1 files changed, 233 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/desktop_capture/win/cursor.cc b/third_party/libwebrtc/modules/desktop_capture/win/cursor.cc
new file mode 100644
index 0000000000..1d645098e2
--- /dev/null
+++ b/third_party/libwebrtc/modules/desktop_capture/win/cursor.cc
@@ -0,0 +1,233 @@
+/*
+ *  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 "modules/desktop_capture/win/cursor.h"
+
+#include <algorithm>
+#include <memory>
+
+#include "modules/desktop_capture/desktop_frame.h"
+#include "modules/desktop_capture/desktop_geometry.h"
+#include "modules/desktop_capture/mouse_cursor.h"
+#include "modules/desktop_capture/win/scoped_gdi_object.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/system/arch.h"
+
+namespace webrtc {
+
+namespace {
+
+#if defined(WEBRTC_ARCH_LITTLE_ENDIAN)
+
+#define RGBA(r, g, b, a)                                   \
+  ((((a) << 24) & 0xff000000) | (((b) << 16) & 0xff0000) | \
+   (((g) << 8) & 0xff00) | ((r)&0xff))
+
+#else  // !defined(WEBRTC_ARCH_LITTLE_ENDIAN)
+
+#define RGBA(r, g, b, a)                                   \
+  ((((r) << 24) & 0xff000000) | (((g) << 16) & 0xff0000) | \
+   (((b) << 8) & 0xff00) | ((a)&0xff))
+
+#endif  // !defined(WEBRTC_ARCH_LITTLE_ENDIAN)
+
+const int kBytesPerPixel = DesktopFrame::kBytesPerPixel;
+
+// Pixel colors used when generating cursor outlines.
+const uint32_t kPixelRgbaBlack = RGBA(0, 0, 0, 0xff);
+const uint32_t kPixelRgbaWhite = RGBA(0xff, 0xff, 0xff, 0xff);
+const uint32_t kPixelRgbaTransparent = RGBA(0, 0, 0, 0);
+
+const uint32_t kPixelRgbWhite = RGB(0xff, 0xff, 0xff);
+
+// Expands the cursor shape to add a white outline for visibility against
+// dark backgrounds.
+void AddCursorOutline(int width, int height, uint32_t* data) {
+  for (int y = 0; y < height; y++) {
+    for (int x = 0; x < width; x++) {
+      // If this is a transparent pixel (bgr == 0 and alpha = 0), check the
+      // neighbor pixels to see if this should be changed to an outline pixel.
+      if (*data == kPixelRgbaTransparent) {
+        // Change to white pixel if any neighbors (top, bottom, left, right)
+        // are black.
+        if ((y > 0 && data[-width] == kPixelRgbaBlack) ||
+            (y < height - 1 && data[width] == kPixelRgbaBlack) ||
+            (x > 0 && data[-1] == kPixelRgbaBlack) ||
+            (x < width - 1 && data[1] == kPixelRgbaBlack)) {
+          *data = kPixelRgbaWhite;
+        }
+      }
+      data++;
+    }
+  }
+}
+
+// Premultiplies RGB components of the pixel data in the given image by
+// the corresponding alpha components.
+void AlphaMul(uint32_t* data, int width, int height) {
+  static_assert(sizeof(uint32_t) == kBytesPerPixel,
+                "size of uint32 should be the number of bytes per pixel");
+
+  for (uint32_t* data_end = data + width * height; data != data_end; ++data) {
+    RGBQUAD* from = reinterpret_cast<RGBQUAD*>(data);
+    RGBQUAD* to = reinterpret_cast<RGBQUAD*>(data);
+    to->rgbBlue =
+        (static_cast<uint16_t>(from->rgbBlue) * from->rgbReserved) / 0xff;
+    to->rgbGreen =
+        (static_cast<uint16_t>(from->rgbGreen) * from->rgbReserved) / 0xff;
+    to->rgbRed =
+        (static_cast<uint16_t>(from->rgbRed) * from->rgbReserved) / 0xff;
+  }
+}
+
+// Scans a 32bpp bitmap looking for any pixels with non-zero alpha component.
+// Returns true if non-zero alpha is found. `stride` is expressed in pixels.
+bool HasAlphaChannel(const uint32_t* data, int stride, int width, int height) {
+  const RGBQUAD* plane = reinterpret_cast<const RGBQUAD*>(data);
+  for (int y = 0; y < height; ++y) {
+    for (int x = 0; x < width; ++x) {
+      if (plane->rgbReserved != 0)
+        return true;
+      plane += 1;
+    }
+    plane += stride - width;
+  }
+
+  return false;
+}
+
+}  // namespace
+
+MouseCursor* CreateMouseCursorFromHCursor(HDC dc, HCURSOR cursor) {
+  ICONINFO iinfo;
+  if (!GetIconInfo(cursor, &iinfo)) {
+    RTC_LOG_F(LS_ERROR) << "Unable to get cursor icon info. Error = "
+                        << GetLastError();
+    return NULL;
+  }
+
+  int hotspot_x = iinfo.xHotspot;
+  int hotspot_y = iinfo.yHotspot;
+
+  // Make sure the bitmaps will be freed.
