fix issue 15?

The window dimensions are integers, so resizing to fit the content may
not be exact.

When computing the optimal size, it could cause to reduce alternatively
the width and height by few pixels, making the "optimal size" unstable.

To avoid this problem, check if the optimal size is already correct
either by keeping the width or the height.

FAQ.md

@@ -134,18 +134,27 @@ that's all. See [#37].
 
 ### The quality is low
 
-On Windows, you may need to configure the [scaling behavior].
+If the definition of your client window is smaller than that of your device
+screen, then you might get poor quality, especially visible on text (see [#40]).
+
+[#40]: https://github.com/Genymobile/scrcpy/issues/40
+
+To improve downscaling quality, trilinear filtering is enabled automatically
+if the renderer is OpenGL and if it supports mipmapping.
+
+On Windows, you might want to force OpenGL:
+
+```
+scrcpy --render-driver=opengl
+```
+
+You may also need to configure the [scaling behavior]:
 
 > `scrcpy.exe` > Properties > Compatibility > Change high DPI settings >
 > Override high DPI scaling behavior > Scaling performed by: _Application_.
 
 [scaling behavior]: https://github.com/Genymobile/scrcpy/issues/40#issuecomment-424466723
 
-If the definition of your client window is far smaller than that of your device
-screen, then you'll get poor quality. This is especially visible on text. See
-[#40].
-
-[#40]: https://github.com/Genymobile/scrcpy/issues/40
 
 
 ### KWin compositor crashes

README.md

@@ -363,7 +363,7 @@ Note that _scrcpy_ manages 3 different rotations:
    current running app may refuse, if it does support the requested
    orientation).
  - `--lock-video-orientation` changes the mirroring orientation (the orientation
-   of the video sent from the device to the computer. This affects the
+   of the video sent from the device to the computer). This affects the
    recording.
  - `--rotation` (or `Ctrl`+`←`/`Ctrl`+`→`) rotates only the window content. This
    affects only the display, not the recording.

app/meson.build

@@ -11,6 +11,7 @@ src = [
     'src/file_handler.c',
     'src/fps_counter.c',
     'src/input_manager.c',
+    'src/opengl.c',
     'src/receiver.c',
     'src/recorder.c',
     'src/scrcpy.c',

app/scrcpy.1

@@ -74,6 +74,10 @@ Disable device control (mirror the device in read\-only).
 .B \-N, \-\-no\-display
 Do not display device (only when screen recording is enabled).
 
+.TP
+.B \-\-no\-mipmaps
+If the renderer is OpenGL 3.0+ or OpenGL ES 2.0+, then mipmaps are automatically generated to improve downscaling quality. This option disables the generation of mipmaps.
+
 .TP
 .BI "\-p, \-\-port " port[:port]
 Set the TCP port (range) used by the client to listen.
@@ -106,6 +110,14 @@ option if set, or by the file extension (.mp4 or .mkv).
 .BI "\-\-record\-format " format
 Force recording format (either mp4 or mkv).
 
+.TP
+.BI "\-\-render\-driver " name
+Request SDL to use the given render driver (this is just a hint).
+
+Supported names are currently "direct3d", "opengl", "opengles2", "opengles", "metal" and "software".
+.UR https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER
+.UE
+
 .TP
 .B \-\-render\-expired\-frames
 By default, to minimize latency, scrcpy always renders the last available decoded frame, and drops any previous ones. This flag forces to render all frames, at a cost of a possible increased latency.

