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- // Copyright 2022 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "ash/ambient/ui/jitter_calculator.h"
- #include <utility>
- #include "base/check.h"
- #include "base/check_op.h"
- #include "base/rand_util.h"
- namespace ash {
- JitterCalculator::JitterCalculator(Config config)
- : JitterCalculator(std::move(config),
- base::BindRepeating(&base::RandInt, 0, 1)) {}
- JitterCalculator::JitterCalculator(
- Config config,
- RandomBinaryGenerator random_binary_generator)
- : config_(std::move(config)),
- random_binary_generator_(std::move(random_binary_generator)) {
- DCHECK_GE(config_.step_size, 0);
- DCHECK_LE(config_.x_min_translation, 0);
- DCHECK_GE(config_.x_max_translation, 0);
- DCHECK_LE(config_.y_min_translation, 0);
- DCHECK_GE(config_.y_max_translation, 0);
- DCHECK(random_binary_generator_);
- }
- JitterCalculator::~JitterCalculator() = default;
- gfx::Vector2d JitterCalculator::Calculate() {
- AssetCurrentTranslationWithinBounds();
- // Move the translation point randomly one step on each x/y direction.
- int x_increment = config_.step_size * random_binary_generator_.Run();
- int y_increment = x_increment == 0
- ? config_.step_size
- : config_.step_size * random_binary_generator_.Run();
- current_translation_.Add(gfx::Vector2d(translate_x_direction * x_increment,
- translate_y_direction * y_increment));
- // If the translation point is out of bounds, reset it within bounds and
- // reverse the direction.
- if (current_translation_.x() < config_.x_min_translation) {
- translate_x_direction = 1;
- current_translation_.set_x(config_.x_min_translation);
- } else if (current_translation_.x() > config_.x_max_translation) {
- translate_x_direction = -1;
- current_translation_.set_x(config_.x_max_translation);
- }
- if (current_translation_.y() > config_.y_max_translation) {
- translate_y_direction = -1;
- current_translation_.set_y(config_.y_max_translation);
- } else if (current_translation_.y() < config_.y_min_translation) {
- translate_y_direction = 1;
- current_translation_.set_y(config_.y_min_translation);
- }
- AssetCurrentTranslationWithinBounds();
- return current_translation_;
- }
- void JitterCalculator::AssetCurrentTranslationWithinBounds() const {
- DCHECK_LE(current_translation_.x(), config_.x_max_translation);
- DCHECK_GE(current_translation_.x(), config_.x_min_translation);
- DCHECK_LE(current_translation_.y(), config_.y_max_translation);
- DCHECK_GE(current_translation_.y(), config_.y_min_translation);
- }
- } // namespace ash
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