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* Copyright 2018 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkRectPriv_DEFINED
#define SkRectPriv_DEFINED
#include "include/core/SkRect.h"
#include "src/core/SkMathPriv.h"
class SkRectPriv {
// Returns an irect that is very large, and can be safely round-trip with SkRect and still
// be considered non-empty (i.e. width/height > 0) even if we round-out the SkRect.
static SkIRect MakeILarge() {
// SK_MaxS32 >> 1 seemed better, but it did not survive round-trip with SkRect and rounding.
// Also, 1 << 29 can be perfectly represented in float, while SK_MaxS32 >> 1 cannot.
const int32_t large = 1 << 29;
return { -large, -large, large, large };
static SkIRect MakeILargestInverted() {
return { SK_MaxS32, SK_MaxS32, SK_MinS32, SK_MinS32 };
static SkRect MakeLargeS32() {
SkRect r;
return r;
static SkRect MakeLargest() {
return { SK_ScalarMin, SK_ScalarMin, SK_ScalarMax, SK_ScalarMax };
static constexpr SkRect MakeLargestInverted() {
return { SK_ScalarMax, SK_ScalarMax, SK_ScalarMin, SK_ScalarMin };
static void GrowToInclude(SkRect* r, const SkPoint& pt) {
r->fLeft = std::min(pt.fX, r->fLeft);
r->fRight = std::max(pt.fX, r->fRight);
r->fTop = std::min(pt.fY, r->fTop);
r->fBottom = std::max(pt.fY, r->fBottom);
// Conservative check if r can be expressed in fixed-point.
// Will return false for very large values that might have fit
static bool FitsInFixed(const SkRect& r) {
return SkFitsInFixed(r.fLeft) && SkFitsInFixed(r.fTop) &&
SkFitsInFixed(r.fRight) && SkFitsInFixed(r.fBottom);
static bool Is16Bit(const SkIRect& r) {
return SkTFitsIn<int16_t>(r.fLeft) && SkTFitsIn<int16_t>(r.fTop) &&
SkTFitsIn<int16_t>(r.fRight) && SkTFitsIn<int16_t>(r.fBottom);
// Returns r.width()/2 but divides first to avoid width() overflowing.
static SkScalar HalfWidth(const SkRect& r) {
return SkScalarHalf(r.fRight) - SkScalarHalf(r.fLeft);
// Returns r.height()/2 but divides first to avoid height() overflowing.
static SkScalar HalfHeight(const SkRect& r) {
return SkScalarHalf(r.fBottom) - SkScalarHalf(r.fTop);
// Evaluate A-B. If the difference shape cannot be represented as a rectangle then false is
// returned and 'out' is set to the largest rectangle contained in said shape. If true is
// returned then A-B is representable as a rectangle, which is stored in 'out'.
static bool Subtract(const SkRect& a, const SkRect& b, SkRect* out);
static bool Subtract(const SkIRect& a, const SkIRect& b, SkIRect* out);
// Evaluate A-B, and return the largest rectangle contained in that shape (since the difference
// may not be representable as rectangle). The returned rectangle will not intersect B.
static SkRect Subtract(const SkRect& a, const SkRect& b) {
SkRect diff;
Subtract(a, b, &diff);
return diff;
static SkIRect Subtract(const SkIRect& a, const SkIRect& b) {
SkIRect diff;
Subtract(a, b, &diff);
return diff;