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