hidpiscale

And update README.

DEVELOP.md

@@ -0,0 +1,238 @@
+# scrcpy for developers
+
+## Overview
+
+This application is composed of two parts:
+ - the server (`scrcpy-server.jar`), to be executed on the device,
+ - the client (the `scrcpy` binary), executed on the host computer.
+
+The client is responsible to push the server to the device and start its
+execution.
+
+Once the client and the server are connected to each other, the server initially
+sends device information (name and initial screen dimensions), then starts to
+send a raw H.264 video stream of the device screen. The client decodes the video
+frames, and display them as soon as possible, without buffering, to minimize
+latency. The client is not aware of the device rotation (which is handled by the
+server), it just knows the dimensions of the video frames.
+
+The client captures relevant keyboard and mouse events, that it transmits to the
+server, which injects them to the device.
+
+
+
+## Server
+
+
+### Privileges
+
+Capturing the screen requires some privileges, which are granted to `shell`.
+
+The server is a Java application (with a [`public static void main(String...
+args)`][main] method), compiled against the Android framework, and executed as
+`shell` on the Android device.
+
+[main]: server/src/main/java/com/genymobile/scrcpy/Server.java#L61
+
+To run such a Java application, the classes must be [_dexed_][dex] (typically,
+to `classes.dex`). If `my.package.MainClass` is the main class, compiled to
+`classes.dex`, pushed to the device in `/data/local/tmp`, then it can be run
+with:
+
+    adb shell CLASSPATH=/data/local/tmp/classes.dex \
+        app_process / my.package.MainClass
+
+_The path `/data/local/tmp` is a good candidate to push the server, since it's
+readable and writable by `shell`, but not world-writable, so a malicious
+application may not replace the server just before the client executes it._
+
+Instead of a raw _dex_ file, `app_process` accepts a _jar_ containing
+`classes.dex` (e.g. an [APK]). For simplicity, and to benefit from the gradle
+build system, the server is built to an (unsigned) APK (renamed to
+`scrcpy-server.jar`).
+
+[dex]: https://en.wikipedia.org/wiki/Dalvik_(software)
+[apk]: https://en.wikipedia.org/wiki/Android_application_package
+
+
+### Hidden methods
+
+Albeit compiled against the Android framework, [hidden] methods and classes are
+not directly accessible (and they may differ from one Android version to
+another).
+
+They can be called using reflection though. The communication with hidden
+components is provided by [_wrappers_ classes][wrappers] and [aidl].
+
+[hidden]: https://stackoverflow.com/a/31908373/1987178
+[wrappers]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/wrappers
+[aidl]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/aidl/android/view
+
+
+### Threading
+
+The server uses 2 threads:
+
+ - the **main** thread, encoding and streaming the video to the client;
+ - the **controller** thread, listening for _control events_ (typically,
+   keyboard and mouse events) from the client.
+
+Since the video encoding is typically hardware, there would be no benefit in
+encoding and streaming in two different threads.
+
+
+### Screen video encoding
+
+The encoding is managed by [`ScreenEncoder`].
+
+The video is encoded using the [`MediaCodec`] API. The codec takes its input
+from a [surface] associated to the display, and writes the resulting H.264
+stream to the provided output stream (the socket connected to the client).
+
+[`ScreenEncoder`]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java
+[`MediaCodec`]: https://developer.android.com/reference/android/media/MediaCodec.html
+[surface]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java#L63-L64
+
+On device [rotation], the codec, surface and display are reinitialized, and a
+new video stream is produced.
+
+New frames are produced only when changes occur on the surface. This is good
+because it avoids to send unnecessary frames, but there are drawbacks:
+
+ - it does not send any frame on start if the device screen does not change,
+ - after fast motion changes, the last frame may have poor quality.
+
+Both problems are [solved][repeat] by the flag
+[`KEY_REPEAT_PREVIOUS_FRAME_AFTER`][repeat-flag].
+
+[rotation]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java#L89-L92
+[repeat]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java#L125-L126
+[repeat-flag]: https://developer.android.com/reference/android/media/MediaFormat.html#KEY_REPEAT_PREVIOUS_FRAME_AFTER
+
+
+### Input events injection
+
+_Control events_ are received from the client by the [`EventController`] (run in
+a separate thread). There are 5 types of input events:
+ - keycode (cf [`KeyEvent`]),
