chromium/media/cast/sender/performance_metrics_overlay.cc

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "media/cast/sender/performance_metrics_overlay.h"

#include <stddef.h>
#include <stdint.h>

#include <algorithm>
#include <string>

#include "base/functional/bind.h"
#include "base/logging.h"
#include "base/numerics/safe_conversions.h"
#include "base/strings/stringprintf.h"
#include "media/base/video_frame.h"

namespace media {
namespace cast {

namespace {

constexpr int kScale = …;             // Physical pixels per one logical pixel.
constexpr int kCharacterWidth = …;    // Logical pixel width of one character.
constexpr int kCharacterHeight = …;   // Logical pixel height of one character.
constexpr int kCharacterSpacing = …;  // Logical pixels between each character.
constexpr int kLineSpacing = …;  // Logical pixels between each line of chars.
constexpr int kPlane = …;        // Y-plane in YUV formats.

// For each pixel in the |rect| (logical coordinates), either decrease the
// intensity or increase it so that the resulting pixel has a perceivably
// different value than it did before.  |p_ul| is a pointer to the pixel at
// coordinate (0,0) in a single-channel 8bpp bitmap.  |stride| is the number of
// bytes per row in the output bitmap.
void DivergePixels(const gfx::Rect& rect, uint8_t* p_ul, int stride) { … }

// Render |line| into |frame| at physical pixel row |top| and aligned to the
// right edge.  Only number digits and a smattering of punctuation characters
// will be rendered.
void RenderLineOfText(const std::string& line, int top, VideoFrame* frame) { … }

}  // namespace

scoped_refptr<VideoFrame> RenderPerformanceMetricsOverlay(
    base::TimeDelta target_playout_delay,
    bool in_low_latency_mode,
    int target_bitrate,
    int frames_ago,
    double encoder_utilization,
    double lossiness,
    scoped_refptr<VideoFrame> source) { … }

}  // namespace cast
}  // namespace media