skia2/include/core/SkScalarCompare.h

47 lines
1.6 KiB
C
Raw Normal View History

/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SkScalarCompare_DEFINED
#define SkScalarCompare_DEFINED
#include "SkFloatBits.h"
#include "SkRect.h"
/** Skia can spend a lot of time just comparing scalars (e.g. quickReject).
When scalar==fixed, this is very fast, and when scalar==hardware-float, this
is also reasonable, but if scalar==software-float, then each compare can be
a function call and take real time. To account for that, we have the flag
SK_SCALAR_SLOW_COMPARES.
If this is defined, we have a special trick where we quickly convert floats
to a 2's compliment form, and then treat them as signed 32bit integers. In
this form we lose a few subtlties (e.g. NaNs always comparing false) but
we gain the speed of integer compares.
*/
#ifdef SK_SCALAR_SLOW_COMPARES
typedef int32_t SkScalarCompareType;
typedef SkIRect SkRectCompareType;
#define SkScalarToCompareType(x) SkScalarAs2sCompliment(x)
#else
typedef SkScalar SkScalarCompareType;
typedef SkRect SkRectCompareType;
#define SkScalarToCompareType(x) (x)
#endif
#endif