+ - text (special characters may not be handled by keycodes directly),
+ - mouse motion/click,
+ - mouse scroll,
+ - custom command (e.g. to switch the screen on).
+
+All of them may need to inject input events to the system. To do so, they use
+the _hidden_ method [`InputManager.injectInputEvent`] (exposed by our
+[`InputManager` wrapper][inject-wrapper]).
+
+[`EventController`]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/EventController.java#L70
+[`KeyEvent`]: https://developer.android.com/reference/android/view/KeyEvent.html
+[`MotionEvent`]: https://developer.android.com/reference/android/view/MotionEvent.html
+[`InputManager.injectInputEvent`]: https://android.googlesource.com/platform/frameworks/base/+/oreo-release/core/java/android/hardware/input/InputManager.java#857
+[inject-wrapper]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java#L27
+
+
+
+## Client
+
+The client relies on [SDL], which provides cross-platform API for UI, input
+events, threading, etc.
+
+The video stream is decoded by [libav] (FFmpeg).
+
+[SDL]: https://www.libsdl.org
+[libav]: https://www.libav.org/
+
+### Initialization
+
+On startup, in addition to _libav_ and _SDL_ initialization, the client must
+push and start the server on the device, and open a socket so that they may
+communicate.
+
+Note that the client-server roles are expressed at the application level:
+
+ - the server _serves_ video stream and handle requests from the client,
+ - the client _controls_ the device through the server.
+
+However, the roles are inverted at the network level:
+
+ - the client opens a server socket and listen on a port before starting the
+   server,
+ - the server connects to the client.
+
+This role inversion guarantees that the connection will not fail due to race
+conditions, and avoids polling.
+
+Once the server is connected, it sends the device information (name and initial
+screen dimensions). Thus, the client may init the window and renderer, before
+the first frame is available.
+
+To minimize startup time, SDL initialization is performed while listening for
+the connection from the server (see commit [90a46b4]).
+
+[90a46b4]: https://github.com/Genymobile/scrcpy/commit/90a46b4c45637d083e877020d85ade52a9a5fa8e
+
+
+### Threading
+
+The client uses 3 threads:
+
+ - the **main** thread, executing the SDL event loop,
+ - the **decoder** thread, decoding video frames,
+ - the **controller** thread, sending _control events_ to the server.
+
+
+### Decoder
+
+The [decoder] runs in a separate thread. It uses _libav_ to decode the H.264
+stream from the socket, and notifies the main thread when a new frame is
+available.
+
+There are two [frames] simultaneously in memory:
+ - the **decoding** frame, written by the decoder from the decoder thread,
+ - the **rendering** frame, rendered in a texture from the main thread.
+
+When a new decoded frame is available, the decoder _swaps_ the decoding and
+rendering frame (with proper synchronization). Thus, it immediatly starts
+to decode a new frame while the main thread renders the last one.
+
+[decoder]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/decoder.c
+[frames]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/frames.h
+
+
+### Controller
+
+The [controller] is responsible to send _control events_ to the device. It runs
+in a separate thread, to avoid I/O on the main thread.
+
+On SDL event, received on the main thread, the [input manager][inputmanager]
+creates appropriate [_control events_][controlevent]. It is responsible to
+convert SDL events to Android events (using [convert]). It pushes the _control
+events_ to a blocking queue hold by the controller. On its own thread, the
+controller takes events from the queue, that it serializes and sends to the
+client.
+
+[controller]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/controller.h
+[controlevent]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/controlevent.h
+[inputmanager]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/inputmanager.h
+[convert]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/convert.h
+
+
+### UI and event loop
+
+Initialization, input events and rendering are all [managed][scrcpy] in the main
+thread.
+
+Events are handled in the [event loop], which either updates the [screen] or
+delegates to the [input manager][inputmanager].
+
+[scrcpy]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/scrcpy.c
+[event loop]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/scrcpy.c#L38
+[screen]: https://github.com/Genymobile/scrcpy/blob/079d750d41b7849eb1b9caaa6151ef2429581584/app/src/screen.h
+
+
+## Hack
+
+For more details, go read the code!
+
+If you find a bug, or have an awesome idea to implement, please discuss and
+contribute ;-)