app/src/cli.c

@@ -75,6 +75,11 @@ scrcpy_print_usage(const char *arg0) {
         "        Do not display device (only when screen recording is\n"
         "        enabled).\n"
         "\n"
+        "    --no-mipmaps\n"
+        "        If the renderer is OpenGL 3.0+ or OpenGL ES 2.0+, then\n"
+        "        mipmaps are automatically generated to improve downscaling\n"
+        "        quality. This option disables the generation of mipmaps.\n"
+        "\n"
         "    -p, --port port[:port]\n"
         "        Set the TCP port (range) used by the client to listen.\n"
         "        Default is %d:%d.\n"
@@ -99,6 +104,13 @@ scrcpy_print_usage(const char *arg0) {
         "    --record-format format\n"
         "        Force recording format (either mp4 or mkv).\n"
         "\n"
+        "    --render-driver name\n"
+        "        Request SDL to use the given render driver (this is just a\n"
+        "        hint).\n"
+        "        Supported names are currently \"direct3d\", \"opengl\",\n"
+        "        \"opengles2\", \"opengles\", \"metal\" and \"software\".\n"
+        "        <https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER>\n"
+        "\n"
         "    --render-expired-frames\n"
         "        By default, to minimize latency, scrcpy always renders the\n"
         "        last available decoded frame, and drops any previous ones.\n"
@@ -454,6 +466,8 @@ guess_record_format(const char *filename) {
 #define OPT_LOCK_VIDEO_ORIENTATION 1013
 #define OPT_DISPLAY_ID             1014
 #define OPT_ROTATION               1015
+#define OPT_RENDER_DRIVER          1016
+#define OPT_NO_MIPMAPS             1017
 
 bool
 scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
@@ -470,10 +484,12 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
         {"max-size",               required_argument, NULL, 'm'},
         {"no-control",             no_argument,       NULL, 'n'},
         {"no-display",             no_argument,       NULL, 'N'},
+        {"no-mipmaps",             no_argument,       NULL, OPT_NO_MIPMAPS},
         {"port",                   required_argument, NULL, 'p'},
         {"push-target",            required_argument, NULL, OPT_PUSH_TARGET},
         {"record",                 required_argument, NULL, 'r'},
         {"record-format",          required_argument, NULL, OPT_RECORD_FORMAT},
+        {"render-driver",          required_argument, NULL, OPT_RENDER_DRIVER},
         {"render-expired-frames",  no_argument,       NULL,
                                                   OPT_RENDER_EXPIRED_FRAMES},
         {"rotation",               required_argument, NULL, OPT_ROTATION},
@@ -617,6 +633,12 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
                     return false;
                 }
                 break;
+            case OPT_RENDER_DRIVER:
+                opts->render_driver = optarg;
+                break;
+            case OPT_NO_MIPMAPS:
+                opts->mipmaps = false;
+                break;
             default:
                 // getopt prints the error message on stderr
                 return false;

app/src/control_msg.c

@@ -45,8 +45,9 @@ control_msg_serialize(const struct control_msg *msg, unsigned char *buf) {
             buffer_write32be(&buf[6], msg->inject_keycode.metastate);
             return 10;
         case CONTROL_MSG_TYPE_INJECT_TEXT: {
-            size_t len = write_string(msg->inject_text.text,
-                                      CONTROL_MSG_TEXT_MAX_LENGTH, &buf[1]);
+            size_t len =
+                write_string(msg->inject_text.text,
+                             CONTROL_MSG_INJECT_TEXT_MAX_LENGTH, &buf[1]);
             return 1 + len;
         }
         case CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT:

app/src/control_msg.h

@@ -10,7 +10,7 @@
 #include "android/keycodes.h"
 #include "common.h"
 
-#define CONTROL_MSG_TEXT_MAX_LENGTH 300
+#define CONTROL_MSG_INJECT_TEXT_MAX_LENGTH 300
 #define CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH 4093
 #define CONTROL_MSG_SERIALIZED_MAX_SIZE \
     (3 + CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH)

app/src/input_manager.c

@@ -442,36 +442,6 @@ input_manager_process_key(struct input_manager *im,
     }
 }
 
-static struct point
-rotate_position(struct screen *screen, int32_t x, int32_t y) {
-    unsigned rotation = screen->rotation;
-    assert(rotation < 4);
-
-    int32_t w = screen->content_size.width;
-    int32_t h = screen->content_size.height;
-    struct point result;
-    switch (rotation) {
-        case 0:
-            result.x = x;
-            result.y = y;
-            break;
-        case 1:
-            result.x = h - y;
-            result.y = x;
-            break;
-        case 2:
-            result.x = w - x;
-            result.y = h - y;
-            break;
-        default:
-            assert(rotation == 3);
-            result.x = y;
-            result.y = w - x;
-            break;
-    }
-    return result;
-}
-
 static bool
 convert_mouse_motion(const SDL_MouseMotionEvent *from, struct screen *screen,
                      struct control_msg *to) {
@@ -480,7 +450,7 @@ convert_mouse_motion(const SDL_MouseMotionEvent *from, struct screen *screen,
     to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
     to->inject_touch_event.position.screen_size = screen->frame_size;
     to->inject_touch_event.position.point =
-        rotate_position(screen, from->x, from->y);
+        screen_convert_to_frame_coords(screen, from->x, from->y);
     to->inject_touch_event.pressure = 1.f;
     to->inject_touch_event.buttons = convert_mouse_buttons(from->state);
 
