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gecko-dev/gfx/src/nsCoord.h

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/* -*- 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"
/*
* 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
NS_WARN_IF_FALSE(aValue <= nscoord_MAX,
"Overflowed nscoord_MAX in conversion to nscoord");
if (aValue >= nscoord_MAX) {
return nscoord_MAX;
}
NS_WARN_IF_FALSE(aValue >= nscoord_MIN,
"Overflowed nscoord_MIN in conversion to nscoord");
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
// This one's only a warning because it may be possible to trigger it with
// valid inputs.
NS_WARN_IF_FALSE((requireNotNegative
? aCoord > 0
: (aCoord > 0) == (aScale > 0))
? floorf(aCoord * aScale) < nscoord_MAX
: ceilf(aCoord * aScale) > nscoord_MIN,
"nscoord multiplication capped");
float product = aCoord * aScale;
if (requireNotNegative ? aCoord > 0 : (aCoord > 0) == (aScale > 0))
return NSToCoordRoundWithClamp(NS_MIN<float>(nscoord_MAX, product));
return NSToCoordRoundWithClamp(NS_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);
}
inline nscoord NSCoordMultiply(nscoord aCoord, int32_t aScale) {
VERIFY_COORD(aCoord);
return aCoord * aScale;
}
inline nscoord NSCoordDivide(nscoord aCoord, float aVal) {
VERIFY_COORD(aCoord);
#ifdef NS_COORD_IS_FLOAT
return floorf(aCoord/aVal);
#else
return (int32_t)(aCoord/aVal);
#endif
}
inline nscoord NSCoordDivide(nscoord aCoord, int32_t aVal) {
VERIFY_COORD(aCoord);
#ifdef NS_COORD_IS_FLOAT
return floorf(aCoord/aVal);
#else
return aCoord/aVal;
#endif
}
/**
* 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);
NS_ASSERTION(a != nscoord_MIN && b != nscoord_MIN,
"NSCoordSaturatingAdd got nscoord_MIN as argument");
#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
NS_ASSERTION(a < nscoord_MAX && b < nscoord_MAX,
"Doing nscoord addition with values > nscoord_MAX");
NS_ASSERTION((int64_t)a + (int64_t)b > (int64_t)nscoord_MIN,
"nscoord addition will reach or pass nscoord_MIN");
// This one's only a warning because the NS_MIN below means that
// we'll handle this case correctly.
NS_WARN_IF_FALSE((int64_t)a + (int64_t)b < (int64_t)nscoord_MAX,
"nscoord addition capped to nscoord_MAX");
// Cap the result, just in case we're dealing with numbers near nscoord_MAX
return NS_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);
NS_ASSERTION(a != nscoord_MIN && b != nscoord_MIN,
"NSCoordSaturatingSubtract got nscoord_MIN as argument");
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
NS_ASSERTION(a < nscoord_MAX && b < nscoord_MAX,
"Doing nscoord subtraction with values > nscoord_MAX");
NS_ASSERTION((int64_t)a - (int64_t)b > (int64_t)nscoord_MIN,
"nscoord subtraction will reach or pass nscoord_MIN");
// This one's only a warning because the NS_MIN below means that
// we'll handle this case correctly.
NS_WARN_IF_FALSE((int64_t)a - (int64_t)b < (int64_t)nscoord_MAX,
"nscoord subtraction capped to nscoord_MAX");
// Cap the result, in case we're dealing with numbers near nscoord_MAX
return NS_MIN(nscoord_MAX, a - b);
}
}
#endif
}
/** compare against a nscoord "b", which might be unconstrained
* "a" must not be unconstrained.
* Every number is smaller than a unconstrained one
*/
inline bool
NSCoordLessThan(nscoord a,nscoord b)
{
NS_ASSERTION(a != nscoord_MAX,
"This coordinate should be constrained");
return ((a < b) || (b == nscoord_MAX));
}
/** compare against a nscoord "b", which might be unconstrained
* "a" must not be unconstrained
* No number is larger than a unconstrained one.
*/
inline bool
NSCoordGreaterThan(nscoord a,nscoord b)
{
NS_ASSERTION(a != nscoord_MAX,
"This coordinate should be constrained");
return ((a > b) && (b != nscoord_MAX));
}
/**
* Convert an nscoord to a int32_t. This *does not* do rounding because
* coords are never fractional. They can be out of range, so this does
* clamp out of bounds coord values to INT32_MIN and INT32_MAX.
*/
inline int32_t NSCoordToInt(nscoord aCoord) {
VERIFY_COORD(aCoord);
#ifdef NS_COORD_IS_FLOAT
NS_ASSERTION(!NS_IEEEIsNan(aCoord), "NaN encountered in int conversion");
if (aCoord < -2147483648.0f) {
// -2147483648 is the smallest 32-bit signed integer that can be
// exactly represented as a float
return INT32_MIN;
} else if (aCoord > 2147483520.0f) {
// 2147483520 is the largest 32-bit signed integer that can be
// exactly represented as an IEEE float
return INT32_MAX;
} else {
return (int32_t)aCoord;
}
#else
return aCoord;
#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
NS_WARN_IF_FALSE(aValue <= nscoord_MAX,
"Overflowed nscoord_MAX in conversion to nscoord");
if (aValue >= nscoord_MAX) {
return nscoord_MAX;
}
NS_WARN_IF_FALSE(aValue >= nscoord_MIN,
"Overflowed nscoord_MIN in conversion to nscoord");
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(float aValue)
{
#ifndef NS_COORD_IS_FLOAT
// Bounds-check before converting out of float, to avoid overflow
NS_WARN_IF_FALSE(aValue <= nscoord_MAX,
"Overflowed nscoord_MAX in conversion to nscoord");
if (aValue >= nscoord_MAX) {
return nscoord_MAX;
}
NS_WARN_IF_FALSE(aValue >= nscoord_MIN,
"Overflowed nscoord_MIN in conversion to nscoord");
if (aValue <= nscoord_MIN) {
return nscoord_MIN;
}
#endif
return NSToCoordCeil(aValue);
}
inline nscoord NSToCoordCeilClamped(double aValue)
{
#ifndef NS_COORD_IS_FLOAT
// Bounds-check before converting out of double, to avoid overflow
NS_WARN_IF_FALSE(aValue <= nscoord_MAX,
"Overflowed nscoord_MAX in conversion to nscoord");
if (aValue >= nscoord_MAX) {
return nscoord_MAX;
}
NS_WARN_IF_FALSE(aValue >= nscoord_MIN,
"Overflowed nscoord_MIN in conversion to nscoord");
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(float aValue)
{
return int32_t(floorf(aValue + 0.5f));
}
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, nscoord aAppUnitsPerPixel)
{
return (double(aAppUnits) / double(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_CENTIMETERS_TO_TWIPS(x) NSUnitsToTwips((x), (POINTS_PER_INCH_FLOAT * 0.3937f))
#define NS_PICAS_TO_TWIPS(x) NSUnitsToTwips((x), 12.0f) // 12 points per pica
#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_POINTS(x) NSTwipsToUnits((x), 1.0f)
#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))
#define NS_TWIPS_TO_CENTIMETERS(x) NSTwipsToUnits((x), 1.0f / (POINTS_PER_INCH_FLOAT * 0.3937f))
#define NS_TWIPS_TO_PICAS(x) NSTwipsToUnits((x), 1.0f / 12.0f)
//@}
#endif /* NSCOORD_H */
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