README.md

@@ -1,141 +1,219 @@
-# ScrCpy
+# scrcpy
 
-This project displays screens of Android devices plugged on USB in live.
+This application provides display and control of Android devices connected on
+USB. It does not require any _root_ access. It works on _GNU/Linux_, _Windows_
+and _Mac OS_.
+
+![screenshot](assets/screenshot-debian-600.jpg)
 
 
-## Run
+## Requirements
 
-### Runtime requirements
+The Android part requires at least API 21 (Android 5.0).
 
-This projects requires _FFmpeg_, _LibSDL2_ and _LibSDL2-net_.
+You need [adb] (recent enough so that `adb reverse` is implemented, it works
+with 1.0.36). It is available in the [Android SDK platform
+tools][platform-tools], on packaged in your distribution (`android-adb-tools`).
+
+On Windows, just download the [platform-tools][platform-tools-windows] and
+extract the following files to a directory accessible from your `PATH`:
+ - `adb.exe`
+ - `AdbWinApi.dll`
+ - `AdbWinUsbApi.dll`
+
+Make sure you [enabled adb debugging][enable-adb] on your device(s).
+
+[adb]: https://developer.android.com/studio/command-line/adb.html
+[enable-adb]: https://developer.android.com/studio/command-line/adb.html#Enabling
+[platform-tools]: https://developer.android.com/studio/releases/platform-tools.html
+[platform-tools-windows]: https://dl.google.com/android/repository/platform-tools-latest-windows.zip
+
+The client requires _FFmpeg_ and _LibSDL2_.
+
+
+## Build and install
+
+### System-specific steps
 
 #### Linux
 
-Install the packages from your package manager. For example, on Debian:
+Install the required packages from your package manager (here, for Debian):
 
-    sudo apt install ffmpeg libsdl2-2.0.0 libsdl2-net-2.0.0
+    # runtime dependencies
+    sudo apt install ffmpeg libsdl2-2.0.0
+
+    # build dependencies
+    sudo apt install make gcc openjdk-8-jdk pkg-config meson zip \
+                     libavcodec-dev libavformat-dev libavutil-dev \
+                     libsdl2-dev
 
 
 #### Windows
 
-From [MSYS2]:
+For Windows, for simplicity, a prebuilt package with all the dependencies
+(including `adb`) is available: TODO.
 
-    pacman -S mingw-w64-x86_64-SDL2
-    pacman -S mingw-w64-x86_64-SDL2_net
-    pacman -S mingw-w64-x86_64-ffmpeg
+Instead, you may want to build it manually. You need [MSYS2] to build the
+project. From an MSYS2 terminal, install the required packages:
 
 [MSYS2]: http://www.msys2.org/
 
+    # runtime dependencies
+    pacman -S mingw-w64-x86_64-SDL2 \
+              mingw-w64-x86_64-ffmpeg
 
-#### MacOS
+    # build dependencies
+    pacman -S mingw-w64-x86_64-make \
+              mingw-w64-x86_64-gcc \
+              mingw-w64-x86_64-pkg-config \
+              mingw-w64-x86_64-meson \
+              zip
 
