Remove differ from ScreenCapturer implementations
We can use ScreenCapturerDifferWrapper if needed, otherwise ScreenCapturer does
not need to calculate updated region itself, setting to entire screen is enough.
BUG=633802
Review-Url: https://codereview.webrtc.org/2348803003
Cr-Commit-Position: refs/heads/master@{#14377}
diff --git a/webrtc/modules/BUILD.gn b/webrtc/modules/BUILD.gn
index fe8124d..6f7f189 100644
--- a/webrtc/modules/BUILD.gn
+++ b/webrtc/modules/BUILD.gn
@@ -525,7 +525,6 @@
sources += [
"desktop_capture/desktop_region_unittest.cc",
"desktop_capture/differ_block_unittest.cc",
- "desktop_capture/differ_unittest.cc",
]
}
diff --git a/webrtc/modules/desktop_capture/BUILD.gn b/webrtc/modules/desktop_capture/BUILD.gn
index 46a768a..e763056 100644
--- a/webrtc/modules/desktop_capture/BUILD.gn
+++ b/webrtc/modules/desktop_capture/BUILD.gn
@@ -124,8 +124,6 @@
if (!is_ios) {
sources += [
- "differ.cc",
- "differ.h",
"differ_block.cc",
"differ_block.h",
"screen_capturer_differ_wrapper.cc",
diff --git a/webrtc/modules/desktop_capture/desktop_capture.gypi b/webrtc/modules/desktop_capture/desktop_capture.gypi
index 521ef27..48bafdf 100644
--- a/webrtc/modules/desktop_capture/desktop_capture.gypi
+++ b/webrtc/modules/desktop_capture/desktop_capture.gypi
@@ -140,8 +140,6 @@
}],
['OS!="ios" ', {
'sources': [
- 'differ.cc',
- 'differ.h',
'differ_block.cc',
'differ_block.h',
'screen_capturer_differ_wrapper.cc',
diff --git a/webrtc/modules/desktop_capture/differ.cc b/webrtc/modules/desktop_capture/differ.cc
deleted file mode 100644
index 8140e61..0000000
--- a/webrtc/modules/desktop_capture/differ.cc
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/modules/desktop_capture/differ.h"
-
-#include "string.h"
-
-#include "webrtc/modules/desktop_capture/differ_block.h"
-#include "webrtc/system_wrappers/include/logging.h"
-
-namespace webrtc {
-
-Differ::Differ(int width, int height, int bpp, int stride) {
- // Dimensions of screen.
- width_ = width;
- height_ = height;
- bytes_per_pixel_ = bpp;
- bytes_per_row_ = stride;
-
- // Calc number of blocks (full and partial) required to cover entire image.
- // One additional row/column is added as a boundary on the right & bottom.
- diff_info_width_ = ((width_ + kBlockSize - 1) / kBlockSize) + 1;
- diff_info_height_ = ((height_ + kBlockSize - 1) / kBlockSize) + 1;
- diff_info_size_ = diff_info_width_ * diff_info_height_ * sizeof(bool);
- diff_info_.reset(new bool[diff_info_size_]);
-}
-
-Differ::~Differ() {}
-
-void Differ::CalcDirtyRegion(const uint8_t* prev_buffer,
- const uint8_t* curr_buffer,
- DesktopRegion* region) {
- // Identify all the blocks that contain changed pixels.
- MarkDirtyBlocks(prev_buffer, curr_buffer);
-
- // Now that we've identified the blocks that have changed, merge adjacent
- // blocks to minimize the number of rects that we return.
- MergeBlocks(region);
-}
-
-void Differ::MarkDirtyBlocks(const uint8_t* prev_buffer,
- const uint8_t* curr_buffer) {
- memset(diff_info_.get(), 0, diff_info_size_);
-
- // Calc number of full blocks.
- int x_full_blocks = width_ / kBlockSize;
- int y_full_blocks = height_ / kBlockSize;
-
- // Calc size of partial blocks which may be present on right and bottom edge.
- int partial_column_width = width_ - (x_full_blocks * kBlockSize);
- int partial_row_height = height_ - (y_full_blocks * kBlockSize);
-
- // Offset from the start of one block-column to the next.
- int block_x_offset = bytes_per_pixel_ * kBlockSize;
- // Offset from the start of one block-row to the next.
- int block_y_stride = (width_ * bytes_per_pixel_) * kBlockSize;
- // Offset from the start of one diff_info row to the next.
- int diff_info_stride = diff_info_width_ * sizeof(bool);
-
- const uint8_t* prev_block_row_start = prev_buffer;
- const uint8_t* curr_block_row_start = curr_buffer;
- bool* diff_info_row_start = diff_info_.get();
-
- for (int y = 0; y < y_full_blocks; y++) {
- const uint8_t* prev_block = prev_block_row_start;
- const uint8_t* curr_block = curr_block_row_start;
- bool* diff_info = diff_info_row_start;
-
- for (int x = 0; x < x_full_blocks; x++) {
- // Mark this block as being modified so that it gets incorporated into
- // a dirty rect.
- *diff_info = BlockDifference(prev_block, curr_block, bytes_per_row_);
- prev_block += block_x_offset;
- curr_block += block_x_offset;
- diff_info += sizeof(bool);
- }
-
- // If there is a partial column at the end, handle it.
- // This condition should rarely, if ever, occur.
- if (partial_column_width != 0) {
- *diff_info = !PartialBlocksEqual(prev_block, curr_block, bytes_per_row_,
- partial_column_width, kBlockSize);
- diff_info += sizeof(bool);
- }
-
- // Update pointers for next row.