@@ -515,14 +485,13 @@ convert_touch(const SDL_TouchFingerEvent *from, struct screen *screen,
         return false;
     }
 
-    struct size frame_size = screen->frame_size;
-
     to->inject_touch_event.pointer_id = from->fingerId;
-    to->inject_touch_event.position.screen_size = frame_size;
+    to->inject_touch_event.position.screen_size = screen->frame_size;
     // SDL touch event coordinates are normalized in the range [0; 1]
-    float x = from->x * frame_size.width;
-    float y = from->y * frame_size.height;
-    to->inject_touch_event.position.point = rotate_position(screen, x, y);
+    float x = from->x * screen->content_size.width;
+    float y = from->y * screen->content_size.height;
+    to->inject_touch_event.position.point =
+        screen_convert_to_frame_coords(screen, x, y);
     to->inject_touch_event.pressure = from->pressure;
     to->inject_touch_event.buttons = 0;
     return true;
@@ -558,7 +527,7 @@ convert_mouse_button(const SDL_MouseButtonEvent *from, struct screen *screen,
     to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
     to->inject_touch_event.position.screen_size = screen->frame_size;
     to->inject_touch_event.position.point =
-        rotate_position(screen, from->x, from->y);
+        screen_convert_to_frame_coords(screen, from->x, from->y);
     to->inject_touch_event.pressure = 1.f;
     to->inject_touch_event.buttons =
         convert_mouse_buttons(SDL_BUTTON(from->button));

app/src/opengl.c

@@ -0,0 +1,56 @@
+#include "opengl.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include "SDL2/SDL.h"
+
+void
+sc_opengl_init(struct sc_opengl *gl) {
+    gl->GetString = SDL_GL_GetProcAddress("glGetString");
+    assert(gl->GetString);
+
+    gl->TexParameterf = SDL_GL_GetProcAddress("glTexParameterf");
+    assert(gl->TexParameterf);
+
+    gl->TexParameteri = SDL_GL_GetProcAddress("glTexParameteri");
+    assert(gl->TexParameteri);
+
+    // optional
+    gl->GenerateMipmap = SDL_GL_GetProcAddress("glGenerateMipmap");
+
+    const char *version = (const char *) gl->GetString(GL_VERSION);
+    assert(version);
+    gl->version = version;
+
+#define OPENGL_ES_PREFIX "OpenGL ES "
+    /* starts with "OpenGL ES " */
+    gl->is_opengles = !strncmp(gl->version, OPENGL_ES_PREFIX,
+                               sizeof(OPENGL_ES_PREFIX) - 1);
+    if (gl->is_opengles) {
+        /* skip the prefix */
+        version += sizeof(PREFIX) - 1;
+    }
+
+    int r = sscanf(version, "%d.%d", &gl->version_major, &gl->version_minor);
+    if (r != 2) {
+        // failed to parse the version
+        gl->version_major = 0;
+        gl->version_minor = 0;
+    }
+}
+
+bool
+sc_opengl_version_at_least(struct sc_opengl *gl,
+                           int minver_major, int minver_minor,
+                           int minver_es_major, int minver_es_minor)
+{
+    if (gl->is_opengles) {
+        return gl->version_major > minver_es_major
+            || (gl->version_major == minver_es_major
+             && gl->version_minor >= minver_es_minor);
+    }
+
+    return gl->version_major > minver_major
+        || (gl->version_major == minver_major
+         && gl->version_minor >= minver_minor);
+}

