The Tor Browser: comparison gfx/src/nsCoord.h

--1:000000000000
+:84da0f6f27ae
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef NSCOORD_H
+#define NSCOORD_H
+#include "nsAlgorithm.h"
+#include "nscore.h"
+#include "nsMathUtils.h"
+#include <math.h>
+#include <float.h>
+#include "nsDebug.h"
+#include <algorithm>
+/*
+* Basic type used for the geometry classes.
+*
+* Normally all coordinates are maintained in an app unit coordinate
+* space. An app unit is 1/60th of a CSS device pixel, which is, in turn
+* an integer number of device pixels, such at the CSS DPI is as close to
+* 96dpi as possible.
+*/
+// This controls whether we're using integers or floats for coordinates. We
+// want to eventually use floats.
+//#define NS_COORD_IS_FLOAT
+inline float NS_IEEEPositiveInfinity() {
+union { uint32_t mPRUint32; float mFloat; } pun;
+pun.mPRUint32 = 0x7F800000;
+return pun.mFloat;
+}
+inline bool NS_IEEEIsNan(float aF) {
+union { uint32_t mBits; float mFloat; } pun;
+pun.mFloat = aF;
+return (pun.mBits & 0x7F800000) == 0x7F800000 &&
+(pun.mBits & 0x007FFFFF) != 0;
+}
+#ifdef NS_COORD_IS_FLOAT
+typedef float nscoord;
+#define nscoord_MAX NS_IEEEPositiveInfinity()
+#else
+typedef int32_t nscoord;
+#define nscoord_MAX nscoord(1 << 30)
+#endif
+#define nscoord_MIN (-nscoord_MAX)
+inline void VERIFY_COORD(nscoord aCoord) {
+#ifdef NS_COORD_IS_FLOAT
+NS_ASSERTION(floorf(aCoord) == aCoord,
+"Coords cannot have fractions");
+#endif
+}
+inline nscoord NSToCoordRound(float aValue)
+{
+#if defined(XP_WIN32) && defined(_M_IX86) && !defined(__GNUC__)
+return NS_lroundup30(aValue);
+#else
+return nscoord(floorf(aValue + 0.5f));
+#endif /* XP_WIN32 && _M_IX86 && !__GNUC__ */
+}
+inline nscoord NSToCoordRound(double aValue)
+{
+#if defined(XP_WIN32) && defined(_M_IX86) && !defined(__GNUC__)
+return NS_lroundup30((float)aValue);
+#else
+return nscoord(floor(aValue + 0.5f));
+#endif /* XP_WIN32 && _M_IX86 && !__GNUC__ */
+}
+inline nscoord NSToCoordRoundWithClamp(float aValue)
+{
+#ifndef NS_COORD_IS_FLOAT
+// Bounds-check before converting out of float, to avoid overflow
+if (aValue >= nscoord_MAX) {
+return nscoord_MAX;
+}
+if (aValue <= nscoord_MIN) {
+return nscoord_MIN;
+}
+#endif
+return NSToCoordRound(aValue);
+}
+/**
+* Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as
+* appropriate for the signs of aCoord and aScale.  If requireNotNegative is
+* true, this method will enforce that aScale is not negative; use that
+* parametrization to get a check of that fact in debug builds.
+*/
+inline nscoord _nscoordSaturatingMultiply(nscoord aCoord, float aScale,
+bool requireNotNegative) {
+VERIFY_COORD(aCoord);
+if (requireNotNegative) {
+NS_ABORT_IF_FALSE(aScale >= 0.0f,
+"negative scaling factors must be handled manually");
+}
+#ifdef NS_COORD_IS_FLOAT
+return floorf(aCoord * aScale);
+#else
+float product = aCoord * aScale;
+if (requireNotNegative ? aCoord > 0 : (aCoord > 0) == (aScale > 0))
+return NSToCoordRoundWithClamp(std::min<float>(nscoord_MAX, product));
+return NSToCoordRoundWithClamp(std::max<float>(nscoord_MIN, product));
+#endif
+}
+/**
+* Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as
+* appropriate for the sign of aCoord.  This method requires aScale to not be
+* negative; use this method when you know that aScale should never be
+* negative to get a sanity check of that invariant in debug builds.
+*/
+inline nscoord NSCoordSaturatingNonnegativeMultiply(nscoord aCoord, float aScale) {
+return _nscoordSaturatingMultiply(aCoord, aScale, true);
+}
+/**
+* Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as
+* appropriate for the signs of aCoord and aScale.
