From 56de0fe9899999a361df2a97d33753043857922d Mon Sep 17 00:00:00 2001
From: David Capello <davidcapello@gmail.com>
Date: Fri, 14 Aug 2015 10:57:40 -0300
Subject: [PATCH] Fix rotation in straight angle (fix #592)

---
 src/app/ui/editor/pixels_movement.cpp |  2 +-
 src/gfx/transformation.cpp            | 18 ++++++++++++------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/app/ui/editor/pixels_movement.cpp b/src/app/ui/editor/pixels_movement.cpp
index 291ad4a52..300fa335f 100644
--- a/src/app/ui/editor/pixels_movement.cpp
+++ b/src/app/ui/editor/pixels_movement.cpp
@@ -396,7 +396,7 @@ void PixelsMovement::moveImage(const gfx::Point& pos, MoveModifier moveModifier)
         if ((moveModifier & AngleSnapMovement) == AngleSnapMovement) {
           // TODO make this configurable
           static const double keyAngles[] = {
-            0.0, 26.565, 45.0, 63.435, 90.0, 116.565, 135.0, 153.435, -180.0,
+            0.0, 26.565, 45.0, 63.435, 90.0, 116.565, 135.0, 153.435, 180.0,
             180.0, -153.435, -135.0, -116, -90.0, -63.435, -45.0, -26.565
           };
 
diff --git a/src/gfx/transformation.cpp b/src/gfx/transformation.cpp
index 59bc095a8..c6bbad32f 100644
--- a/src/gfx/transformation.cpp
+++ b/src/gfx/transformation.cpp
@@ -11,6 +11,7 @@
 #include "gfx/transformation.h"
 #include "gfx/point.h"
 #include "gfx/size.h"
+#include "fixmath/fixmath.h"
 
 #include <cmath>
 
@@ -72,13 +73,18 @@ PointT<double> Transformation::rotatePoint(
     const PointT<double>& pivot,
     double angle)
 {
-  double cos = std::cos(-angle);
-  double sin = std::sin(-angle);
-  double dx = (point.x-pivot.x);
-  double dy = (point.y-pivot.y);
+  using namespace fixmath;
+
+  fixed fixangle = ftofix(-angle);
+  fixangle = fixmul(fixangle, radtofix_r);
+
+  fixed cos = fixcos(fixangle);
+  fixed sin = fixsin(fixangle);
+  fixed dx = fixsub(ftofix(point.x), ftofix(pivot.x));
+  fixed dy = fixsub(ftofix(point.y), ftofix(pivot.y));
   return PointT<double>(
-      pivot.x + dx*cos - dy*sin,
-      pivot.y + dy*cos + dx*sin);
+    fixtof(fixadd(ftofix(pivot.x), fixsub(fixmul(dx, cos), fixmul(dy, sin)))),
+    fixtof(fixadd(ftofix(pivot.y), fixadd(fixmul(dy, cos), fixmul(dx, sin)))));
 }
 
 Rect Transformation::transformedBounds() const