- prev_block_row_start += block_y_stride;
- curr_block_row_start += block_y_stride;
- diff_info_row_start += diff_info_stride;
- }
-
- // If the screen height is not a multiple of the block size, then this
- // handles the last partial row. This situation is far more common than the
- // 'partial column' case.
- if (partial_row_height != 0) {
- const uint8_t* prev_block = prev_block_row_start;
- const uint8_t* curr_block = curr_block_row_start;
- bool* diff_info = diff_info_row_start;
- for (int x = 0; x < x_full_blocks; x++) {
- *diff_info = !PartialBlocksEqual(prev_block, curr_block,
- bytes_per_row_,
- kBlockSize, partial_row_height);
- prev_block += block_x_offset;
- curr_block += block_x_offset;
- diff_info += sizeof(bool);
- }
- if (partial_column_width != 0) {
- *diff_info = !PartialBlocksEqual(prev_block, curr_block, bytes_per_row_,
- partial_column_width,
- partial_row_height);
- diff_info += sizeof(bool);
- }
- }
-}
-
-bool Differ::PartialBlocksEqual(const uint8_t* prev_buffer,
- const uint8_t* curr_buffer,
- int stride, int width, int height) {
- int width_bytes = width * bytes_per_pixel_;
- for (int y = 0; y < height; y++) {
- if (memcmp(prev_buffer, curr_buffer, width_bytes) != 0)
- return false;
- prev_buffer += bytes_per_row_;
- curr_buffer += bytes_per_row_;
- }
- return true;
-}
-
-void Differ::MergeBlocks(DesktopRegion* region) {
- region->Clear();
-
- bool* diff_info_row_start = diff_info_.get();
- int diff_info_stride = diff_info_width_ * sizeof(bool);
-
- for (int y = 0; y < diff_info_height_; y++) {
- bool* diff_info = diff_info_row_start;
- for (int x = 0; x < diff_info_width_; x++) {
- if (*diff_info) {
- // We've found a modified block. Look at blocks to the right and below
- // to group this block with as many others as we can.
- int left = x * kBlockSize;
- int top = y * kBlockSize;
- int width = 1;
- int height = 1;
- *diff_info = false;
-
- // Group with blocks to the right.
- // We can keep looking until we find an unchanged block because we
- // have a boundary block which is never marked as having diffs.
- bool* right = diff_info + 1;
- while (*right) {
- *right++ = false;
- width++;
- }
-
- // Group with blocks below.
- // The entire width of blocks that we matched above much match for
- // each row that we add.
- bool* bottom = diff_info;
- bool found_new_row;
- do {
- found_new_row = true;
- bottom += diff_info_stride;
- right = bottom;
- for (int x2 = 0; x2 < width; x2++) {
- if (!*right++) {
- found_new_row = false;
- }
- }
-
- if (found_new_row) {
- height++;
-
- // We need to go back and erase the diff markers so that we don't
- // try to add these blocks a second time.
- right = bottom;
- for (int x2 = 0; x2 < width; x2++) {
- *right++ = false;
- }
- }
- } while (found_new_row);
-
- // Add rect to list of dirty rects.
- width *= kBlockSize;
- if (left + width > width_) {
- width = width_ - left;
- }
- height *= kBlockSize;
- if (top + height > height_) {
- height = height_ - top;
- }
- region->AddRect(DesktopRect::MakeXYWH(left, top, width, height));
- }
-
- // Increment to next block in this row.
- diff_info++;
- }
-
- // Go to start of next row.
- diff_info_row_start += diff_info_stride;
- }
-}
-
-} // namespace webrtc
diff --git a/webrtc/modules/desktop_capture/differ.h b/webrtc/modules/desktop_capture/differ.h
deleted file mode 100644
index 9ab059b..0000000
--- a/webrtc/modules/desktop_capture/differ.h
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_H_
-#define WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_H_
-
-#include <memory>
-#include <vector>
-
-#include "webrtc/base/constructormagic.h"
-#include "webrtc/modules/desktop_capture/desktop_region.h"
-
-namespace webrtc {
-
-// TODO(sergeyu): Simplify differ now that we are working with DesktopRegion.
-// diff_info_ should no longer be needed, as we can put our data directly into
-// the region that we are calculating.
-// http://crbug.com/92379
-// TODO(sergeyu): Rename this class to something more sensible, e.g.
-// ScreenCaptureFrameDifferencer.
-class Differ {
- public:
- // Create a differ that operates on bitmaps with the specified width, height
- // and bytes_per_pixel.
- Differ(int width, int height, int bytes_per_pixel, int stride);
- ~Differ();
-
- int width() { return width_; }
- int height() { return height_; }
- int bytes_per_pixel() { return bytes_per_pixel_; }
- int bytes_per_row() { return bytes_per_row_; }
-
- // Given the previous and current screen buffer, calculate the dirty region
- // that encloses all of the changed pixels in the new screen.
- void CalcDirtyRegion(const uint8_t* prev_buffer, const uint8_t* curr_buffer,
- DesktopRegion* region);
-
- private:
- // Allow tests to access our private parts.
- friend class DifferTest;
-
- // Identify all of the blocks that contain changed pixels.
- void MarkDirtyBlocks(const uint8_t* prev_buffer, const uint8_t* curr_buffer);
-
- // After the dirty blocks have been identified, this routine merges adjacent
- // blocks into a region.
- // The goal is to minimize the region that covers the dirty blocks.
- void MergeBlocks(DesktopRegion* region);
-
- // Checks whether the upper-left portions of the buffers are equal. The size
- // of the portion to check is specified by the |width| and |height| values.
- // Note that if we force the capturer to always return images whose width and
- // height are multiples of kBlockSize, then this will never be called.
