Use C++ <cmath> instead of <math.h>

Including math.h can pollute the default namespace, and break
some compilers if cmath versions of the method are declared as using.

Switching to C++ math functions also greatly simplifies handling of
float qreal as C++ automatically chooses the right method.

[ChangeLog][QtCore][QtMath] qmath.h no longer includes math.h, so any
sources depending on that indirect inclusion may fail to build.

Change-Id: I4d0e331dafba354ec05dc5052e61ef4ff8d387fe
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>

3 files changed, 10 insertions, 21 deletions

diff --git a/src/gui/painting/qdrawhelper.cpp b/src/gui/painting/qdrawhelper.cpp
index f461dfef06..84063eb692 100644
--- a/src/gui/painting/qdrawhelper.cpp
+++ b/src/gui/painting/qdrawhelper.cpp
@@ -1684,7 +1684,7 @@ static const uint * QT_FASTCALL fetchTransformedBilinearARGB32PM(uint *buffer, c
                     b++;
                     fx += fdx;
                 }
-            } else if ((fdx < 0 && fdx > -(fixed_scale / 8)) || fabs(data->m22) < (1./8.)) { // scale up more than 8x
+            } else if ((fdx < 0 && fdx > -(fixed_scale / 8)) || std::abs(data->m22) < (1./8.)) { // scale up more than 8x
                 int y1 = (fy >> 16);
                 int y2;
                 fetchTransformedBilinear_pixelBounds<blendType>(image_height, image_y1, image_y2, y1, y2);
@@ -1843,7 +1843,7 @@ static const uint * QT_FASTCALL fetchTransformedBilinearARGB32PM(uint *buffer, c
                 }
             }
         } else { //rotation
-            if (fabs(data->m11) > 8 || fabs(data->m22) > 8) {
+            if (std::abs(data->m11) > 8 || std::abs(data->m22) > 8) {
                 //if we are zooming more than 8 times, we use 8bit precision for the position.
                 while (b < end) {
                     int x1 = (fx >> 16);
@@ -2196,7 +2196,7 @@ static const uint *QT_FASTCALL fetchTransformedBilinear(uint *buffer, const Oper
                     layout->convertToARGB32PM(buf1, buf1, len * 2, layout, clut);
                     layout->convertToARGB32PM(buf2, buf2, len * 2, layout, clut);
 
-                    if ((fdx < 0 && fdx > -(fixed_scale / 8)) || fabs(data->m22) < (1./8.)) { // scale up more than 8x
+                    if ((fdx < 0 && fdx > -(fixed_scale / 8)) || std::abs(data->m22) < (1./8.)) { // scale up more than 8x
                         int disty = (fy & 0x0000ffff) >> 8;
                         for (int i = 0; i < len; ++i) {
                             uint tl = buf1[i * 2 + 0];
@@ -2255,7 +2255,7 @@ static const uint *QT_FASTCALL fetchTransformedBilinear(uint *buffer, const Oper
                 layout->convertToARGB32PM(buf1, buf1, len * 2, layout, clut);
                 layout->convertToARGB32PM(buf2, buf2, len * 2, layout, clut);
 
-                if (fabs(data->m11) > 8 || fabs(data->m22) > 8) {
+                if (std::abs(data->m11) > 8 || std::abs(data->m22) > 8) {
                     //if we are zooming more than 8 times, we use 8bit precision for the position.
                     for (int i = 0; i < len; ++i) {
                         uint tl = buf1[i * 2 + 0];
diff --git a/src/gui/painting/qmath_p.h b/src/gui/painting/qmath_p.h
index 50a49c2cb5..9cb64a46cb 100644
--- a/src/gui/painting/qmath_p.h
+++ b/src/gui/painting/qmath_p.h
@@ -45,14 +45,13 @@
 // We mean it.
 //
 
-#include <math.h>
 #include <qmath.h>
 
 QT_BEGIN_NAMESPACE
 
-static const qreal Q_PI   = qreal(3.14159265358979323846);   // pi
-static const qreal Q_2PI  = qreal(6.28318530717958647693);   // 2*pi
-static const qreal Q_PI2  = qreal(1.57079632679489661923);   // pi/2
+static const qreal Q_PI   = qreal(M_PI);     // pi
+static const qreal Q_2PI  = qreal(2 * M_PI); // 2*pi
+static const qreal Q_PI2  = qreal(M_PI_2);   // pi/2
 static const qreal Q_MM_PER_INCH = 25.4;
 
 inline int qIntSqrtInt(int v)
diff --git a/src/gui/painting/qrasterizer.cpp b/src/gui/painting/qrasterizer.cpp
index 426dd846ed..75bf31cde1 100644
--- a/src/gui/painting/qrasterizer.cpp
+++ b/src/gui/painting/qrasterizer.cpp
@@ -712,20 +712,10 @@ static inline bool q26Dot6Compare(qreal p1, qreal p2)
     return int((p2  - p1) * 64.) == 0;
 }
 
-static inline qreal qFloorF(qreal v)
-{
-#ifdef QT_USE_MATH_H_FLOATS
-    if (sizeof(qreal) == sizeof(float))
-        return floorf(v);
-    else
-#endif
-        return floor(v);
-}
-
 static inline QPointF snapTo26Dot6Grid(const QPointF &p)
 {
-    return QPointF(qFloorF(p.x() * 64) * (1 / qreal(64)),
-                   qFloorF(p.y() * 64) * (1 / qreal(64)));
+    return QPointF(std::floor(p.x() * 64) * (1 / qreal(64)),
+                   std::floor(p.y() * 64) * (1 / qreal(64)));
 }
 
 /*
@@ -832,7 +822,7 @@ void QRasterizer::rasterizeLine(const QPointF &a, const QPointF &b, qreal width,
             return;
 
         // adjust width which is given relative to |b - a|
-        width *= sqrt(w0 / w);
+        width *= qSqrt(w0 / w);
     }
 
     QSpanBuffer buffer(d->blend, d->data, d->clipRect);