Use the physical size for the renderer

Position and scale the frames manually instead of relying on the
renderer "logical size".

This will allow to draw elements having a size independant of the device
frame.

app/src/event_converter.c

@@ -5,7 +5,7 @@
 #define MAP(FROM, TO) case FROM: *to = TO; return true
 #define FAIL default: return false
 
-static bool
+bool
 convert_keycode_action(SDL_EventType from, enum android_keyevent_action *to) {
     switch (from) {
         MAP(SDL_KEYDOWN, AKEY_EVENT_ACTION_DOWN);
@@ -33,7 +33,7 @@ autocomplete_metastate(enum android_metastate metastate) {
     return metastate;
 }
 
-static enum android_metastate
+enum android_metastate
 convert_meta_state(SDL_Keymod mod) {
     enum android_metastate metastate = 0;
     if (mod & KMOD_LSHIFT) {
@@ -74,7 +74,7 @@ convert_meta_state(SDL_Keymod mod) {
     return autocomplete_metastate(metastate);
 }
 
-static bool
+bool
 convert_keycode(SDL_Keycode from, enum android_keycode *to, uint16_t mod) {
     switch (from) {
         MAP(SDLK_RETURN,       AKEYCODE_ENTER);
@@ -128,7 +128,7 @@ convert_keycode(SDL_Keycode from, enum android_keycode *to, uint16_t mod) {
     }
 }
 
-static enum android_motionevent_buttons
+enum android_motionevent_buttons
 convert_mouse_buttons(uint32_t state) {
     enum android_motionevent_buttons buttons = 0;
     if (state & SDL_BUTTON_LMASK) {
@@ -150,24 +150,6 @@ convert_mouse_buttons(uint32_t state) {
 }
 
 bool
-convert_input_key(const SDL_KeyboardEvent *from, struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_KEYCODE;
-
-    if (!convert_keycode_action(from->type, &to->inject_keycode.action)) {
-        return false;
-    }
-
-    uint16_t mod = from->keysym.mod;
-    if (!convert_keycode(from->keysym.sym, &to->inject_keycode.keycode, mod)) {
-        return false;
-    }
-
-    to->inject_keycode.metastate = convert_meta_state(mod);
-
-    return true;
-}
-
-static bool
 convert_mouse_action(SDL_EventType from, enum android_motionevent_action *to) {
     switch (from) {
         MAP(SDL_MOUSEBUTTONDOWN, AMOTION_EVENT_ACTION_DOWN);
@@ -176,57 +158,7 @@ convert_mouse_action(SDL_EventType from, enum android_motionevent_action *to) {
     }
 }
 