+*/
+inline nscoord NSCoordSaturatingMultiply(nscoord aCoord, float aScale) {
+return _nscoordSaturatingMultiply(aCoord, aScale, false);
+}
+/**
+* Returns a + b, capping the sum to nscoord_MAX.
+*
+* This function assumes that neither argument is nscoord_MIN.
+*
+* Note: If/when we start using floats for nscoords, this function won't be as
+* necessary.  Normal float addition correctly handles adding with infinity,
+* assuming we aren't adding nscoord_MIN. (-infinity)
+*/
+inline nscoord
+NSCoordSaturatingAdd(nscoord a, nscoord b)
+{
+VERIFY_COORD(a);
+VERIFY_COORD(b);
+#ifdef NS_COORD_IS_FLOAT
+// Float math correctly handles a+b, given that neither is -infinity.
+return a + b;
+#else
+if (a == nscoord_MAX || b == nscoord_MAX) {
+// infinity + anything = anything + infinity = infinity
+return nscoord_MAX;
+} else {
+// a + b = a + b
+// Cap the result, just in case we're dealing with numbers near nscoord_MAX
+return std::min(nscoord_MAX, a + b);
+}
+#endif
+}
+/**
+* Returns a - b, gracefully handling cases involving nscoord_MAX.
+* This function assumes that neither argument is nscoord_MIN.
+*
+* The behavior is as follows:
+*
+*  a)  infinity - infinity -> infMinusInfResult
+*  b)  N - infinity        -> 0  (unexpected -- triggers NOTREACHED)
+*  c)  infinity - N        -> infinity
+*  d)  N1 - N2             -> N1 - N2
+*
+* Note: For float nscoords, cases (c) and (d) are handled by normal float
+* math.  We still need to explicitly specify the behavior for cases (a)
+* and (b), though.  (Under normal float math, those cases would return NaN
+* and -infinity, respectively.)
+*/
+inline nscoord
+NSCoordSaturatingSubtract(nscoord a, nscoord b,
+nscoord infMinusInfResult)
+{
+VERIFY_COORD(a);
+VERIFY_COORD(b);
+if (b == nscoord_MAX) {
+if (a == nscoord_MAX) {
+// case (a)
+return infMinusInfResult;
+} else {
+// case (b)
+NS_NOTREACHED("Attempted to subtract [n - nscoord_MAX]");
+return 0;
+}
+} else {
+#ifdef NS_COORD_IS_FLOAT
+// case (c) and (d) for floats.  (float math handles both)
+return a - b;
+#else
+if (a == nscoord_MAX) {
+// case (c) for integers
+return nscoord_MAX;
+} else {
+// case (d) for integers
+// Cap the result, in case we're dealing with numbers near nscoord_MAX
+return std::min(nscoord_MAX, a - b);
+}
+}
+#endif
+}
+inline float NSCoordToFloat(nscoord aCoord) {
+VERIFY_COORD(aCoord);
+#ifdef NS_COORD_IS_FLOAT
+NS_ASSERTION(!NS_IEEEIsNan(aCoord), "NaN encountered in float conversion");
+#endif
+return (float)aCoord;
+}
+/*
+* Coord Rounding Functions
+*/
+inline nscoord NSToCoordFloor(float aValue)
+{
+return nscoord(floorf(aValue));
+}
+inline nscoord NSToCoordFloor(double aValue)
+{
+return nscoord(floor(aValue));
+}
+inline nscoord NSToCoordFloorClamped(float aValue)
+{
+#ifndef NS_COORD_IS_FLOAT
+// Bounds-check before converting out of float, to avoid overflow
+if (aValue >= nscoord_MAX) {
+return nscoord_MAX;
+}
+if (aValue <= nscoord_MIN) {
+return nscoord_MIN;
+}
+#endif
+return NSToCoordFloor(aValue);
+}
+inline nscoord NSToCoordCeil(float aValue)
+{
+return nscoord(ceilf(aValue));
+}
+inline nscoord NSToCoordCeil(double aValue)
+{