-TODO
-
-
-## Build
-
-The project is divided into two parts:
- - the server, running on the device (in `server/`);
- - the client, running on the computer (in `app/`).
-
-The server is a raw Java project requiring Android SDK. It not an Android
-project: the target file is a `.jar`, and a `main()` method is executed with
-_shell_ rights.
-
-The client is a C project using [SDL] and [FFmpeg], built with [Meson]/[Ninja].
-
-The root directory contains a `Makefile` to build both parts.
-
-[sdl]: https://www.libsdl.org/
-[ffmpeg]: https://www.ffmpeg.org/
-[meson]: http://mesonbuild.com/
-[ninja]: https://ninja-build.org/
-
-
-### Build requirements
-
-Install the [Android SDK], the JDK 8 (`openjdk-8-jdk`), and the packages
-described below.
-
-[Android SDK]: https://developer.android.com/studio/index.html
-
-
-#### Linux
-
-    sudo apt install make gcc openjdk-8-jdk pkg-config meson zip \
-                     libavcodec-dev libavformat-dev libavutil-dev \
-                     libsdl2-dev libsdl2-net-dev
-
-
-#### Windows
-
-Install these packages:
-
-    pacman -S mingw-w64-x86_64-make
-    pacman -S mingw-w64-x86_64-gcc
-    pacman -S mingw-w64-x86_64-pkg-config
-    pacman -S mingw-w64-x86_64-meson
-    pacman -S zip
-
-Java 8 is not available in MSYS2, so install it manually and make it available
-from the `PATH`:
+Java (>= 7) is not available in MSYS2, so if you plan to build the server,
+install it manually and make it available from the `PATH`:
 
     export PATH="$JAVA_HOME/bin:$PATH"
 
 
-### Build
+#### Mac OS
 
-Make sure your `ANDROID_HOME` variable is set to your Android SDK directory:
+Use [Homebrew] to install the packages:
+
+[Homebrew]: https://brew.sh/
+
+    # runtime dependencies
+    brew install sdl2 ffmpeg
+
+    # build dependencies
+    brew install gcc pkg-config meson zip
+
+Java (>= 7) is not available in Homebrew, so if you plan to build the server,
+install it manually and make it available from the `PATH`:
+
+    export PATH="$JAVA_HOME/bin:$PATH"
+
+
+### Common steps
+
+Install the [Android SDK] (_Android Studio_), and set `ANDROID_HOME` to
+its directory. For example:
+
+[Android SDK]: https://developer.android.com/studio/index.html
 
     export ANDROID_HOME=~/android/sdk
 
-From the project root directory, execute:
+Then, build `scrcpy`:
 
-    make build
+    meson x --buildtype release --strip -Db_lto=true
+    cd x
+    ninja
 
-To run the build:
+You can test it from here:
 
-    make run
+    ninja run
 
-It is also pass arguments to `scrcpy` via `make`:
+Or you can install it on the system:
 
-    make run ARGS="-p 1234"
+    sudo ninja install    # without sudo on Windows
 
-The purpose of this command is to execute `scrcpy` during the development.
+This installs two files:
+
+ - `/usr/local/bin/scrcpy`
+ - `/usr/local/share/scrcpy/scrcpy-server.jar`
+
+Just remove them to "uninstall" the application.
 
 
-### Test
+#### Prebuilt server
 
-To execute unit tests:
+Since the server binary, that will be pushed to the Android device, does not
+depend on your system and architecture, you may want to use the prebuilt binary
+instead: [`scrcpy-server.jar`](TODO).
 
-    make test
+In that case, the build does not require Java or the Android SDK.
 
