Make clip optional in FPDFPage_TransFormWithClip.chromium/3273

Add checks for matrix and clipRect in function
FPDFPage_TransFormWithClip.  If both are null,
abort transformation. If either is null, skip
that particular transaction.

Change-Id: I65611508c064c0b929a11eace99ad532d3402138
Reviewed-on: https://pdfium-review.googlesource.com/18710
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

2 files changed, 27 insertions, 15 deletions

diff --git a/fpdfsdk/fpdf_transformpage.cpp b/fpdfsdk/fpdf_transformpage.cpp
index b607dffc4e..4f29fd69d6 100644
--- a/fpdfsdk/fpdf_transformpage.cpp
+++ b/fpdfsdk/fpdf_transformpage.cpp
@@ -106,19 +106,27 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPage_TransFormWithClip(FPDF_PAGE page,
                            FS_MATRIX* matrix,
                            FS_RECTF* clipRect) {
+  if (!matrix && !clipRect)
+    return false;
+
   CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
   if (!pPage)
     return false;
 
   std::ostringstream textBuf;
   textBuf << "q ";
-  CFX_FloatRect rect = CFXFloatRectFromFSRECTF(*clipRect);
-  rect.Normalize();
 
-  textBuf << ByteString::Format("%f %f %f %f re W* n ", rect.left, rect.bottom,
-                                rect.Width(), rect.Height());
-  textBuf << ByteString::Format("%f %f %f %f %f %f cm ", matrix->a, matrix->b,
-                                matrix->c, matrix->d, matrix->e, matrix->f);
+  if (clipRect) {
+    CFX_FloatRect rect = CFXFloatRectFromFSRECTF(*clipRect);
+    rect.Normalize();
+
+    textBuf << ByteString::Format("%f %f %f %f re W* n ", rect.left,
+                                  rect.bottom, rect.Width(), rect.Height());
+  }
+  if (matrix) {
+    textBuf << ByteString::Format("%f %f %f %f %f %f cm ", matrix->a, matrix->b,
+                                  matrix->c, matrix->d, matrix->e, matrix->f);
+  }
 
   CPDF_Dictionary* pPageDict = pPage->m_pFormDict.Get();
   CPDF_Object* pContentObj = GetPageContent(pPageDict);
diff --git a/public/fpdf_transformpage.h b/public/fpdf_transformpage.h
index f26c077bde..a6ed04a511 100644
--- a/public/fpdf_transformpage.h
+++ b/public/fpdf_transformpage.h
@@ -84,15 +84,19 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFPage_GetCropBox(FPDF_PAGE page,
                                                         float* top);
 
 /**
-* Transform the whole page with a specified matrix, then clip the page content
-* region.
-*
-* @param[in] page        - A page handle.
-* @param[in] matrix      - The transform matrix.
-* @param[in] clipRect    - A rectangle page area to be clipped.
-* @Note. This function will transform the whole page, and would take effect to
-* all the objects in the page.
-*/
+ * Apply transforms to |page|.
+ *
+ * If |matrix| is provided it will be applied to transform the page.
+ * If |clipRect| is provided it will be used to clip the resulting page.
+ * If neither |matrix| or |clipRect| are provided this method returns |false|.
+ * Returns |true| if transforms are applied.
+ *
+ * @param[in] page        - Page handle.
+ * @param[in] matrix      - Transform matrix.
+ * @param[in] clipRect    - Clipping rectangle.
+ * @Note. This function will transform the whole page, and would take effect to
+ * all the objects in the page.
+ */
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPage_TransFormWithClip(FPDF_PAGE page,
                            FS_MATRIX* matrix,