app/src/opengl.h

@@ -0,0 +1,36 @@
+#ifndef SC_OPENGL_H
+#define SC_OPENGL_H
+
+#include <stdbool.h>
+#include <SDL2/SDL_opengl.h>
+
+#include "config.h"
+
+struct sc_opengl {
+    const char *version;
+    bool is_opengles;
+    int version_major;
+    int version_minor;
+
+    const GLubyte *
+    (*GetString)(GLenum name);
+
+    void
+    (*TexParameterf)(GLenum target, GLenum pname, GLfloat param);
+
+    void
+    (*TexParameteri)(GLenum target, GLenum pname, GLint param);
+
+    void
+    (*GenerateMipmap)(GLenum target);
+};
+
+void
+sc_opengl_init(struct sc_opengl *gl);
+
+bool
+sc_opengl_version_at_least(struct sc_opengl *gl,
+                           int minver_major, int minver_minor,
+                           int minver_es_major, int minver_es_minor);
+
+#endif

app/src/scrcpy.c

@@ -47,7 +47,7 @@ static struct input_manager input_manager = {
 
 // init SDL and set appropriate hints
 static bool
-sdl_init_and_configure(bool display) {
+sdl_init_and_configure(bool display, const char *render_driver) {
     uint32_t flags = display ? SDL_INIT_VIDEO : SDL_INIT_EVENTS;
     if (SDL_Init(flags)) {
         LOGC("Could not initialize SDL: %s", SDL_GetError());
@@ -60,6 +60,10 @@ sdl_init_and_configure(bool display) {
         return true;
     }
 
+    if (render_driver && !SDL_SetHint(SDL_HINT_RENDER_DRIVER, render_driver)) {
+        LOGW("Could not set render driver");
+    }
+
     // Linear filtering
     if (!SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "1")) {
         LOGW("Could not enable linear filtering");
@@ -105,9 +109,10 @@ static int
 event_watcher(void *data, SDL_Event *event) {
     (void) data;
     if (event->type == SDL_WINDOWEVENT
-            && event->window.event == SDL_WINDOWEVENT_RESIZED) {
-        // called from another thread, not very safe, but it's a workaround!
-        screen_render(&screen);
+            && event->window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
+        // In practice, it seems to always be called from the same thread in
+        // that specific case. Anyway, it's just a workaround.
+        screen_handle_window_event(&screen, &event->window);
     }
     return 0;
 }
@@ -310,7 +315,7 @@ scrcpy(const struct scrcpy_options *options) {
     bool controller_initialized = false;
     bool controller_started = false;
 
-    if (!sdl_init_and_configure(options->display)) {
+    if (!sdl_init_and_configure(options->display, options->render_driver)) {
         goto end;
     }
 
@@ -397,7 +402,7 @@ scrcpy(const struct scrcpy_options *options) {
                                    options->window_y, options->window_width,
                                    options->window_height,
                                    options->window_borderless,
-                                   options->rotation)) {
+                                   options->rotation, options-> mipmaps)) {
             goto end;
         }
 

app/src/scrcpy.h

@@ -15,6 +15,7 @@ struct scrcpy_options {
     const char *record_filename;
     const char *window_title;
     const char *push_target;
+    const char *render_driver;
     enum recorder_format record_format;
     struct port_range port_range;
     uint16_t max_size;
@@ -36,6 +37,7 @@ struct scrcpy_options {
     bool render_expired_frames;
     bool prefer_text;
     bool window_borderless;
+    bool mipmaps;
 };
 
 #define SCRCPY_OPTIONS_DEFAULT { \
@@ -44,6 +46,7 @@ struct scrcpy_options {
     .record_filename = NULL, \
     .window_title = NULL, \
     .push_target = NULL, \
+    .render_driver = NULL, \
     .record_format = RECORDER_FORMAT_AUTO, \
     .port_range = { \
         .first = DEFAULT_LOCAL_PORT_RANGE_FIRST, \
@@ -68,6 +71,7 @@ struct scrcpy_options {
     .render_expired_frames = false, \
     .prefer_text = false, \
     .window_borderless = false, \
+    .mipmaps = true, \
 }
 
 bool

app/src/screen.c

@@ -113,6 +113,13 @@ get_optimal_size(struct size current_size, struct size content_size) {
         h = MIN(current_size.height, display_size.height);
     }
 
