From fa6abac1f89bac43e9d34f544a93cdebbd209278 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Michal=20Mal=C3=BD?= <madcatxster@devoid-pointer.net>
Date: Fri, 10 Oct 2014 20:27:14 +0200
Subject: [PATCH] Fix calculation of absolute values of the first tick on
 scales

---
 Anyanka.pro          |  3 ++-
 helpers.cpp          | 48 ++++++++++++++++++++++++++++++++++++++++++++
 helpers.h            | 24 ++++++++++------------
 signalcontroller.cpp | 10 +++------
 signaldrawer.cpp     |  4 ++--
 5 files changed, 66 insertions(+), 23 deletions(-)
 create mode 100644 helpers.cpp

diff --git a/Anyanka.pro b/Anyanka.pro
index aebc60b..d7ad74f 100644
--- a/Anyanka.pro
+++ b/Anyanka.pro
@@ -50,7 +50,8 @@ SOURCES += main.cpp\
     signaldrawer.cpp \
     jsonserializable.cpp \
     libHPCS/libhpcs.c \
-    gui/failedfilesdialog.cpp
+    gui/failedfilesdialog.cpp \
+    helpers.cpp
 
 HEADERS  += \
     datafilesloader.h \
diff --git a/helpers.cpp b/helpers.cpp
new file mode 100644
index 0000000..046e4dd
--- /dev/null
+++ b/helpers.cpp
@@ -0,0 +1,48 @@
+/*
+  Copyright (c) 2013 Michal Malý <madcatxster@prifuk.cz>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+#include "helpers.h"
+
+const double Helpers::EPSILON = 2e-14;
+
+double Helpers::firstTick(const double from, const double step)
+{
+  const double mod = fabs(fmod(from, step));
+  double ret;
+
+  if (fabs(mod - 0.0) < EPSILON)
+    ret = from;
+  else
+    ret = from + (step - fmod(from, step));
+
+  return ret;
+}
+
+QString Helpers::getFileNameSuffix(const QString& name)
+{
+  int dotIdx = name.lastIndexOf('.');
+
+  if (dotIdx < 0)
+    return "";
+
+  return name.mid(dotIdx+1).toLower();
+}
diff --git a/helpers.h b/helpers.h
index 5aaaa91..bef1ad5 100644
--- a/helpers.h
+++ b/helpers.h
@@ -24,36 +24,33 @@
 #ifndef HELPERS_H
 #define HELPERS_H
 
+#include "logger.h"
 #include <QtCore/QString>
 
-
 class Helpers {
 
 public:
-  template <typename T> static T average(T* vals, size_t len) {
+  static const double EPSILON;
+
+  static double firstTick(const double from, const double step);
+  static QString getFileNameSuffix(const QString& name);
+
+  template <typename T> static T average(T* vals, size_t len)
+  {
     T sum = 0;
     for (size_t i = 0; i < len; i++)
       sum += vals[i];
     return sum / len;
   }
 
-  template <typename T> static T clamp(T in, T min, T max) {
+  template <typename T> static T clamp(T in, T min, T max)
+  {
     if (in < min)
       return min;
     if (in > max)
       return max;
   }
 
-  static QString getFileNameSuffix(const QString& name)
-  {
-    int dotIdx = name.lastIndexOf('.');
-
-    if (dotIdx < 0)
-      return "";
-
-    return name.mid(dotIdx+1).toLower();
-  }
-
   template <typename T> static T maxof(T n, ...)
   {
     T idx;
@@ -85,4 +82,5 @@ public:
   }
 
 };
+
 #endif // HELPERS_H
diff --git a/signalcontroller.cpp b/signalcontroller.cpp
index da3e5c3..452189c 100644
--- a/signalcontroller.cpp
+++ b/signalcontroller.cpp
@@ -20,6 +20,7 @@
   THE SOFTWARE.
 */
 
+#include "helpers.h"
 #include "signalcontroller.h"
 #include "logger.h"
 #include <cfloat>
@@ -195,13 +196,8 @@ RulerDrawData SignalController::getRulerDrawData(const double from, const double
   //qDebug() << __QFUNC__ << "Step" << step << "RelStep" << relStep << "relDiff" << diffRel << fromAbs;
 
   /* Calculate position of the first major tick */
-  if (from == 0.0) {
-    firstTickAbs = fromAbs;
-    firstTickRel = from;
-  } else {
-    firstTickAbs = fromAbs + (step - fmod(fromAbs, step));
-    firstTickRel = from + (relStep - fmod(from, relStep));
-  }
+  firstTickAbs = Helpers::firstTick(fromAbs, step);
+  firstTickRel = Helpers::firstTick(from, relStep);
   //qDebug() << __QFUNC__ << "First tick Abs:" << firstTickAbs << "Rel:" << firstTickRel;
 
   return RulerDrawData(firstTickAbs, firstTickRel, step, relStep);
diff --git a/signaldrawer.cpp b/signaldrawer.cpp
index cda8ca9..a07b478 100644
--- a/signaldrawer.cpp
+++ b/signaldrawer.cpp
@@ -20,6 +20,7 @@
   THE SOFTWARE.
 */
 
+#include "helpers.h"
 #include "logger.h"
 #include "signaldrawer.h"
 #include <QFontMetrics>
@@ -233,8 +234,7 @@ void SignalDrawer::drawLeadingSubticks(const RulerDrawData& rd, std::function<vo
                                       const double relMin)
 {
   const double subRelStep = subStep(rd.relStep);
-  const double subRelRem = fmod(relMin, subRelStep);
-  const double subRelMin = relMin + (subRelStep - subRelRem);
+  const double subRelMin = Helpers::firstTick(relMin, subRelStep);
   const double subAbsMin = (rd.firstTickRel - subRelMin) * (subStep(rd.step)) / subRelStep;
 
   drawScaleBySubticks(rd, drawFunc, subRelMin, subAbsMin, rd.firstTickRel);
-- 
2.43.5