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// Copyright (c) 2014 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 "content/browser/renderer_host/frame_metadata_util.h"
#include "cc/output/compositor_frame_metadata.h"
namespace {
// Used to accomodate finite precision when comparing scaled viewport and
// content widths. While this value may seem large, width=device-width on an N7
// V1 saw errors of ~0.065 between computed window and content widths.
const float kMobileViewportWidthEpsilon = 0.15f;
bool HasFixedPageScale(const cc::CompositorFrameMetadata& frame_metadata) {
return frame_metadata.min_page_scale_factor ==
frame_metadata.max_page_scale_factor;
}
bool HasMobileViewport(const cc::CompositorFrameMetadata& frame_metadata) {
float window_width_dip =
frame_metadata.page_scale_factor *
frame_metadata.scrollable_viewport_size.width();
float content_width_css = frame_metadata.root_layer_size.width();
return content_width_css <= window_width_dip + kMobileViewportWidthEpsilon;
}
} // namespace
namespace content {
bool IsMobileOptimizedFrame(const cc::CompositorFrameMetadata& frame_metadata) {
bool has_mobile_viewport = HasMobileViewport(frame_metadata);
bool has_fixed_page_scale = HasFixedPageScale(frame_metadata);
return has_fixed_page_scale || has_mobile_viewport;
}
} // namespace content
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