+    if (h == w * content_size.height / content_size.width
+     || w == h * content_size.width / content_size.height) {
+        // The size is already optimal, if we ignore rounding errors due to
+        // integer window dimensions
+        return (struct size) {w, h};
+    }
+
     bool keep_width = content_size.width * h > content_size.height * w;
     if (keep_width) {
         // remove black borders on top and bottom
@@ -168,10 +175,30 @@ screen_init(struct screen *screen) {
 }
 
 static inline SDL_Texture *
-create_texture(SDL_Renderer *renderer, struct size frame_size) {
-    return SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12,
-                             SDL_TEXTUREACCESS_STREAMING,
-                             frame_size.width, frame_size.height);
+create_texture(struct screen *screen) {
+    SDL_Renderer *renderer = screen->renderer;
+    struct size size = screen->frame_size;
+    SDL_Texture *texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_YV12,
+                                             SDL_TEXTUREACCESS_STREAMING,
+                                             size.width, size.height);
+    if (!texture) {
+        return NULL;
+    }
+
+    if (screen->mipmaps) {
+        struct sc_opengl *gl = &screen->gl;
+
+        SDL_GL_BindTexture(texture, NULL, NULL);
+
+        // Enable trilinear filtering for downscaling
+        gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
+                          GL_LINEAR_MIPMAP_LINEAR);
+        gl->TexParameterf(GL_TEXTURE_2D, GL_TEXTURE_LOD_BIAS, -.5f);
+
+        SDL_GL_UnbindTexture(texture);
+    }
+
+    return texture;
 }
 
 bool
@@ -179,7 +206,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
                       int16_t window_x, int16_t window_y, uint16_t window_width,
                       uint16_t window_height, bool window_borderless,
-                      uint8_t rotation) {
+                      uint8_t rotation, bool mipmaps) {
     screen->frame_size = frame_size;
     screen->rotation = rotation;
     if (rotation) {
@@ -226,6 +253,11 @@ screen_init_rendering(struct screen *screen, const char *window_title,
         return false;
     }
 
+    SDL_RendererInfo renderer_info;
+    int r = SDL_GetRendererInfo(screen->renderer, &renderer_info);
+    const char *renderer_name = r ? NULL : renderer_info.name;
+    LOGI("Renderer: %s", renderer_name ? renderer_name : "(unknown)");
+
     if (SDL_RenderSetLogicalSize(screen->renderer, content_size.width,
                                  content_size.height)) {
         LOGE("Could not set renderer logical size: %s", SDL_GetError());
@@ -233,6 +265,32 @@ screen_init_rendering(struct screen *screen, const char *window_title,
         return false;
     }
 
+    // stats with "opengl"
+    screen->use_opengl = renderer_name && !strncmp(renderer_name, "opengl", 6);
+    if (screen->use_opengl) {
+        struct sc_opengl *gl = &screen->gl;
+        sc_opengl_init(gl);
+
+        LOGI("OpenGL version: %s", gl->version);
+
+        if (mipmaps) {
+            bool supports_mipmaps =
+                sc_opengl_version_at_least(gl, 3, 0, /* OpenGL 3.0+ */
+                                               2, 0  /* OpenGL ES 2.0+ */);
+            if (supports_mipmaps) {
+                LOGI("Trilinear filtering enabled");
+                screen->mipmaps = true;
+            } else {
+                LOGW("Trilinear filtering disabled "
+                     "(OpenGL 3.0+ or ES 2.0+ required)");
+            }
+        } else {
+            LOGI("Trilinear filtering disabled");
+        }
+    } else {
+        LOGW("Trilinear filtering disabled (not an OpenGL renderer)");
+    }
+
     SDL_Surface *icon = read_xpm(icon_xpm);
     if (icon) {
         SDL_SetWindowIcon(screen->window, icon);
@@ -243,7 +301,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
 
     LOGI("Initial texture: %" PRIu16 "x%" PRIu16, frame_size.width,
                                                   frame_size.height);
-    screen->texture = create_texture(screen->renderer, frame_size);
+    screen->texture = create_texture(screen);
     if (!screen->texture) {
         LOGC("Could not create texture: %s", SDL_GetError());
         screen_destroy(screen);
@@ -341,7 +399,7 @@ prepare_for_frame(struct screen *screen, struct size new_frame_size) {
 
