDFObjectHandle::assertType(char const* type_name, bool istype)
 {

qpdf/test_driver.cc

@@ -1449,6 +1449,17 @@ void runtest(int n, char const* filename1, char const* arg2)
         QPDFObjectHandle page = pdf.getAllPages()[0];
         assert("/QPDFFakeName" ==
                page.getKey("/Contents").getDict().getKey("/Potato").getName());
+        // Rectangles
+        QPDFObjectHandle::Rectangle r0 = integer.getArrayAsRectangle();
+        assert((r0.llx == 0) && (r0.lly == 0) &&
+               (r0.urx == 0) && (r0.ury == 0));
+        QPDFObjectHandle rect = QPDFObjectHandle::newFromRectangle(
+            QPDFObjectHandle::Rectangle(1.2, 3.4, 5.6, 7.8));
+        QPDFObjectHandle::Rectangle r1 = rect.getArrayAsRectangle();
+        assert((r1.llx > 1.19) && (r1.llx < 1.21) &&
+               (r1.lly > 3.39) && (r1.lly < 3.41) &&
+               (r1.urx > 5.59) && (r1.urx < 5.61) &&
+               (r1.ury > 7.79) && (r1.ury < 7.81));
     }
     else
     {