1 2 /* 3 * Copyright 2017 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 #ifndef SkShadowUtils_DEFINED 9 #define SkShadowUtils_DEFINED 10 11 #include "include/core/SkColor.h" 12 #include "include/core/SkPoint3.h" 13 #include "include/core/SkScalar.h" 14 #include "include/private/SkShadowFlags.h" 15 16 class SkCanvas; 17 class SkPath; 18 class SkResourceCache; 19 20 class SK_API SkShadowUtils { 21 public: 22 /** 23 * Draw an offset spot shadow and outlining ambient shadow for the given path using a disc 24 * light. The shadow may be cached, depending on the path type and canvas matrix. If the 25 * matrix is perspective or the path is volatile, it will not be cached. 26 * 27 * @param canvas The canvas on which to draw the shadows. 28 * @param path The occluder used to generate the shadows. 29 * @param zPlaneParams Values for the plane function which returns the Z offset of the 30 * occluder from the canvas based on local x and y values (the current matrix is not applied). 31 * @param lightPos The 3D position of the light relative to the canvas plane. This is 32 * independent of the canvas's current matrix. 33 * @param lightRadius The radius of the disc light. 34 * @param ambientColor The color of the ambient shadow. 35 * @param spotColor The color of the spot shadow. 36 * @param flags Options controlling opaque occluder optimizations and shadow appearance. See 37 * SkShadowFlags. 38 */ 39 static void DrawShadow(SkCanvas* canvas, const SkPath& path, const SkPoint3& zPlaneParams, 40 const SkPoint3& lightPos, SkScalar lightRadius, 41 SkColor ambientColor, SkColor spotColor, 42 uint32_t flags = SkShadowFlags::kNone_ShadowFlag); 43 44 /** 45 * Helper routine to compute color values for one-pass tonal alpha. 46 * 47 * @param inAmbientColor Original ambient color 48 * @param inSpotColor Original spot color 49 * @param outAmbientColor Modified ambient color 50 * @param outSpotColor Modified spot color 51 */ 52 static void ComputeTonalColors(SkColor inAmbientColor, SkColor inSpotColor, 53 SkColor* outAmbientColor, SkColor* outSpotColor); 54 }; 55 56 #endif 57