| |
| /* |
| * 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 "SkColor.h" |
| #include "SkPoint3.h" |
| #include "SkScalar.h" |
| #include "../private/SkShadowFlags.h" |
| |
| class SkCanvas; |
| class SkPath; |
| class SkResourceCache; |
| |
| class SK_API SkShadowUtils { |
| public: |
| /** |
| * 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); |
| |
| /** |
| * Deprecated version that uses one color and two alphas, and supports tonal color. |
| * |
| * 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 ambientAlpha The maximum alpha of the ambient shadow. |
| * @param spotAlpha The maxium alpha of the spot shadow. |
| * @param color The shadow color. |
| * @param flags Options controlling opaque occluder optimizations and shadow appearance. See |
| * SkShadowFlags. |
| */ |
| static void DrawShadow(SkCanvas* canvas, const SkPath& path, const SkPoint3& zPlane, |
| const SkPoint3& lightPos, SkScalar lightRadius, SkScalar ambientAlpha, |
| SkScalar spotAlpha, SkColor color, |
| uint32_t flags = SkShadowFlags::kNone_ShadowFlag) { |
| SkColor ambientColor; |
| SkColor spotColor; |
| if (flags & SkShadowFlags::kDisableTonalColor_ShadowFlag) { |
| ambientColor = SkColorSetARGB(ambientAlpha*SkColorGetA(color), SkColorGetR(color), |
| SkColorGetG(color), SkColorGetB(color)); |
| spotColor = SkColorSetARGB(spotAlpha*SkColorGetA(color), SkColorGetR(color), |
| SkColorGetG(color), SkColorGetB(color)); |
| } else { |
| SkColor inAmbient = SkColorSetA(color, ambientAlpha*SkColorGetA(color)); |
| SkColor inSpot = SkColorSetA(color, spotAlpha*SkColorGetA(color)); |
| ComputeTonalColors(inAmbient, inSpot, &ambientColor, &spotColor); |
| } |
| |
| DrawShadow(canvas, path, zPlane, lightPos, lightRadius, ambientColor, spotColor, flags); |
| } |
| |
| /** |
| * Deprecated version with height value (to be removed when Flutter is updated). |
| * |
| * Draw an offset spot shadow and outlining ambient shadow for the given path using a disc |
| * light. |
| * |
| * @param canvas The canvas on which to draw the shadows. |
| * @param path The occluder used to generate the shadows. |
| * @param occluderHeight The vertical offset of the occluder from the canvas. This is |
| * independent of the canvas's current matrix. |
| * @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 ambientAlpha The maximum alpha of the ambient shadow. |
| * @param spotAlpha The maxium alpha of the spot shadow. |
| * @param color The shadow color. |
| * @param flags Options controlling opaque occluder optimizations and shadow appearance. See |
| * SkShadowFlags. |
| */ |
| static void DrawShadow(SkCanvas* canvas, const SkPath& path, SkScalar occluderHeight, |
| const SkPoint3& lightPos, SkScalar lightRadius, SkScalar ambientAlpha, |
| SkScalar spotAlpha, SkColor color, |
| uint32_t flags = SkShadowFlags::kNone_ShadowFlag) { |
| SkPoint3 zPlane = SkPoint3::Make(0, 0, occluderHeight); |
| DrawShadow(canvas, path, zPlane, lightPos, lightRadius, ambientAlpha, spotAlpha, |
| color, flags); |
| } |
| |
| /** |
| * 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); |
| }; |
| |
| #endif |