+return nscoord(ceil(aValue));
+}
+inline nscoord NSToCoordCeilClamped(double aValue)
+{
+#ifndef NS_COORD_IS_FLOAT
+// Bounds-check before converting out of double, to avoid overflow
+if (aValue >= nscoord_MAX) {
+return nscoord_MAX;
+}
+if (aValue <= nscoord_MIN) {
+return nscoord_MIN;
+}
+#endif
+return NSToCoordCeil(aValue);
+}
+/*
+* Int Rounding Functions
+*/
+inline int32_t NSToIntFloor(float aValue)
+{
+return int32_t(floorf(aValue));
+}
+inline int32_t NSToIntCeil(float aValue)
+{
+return int32_t(ceilf(aValue));
+}
+inline int32_t NSToIntRound(float aValue)
+{
+return NS_lroundf(aValue);
+}
+inline int32_t NSToIntRound(double aValue)
+{
+return NS_lround(aValue);
+}
+inline int32_t NSToIntRoundUp(double aValue)
+{
+return int32_t(floor(aValue + 0.5));
+}
+/*
+* App Unit/Pixel conversions
+*/
+inline nscoord NSFloatPixelsToAppUnits(float aPixels, float aAppUnitsPerPixel)
+{
+return NSToCoordRoundWithClamp(aPixels * aAppUnitsPerPixel);
+}
+inline nscoord NSIntPixelsToAppUnits(int32_t aPixels, int32_t aAppUnitsPerPixel)
+{
+// The cast to nscoord makes sure we don't overflow if we ever change
+// nscoord to float
+nscoord r = aPixels * (nscoord)aAppUnitsPerPixel;
+VERIFY_COORD(r);
+return r;
+}
+inline float NSAppUnitsToFloatPixels(nscoord aAppUnits, float aAppUnitsPerPixel)
+{
+return (float(aAppUnits) / aAppUnitsPerPixel);
+}
+inline double NSAppUnitsToDoublePixels(nscoord aAppUnits, double aAppUnitsPerPixel)
+{
+return (double(aAppUnits) / aAppUnitsPerPixel);
+}
+inline int32_t NSAppUnitsToIntPixels(nscoord aAppUnits, float aAppUnitsPerPixel)
+{
+return NSToIntRound(float(aAppUnits) / aAppUnitsPerPixel);
+}
+inline float NSCoordScale(nscoord aCoord, int32_t aFromAPP, int32_t aToAPP)
+{
+return (NSCoordToFloat(aCoord) * aToAPP) / aFromAPP;
+}
+/// handy constants
+#define TWIPS_PER_POINT_INT           20
+#define TWIPS_PER_POINT_FLOAT         20.0f
+#define POINTS_PER_INCH_INT           72
+#define POINTS_PER_INCH_FLOAT         72.0f
+#define CM_PER_INCH_FLOAT             2.54f
+#define MM_PER_INCH_FLOAT             25.4f
+/*
+* Twips/unit conversions
+*/
+inline float NSUnitsToTwips(float aValue, float aPointsPerUnit)
+{
+return aValue * aPointsPerUnit * TWIPS_PER_POINT_FLOAT;
+}
+inline float NSTwipsToUnits(float aTwips, float aUnitsPerPoint)
+{
+return (aTwips * (aUnitsPerPoint / TWIPS_PER_POINT_FLOAT));
+}
+/// Unit conversion macros
+//@{
+#define NS_POINTS_TO_TWIPS(x)         NSUnitsToTwips((x), 1.0f)
+#define NS_INCHES_TO_TWIPS(x)         NSUnitsToTwips((x), POINTS_PER_INCH_FLOAT)                      // 72 points per inch
+#define NS_MILLIMETERS_TO_TWIPS(x)    NSUnitsToTwips((x), (POINTS_PER_INCH_FLOAT * 0.03937f))
+#define NS_POINTS_TO_INT_TWIPS(x)     NSToIntRound(NS_POINTS_TO_TWIPS(x))
+#define NS_INCHES_TO_INT_TWIPS(x)     NSToIntRound(NS_INCHES_TO_TWIPS(x))
+#define NS_TWIPS_TO_INCHES(x)         NSTwipsToUnits((x), 1.0f / POINTS_PER_INCH_FLOAT)
+#define NS_TWIPS_TO_MILLIMETERS(x)    NSTwipsToUnits((x), 1.0f / (POINTS_PER_INCH_FLOAT * 0.03937f))
+//@}
+#endif /* NSCOORD_H */

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comparison: gfx/src/nsCoord.h

gfx/src/nsCoord.h