[poppler] poppler/CairoOutputDev.cc

[Carlos Garcia Campos]

 poppler/CairoOutputDev.cc |   26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

New commits:
commit d7717cf18d0db5663687690ccf66102e9a124025
Author: Jason Crain <jason at aquaticape.us>
Date:   Fri Aug 22 00:51:36 2014 -0500

    cairo: Scale radial pattern
    
    Scale the radial pattern because cairo/pixman do not work well with a
    very large or small scaled matrix.  See cairo bug #81657.
    
    bug #22098

diff --git a/poppler/CairoOutputDev.cc b/poppler/CairoOutputDev.cc
index 3916485..5781c08 100644
--- a/poppler/CairoOutputDev.cc
+++ b/poppler/CairoOutputDev.cc
@@ -963,18 +963,32 @@ GBool CairoOutputDev::axialShadedSupportExtend(GfxState *state, GfxAxialShading
 GBool CairoOutputDev::radialShadedFill(GfxState *state, GfxRadialShading *shading, double sMin, double sMax) {
   double x0, y0, r0, x1, y1, r1;
   double dx, dy, dr;
+  cairo_matrix_t matrix;
+  double scale;
 
   shading->getCoords(&x0, &y0, &r0, &x1, &y1, &r1);
   dx = x1 - x0;
   dy = y1 - y0;
   dr = r1 - r0;
+
+  // Cairo/pixman do not work well with a very large or small scaled
+  // matrix.  See cairo bug #81657.
+  //
+  // As a workaround, scale the pattern by the average of the vertical
+  // and horizontal scaling of the current transformation matrix.
+  cairo_get_matrix(cairo, &matrix);
+  scale = (sqrt(matrix.xx * matrix.xx + matrix.yx * matrix.yx)
+	   + sqrt(matrix.xy * matrix.xy + matrix.yy * matrix.yy)) / 2;
+  cairo_matrix_init_scale(&matrix, scale, scale);
+
   cairo_pattern_destroy(fill_pattern);
-  fill_pattern = cairo_pattern_create_radial (x0 + sMin * dx,
-					      y0 + sMin * dy,
-					      r0 + sMin * dr,
-					      x0 + sMax * dx,
-					      y0 + sMax * dy,
-					      r0 + sMax * dr);
+  fill_pattern = cairo_pattern_create_radial ((x0 + sMin * dx) * scale,
+					      (y0 + sMin * dy) * scale,
+					      (r0 + sMin * dr) * scale,
+					      (x0 + sMax * dx) * scale,
+					      (y0 + sMax * dy) * scale,
+					      (r0 + sMax * dr) * scale);
+  cairo_pattern_set_matrix(fill_pattern, &matrix);
   if (shading->getExtend0() && shading->getExtend1())
     cairo_pattern_set_extend (fill_pattern, CAIRO_EXTEND_PAD);
   else