         LOGI("New texture: %" PRIu16 "x%" PRIu16,
                      screen->frame_size.width, screen->frame_size.height);
-        screen->texture = create_texture(screen->renderer, new_frame_size);
+        screen->texture = create_texture(screen);
         if (!screen->texture) {
             LOGC("Could not create texture: %s", SDL_GetError());
             return false;
@@ -358,6 +416,13 @@ update_texture(struct screen *screen, const AVFrame *frame) {
             frame->data[0], frame->linesize[0],
             frame->data[1], frame->linesize[1],
             frame->data[2], frame->linesize[2]);
+
+    if (screen->mipmaps) {
+        assert(screen->use_opengl);
+        SDL_GL_BindTexture(screen->texture, NULL, NULL);
+        screen->gl.GenerateMipmap(GL_TEXTURE_2D);
+        SDL_GL_UnbindTexture(screen->texture);
+    }
 }
 
 bool
@@ -433,7 +498,8 @@ screen_resize_to_fit(struct screen *screen) {
     struct size optimal_size =
         get_optimal_window_size(screen, screen->content_size);
     SDL_SetWindowSize(screen->window, optimal_size.width, optimal_size.height);
-    LOGD("Resized to optimal size");
+    LOGD("Resized to optimal size: %ux%u", optimal_size.width,
+                                           optimal_size.height);
 }
 
 void
@@ -449,7 +515,17 @@ screen_resize_to_pixel_perfect(struct screen *screen) {
 
     struct size content_size = screen->content_size;
     SDL_SetWindowSize(screen->window, content_size.width, content_size.height);
-    LOGD("Resized to pixel-perfect");
+    LOGD("Resized to pixel-perfect: %ux%u", content_size.width,
+                                            content_size.height);
+}
+
+static void
+screen_reset_logical_size(struct screen *screen) {
+    // Re-apply the current logical size.
+    if (SDL_RenderSetLogicalSize(screen->renderer, screen->content_size.width,
+                                 screen->content_size.height)) {
+        LOGE("Could not reset renderer logical size: %s", SDL_GetError());
+    }
 }
 
 void
@@ -457,6 +533,10 @@ screen_handle_window_event(struct screen *screen,
                            const SDL_WindowEvent *event) {
     switch (event->event) {
         case SDL_WINDOWEVENT_EXPOSED:
+            // Re-apply the current logical size, in case the window has been
+            // moved to a screen with a different HiDPI scaling
+            // <https://github.com/Genymobile/scrcpy/issues/15>
+            screen_reset_logical_size(screen);
             screen_render(screen);
             break;
         case SDL_WINDOWEVENT_SIZE_CHANGED:
@@ -493,3 +573,33 @@ screen_handle_window_event(struct screen *screen,
             break;
     }
 }
+
+struct point
+screen_convert_to_frame_coords(struct screen *screen, int32_t x, int32_t y) {
+    unsigned rotation = screen->rotation;
+    assert(rotation < 4);
+
+    int32_t w = screen->content_size.width;
+    int32_t h = screen->content_size.height;
+    struct point result;
+    switch (rotation) {
+        case 0:
+            result.x = x;
+            result.y = y;
+            break;
+        case 1:
+            result.x = h - y;
+            result.y = x;
+            break;
+        case 2:
+            result.x = w - x;
+            result.y = h - y;
+            break;
+        default:
+            assert(rotation == 3);
+            result.x = y;
+            result.y = w - x;
+            break;
+    }
+    return result;
+}

app/src/screen.h

@@ -7,6 +7,7 @@
 
 #include "config.h"
 #include "common.h"
+#include "opengl.h"
 
 #define WINDOW_POSITION_UNDEFINED (-0x8000)
 
@@ -16,6 +17,8 @@ struct screen {
     SDL_Window *window;
     SDL_Renderer *renderer;
     SDL_Texture *texture;
+    bool use_opengl;
+    struct sc_opengl gl;
     struct size frame_size;
     struct size content_size; // rotated frame_size
     // The window size the last time it was not maximized or fullscreen.
@@ -29,12 +32,15 @@ struct screen {
     bool fullscreen;
     bool maximized;
     bool no_window;
+    bool mipmaps;
 };
 
 #define SCREEN_INITIALIZER { \
     .window = NULL, \
     .renderer = NULL, \
     .texture = NULL, \
+    .use_opengl = false, \
+    .gl = {0}, \
     .frame_size = { \
         .width = 0, \
         .height = 0, \
@@ -56,6 +62,7 @@ struct screen {
     .fullscreen = false, \
     .maximized = false, \
     .no_window = false, \
+    .mipmaps = false, \
 }
 
