1 files changed, 75 insertions, 0 deletions
diff --git a/xfa_test/pdf/fading_control.cc b/xfa_test/pdf/fading_control.cc
new file mode 100644
index 0000000000..7e4d8ef63e
--- /dev/null
+++ b/xfa_test/pdf/fading_control.cc
@@ -0,0 +1,75 @@
+// 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