-The server-side tests require JUnit 4:
+Download the prebuilt server somewhere, and specify its path during the Meson
+configuration:
 
-    sudo apt install junit4
-
-
-### Generate a release
-
-From the project root directory, execute:
-
-    make release
-
-This will generate the application in `dist/scrcpy/`.
+    meson x --buildtype release --strip -Db_lto=true \
+        -Dprebuilt_server=/path/to/scrcpy-server.jar
+    cd x
+    ninja
+    sudo ninja install
 
 
 ## Run
 
-Plug a device, and from `dist/scrcpy/`, execute:
+_At runtime, `adb` must be accessible from your `PATH`._
 
-    ./scrcpy
+If everything is ok, just plug an Android device, and execute:
+
+    scrcpy
+
+It accepts command-line arguments, listed by:
+
+    scrcpy --help
+
+For example, to decrease video bitrate to 2Mbps (default is 8Mbps):
+
+    scrcpy -b 2M
+
+To limit the video dimensions (e.g. if the device is 2540×1440, but the host
+screen is smaller, or cannot decode such a high definition):
+
+    scrcpy -m 1024
 
 If several devices are listed in `adb devices`, you must specify the _serial_:
 
-    ./scrcpy 0123456789abcdef
+    scrcpy -s 0123456789abcdef
 
-To change the default port (useful to launch several `scrcpy` simultaneously):
 
-    ./scrcpy -p 1234
+## Shortcuts
 
-Other options are available, check `scrcpy --help`.
+ | Action                                 |   Shortcut    |
+ | -------------------------------------  | -------------:|
+ | switch fullscreen mode                 | `Ctrl`+`f`    |
+ | resize window to 1:1 (pixel-perfect)   | `Ctrl`+`g`    |
+ | resize window to remove black borders  | `Ctrl`+`x`    |
+ | click on `HOME`                        | `Ctrl`+`h`    |
+ | click on `BACK`                        | `Ctrl`+`b`    |
+ | click on `APP_SWITCH`                  | `Ctrl`+`m`    |
+ | click on `VOLUME_UP`                   | `Ctrl`+`+`    |
+ | click on `VOLUME_DOWN`                 | `Ctrl`+`-`    |
+ | click on `POWER`                       | `Ctrl`+`p`    |
+ | turn screen on                         | _Right-click_ |
+ | enable/disable FPS counter (on stdout) | `Ctrl`+`i`    |
+
+
+## Why _scrcpy_?
+
+A colleague challenged me to find a name as unpronounceable as [gnirehtet].
+
+[`strcpy`] copies a **str**ing; `scrcpy` copies a **scr**een.
+
+[gnirehtet]: https://github.com/Genymobile/gnirehtet
+[`strcpy`]: http://man7.org/linux/man-pages/man3/strcpy.3.html
+
+
+## Developers
+
+Read the [developers page].
+
+[developers page]: DEVELOP.md
+
+
+## Licence
+
+    Copyright (C) 2018 Genymobile
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.

app/meson.build

@@ -8,6 +8,7 @@ src = [
     'src/device.c',
     'src/fpscounter.c',
     'src/frames.c',
+    'src/hidpi.c',
     'src/inputmanager.c',
     'src/lockutil.c',
     'src/net.c',
@@ -73,7 +74,7 @@ conf.set('DEFAULT_MAX_SIZE', '0')  # 0: unlimited
 
 # the default video bitrate, in bits/second
 # overridden by option --bit-rate
-conf.set('DEFAULT_BIT_RATE', '4000000')  # 4Mbps
+conf.set('DEFAULT_BIT_RATE', '8000000')  # 8Mbps
 
 # whether the app should always display the most recent available frame, even
 # if the previous one has not been displayed

app/src/convert.c

@@ -136,6 +136,7 @@ SDL_bool input_key_from_sdl_to_android(const SDL_KeyboardEvent *from,
 
 SDL_bool mouse_button_from_sdl_to_android(const SDL_MouseButtonEvent *from,
                                           struct size screen_size,
+                                          struct hidpi_scale *hidpi_scale,
                                           struct control_event *to) {
     to->type = CONTROL_EVENT_TYPE_MOUSE;
 