 // initialize default values
@@ -69,7 +76,7 @@ screen_init_rendering(struct screen *screen, const char *window_title,
                       struct size frame_size, bool always_on_top,
                       int16_t window_x, int16_t window_y, uint16_t window_width,
                       uint16_t window_height, bool window_borderless,
-                      uint8_t rotation);
+                      uint8_t rotation, bool mipmaps);
 
 // show the window
 void
@@ -107,4 +114,9 @@ screen_set_rotation(struct screen *screen, unsigned rotation);
 void
 screen_handle_window_event(struct screen *screen, const SDL_WindowEvent *event);
 
+// convert point from window coordinates to frame coordinates
+// x and y are expressed in pixels
+struct point
+screen_convert_to_frame_coords(struct screen *screen, int32_t x, int32_t y);
+
 #endif

app/tests/test_control_msg_serialize.c

@@ -49,20 +49,20 @@ static void test_serialize_inject_text(void) {
 static void test_serialize_inject_text_long(void) {
     struct control_msg msg;
     msg.type = CONTROL_MSG_TYPE_INJECT_TEXT;
-    char text[CONTROL_MSG_TEXT_MAX_LENGTH + 1];
+    char text[CONTROL_MSG_INJECT_TEXT_MAX_LENGTH + 1];
     memset(text, 'a', sizeof(text));
-    text[CONTROL_MSG_TEXT_MAX_LENGTH] = '\0';
+    text[CONTROL_MSG_INJECT_TEXT_MAX_LENGTH] = '\0';
     msg.inject_text.text = text;
 
     unsigned char buf[CONTROL_MSG_SERIALIZED_MAX_SIZE];
     int size = control_msg_serialize(&msg, buf);
-    assert(size == 3 + CONTROL_MSG_TEXT_MAX_LENGTH);
+    assert(size == 3 + CONTROL_MSG_INJECT_TEXT_MAX_LENGTH);
 
-    unsigned char expected[3 + CONTROL_MSG_TEXT_MAX_LENGTH];
+    unsigned char expected[3 + CONTROL_MSG_INJECT_TEXT_MAX_LENGTH];
     expected[0] = CONTROL_MSG_TYPE_INJECT_TEXT;
     expected[1] = 0x01;
     expected[2] = 0x2c; // text length (16 bits)
-    memset(&expected[3], 'a', CONTROL_MSG_TEXT_MAX_LENGTH);
+    memset(&expected[3], 'a', CONTROL_MSG_INJECT_TEXT_MAX_LENGTH);
 
     assert(!memcmp(buf, expected, sizeof(expected)));
 }

meson.build

@@ -1,6 +1,6 @@
 project('scrcpy', 'c',
         version: '1.12.1',
-        meson_version: '>= 0.37',
+        meson_version: '>= 0.48',
         default_options: [
             'c_std=c11',
             'warning_level=2',

server/meson.build

@@ -3,7 +3,9 @@
 prebuilt_server = get_option('prebuilt_server')
 if prebuilt_server == ''
     custom_target('scrcpy-server',
-                  build_always: true,  # gradle is responsible for tracking source changes
+                  # gradle is responsible for tracking source changes
+                  build_by_default: true,
+                  build_always_stale: true,
                   output: 'scrcpy-server',
                   command: [find_program('./scripts/build-wrapper.sh'), meson.current_source_dir(), '@OUTPUT@', get_option('buildtype')],
                   console: true,

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

@@ -13,8 +13,8 @@ public class ControlMessageReader {
     static final int INJECT_SCROLL_EVENT_PAYLOAD_LENGTH = 20;
     static final int SET_SCREEN_POWER_MODE_PAYLOAD_LENGTH = 1;
 
-    public static final int TEXT_MAX_LENGTH = 300;
     public static final int CLIPBOARD_TEXT_MAX_LENGTH = 4093;
+    public static final int INJECT_TEXT_MAX_LENGTH = 300;
     private static final int RAW_BUFFER_SIZE = 1024;
 
     private final byte[] rawBuffer = new byte[RAW_BUFFER_SIZE];

