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* 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 SkShadowUtils_DEFINED
#define SkShadowUtils_DEFINED
#include "include/core/SkColor.h"
#include "include/core/SkPoint3.h"
#include "include/core/SkScalar.h"
#include "include/private/SkShadowFlags.h"
class SkCanvas;
class SkPath;
class SkResourceCache;
class SK_API SkShadowUtils {
* Draw an offset spot shadow and outlining ambient shadow for the given path using a disc
* light. The shadow may be cached, depending on the path type and canvas matrix. If the
* matrix is perspective or the path is volatile, it will not be cached.
* @param canvas The canvas on which to draw the shadows.
* @param path The occluder used to generate the shadows.
* @param zPlaneParams Values for the plane function which returns the Z offset of the
* occluder from the canvas based on local x and y values (the current matrix is not applied).
* @param lightPos The 3D position of the light relative to the canvas plane. This is
* independent of the canvas's current matrix.
* @param lightRadius The radius of the disc light.
* @param ambientColor The color of the ambient shadow.
* @param spotColor The color of the spot shadow.
* @param flags Options controlling opaque occluder optimizations and shadow appearance. See
* SkShadowFlags.
static void DrawShadow(SkCanvas* canvas, const SkPath& path, const SkPoint3& zPlaneParams,
const SkPoint3& lightPos, SkScalar lightRadius,
SkColor ambientColor, SkColor spotColor,
uint32_t flags = SkShadowFlags::kNone_ShadowFlag);
* Helper routine to compute color values for one-pass tonal alpha.
* @param inAmbientColor Original ambient color
* @param inSpotColor Original spot color
* @param outAmbientColor Modified ambient color
* @param outSpotColor Modified spot color
static void ComputeTonalColors(SkColor inAmbientColor, SkColor inSpotColor,
SkColor* outAmbientColor, SkColor* outSpotColor);