@@ -145,21 +146,30 @@ SDL_bool mouse_button_from_sdl_to_android(const SDL_MouseButtonEvent *from,
 
     to->mouse_event.buttons = convert_mouse_buttons(SDL_BUTTON(from->button));
     to->mouse_event.position.screen_size = screen_size;
-    to->mouse_event.position.point.x = (Uint16) from->x;
-    to->mouse_event.position.point.y = (Uint16) from->y;
+
+    Sint32 x = from->x;
+    Sint32 y = from->y;
+    hidpi_unscale_coordinates(hidpi_scale, &x, &y);
+    to->mouse_event.position.point.x = (Uint16) x;
+    to->mouse_event.position.point.y = (Uint16) y;
 
     return SDL_TRUE;
 }
 
 SDL_bool mouse_motion_from_sdl_to_android(const SDL_MouseMotionEvent *from,
                                           struct size screen_size,
+                                          struct hidpi_scale *hidpi_scale,
                                           struct control_event *to) {
     to->type = CONTROL_EVENT_TYPE_MOUSE;
     to->mouse_event.action = AMOTION_EVENT_ACTION_MOVE;
     to->mouse_event.buttons = convert_mouse_buttons(from->state);
     to->mouse_event.position.screen_size = screen_size;
-    to->mouse_event.position.point.x = from->x;
-    to->mouse_event.position.point.y = from->y;
+
+    Sint32 x = from->x;
+    Sint32 y = from->y;
+    hidpi_unscale_coordinates(hidpi_scale, &x, &y);
+    to->mouse_event.position.point.x = (Uint16) x;
+    to->mouse_event.position.point.y = (Uint16) y;
 
     return SDL_TRUE;
 }

app/src/convert.h

@@ -3,7 +3,10 @@
 
 #include <SDL2/SDL_stdinc.h>
 #include <SDL2/SDL_events.h>
+
+#include "common.h"
 #include "controlevent.h"
+#include "hidpi.h"
 
 struct complete_mouse_motion_event {
     SDL_MouseMotionEvent *mouse_motion_event;
@@ -19,12 +22,14 @@ SDL_bool input_key_from_sdl_to_android(const SDL_KeyboardEvent *from,
                                        struct control_event *to);
 SDL_bool mouse_button_from_sdl_to_android(const SDL_MouseButtonEvent *from,
                                           struct size screen_size,
+                                          struct hidpi_scale *hidpi_scale,
                                           struct control_event *to);
 
 // the video size may be different from the real device size, so we need the size
 // to which the absolute position apply, to scale it accordingly
 SDL_bool mouse_motion_from_sdl_to_android(const SDL_MouseMotionEvent *from,
                                           struct size screen_size,
+                                          struct hidpi_scale *hidpi_scale,
                                           struct control_event *to);
 
 // on Android, a scroll event requires the current mouse position

app/src/hidpi.c

@@ -0,0 +1,16 @@
+#include "hidpi.h"
+
+void hidpi_get_scale(struct screen *screen, struct hidpi_scale *scale) {
+    SDL_GL_GetDrawableSize(screen->window, &scale->horizontal.num, &scale->vertical.num);
+    SDL_GetWindowSize(screen->window, &scale->horizontal.div, &scale->vertical.div);
+}
+
+void hidpi_unscale_coordinates(struct hidpi_scale *scale, Sint32 *x, Sint32 *y) {
+    // to unscale, we devide by the ratio (so num and div are reversed)
+    if (scale->horizontal.num) {
+        *x = ((Sint64) *x) * scale->horizontal.div / scale->horizontal.num;
+    }
+    if (scale->vertical.num) {
+        *y = ((Sint64) *y) * scale->vertical.div / scale->vertical.num;
+    }
+}