-static inline void
-map_coords(int32_t *x, int32_t *y, const SDL_Rect *rect,
-           struct size frame_size) {
-    *x = (*x - rect->x) * frame_size.width / rect->w;
-    *y = (*y - rect->y) * frame_size.height / rect->h;
-}
-
 bool
-convert_mouse_button(const SDL_MouseButtonEvent *from, const SDL_Rect *rect,
-                     struct size frame_size, struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
-
-    if (!convert_mouse_action(from->type, &to->inject_touch_event.action)) {
-        return false;
-    }
-
-    int32_t x = from->x;
-    int32_t y = from->y;
-    map_coords(&x, &y, rect, frame_size);
-
-    to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
-    to->inject_touch_event.position.screen_size = frame_size;
-    to->inject_touch_event.position.point.x = x;
-    to->inject_touch_event.position.point.y = y;
-    to->inject_touch_event.pressure = 1.f;
-    to->inject_touch_event.buttons =
-        convert_mouse_buttons(SDL_BUTTON(from->button));
-
-    return true;
-}
-
-bool
-convert_mouse_motion(const SDL_MouseMotionEvent *from, const SDL_Rect *rect,
-                     struct size frame_size, struct control_msg *to) {
-    int32_t x = from->x;
-    int32_t y = from->y;
-    map_coords(&x, &y, rect, frame_size);
-
-    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
-    to->inject_touch_event.action = AMOTION_EVENT_ACTION_MOVE;
-    to->inject_touch_event.pointer_id = POINTER_ID_MOUSE;
-    to->inject_touch_event.position.screen_size = frame_size;
-    to->inject_touch_event.position.point.x = x;
-    to->inject_touch_event.position.point.y = y;
-    to->inject_touch_event.pressure = 1.f;
-    to->inject_touch_event.buttons = convert_mouse_buttons(from->state);
-
-    return true;
-}
-
-static bool
 convert_touch_action(SDL_EventType from, enum android_motionevent_action *to) {
     switch (from) {
         MAP(SDL_FINGERMOTION, AMOTION_EVENT_ACTION_MOVE);
@@ -235,40 +167,3 @@ convert_touch_action(SDL_EventType from, enum android_motionevent_action *to) {
         FAIL;
     }
 }
-
-bool
-convert_touch(const SDL_TouchFingerEvent *from, struct size screen_size,
-              struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
-
-    if (!convert_touch_action(from->type, &to->inject_touch_event.action)) {
-        return false;
-    }
-
-    to->inject_touch_event.pointer_id = from->fingerId;
-    to->inject_touch_event.position.screen_size = screen_size;
-    // SDL touch event coordinates are normalized in the range [0; 1]
-    to->inject_touch_event.position.point.x = from->x * screen_size.width;
-    to->inject_touch_event.position.point.y = from->y * screen_size.height;
-    to->inject_touch_event.pressure = from->pressure;
-    to->inject_touch_event.buttons = 0;
-    return true;
-}
-
-bool
-convert_mouse_wheel(const SDL_MouseWheelEvent *from, struct position position,
-                    struct control_msg *to) {
-    to->type = CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT;
-
-    // TODO map coords
-    to->inject_scroll_event.position = position;
-
-    int mul = from->direction == SDL_MOUSEWHEEL_NORMAL ? 1 : -1;
-    // SDL behavior seems inconsistent between horizontal and vertical scrolling
-    // so reverse the horizontal
-    // <https://wiki.libsdl.org/SDL_MouseWheelEvent#Remarks>
-    to->inject_scroll_event.hscroll = -mul * from->x;
-    to->inject_scroll_event.vscroll = mul * from->y;
-
-    return true;
-}

app/src/event_converter.h

@@ -7,36 +7,22 @@
 #include "config.h"
 #include "control_msg.h"
 
-struct complete_mouse_motion_event {
-    SDL_MouseMotionEvent *mouse_motion_event;
-    struct size screen_size;
-};
+bool
+convert_keycode_action(SDL_EventType from, enum android_keyevent_action *to);
 
-struct complete_mouse_wheel_event {
-    SDL_MouseWheelEvent *mouse_wheel_event;
-    struct point position;
-};
+enum android_metastate
+convert_meta_state(SDL_Keymod mod);
 
 bool
-convert_input_key(const SDL_KeyboardEvent *from, struct control_msg *to);
+convert_keycode(SDL_Keycode from, enum android_keycode *to, uint16_t mod);
+
+enum android_motionevent_buttons
+convert_mouse_buttons(uint32_t state);
 
 bool
-convert_mouse_button(const SDL_MouseButtonEvent *from, const SDL_Rect *rect,
-                     struct size frame_size, struct control_msg *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
-bool
-convert_mouse_motion(const SDL_MouseMotionEvent *from, const SDL_Rect *rect,
-                     struct size frame_size, struct control_msg *to);
+convert_mouse_action(SDL_EventType from, enum android_motionevent_action *to);
 
 bool
-convert_touch(const SDL_TouchFingerEvent *from, struct size screen_size,
-              struct control_msg *to);
-
-// on Android, a scroll event requires the current mouse position
-bool
-convert_mouse_wheel(const SDL_MouseWheelEvent *from, struct position position,
-                    struct control_msg *to);
+convert_touch_action(SDL_EventType from, enum android_motionevent_action *to);
 
 #endif

app/src/input_manager.c

@@ -7,33 +7,6 @@
 #include "lock_util.h"
 #include "log.h"
 
-// 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 x;
-    int y;
-    SDL_GetMouseState(&x, &y);
-    convert_to_renderer_coordinates(screen->renderer, &x, &y);
-    return (struct point) {
-        .x = x,
-        .y = y,
-    };
-}
-
 static const int ACTION_DOWN = 1;
 static const int ACTION_UP = 1 << 1;
 