- bool PartialBlocksEqual(const uint8_t* prev_buffer,
- const uint8_t* curr_buffer,
- int stride,
- int width, int height);
-
- // Dimensions of screen.
- int width_;
- int height_;
-
- // Number of bytes for each pixel in source and dest bitmap.
- // (Yes, they must match.)
- int bytes_per_pixel_;
-
- // Number of bytes in each row of the image (AKA: stride).
- int bytes_per_row_;
-
- // Diff information for each block in the image.
- std::unique_ptr<bool[]> diff_info_;
-
- // Dimensions and total size of diff info array.
- int diff_info_width_;
- int diff_info_height_;
- int diff_info_size_;
-
- RTC_DISALLOW_COPY_AND_ASSIGN(Differ);
-};
-
-} // namespace webrtc
-
-#endif // WEBRTC_MODULES_DESKTOP_CAPTURE_DIFFER_H_
diff --git a/webrtc/modules/desktop_capture/differ_unittest.cc b/webrtc/modules/desktop_capture/differ_unittest.cc
deleted file mode 100644
index 543910d..0000000
--- a/webrtc/modules/desktop_capture/differ_unittest.cc
+++ /dev/null
@@ -1,654 +0,0 @@
-/*
- * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
- *
- * Use of this source code is governed by a BSD-style license
- * that can be found in the LICENSE file in the root of the source
- * tree. An additional intellectual property rights grant can be found
- * in the file PATENTS. All contributing project authors may
- * be found in the AUTHORS file in the root of the source tree.
- */
-
-#include <memory>
-
-#include "testing/gmock/include/gmock/gmock.h"
-#include "webrtc/base/constructormagic.h"
-#include "webrtc/modules/desktop_capture/differ.h"
-#include "webrtc/modules/desktop_capture/differ_block.h"
-
-namespace webrtc {
-
-// 96x96 screen gives a 4x4 grid of blocks.
-const int kScreenWidth= 96;
-const int kScreenHeight = 96;
-
-// To test partial blocks, we need a width and height that are not multiples
-// of 16 (or 32, depending on current block size).
-const int kPartialScreenWidth = 70;
-const int kPartialScreenHeight = 70;
-
-class DifferTest : public testing::Test {
- public:
- DifferTest() {
- }
-
- protected:
- void InitDiffer(int width, int height) {
- width_ = width;
- height_ = height;
- bytes_per_pixel_ = kBytesPerPixel;
- stride_ = (kBytesPerPixel * width);
- buffer_size_ = width_ * height_ * bytes_per_pixel_;
-
- differ_.reset(new Differ(width_, height_, bytes_per_pixel_, stride_));
-
- prev_.reset(new uint8_t[buffer_size_]);
- memset(prev_.get(), 0, buffer_size_);
-
- curr_.reset(new uint8_t[buffer_size_]);
- memset(curr_.get(), 0, buffer_size_);
- }
-
- void ClearBuffer(uint8_t* buffer) {
- memset(buffer, 0, buffer_size_);
- }
-
- // Here in DifferTest so that tests can access private methods of Differ.
- void MarkDirtyBlocks(const uint8_t* prev_buffer, const uint8_t* curr_buffer) {
- differ_->MarkDirtyBlocks(prev_buffer, curr_buffer);
- }
-
- void MergeBlocks(DesktopRegion* dirty) {
- differ_->MergeBlocks(dirty);
- }
-
- // Convenience method to count rectangles in a region.
- int RegionRectCount(const DesktopRegion& region) {
- int count = 0;
- for (DesktopRegion::Iterator iter(region);
- !iter.IsAtEnd(); iter.Advance()) {
- ++count;
- }
- return count;
- }
-
- // Convenience wrapper for Differ's DiffBlock that calculates the appropriate
- // offset to the start of the desired block.
- bool DiffBlock(int block_x, int block_y) {
- // Offset from upper-left of buffer to upper-left of requested block.
- int block_offset = ((block_y * stride_) + (block_x * bytes_per_pixel_))
- * kBlockSize;
- return BlockDifference(prev_.get() + block_offset,
- curr_.get() + block_offset,
- stride_);
- }
-
- // Write the pixel |value| into the specified block in the |buffer|.
- // This is a convenience wrapper around WritePixel().
- void WriteBlockPixel(uint8_t* buffer, int block_x, int block_y,
- int pixel_x, int pixel_y, uint32_t value) {
- WritePixel(buffer, (block_x * kBlockSize) + pixel_x,
- (block_y * kBlockSize) + pixel_y, value);
- }
-
- // Write the test pixel |value| into the |buffer| at the specified |x|,|y|
- // location.
- // Only the low-order bytes from |value| are written (assuming little-endian).
- // So, for |value| = 0xaabbccdd:
- // If bytes_per_pixel = 4, then ddccbbaa will be written as the pixel value.
- // If = 3, ddccbb
- // If = 2, ddcc
- // If = 1, dd
- void WritePixel(uint8_t* buffer, int x, int y, uint32_t value) {
- uint8_t* pixel = reinterpret_cast<uint8_t*>(&value);
- buffer += (y * stride_) + (x * bytes_per_pixel_);
- for (int b = bytes_per_pixel_ - 1; b >= 0; b--) {
- *buffer++ = pixel[b];
- }
- }
-
- // DiffInfo utility routines.
- // These are here so that we don't have to make each DifferText_Xxx_Test
- // class a friend class to Differ.
-
- // Clear out the entire |diff_info_| buffer.
- void ClearDiffInfo() {
- memset(differ_->diff_info_.get(), 0, differ_->diff_info_size_);
- }
-
- // Get the value in the |diff_info_| array at (x,y).