app/src/hidpi.h

@@ -0,0 +1,24 @@
+#ifndef HIDPI_H
+#define HIDPI_H
+
+#include "common.h"
+#include "screen.h"
+
+// rational number p/q
+struct rational {
+    int num;
+    int div;
+};
+
+struct hidpi_scale {
+    struct rational horizontal; // drawable.width / window.width
+    struct rational vertical; // drawable.height / window.height
+};
+
+void hidpi_get_scale(struct screen *screen, struct hidpi_scale *hidpi_scale);
+
+// mouse location need to be "unscaled" if hidpi is enabled
+// <https://nlguillemot.wordpress.com/2016/12/11/high-dpi-rendering/>
+void hidpi_unscale_coordinates(struct hidpi_scale *hidpi_scale, Sint32 *x, Sint32 *y);
+
+#endif

app/src/inputmanager.c

@@ -1,13 +1,37 @@
 #include "inputmanager.h"
 
 #include "convert.h"
+#include "hidpi.h"
 #include "lockutil.h"
 #include "log.h"
 
-static struct point get_mouse_point(void) {
-    int x;
-    int y;
-    SDL_GetMouseState(&x, &y);
+// Convert window coordinates (as provided by SDL_GetMouseState() to renderer coordinates (as provided in SDL mouse events)
+//
+// See my question:
+// <https://stackoverflow.com/questions/49111054/how-to-get-mouse-position-on-mouse-wheel-event>
+static void convert_to_renderer_coordinates(SDL_Renderer *renderer, int *x, int *y) {
+    SDL_Rect viewport;
+    float scale_x, scale_y;
+    SDL_RenderGetViewport(renderer, &viewport);
+    SDL_RenderGetScale(renderer, &scale_x, &scale_y);
+    *x = (int) (*x / scale_x) - viewport.x;
+    *y = (int) (*y / scale_y) - viewport.y;
+}
+
+static struct point get_mouse_point(struct screen *screen) {
+    int mx;
+    int my;
+    SDL_GetMouseState(&mx, &my);
+    convert_to_renderer_coordinates(screen->renderer, &mx, &my);
+
+    struct hidpi_scale hidpi_scale;
+    hidpi_get_scale(screen, &hidpi_scale);
+
+    // SDL sometimes uses "int", sometimes "Sint32"
+    Sint32 x = mx;
+    Sint32 y = my;
+    hidpi_unscale_coordinates(&hidpi_scale, &x, &y);
+
     SDL_assert_release(x >= 0 && x < 0x10000 && y >= 0 && y < 0x10000);
     return (struct point) {
         .x = (Uint16) x,
@@ -178,8 +202,12 @@ void input_manager_process_mouse_motion(struct input_manager *input_manager,
         // do not send motion events when no button is pressed
         return;
     }
+
+    struct hidpi_scale hidpi_scale;
+    hidpi_get_scale(input_manager->screen, &hidpi_scale);
+
     struct control_event control_event;
-    if (mouse_motion_from_sdl_to_android(event, input_manager->screen->frame_size, &control_event)) {
+    if (mouse_motion_from_sdl_to_android(event, input_manager->screen->frame_size, &hidpi_scale, &control_event)) {
         if (!controller_push_event(input_manager->controller, &control_event)) {
             LOGW("Cannot send mouse motion event");
         }
@@ -192,8 +220,12 @@ void input_manager_process_mouse_button(struct input_manager *input_manager,
         turn_screen_on(input_manager->controller);
         return;
     };
+
+    struct hidpi_scale hidpi_scale;
+    hidpi_get_scale(input_manager->screen, &hidpi_scale);
+
     struct control_event control_event;
-    if (mouse_button_from_sdl_to_android(event, input_manager->screen->frame_size, &control_event)) {
+    if (mouse_button_from_sdl_to_android(event, input_manager->screen->frame_size, &hidpi_scale, &control_event)) {
         if (!controller_push_event(input_manager->controller, &control_event)) {
             LOGW("Cannot send mouse button event");
         }
@@ -204,7 +236,7 @@ void input_manager_process_mouse_wheel(struct input_manager *input_manager,
                                        const SDL_MouseWheelEvent *event) {
     struct position position = {
         .screen_size = input_manager->screen->frame_size,
-        .point = get_mouse_point(),
+        .point = get_mouse_point(input_manager->screen),
     };
     struct control_event control_event;
     if (mouse_wheel_from_sdl_to_android(event, position, &control_event)) {

