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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "pdf/fading_control.h" |
| 6 |
| 7 #include <math.h> |
| 8 |
| 9 #include "base/logging.h" |
| 10 #include "pdf/draw_utils.h" |
| 11 #include "pdf/resource_consts.h" |
| 12 |
| 13 namespace chrome_pdf { |
| 14 |
| 15 FadingControl::FadingControl() |
| 16 : alpha_shift_(0), timer_id_(0) { |
| 17 } |
| 18 |
| 19 FadingControl::~FadingControl() { |
| 20 } |
| 21 |
| 22 void FadingControl::OnTimerFired(uint32 timer_id) { |
| 23 if (timer_id == timer_id_) { |
| 24 int32 new_alpha = transparency() + alpha_shift_; |
| 25 if (new_alpha <= kTransparentAlpha) { |
| 26 Show(false, true); |
| 27 OnFadeOutComplete(); |
| 28 return; |
| 29 } |
| 30 if (new_alpha >= kOpaqueAlpha) { |
| 31 AdjustTransparency(kOpaqueAlpha, true); |
| 32 OnFadeInComplete(); |
| 33 return; |
| 34 } |
| 35 |
| 36 AdjustTransparency(static_cast<uint8>(new_alpha), true); |
| 37 timer_id_ = owner()->ScheduleTimer(id(), kFadingTimeoutMs); |
| 38 } |
| 39 } |
| 40 |
| 41 // Fade In/Out control depending on visible flag over the time of time_ms. |
| 42 void FadingControl::Fade(bool show, uint32 time_ms) { |
| 43 DCHECK(time_ms != 0); |
| 44 // Check if we already in the same state. |
| 45 if (!visible() && !show) |
| 46 return; |
| 47 if (!visible() && show) { |
| 48 Show(show, false); |
| 49 AdjustTransparency(kTransparentAlpha, false); |
| 50 OnFadeOutComplete(); |
| 51 } |
| 52 if (transparency() == kOpaqueAlpha && show) { |
| 53 OnFadeInComplete(); |
| 54 return; |
| 55 } |
| 56 |
| 57 int delta = show ? kOpaqueAlpha - transparency() : transparency(); |
| 58 double shift = |
| 59 static_cast<double>(delta) * kFadingTimeoutMs / time_ms; |
| 60 if (shift > delta) |
| 61 alpha_shift_ = delta; |
| 62 else |
| 63 alpha_shift_ = static_cast<int>(ceil(shift)); |
| 64 |
| 65 if (alpha_shift_ == 0) |
| 66 alpha_shift_ = 1; |
| 67 |
| 68 // If disabling, make alpha shift negative. |
| 69 if (!show) |
| 70 alpha_shift_ = -alpha_shift_; |
| 71 |
| 72 timer_id_ = owner()->ScheduleTimer(id(), kFadingTimeoutMs); |
| 73 } |
| 74 |
| 75 } // namespace chrome_pdf |
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