commit b3aad3237e777635e0e0249e56f9290ea130fe28
Author: William Bader <william@newspapersystems.com>
Date:   Sun Feb 21 03:02:00 2016 +0100

    Merge change from poppler/Gfx.cc to avoid attempting a tiling pattern fill
    with a singular transform matrix (abs(determinant) < 0.000001).
---
 poppler/Gfx.cc | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/poppler/Gfx.cc b/poppler/Gfx.cc
index 577c482..bb5f9b1 100644
--- a/poppler/Gfx.cc
+++ b/poppler/Gfx.cc
@@ -2126,7 +2126,12 @@ void Gfx::doTilingPatternFill(GfxTilingPattern *tPat,
   btm = baseMatrix;
   ptm = tPat->getMatrix();
   // iCTM = invert CTM
-  det = 1 / (ctm[0] * ctm[3] - ctm[1] * ctm[2]);
+  det = ctm[0] * ctm[3] - ctm[1] * ctm[2];
+  if (fabs(det) < 0.000001) {
+    error(errSyntaxError, getPos(), "Singular matrix in tiling pattern fill");
+    return;
+  }
+  det = 1 / det;
   ictm[0] = ctm[3] * det;
   ictm[1] = -ctm[1] * det;
   ictm[2] = -ctm[2] * det;
@@ -2149,7 +2154,12 @@ void Gfx::doTilingPatternFill(GfxTilingPattern *tPat,
   m[5] = m1[4] * ictm[1] + m1[5] * ictm[3] + ictm[5];
 
   // construct a (device space) -> (pattern space) transform matrix
-  det = 1 / (m1[0] * m1[3] - m1[1] * m1[2]);
+  det = m1[0] * m1[3] - m1[1] * m1[2];
+  if (fabs(det) < 0.000001) {
+    error(errSyntaxError, getPos(), "Singular matrix in tiling pattern fill");
+    return;
+  }
+  det = 1 / det;
   imb[0] = m1[3] * det;
   imb[1] = -m1[1] * det;
   imb[2] = -m1[2] * det;
@@ -2335,7 +2345,12 @@ void Gfx::doShadingPatternFill(GfxShadingPattern *sPat,
   btm = baseMatrix;
   ptm = sPat->getMatrix();
   // iCTM = invert CTM
-  det = 1 / (ctm[0] * ctm[3] - ctm[1] * ctm[2]);
+  det = ctm[0] * ctm[3] - ctm[1] * ctm[2];
+  if (fabs(det) < 0.000001) {
+    error(errSyntaxError, getPos(), "Singular matrix in shading pattern fill");
+    return;
+  }
+  det = 1 / det;
   ictm[0] = ctm[3] * det;
   ictm[1] = -ctm[1] * det;
   ictm[2] = -ctm[2] * det;