app/src/screen.c

@@ -141,7 +141,8 @@ SDL_bool screen_init_rendering(struct screen *screen, const char *device_name, s
 
     struct size window_size = get_initial_optimal_size(frame_size);
     screen->window = SDL_CreateWindow(device_name, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
-                                      window_size.width, window_size.height, SDL_WINDOW_HIDDEN | SDL_WINDOW_RESIZABLE);
+                                      window_size.width, window_size.height,
+                                      SDL_WINDOW_HIDDEN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     if (!screen->window) {
         LOGC("Could not create window: %s", SDL_GetError());
         return SDL_FALSE;

app/src/server.c

@@ -71,6 +71,7 @@ static socket_t listen_on_port(Uint16 port) {
 
 static void close_socket(socket_t *socket) {
     SDL_assert(*socket != INVALID_SOCKET);
+    net_shutdown(*socket, SHUT_RDWR);
     if (!net_close(*socket)) {
         LOGW("Cannot close socket");
         return;
@@ -95,10 +96,10 @@ SDL_bool server_start(struct server *server, const char *serial, Uint16 local_po
     }
 
     // At the application level, the device part is "the server" because it
-    // serves video stream and control. However, at network level, the client
-    // listens and the server connects to the client. That way, the client can
-    // listen before starting the server app, so there is no need to try to
-    // connect until the server socket is listening on the device.
+    // serves video stream and control. However, at the network level, the
+    // client listens and the server connects to the client. That way, the
+    // client can listen before starting the server app, so there is no need to
+    // try to connect until the server socket is listening on the device.
 
     server->server_socket = listen_on_port(local_port);
     if (server->server_socket == INVALID_SOCKET) {

server/src/main/java/com/genymobile/scrcpy/ScreenEncoder.java

@@ -16,7 +16,6 @@ import java.util.concurrent.atomic.AtomicBoolean;
 
 public class ScreenEncoder implements Device.RotationListener {
 
-    private static final int DEFAULT_BIT_RATE = 4_000_000; // bits per second
     private static final int DEFAULT_FRAME_RATE = 60; // fps
     private static final int DEFAULT_I_FRAME_INTERVAL = 10; // seconds
 
@@ -40,16 +39,12 @@ public class ScreenEncoder implements Device.RotationListener {
         this(bitRate, DEFAULT_FRAME_RATE, DEFAULT_I_FRAME_INTERVAL);
     }
 
-    public ScreenEncoder() {
-        this(DEFAULT_BIT_RATE, DEFAULT_FRAME_RATE, DEFAULT_I_FRAME_INTERVAL);
-    }
-
     @Override
     public void onRotationChanged(int rotation) {
         rotationChanged.set(true);
     }
 
-    public boolean checkRotationChanged() {
+    public boolean consumeRotationChange() {
         return rotationChanged.getAndSet(false);
     }
 
@@ -87,11 +82,11 @@ public class ScreenEncoder implements Device.RotationListener {
         byte[] buf = new byte[bitRate / 8]; // may contain up to 1 second of video
         boolean eof = false;
         MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
-        while (!checkRotationChanged() && !eof) {
+        while (!consumeRotationChange() && !eof) {
             int outputBufferId = codec.dequeueOutputBuffer(bufferInfo, -1);
             eof = (bufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0;
             try {
-                if (checkRotationChanged()) {
+                if (consumeRotationChange()) {
                     // must restart encoding with new size
                     break;
                 }