- bool GetDiffInfo(int x, int y) {
- bool* diff_info = differ_->diff_info_.get();
- return diff_info[(y * GetDiffInfoWidth()) + x];
- }
-
- // Width of |diff_info_| array.
- int GetDiffInfoWidth() {
- return differ_->diff_info_width_;
- }
-
- // Height of |diff_info_| array.
- int GetDiffInfoHeight() {
- return differ_->diff_info_height_;
- }
-
- // Size of |diff_info_| array.
- int GetDiffInfoSize() {
- return differ_->diff_info_size_;
- }
-
- void SetDiffInfo(int x, int y, bool value) {
- bool* diff_info = differ_->diff_info_.get();
- diff_info[(y * GetDiffInfoWidth()) + x] = value;
- }
-
- // Mark the range of blocks specified.
- void MarkBlocks(int x_origin, int y_origin, int width, int height) {
- for (int y = 0; y < height; y++) {
- for (int x = 0; x < width; x++) {
- SetDiffInfo(x_origin + x, y_origin + y, true);
- }
- }
- }
-
- // Verify that |region| contains a rectangle defined by |x|, |y|, |width| and
- // |height|.
- // |x|, |y|, |width| and |height| are specified in block (not pixel) units.
- bool CheckDirtyRegionContainsRect(const DesktopRegion& region,
- int x, int y,
- int width, int height) {
- DesktopRect r =
- DesktopRect::MakeXYWH(x * kBlockSize, y * kBlockSize,
- width * kBlockSize, height * kBlockSize);
- for (DesktopRegion::Iterator i(region); !i.IsAtEnd(); i.Advance()) {
- if (i.rect().equals(r))
- return true;
- }
- return false;
- }
-
- // Mark the range of blocks specified and then verify that they are
- // merged correctly.
- // Only one rectangular region of blocks can be checked with this routine.
- bool MarkBlocksAndCheckMerge(int x_origin, int y_origin,
- int width, int height) {
- ClearDiffInfo();
- MarkBlocks(x_origin, y_origin, width, height);
-
- DesktopRegion dirty;
- MergeBlocks(&dirty);
-
-
- DesktopRect expected_rect = DesktopRect::MakeXYWH(
- x_origin * kBlockSize, y_origin * kBlockSize,
- width * kBlockSize, height * kBlockSize);
-
- // Verify that the region contains expected_rect and it's the only
- // rectangle.
- DesktopRegion::Iterator it(dirty);
- return !it.IsAtEnd() && expected_rect.equals(it.rect()) &&
- (it.Advance(), it.IsAtEnd());
- }
-
- // The differ class we're testing.
- std::unique_ptr<Differ> differ_;
-
- // Screen/buffer info.
- int width_;
- int height_;
- int bytes_per_pixel_;
- int stride_;
-
- // Size of each screen buffer.
- int buffer_size_;
-
- // Previous and current screen buffers.
- std::unique_ptr<uint8_t[]> prev_;
- std::unique_ptr<uint8_t[]> curr_;
-
- private:
- RTC_DISALLOW_COPY_AND_ASSIGN(DifferTest);
-};
-
-TEST_F(DifferTest, Setup) {
- InitDiffer(kScreenWidth, kScreenHeight);
- // 96x96 pixels results in 3x3 array. Add 1 to each dimension as boundary.
- // +---+---+---+---+
- // | o | o | o | _ |
- // +---+---+---+---+ o = blocks mapped to screen pixels
- // | o | o | o | _ |
- // +---+---+---+---+ _ = boundary blocks
- // | o | o | o | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- EXPECT_EQ(4, GetDiffInfoWidth());
- EXPECT_EQ(4, GetDiffInfoHeight());
- EXPECT_EQ(16, GetDiffInfoSize());
-}
-
-TEST_F(DifferTest, MarkDirtyBlocks_All) {
- InitDiffer(kScreenWidth, kScreenHeight);
- ClearDiffInfo();
-
- // Update a pixel in each block.
- for (int y = 0; y < GetDiffInfoHeight() - 1; y++) {
- for (int x = 0; x < GetDiffInfoWidth() - 1; x++) {
- WriteBlockPixel(curr_.get(), x, y, 10, 10, 0xff00ff);
- }
- }
-
- MarkDirtyBlocks(prev_.get(), curr_.get());
-
- // Make sure each block is marked as dirty.
- for (int y = 0; y < GetDiffInfoHeight() - 1; y++) {
- for (int x = 0; x < GetDiffInfoWidth() - 1; x++) {
- EXPECT_TRUE(GetDiffInfo(x, y))
- << "when x = " << x << ", and y = " << y;
- }
- }
-}
-
-TEST_F(DifferTest, MarkDirtyBlocks_Sampling) {
- InitDiffer(kScreenWidth, kScreenHeight);
- ClearDiffInfo();
-
- // Update some pixels in image.
- WriteBlockPixel(curr_.get(), 1, 0, 10, 10, 0xff00ff);
- WriteBlockPixel(curr_.get(), 2, 1, 10, 10, 0xff00ff);
- WriteBlockPixel(curr_.get(), 0, 2, 10, 10, 0xff00ff);
-
- MarkDirtyBlocks(prev_.get(), curr_.get());
-
- // Make sure corresponding blocks are updated.
- EXPECT_FALSE(GetDiffInfo(0, 0));
- EXPECT_FALSE(GetDiffInfo(0, 1));
- EXPECT_TRUE(GetDiffInfo(0, 2));
- EXPECT_TRUE(GetDiffInfo(1, 0));
- EXPECT_FALSE(GetDiffInfo(1, 1));
- EXPECT_FALSE(GetDiffInfo(1, 2));
- EXPECT_FALSE(GetDiffInfo(2, 0));
- EXPECT_TRUE(GetDiffInfo(2, 1));
- EXPECT_FALSE(GetDiffInfo(2, 2));
-}
-
-TEST_F(DifferTest, DiffBlock) {
- InitDiffer(kScreenWidth, kScreenHeight);
-
- // Verify no differences at start.
