blob: 7e4d8ef63e4a34a8ffdf03edcde6e4dc0ba949f2 [file] [log] [blame]
// Copyright (c) 2012 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 "pdf/fading_control.h"
#include <math.h>
#include "base/logging.h"
#include "pdf/draw_utils.h"
#include "pdf/resource_consts.h"
namespace chrome_pdf {
FadingControl::FadingControl()
: alpha_shift_(0), timer_id_(0) {
}
FadingControl::~FadingControl() {
}
void FadingControl::OnTimerFired(uint32 timer_id) {
if (timer_id == timer_id_) {
int32 new_alpha = transparency() + alpha_shift_;
if (new_alpha <= kTransparentAlpha) {
Show(false, true);
OnFadeOutComplete();
return;
}
if (new_alpha >= kOpaqueAlpha) {
AdjustTransparency(kOpaqueAlpha, true);
OnFadeInComplete();
return;
}
AdjustTransparency(static_cast<uint8>(new_alpha), true);
timer_id_ = owner()->ScheduleTimer(id(), kFadingTimeoutMs);
}
}
// Fade In/Out control depending on visible flag over the time of time_ms.
void FadingControl::Fade(bool show, uint32 time_ms) {
DCHECK(time_ms != 0);
// Check if we already in the same state.
if (!visible() && !show)
return;
if (!visible() && show) {
Show(show, false);
AdjustTransparency(kTransparentAlpha, false);
OnFadeOutComplete();
}
if (transparency() == kOpaqueAlpha && show) {
OnFadeInComplete();
return;
}
int delta = show ? kOpaqueAlpha - transparency() : transparency();
double shift =
static_cast<double>(delta) * kFadingTimeoutMs / time_ms;
if (shift > delta)
alpha_shift_ = delta;
else
alpha_shift_ = static_cast<int>(ceil(shift));
if (alpha_shift_ == 0)
alpha_shift_ = 1;
// If disabling, make alpha shift negative.
if (!show)
alpha_shift_ = -alpha_shift_;
timer_id_ = owner()->ScheduleTimer(id(), kFadingTimeoutMs);
}
} // namespace chrome_pdf