| // Copyright 2016 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_RENDER_TREE_SHADOW_H_ |
| #define COBALT_RENDER_TREE_SHADOW_H_ |
| |
| #include <algorithm> |
| |
| #include "cobalt/math/rect_f.h" |
| #include "cobalt/math/vector2d_f.h" |
| #include "cobalt/render_tree/color_rgba.h" |
| |
| namespace cobalt { |
| namespace render_tree { |
| |
| // Describes a shadow effect that can be applied as a filter or to a shape. |
| // The |blur_sigma| value is given in units of Gaussian standard deviations for |
| // the Gaussian kernel that will be used to blur them. |
| struct Shadow { |
| Shadow(const math::Vector2dF& offset, float blur_sigma, |
| const ColorRGBA& color) |
| : offset(offset), blur_sigma(blur_sigma), color(color) {} |
| |
| // Since the blur parameters represent standard deviations, most of the |
| // blur is contained within 3 of them, so report that as the extent of the |
| // blur. |
| math::Vector2dF BlurExtent() const { |
| return math::Vector2dF(blur_sigma * 3, blur_sigma * 3); |
| } |
| |
| // Returns a bounding rectangle for the shadow if it were to be applied to |
| // the input bounding rectangle. |
| math::RectF ToShadowBounds(const math::RectF& source_bound) const { |
| math::RectF ret(source_bound); |
| ret.Offset(offset); |
| |
| math::Vector2dF blur_extent = BlurExtent(); |
| ret.Outset(blur_extent.x(), blur_extent.y()); |
| return ret; |
| } |
| |
| math::Vector2dF offset; |
| float blur_sigma; |
| ColorRGBA color; |
| }; |
| |
| } // namespace render_tree |
| } // namespace cobalt |
| |
| #endif // COBALT_RENDER_TREE_SHADOW_H_ |