- EXPECT_FALSE(DiffBlock(0, 0));
- EXPECT_FALSE(DiffBlock(1, 1));
-
- // Write new data into the 4 corners of the middle block and verify that
- // neighboring blocks are not affected.
- int max = kBlockSize - 1;
- WriteBlockPixel(curr_.get(), 1, 1, 0, 0, 0xffffff);
- WriteBlockPixel(curr_.get(), 1, 1, 0, max, 0xffffff);
- WriteBlockPixel(curr_.get(), 1, 1, max, 0, 0xffffff);
- WriteBlockPixel(curr_.get(), 1, 1, max, max, 0xffffff);
- EXPECT_FALSE(DiffBlock(0, 0));
- EXPECT_FALSE(DiffBlock(0, 1));
- EXPECT_FALSE(DiffBlock(0, 2));
- EXPECT_FALSE(DiffBlock(1, 0));
- EXPECT_TRUE(DiffBlock(1, 1)); // Only this block should change.
- EXPECT_FALSE(DiffBlock(1, 2));
- EXPECT_FALSE(DiffBlock(2, 0));
- EXPECT_FALSE(DiffBlock(2, 1));
- EXPECT_FALSE(DiffBlock(2, 2));
-}
-
-TEST_F(DifferTest, Partial_Setup) {
- InitDiffer(kPartialScreenWidth, kPartialScreenHeight);
- // 70x70 pixels results in 3x3 array: 2x2 full blocks + partials around
- // the edge. One more is added to each dimension as a boundary.
- // +---+---+---+---+
- // | o | o | + | _ |
- // +---+---+---+---+ o = blocks mapped to screen pixels
- // | o | o | + | _ |
- // +---+---+---+---+ + = partial blocks (top/left mapped to screen pixels)
- // | + | + | + | _ |
- // +---+---+---+---+ _ = boundary blocks
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- EXPECT_EQ(4, GetDiffInfoWidth());
- EXPECT_EQ(4, GetDiffInfoHeight());
- EXPECT_EQ(16, GetDiffInfoSize());
-}
-
-TEST_F(DifferTest, Partial_FirstPixel) {
- InitDiffer(kPartialScreenWidth, kPartialScreenHeight);
- ClearDiffInfo();
-
- // Update the first pixel in each block.
- for (int y = 0; y < GetDiffInfoHeight() - 1; y++) {
- for (int x = 0; x < GetDiffInfoWidth() - 1; x++) {
- WriteBlockPixel(curr_.get(), x, y, 0, 0, 0xff00ff);
- }
- }
-
- MarkDirtyBlocks(prev_.get(), curr_.get());
-
- // Make sure each block is marked as dirty.
- for (int y = 0; y < GetDiffInfoHeight() - 1; y++) {
- for (int x = 0; x < GetDiffInfoWidth() - 1; x++) {
- EXPECT_TRUE(GetDiffInfo(x, y))
- << "when x = " << x << ", and y = " << y;
- }
- }
-}
-
-TEST_F(DifferTest, Partial_BorderPixel) {
- InitDiffer(kPartialScreenWidth, kPartialScreenHeight);
- ClearDiffInfo();
-
- // Update the right/bottom border pixels.
- for (int y = 0; y < height_; y++) {
- WritePixel(curr_.get(), width_ - 1, y, 0xff00ff);
- }
- for (int x = 0; x < width_; x++) {
- WritePixel(curr_.get(), x, height_ - 1, 0xff00ff);
- }
-
- MarkDirtyBlocks(prev_.get(), curr_.get());
-
- // Make sure last (partial) block in each row/column is marked as dirty.
- int x_last = GetDiffInfoWidth() - 2;
- for (int y = 0; y < GetDiffInfoHeight() - 1; y++) {
- EXPECT_TRUE(GetDiffInfo(x_last, y))
- << "when x = " << x_last << ", and y = " << y;
- }
- int y_last = GetDiffInfoHeight() - 2;
- for (int x = 0; x < GetDiffInfoWidth() - 1; x++) {
- EXPECT_TRUE(GetDiffInfo(x, y_last))
- << "when x = " << x << ", and y = " << y_last;
- }
- // All other blocks are clean.
- for (int y = 0; y < GetDiffInfoHeight() - 2; y++) {
- for (int x = 0; x < GetDiffInfoWidth() - 2; x++) {
- EXPECT_FALSE(GetDiffInfo(x, y)) << "when x = " << x << ", and y = " << y;
- }
- }
-}
-
-TEST_F(DifferTest, MergeBlocks_Empty) {
- InitDiffer(kScreenWidth, kScreenHeight);
-
- // No blocks marked:
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ClearDiffInfo();
-
- DesktopRegion dirty;
- MergeBlocks(&dirty);
-
- EXPECT_TRUE(dirty.is_empty());
-}
-
-TEST_F(DifferTest, MergeBlocks_SingleBlock) {
- InitDiffer(kScreenWidth, kScreenHeight);
- // Mark a single block and make sure that there is a single merged
- // rect with the correct bounds.
