From e454411a7e80bd8e35424b720277d791b722a591 Mon Sep 17 00:00:00 2001
From: Adrian Johnson <ajohnson@redneon.com>
Date: Sun, 8 Apr 2012 23:11:30 +0930
Subject: [PATCH] cairo: only align stroke coords for horizontal and vertical
 lines

Bug 48318
---
 poppler/CairoOutputDev.cc |   67 ++++++++++++++++++++++++++++++++-------------
 poppler/CairoOutputDev.h  |    2 +-
 2 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/poppler/CairoOutputDev.cc b/poppler/CairoOutputDev.cc
index 22fdaca..88d2f7f 100644
--- a/poppler/CairoOutputDev.cc
+++ b/poppler/CairoOutputDev.cc
@@ -640,48 +640,77 @@ void CairoOutputDev::updateFont(GfxState *state) {
   cairo_set_font_matrix (cairo, &matrix);
 }
 
-void CairoOutputDev::alignStrokeCoords(double *x, double *y)
+/* Align stroke coordinate i if the point is the start or end of a
+ * horizontal or vertical line */
+void CairoOutputDev::alignStrokeCoords(GfxSubpath *subpath, int i, double *x, double *y)
 {
-  /* see http://www.cairographics.org/FAQ/#sharp_lines */
-  cairo_user_to_device (cairo, x, y);
-  *x = floor(*x) + 0.5;
-  *y = floor(*y) + 0.5;
-  cairo_device_to_user (cairo, x, y);
+  double x1, y1;
+  GBool align = gFalse;
+
+  *x = subpath->getX(i);
+  *y = subpath->getY(i);
+
+  if (i > 0 && !subpath->getCurve(i - 1)) {
+    x1 = subpath->getX(i - 1);
+    y1 = subpath->getY(i - 1);
+    if (*x == x1 || *y == y1)
+      align = gTrue;
+  }
+
+  if (i < subpath->getNumPoints() - 1 && !subpath->getCurve(i + 1)) {
+    x1 = subpath->getX(i + 1);
+    y1 = subpath->getY(i + 1);
+    if (*x == x1 || *y == y1)
+      align = gTrue;
+  }
+
+  if (align) {
+    /* see http://www.cairographics.org/FAQ/#sharp_lines */
+    cairo_user_to_device (cairo, x, y);
+    *x = floor(*x) + 0.5;
+    *y = floor(*y) + 0.5;
+    cairo_device_to_user (cairo, x, y);
+  }
 }
 
 void CairoOutputDev::doPath(cairo_t *cairo, GfxState *state, GfxPath *path) {
   GfxSubpath *subpath;
   int i, j;
+  double x, y;
   cairo_new_path (cairo);
   for (i = 0; i < path->getNumSubpaths(); ++i) {
     subpath = path->getSubpath(i);
     if (subpath->getNumPoints() > 0) {
       if (align_stroke_coords) {
-	double x = subpath->getX(0);
-	double y = subpath->getY(0);
-	alignStrokeCoords(&x, &y);
-	cairo_move_to (cairo, x, y);
+        alignStrokeCoords(subpath, 0, &x, &y);
       } else {
-	cairo_move_to (cairo, subpath->getX(0), subpath->getY(0));
+        x = subpath->getX(0);
+        y = subpath->getY(0);
       }
+      cairo_move_to (cairo, x, y);
       j = 1;
       while (j < subpath->getNumPoints()) {
 	if (subpath->getCurve(j)) {
+	  if (align_stroke_coords) {
+            alignStrokeCoords(subpath, j + 2, &x, &y);
+          } else {
+            x = subpath->getX(j+2);
+            y = subpath->getY(j+2);
+          }
 	  cairo_curve_to( cairo,
 			  subpath->getX(j), subpath->getY(j),
 			  subpath->getX(j+1), subpath->getY(j+1),
-			  subpath->getX(j+2), subpath->getY(j+2));
+			  x, y);
 
 	  j += 3;
 	} else {
 	  if (align_stroke_coords) {
-	    double x = subpath->getX(j);
-	    double y = subpath->getY(j);
-	    alignStrokeCoords(&x, &y);
-	    cairo_line_to (cairo, x, y);
-	  } else {
-	    cairo_line_to (cairo, subpath->getX(j), subpath->getY(j));
-	  }
+            alignStrokeCoords(subpath, j, &x, &y);
+          } else {
+            x = subpath->getX(j);
+            y = subpath->getY(j);
+          }
+          cairo_line_to (cairo, x, y);
 	  ++j;
 	}
       }
diff --git a/poppler/CairoOutputDev.h b/poppler/CairoOutputDev.h
index 873dd43..f0c1666 100644
--- a/poppler/CairoOutputDev.h
+++ b/poppler/CairoOutputDev.h
@@ -274,7 +274,7 @@ protected:
   GBool getStreamData (Stream *str, char **buffer, int *length);
   void setMimeData(Stream *str, Object *ref, cairo_surface_t *image);
   void fillToStrokePathClip();
-  void alignStrokeCoords(double *x, double *y);
+  void alignStrokeCoords(GfxSubpath *subpath, int i, double *x, double *y);
 
   GfxRGB fill_color, stroke_color;
   cairo_pattern_t *fill_pattern, *stroke_pattern;
-- 
1.7.5.4