+  win::ScopedBitmap scoped_mask(iinfo.hbmMask);
+  win::ScopedBitmap scoped_color(iinfo.hbmColor);
+  bool is_color = iinfo.hbmColor != NULL;
+
+  // Get `scoped_mask` dimensions.
+  BITMAP bitmap_info;
+  if (!GetObject(scoped_mask, sizeof(bitmap_info), &bitmap_info)) {
+    RTC_LOG_F(LS_ERROR) << "Unable to get bitmap info. Error = "
+                        << GetLastError();
+    return NULL;
+  }
+
+  int width = bitmap_info.bmWidth;
+  int height = bitmap_info.bmHeight;
+  std::unique_ptr<uint32_t[]> mask_data(new uint32_t[width * height]);
+
+  // Get pixel data from `scoped_mask` converting it to 32bpp along the way.
+  // GetDIBits() sets the alpha component of every pixel to 0.
+  BITMAPV5HEADER bmi = {0};
+  bmi.bV5Size = sizeof(bmi);
+  bmi.bV5Width = width;
+  bmi.bV5Height = -height;  // request a top-down bitmap.
+  bmi.bV5Planes = 1;
+  bmi.bV5BitCount = kBytesPerPixel * 8;
+  bmi.bV5Compression = BI_RGB;
+  bmi.bV5AlphaMask = 0xff000000;
+  bmi.bV5CSType = LCS_WINDOWS_COLOR_SPACE;
+  bmi.bV5Intent = LCS_GM_BUSINESS;
+  if (!GetDIBits(dc, scoped_mask, 0, height, mask_data.get(),
+                 reinterpret_cast<BITMAPINFO*>(&bmi), DIB_RGB_COLORS)) {
+    RTC_LOG_F(LS_ERROR) << "Unable to get bitmap bits. Error = "
+                        << GetLastError();
+    return NULL;
+  }
+
+  uint32_t* mask_plane = mask_data.get();
+  std::unique_ptr<DesktopFrame> image(
+      new BasicDesktopFrame(DesktopSize(width, height)));
+  bool has_alpha = false;
+
+  if (is_color) {
+    image.reset(new BasicDesktopFrame(DesktopSize(width, height)));
+    // Get the pixels from the color bitmap.
+    if (!GetDIBits(dc, scoped_color, 0, height, image->data(),
+                   reinterpret_cast<BITMAPINFO*>(&bmi), DIB_RGB_COLORS)) {
+      RTC_LOG_F(LS_ERROR) << "Unable to get bitmap bits. Error = "
+                          << GetLastError();
+      return NULL;
+    }
+
+    // GetDIBits() does not provide any indication whether the bitmap has alpha
+    // channel, so we use HasAlphaChannel() below to find it out.
+    has_alpha = HasAlphaChannel(reinterpret_cast<uint32_t*>(image->data()),
+                                width, width, height);
+  } else {
+    // For non-color cursors, the mask contains both an AND and an XOR mask and
+    // the height includes both. Thus, the width is correct, but we need to
+    // divide by 2 to get the correct mask height.
+    height /= 2;
+
+    image.reset(new BasicDesktopFrame(DesktopSize(width, height)));
+
+    // The XOR mask becomes the color bitmap.
+    memcpy(image->data(), mask_plane + (width * height),
+           image->stride() * height);
+  }
+
+  // Reconstruct transparency from the mask if the color image does not has
+  // alpha channel.
+  if (!has_alpha) {
+    bool add_outline = false;
+    uint32_t* dst = reinterpret_cast<uint32_t*>(image->data());
+    uint32_t* mask = mask_plane;
+    for (int y = 0; y < height; y++) {
+      for (int x = 0; x < width; x++) {
+        // The two bitmaps combine as follows:
+        //  mask  color   Windows Result   Our result    RGB   Alpha
+        //   0     00      Black            Black         00    ff
+        //   0     ff      White            White         ff    ff
+        //   1     00      Screen           Transparent   00    00
+        //   1     ff      Reverse-screen   Black         00    ff
+        //
+        // Since we don't support XOR cursors, we replace the "Reverse Screen"
+        // with black. In this case, we also add an outline around the cursor
+        // so that it is visible against a dark background.
+        if (*mask == kPixelRgbWhite) {
+          if (*dst != 0) {
+            add_outline = true;
+            *dst = kPixelRgbaBlack;
+          } else {
+            *dst = kPixelRgbaTransparent;
+          }
+        } else {
+          *dst = kPixelRgbaBlack ^ *dst;
+        }
+
+        ++dst;
+        ++mask;
+      }
+    }
+    if (add_outline) {
+      AddCursorOutline(width, height,
+                       reinterpret_cast<uint32_t*>(image->data()));
+    }
+  }
+
+  // Pre-multiply the resulting pixels since MouseCursor uses premultiplied
+  // images.
+  AlphaMul(reinterpret_cast<uint32_t*>(image->data()), width, height);
+
+  return new MouseCursor(image.release(), DesktopVector(hotspot_x, hotspot_y));
+}
+
+}  // namespace webrtc