- for (int y = 0; y < GetDiffInfoHeight() - 1; y++) {
- for (int x = 0; x < GetDiffInfoWidth() - 1; x++) {
- ASSERT_TRUE(MarkBlocksAndCheckMerge(x, y, 1, 1)) << "x: " << x
- << "y: " << y;
- }
- }
-}
-
-TEST_F(DifferTest, MergeBlocks_BlockRow) {
- InitDiffer(kScreenWidth, kScreenHeight);
-
- // +---+---+---+---+
- // | X | X | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(0, 0, 2, 1));
-
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | X | X | X | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(0, 1, 3, 1));
-
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | X | X | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(1, 2, 2, 1));
-}
-
-TEST_F(DifferTest, MergeBlocks_BlockColumn) {
- InitDiffer(kScreenWidth, kScreenHeight);
-
- // +---+---+---+---+
- // | X | | | _ |
- // +---+---+---+---+
- // | X | | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(0, 0, 1, 2));
-
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | X | | _ |
- // +---+---+---+---+
- // | | X | | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(1, 1, 1, 2));
-
- // +---+---+---+---+
- // | | | X | _ |
- // +---+---+---+---+
- // | | | X | _ |
- // +---+---+---+---+
- // | | | X | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(2, 0, 1, 3));
-}
-
-TEST_F(DifferTest, MergeBlocks_BlockRect) {
- InitDiffer(kScreenWidth, kScreenHeight);
-
- // +---+---+---+---+
- // | X | X | | _ |
- // +---+---+---+---+
- // | X | X | | _ |
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(0, 0, 2, 2));
-
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | | X | X | _ |
- // +---+---+---+---+
- // | | X | X | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(1, 1, 2, 2));
-
- // +---+---+---+---+
- // | | X | X | _ |
- // +---+---+---+---+
- // | | X | X | _ |
- // +---+---+---+---+
- // | | X | X | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(1, 0, 2, 3));
-
- // +---+---+---+---+
- // | | | | _ |
- // +---+---+---+---+
- // | X | X | X | _ |
- // +---+---+---+---+
- // | X | X | X | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(0, 1, 3, 2));
-
- // +---+---+---+---+
- // | X | X | X | _ |
- // +---+---+---+---+
- // | X | X | X | _ |
- // +---+---+---+---+
- // | X | X | X | _ |
- // +---+---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ASSERT_TRUE(MarkBlocksAndCheckMerge(0, 0, 3, 3));
-}
-
-// This tests marked regions that require more than 1 single dirty rect.
-// The exact rects returned depend on the current implementation, so these
-// may need to be updated if we modify how we merge blocks.
-TEST_F(DifferTest, MergeBlocks_MultiRect) {
- InitDiffer(kScreenWidth, kScreenHeight);
- DesktopRegion dirty;
-
- // +---+---+---+---+ +---+---+---+
- // | | X | | _ | | | 0 | |
- // +---+---+---+---+ +---+---+---+
- // | X | | | _ | | 1 | | |
- // +---+---+---+---+ => +---+---+---+
- // | | | X | _ | | | | 2 |
- // +---+---+---+---+ +---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ClearDiffInfo();
- MarkBlocks(1, 0, 1, 1);
- MarkBlocks(0, 1, 1, 1);
- MarkBlocks(2, 2, 1, 1);
-
- dirty.Clear();
- MergeBlocks(&dirty);
-
- ASSERT_EQ(3, RegionRectCount(dirty));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 1, 0, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 1, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 2, 2, 1, 1));
-
- // +---+---+---+---+ +---+---+---+
- // | | | X | _ | | | | 0 |
- // +---+---+---+---+ +---+---+---+
- // | X | X | X | _ | | 1 1 1 |
- // +---+---+---+---+ => + +
- // | X | X | X | _ | | 1 1 1 |
- // +---+---+---+---+ +---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ClearDiffInfo();
- MarkBlocks(2, 0, 1, 1);
- MarkBlocks(0, 1, 3, 2);
-
- dirty.Clear();
- MergeBlocks(&dirty);
-
- ASSERT_EQ(2, RegionRectCount(dirty));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 2, 0, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 1, 3, 2));
-
- // +---+---+---+---+ +---+---+---+
- // | | | | _ | | | | |
- // +---+---+---+---+ +---+---+---+
- // | X | | X | _ | | 0 | | 1 |
- // +---+---+---+---+ => +---+---+---+
- // | X | X | X | _ | | 2 2 2 |
- // +---+---+---+---+ +---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ClearDiffInfo();
- MarkBlocks(0, 1, 1, 1);
- MarkBlocks(2, 1, 1, 1);
- MarkBlocks(0, 2, 3, 1);
-
- dirty.Clear();
- MergeBlocks(&dirty);
-
- ASSERT_EQ(3, RegionRectCount(dirty));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 1, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 2, 1, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 2, 3, 1));
-
- // +---+---+---+---+ +---+---+---+
- // | X | X | X | _ | | 0 0 0 |
- // +---+---+---+---+ +---+---+---+
- // | X | | X | _ | | 1 | | 2 |
- // +---+---+---+---+ => +---+---+---+
- // | X | X | X | _ | | 3 3 3 |
- // +---+---+---+---+ +---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ClearDiffInfo();
- MarkBlocks(0, 0, 3, 1);
- MarkBlocks(0, 1, 1, 1);
- MarkBlocks(2, 1, 1, 1);
- MarkBlocks(0, 2, 3, 1);
-
- dirty.Clear();
- MergeBlocks(&dirty);
-
- ASSERT_EQ(4, RegionRectCount(dirty));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 0, 3, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 1, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 2, 1, 1, 1));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 2, 3, 1));
-
- // +---+---+---+---+ +---+---+---+
- // | X | X | | _ | | 0 0 | |
- // +---+---+---+---+ + +---+
- // | X | X | | _ | | 0 0 | |
- // +---+---+---+---+ => +---+---+---+
- // | | X | | _ | | | 1 | |
- // +---+---+---+---+ +---+---+---+
- // | _ | _ | _ | _ |
- // +---+---+---+---+
- ClearDiffInfo();
- MarkBlocks(0, 0, 2, 2);
- MarkBlocks(1, 2, 1, 1);
-
- dirty.Clear();
- MergeBlocks(&dirty);
-
- ASSERT_EQ(2, RegionRectCount(dirty));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 0, 0, 2, 2));
- ASSERT_TRUE(CheckDirtyRegionContainsRect(dirty, 1, 2, 1, 1));
-}
-
-} // namespace webrtc
diff --git a/webrtc/modules/desktop_capture/screen_capturer_x11.cc b/webrtc/modules/desktop_capture/screen_capturer_x11.cc
index d274140..6f5e520 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_x11.cc
+++ b/webrtc/modules/desktop_capture/screen_capturer_x11.cc
@@ -26,7 +26,6 @@
#include "webrtc/base/timeutils.h"
#include "webrtc/modules/desktop_capture/desktop_capture_options.h"
#include "webrtc/modules/desktop_capture/desktop_frame.h"
-#include "webrtc/modules/desktop_capture/differ.h"
#include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
#include "webrtc/modules/desktop_capture/screen_capturer_differ_wrapper.h"
#include "webrtc/modules/desktop_capture/screen_capturer_helper.h"
@@ -38,6 +37,12 @@
namespace {
// A class to perform video frame capturing for Linux.
