chromium/third_party/skia/src/core/SkDrawShadowInfo.h

/*
 * Copyright 2017 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkDrawShadowInfo_DEFINED
#define SkDrawShadowInfo_DEFINED

#include "include/core/SkColor.h"
#include "include/core/SkPoint.h"
#include "include/core/SkPoint3.h"
#include "include/core/SkScalar.h"
#include "include/private/base/SkAssert.h"
#include "include/private/base/SkFloatingPoint.h"
#include "include/private/base/SkTPin.h"

#include <algorithm>
#include <cstdint>

class SkMatrix;
class SkPath;
struct SkRect;

struct SkDrawShadowRec { … };

namespace SkDrawShadowMetrics {

static constexpr auto kAmbientHeightFactor = …;
static constexpr auto kAmbientGeomFactor = …;
// Assuming that we have a light height of 600 for the spot shadow,
// the spot values will reach their maximum at a height of approximately 292.3077.
// We'll round up to 300 to keep it simple.
static constexpr auto kMaxAmbientRadius = …;

static inline float divide_and_pin(float numer, float denom, float min, float max) { … }

inline SkScalar AmbientBlurRadius(SkScalar height) { … }

inline SkScalar AmbientRecipAlpha(SkScalar height) { … }

inline SkScalar SpotBlurRadius(SkScalar occluderZ, SkScalar lightZ, SkScalar lightRadius) { … }

inline void GetSpotParams(SkScalar occluderZ, SkScalar lightX, SkScalar lightY, SkScalar lightZ,
                          SkScalar lightRadius,
                          SkScalar* blurRadius, SkScalar* scale, SkVector* translate) { … }

inline void GetDirectionalParams(SkScalar occluderZ, SkScalar lightX, SkScalar lightY,
                                 SkScalar lightZ, SkScalar lightRadius,
                                 SkScalar* blurRadius, SkScalar* scale, SkVector* translate) { … }

// Create the transformation to apply to a path to get its base shadow outline, given the light
// parameters and the path's 3D transformation (given by ctm and zPlaneParams).
// Also computes the blur radius to apply the transformed outline.
bool GetSpotShadowTransform(const SkPoint3& lightPos, SkScalar lightRadius,
                            const SkMatrix& ctm, const SkPoint3& zPlaneParams,
                            const SkRect& pathBounds, bool directional,
                            SkMatrix* shadowTransform, SkScalar* radius);

// get bounds prior to the ctm being applied
void GetLocalBounds(const SkPath&, const SkDrawShadowRec&, const SkMatrix& ctm, SkRect* bounds);

}  // namespace SkDrawShadowMetrics

#endif