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

@@ -36,10 +36,7 @@ public final class Device {
      */
     private final int layerStack;
 
-    /**
-     * The FLAG_PRESENTATION from the DisplayInfo
-     */
-    private final boolean isPresentationDisplay;
+    private final boolean supportsInputEvents;
 
     public Device(Options options) {
         displayId = options.getDisplayId();
@@ -53,7 +50,6 @@ public final class Device {
 
         screenInfo = ScreenInfo.computeScreenInfo(displayInfo, options.getCrop(), options.getMaxSize(), options.getLockedVideoOrientation());
         layerStack = displayInfo.getLayerStack();
-        isPresentationDisplay = (displayInfoFlags & DisplayInfo.FLAG_PRESENTATION) != 0;
 
         registerRotationWatcher(new IRotationWatcher.Stub() {
             @Override
@@ -73,8 +69,10 @@ public final class Device {
             Ln.w("Display doesn't have FLAG_SUPPORTS_PROTECTED_BUFFERS flag, mirroring can be restricted");
         }
 
-        if (!supportsInputEvents()) {
-            Ln.w("Input events are not supported for displays with FLAG_PRESENTATION enabled for devices with API lower than 29");
+        // main display or any display on Android >= Q
+        supportsInputEvents = displayId == 0 || Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q;
+        if (!supportsInputEvents) {
+            Ln.w("Input events are not supported for secondary displays before Android 10");
         }
     }
 
@@ -116,10 +114,7 @@ public final class Device {
     }
 
     public boolean supportsInputEvents() {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
-            return true;
-        }
-        return !isPresentationDisplay;
+        return supportsInputEvents;
     }
 
     public boolean injectInputEvent(InputEvent inputEvent, int mode) {

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

@@ -8,7 +8,6 @@ public final class DisplayInfo {
     private final int flags;
 
     public static final int FLAG_SUPPORTS_PROTECTED_BUFFERS = 0x00000001;
-    public static final int FLAG_PRESENTATION = 0x00000008;
 
     public DisplayInfo(int displayId, Size size, int rotation, int layerStack, int flags) {
         this.displayId = displayId;

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

@@ -136,12 +136,12 @@ public class ScreenEncoder implements Device.RotationListener {
     }
 
     private static MediaCodec createCodec() throws IOException {
-        return MediaCodec.createEncoderByType("video/avc");
+        return MediaCodec.createEncoderByType(MediaFormat.MIMETYPE_VIDEO_AVC);
     }
 
     private static MediaFormat createFormat(int bitRate, int maxFps, int iFrameInterval) {
         MediaFormat format = new MediaFormat();
-        format.setString(MediaFormat.KEY_MIME, "video/avc");
+        format.setString(MediaFormat.KEY_MIME, MediaFormat.MIMETYPE_VIDEO_AVC);
         format.setInteger(MediaFormat.KEY_BIT_RATE, bitRate);
         // must be present to configure the encoder, but does not impact the actual frame rate, which is variable
         format.setInteger(MediaFormat.KEY_FRAME_RATE, 60);

server/src/main/java/com/genymobile/scrcpy/wrappers/InputManager.java

@@ -53,8 +53,7 @@ public final class InputManager {
             method.invoke(inputEvent, displayId);
             return true;
         } catch (InvocationTargetException | IllegalAccessException | NoSuchMethodException e) {
-            // just a warning, it might happen on old devices
-            Ln.w("Cannot associate a display id to the input event");
+            Ln.e("Cannot associate a display id to the input event", e);
             return false;
         }
     }

server/src/test/java/com/genymobile/scrcpy/ControlMessageReaderTest.java

@@ -66,7 +66,7 @@ public class ControlMessageReaderTest {
         ByteArrayOutputStream bos = new ByteArrayOutputStream();
         DataOutputStream dos = new DataOutputStream(bos);
         dos.writeByte(ControlMessage.TYPE_INJECT_TEXT);
-        byte[] text = new byte[ControlMessageReader.TEXT_MAX_LENGTH];
+        byte[] text = new byte[ControlMessageReader.INJECT_TEXT_MAX_LENGTH];
         Arrays.fill(text, (byte) 'a');
         dos.writeShort(text.length);
         dos.write(text);