+//
+// If XDamage is used, this class sets DesktopFrame::updated_region() according
+// to the areas reported by XDamage. Otherwise this class does not detect
+// DesktopFrame::updated_region(), the field is always set to the entire frame
+// rectangle. ScreenCapturerDifferWrapper should be used if that functionality
+// is necessary.
class ScreenCapturerLinux : public ScreenCapturer,
public SharedXDisplay::XEventHandler {
public:
@@ -116,9 +121,6 @@
// current with the last buffer used.
DesktopRegion last_invalid_region_;
- // |Differ| for use when polling for changes.
- std::unique_ptr<Differ> differ_;
-
RTC_DISALLOW_COPY_AND_ASSIGN(ScreenCapturerLinux);
};
@@ -253,16 +255,6 @@
new BasicDesktopFrame(x_server_pixel_buffer_.window_size()))));
}
- // Refresh the Differ helper used by CaptureFrame(), if needed.
- DesktopFrame* frame = queue_.current_frame();
- if (!use_damage_ &&
- (!differ_ || (differ_->width() != frame->size().width()) ||
- (differ_->height() != frame->size().height()) ||
- (differ_->bytes_per_row() != frame->stride()))) {
- differ_.reset(new Differ(frame->size().width(), frame->size().height(),
- DesktopFrame::kBytesPerPixel, frame->stride()));
- }
-
std::unique_ptr<DesktopFrame> result = CaptureScreen();
last_invalid_region_ = result->updated_region();
result->set_capture_time_ms((rtc::TimeNanos() - capture_start_time_nanos) /
@@ -349,21 +341,7 @@
// screen-resolution change. In either case, need a full-screen capture.
DesktopRect screen_rect = DesktopRect::MakeSize(frame->size());
x_server_pixel_buffer_.CaptureRect(screen_rect, frame.get());
-
- if (queue_.previous_frame()) {
- // Full-screen polling, so calculate the invalid rects here, based on the
- // changed pixels between current and previous buffers.
- RTC_DCHECK(differ_);
- RTC_DCHECK(queue_.previous_frame()->data());
- differ_->CalcDirtyRegion(queue_.previous_frame()->data(),
- frame->data(), updated_region);
- } else {
- // No previous buffer, so always invalidate the whole screen, whether
- // or not DAMAGE is being used. DAMAGE doesn't necessarily send a
- // full-screen notification after a screen-resolution change, so
- // this is done here.
- updated_region->SetRect(screen_rect);
- }
+ updated_region->SetRect(screen_rect);
}
return std::move(frame);
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
index 80d2da5..2c2178d 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.cc
@@ -20,7 +20,6 @@
#include "webrtc/modules/desktop_capture/desktop_frame.h"
#include "webrtc/modules/desktop_capture/desktop_frame_win.h"
#include "webrtc/modules/desktop_capture/desktop_region.h"
-#include "webrtc/modules/desktop_capture/differ.h"
#include "webrtc/modules/desktop_capture/mouse_cursor.h"
#include "webrtc/modules/desktop_capture/win/cursor.h"
#include "webrtc/modules/desktop_capture/win/desktop.h"
@@ -86,41 +85,13 @@
return;
}
- const DesktopFrame* current_frame = queue_.current_frame();
- const DesktopFrame* last_frame = queue_.previous_frame();
- if (last_frame && last_frame->size().equals(current_frame->size())) {
- // Make sure the differencer is set up correctly for these previous and
- // current screens.
- if (!differ_.get() ||
- (differ_->width() != current_frame->size().width()) ||
- (differ_->height() != current_frame->size().height()) ||
- (differ_->bytes_per_row() != current_frame->stride())) {
- differ_.reset(new Differ(current_frame->size().width(),
- current_frame->size().height(),
- DesktopFrame::kBytesPerPixel,
- current_frame->stride()));
- }
-
- // Calculate difference between the two last captured frames.
- DesktopRegion region;
- differ_->CalcDirtyRegion(last_frame->data(), current_frame->data(),
- ®ion);
- helper_.InvalidateRegion(region);
- } else {
- // No previous frame is available, or the screen is resized. Invalidate the
- // whole screen.
- helper_.InvalidateScreen(current_frame->size());
- }
-
- helper_.set_size_most_recent(current_frame->size());
-
// Emit the current frame.
std::unique_ptr<DesktopFrame> frame = queue_.current_frame()->Share();
frame->set_dpi(DesktopVector(
GetDeviceCaps(desktop_dc_, LOGPIXELSX),
GetDeviceCaps(desktop_dc_, LOGPIXELSY)));
- frame->mutable_updated_region()->Clear();
- helper_.TakeInvalidRegion(frame->mutable_updated_region());
+ frame->mutable_updated_region()->SetRect(
+ DesktopRect::MakeSize(frame->size()));
frame->set_capture_time_ms(
(rtc::TimeNanos() - capture_start_time_nanos) /
rtc::kNumNanosecsPerMillisec);
@@ -212,8 +183,6 @@
// Make sure the frame buffers will be reallocated.
queue_.Reset();
-
- helper_.ClearInvalidRegion();
}
}
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.h b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.h
index d1b6395..01a5991 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.h
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_gdi.h
@@ -19,17 +19,17 @@
#include "webrtc/base/constructormagic.h"
#include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
-#include "webrtc/modules/desktop_capture/screen_capturer_helper.h"
#include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
#include "webrtc/modules/desktop_capture/win/scoped_thread_desktop.h"
namespace webrtc {
-class Differ;
-
// ScreenCapturerWinGdi captures 32bit RGB using GDI.
//
// ScreenCapturerWinGdi is double-buffered as required by ScreenCapturer.
+// This class does not detect DesktopFrame::updated_region(), the field is
+// always set to the entire frame rectangle. ScreenCapturerDifferWrapper should
+// be used if that functionality is necessary.
class ScreenCapturerWinGdi : public ScreenCapturer {
public:
explicit ScreenCapturerWinGdi(const DesktopCaptureOptions& options);
@@ -61,10 +61,6 @@
ScreenId current_screen_id_ = kFullDesktopScreenId;
std::wstring current_device_key_;
- // A thread-safe list of invalid rectangles, and the size of the most
- // recently captured screen.
- ScreenCapturerHelper helper_;
-
ScopedThreadDesktop desktop_;
// GDI resources used for screen capture.
@@ -78,9 +74,6 @@
// the primary display's top-left.
DesktopRect desktop_dc_rect_;
- // Class to calculate the difference between two screen bitmaps.
- std::unique_ptr<Differ> differ_;
-
HMODULE dwmapi_library_ = NULL;
DwmEnableCompositionFunc composition_func_ = nullptr;
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
index e22b272..e5a37c9 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.cc
@@ -18,7 +18,6 @@
#include "webrtc/modules/desktop_capture/desktop_frame.h"
#include "webrtc/modules/desktop_capture/desktop_frame_win.h"
#include "webrtc/modules/desktop_capture/desktop_region.h"
-#include "webrtc/modules/desktop_capture/differ.h"
#include "webrtc/modules/desktop_capture/mouse_cursor.h"
#include "webrtc/modules/desktop_capture/win/cursor.h"
#include "webrtc/modules/desktop_capture/win/desktop.h"
@@ -116,33 +115,12 @@
return;
}
- const DesktopFrame* current_frame = queue_.current_frame();
- const DesktopFrame* last_frame = queue_.previous_frame();
- DesktopRegion updated_region;
- if (last_frame && last_frame->size().equals(current_frame->size())) {
- // Make sure the differencer is set up correctly for these previous and
- // current screens.
- if (!differ_.get() || (differ_->width() != current_frame->size().width()) ||
- (differ_->height() != current_frame->size().height()) ||
- (differ_->bytes_per_row() != current_frame->stride())) {
- differ_.reset(new Differ(current_frame->size().width(),
- current_frame->size().height(),
- DesktopFrame::kBytesPerPixel,
- current_frame->stride()));
- }
-
- // Calculate difference between the two last captured frames.
- differ_->CalcDirtyRegion(
- last_frame->data(), current_frame->data(), &updated_region);
- } else {
- updated_region.SetRect(DesktopRect::MakeSize(current_frame->size()));
- }
-
// Emit the current frame.
std::unique_ptr<DesktopFrame> frame = queue_.current_frame()->Share();
frame->set_dpi(DesktopVector(GetDeviceCaps(desktop_dc_, LOGPIXELSX),
GetDeviceCaps(desktop_dc_, LOGPIXELSY)));
- frame->mutable_updated_region()->Swap(&updated_region);
+ frame->mutable_updated_region()->SetRect(
+ DesktopRect::MakeSize(frame->size()));
frame->set_capture_time_ms((rtc::TimeNanos() - capture_start_time_nanos) /
rtc::kNumNanosecsPerMillisec);
callback_->OnCaptureResult(Result::SUCCESS, std::move(frame));
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.h b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.h
index 969cb83..080a57c 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.h
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_magnifier.h
@@ -29,12 +29,15 @@
class DesktopFrame;
class DesktopRect;
-class Differ;
// Captures the screen using the Magnification API to support window exclusion.
// Each capturer must run on a dedicated thread because it uses thread local
// storage for redirecting the library callback. Also the thread must have a UI
// message loop to handle the window messages for the magnifier window.
+//
+// This class does not detect DesktopFrame::updated_region(), the field is
+// always set to the entire frame rectangle. ScreenCapturerDifferWrapper should
+// be used if that functionality is necessary.
class ScreenCapturerWinMagnifier : public ScreenCapturer {
public:
// |fallback_capturer| will be used to capture the screen if a non-primary
@@ -116,9 +119,6 @@
// Queue of the frames buffers.
ScreenCaptureFrameQueue<SharedDesktopFrame> queue_;
- // Class to calculate the difference between two screen bitmaps.
- std::unique_ptr<Differ> differ_;
-
ScopedThreadDesktop desktop_;
// Used for getting the screen dpi.