@@ -212,7 +185,7 @@ clipboard_paste(struct controller *controller) {
 }
 
 void
-input_manager_process_text_input(struct input_manager *input_manager,
+input_manager_process_text_input(struct input_manager *im,
                                  const SDL_TextInputEvent *event) {
     char c = event->text[0];
     if (isalpha(c) || c == ' ') {
@@ -227,14 +200,32 @@ input_manager_process_text_input(struct input_manager *input_manager,
         LOGW("Could not strdup input text");
         return;
     }
-    if (!controller_push_msg(input_manager->controller, &msg)) {
+    if (!controller_push_msg(im->controller, &msg)) {
         SDL_free(msg.inject_text.text);
         LOGW("Could not request 'inject text'");
     }
 }
 
+static bool
+convert_input_key(const SDL_KeyboardEvent *from, struct control_msg *to) {
+    to->type = CONTROL_MSG_TYPE_INJECT_KEYCODE;
+
+    if (!convert_keycode_action(from->type, &to->inject_keycode.action)) {
+        return false;
+    }
+
+    uint16_t mod = from->keysym.mod;
+    if (!convert_keycode(from->keysym.sym, &to->inject_keycode.keycode, mod)) {
+        return false;
+    }
+
+    to->inject_keycode.metastate = convert_meta_state(mod);
+
+    return true;
+}
+
 void
-input_manager_process_key(struct input_manager *input_manager,
+input_manager_process_key(struct input_manager *im,
                           const SDL_KeyboardEvent *event,
                           bool control) {
     // control: indicates the state of the command-line option --no-control
@@ -261,7 +252,7 @@ input_manager_process_key(struct input_manager *input_manager,
         return;
     }
 
-    struct controller *controller = input_manager->controller;
+    struct controller *controller = im->controller;
 
     // capture all Ctrl events
     if (ctrl || cmd) {
@@ -336,23 +327,23 @@ input_manager_process_key(struct input_manager *input_manager,
                 return;
             case SDLK_f:
                 if (!shift && cmd && !repeat && down) {
-                    screen_switch_fullscreen(input_manager->screen);
+                    screen_switch_fullscreen(im->screen);
                 }
                 return;
             case SDLK_x:
                 if (!shift && cmd && !repeat && down) {
-                    screen_resize_to_fit(input_manager->screen);
+                    screen_resize_to_fit(im->screen);
                 }
                 return;
             case SDLK_g:
                 if (!shift && cmd && !repeat && down) {
-                    screen_resize_to_pixel_perfect(input_manager->screen);
+                    screen_resize_to_pixel_perfect(im->screen);
                 }
                 return;
             case SDLK_i:
                 if (!shift && cmd && !repeat && down) {
                     struct fps_counter *fps_counter =
-                        input_manager->video_buffer->fps_counter;
+                        im->video_buffer->fps_counter;
                     switch_fps_counter_state(fps_counter);
                 }
                 return;
@@ -382,8 +373,23 @@ input_manager_process_key(struct input_manager *input_manager,
     }
 }
 
+static bool
+convert_mouse_motion(const SDL_MouseMotionEvent *from, struct screen *screen,
+                     struct control_msg *to) {
+    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
+    to->inject_touch_event.action = AMOTION_EVENT_ACTION_MOVE;
+    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 =
+        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);
+
+    return true;
+}
+
 void
-input_manager_process_mouse_motion(struct input_manager *input_manager,
+input_manager_process_mouse_motion(struct input_manager *im,
                                    const SDL_MouseMotionEvent *event) {
     if (!event->state) {
         // do not send motion events when no button is pressed
@@ -394,33 +400,76 @@ input_manager_process_mouse_motion(struct input_manager *input_manager,
         return;
     }
     struct control_msg msg;
-    if (convert_mouse_motion(event, &input_manager->screen->rect, input_manager->screen->frame_size, &msg)) {
-        if (!controller_push_msg(input_manager->controller, &msg)) {
+    if (convert_mouse_motion(event, im->screen, &msg)) {
+        if (!controller_push_msg(im->controller, &msg)) {
             LOGW("Could not request 'inject mouse motion event'");
         }
     }
 }
 
+static bool
+convert_touch(const SDL_TouchFingerEvent *from, struct screen *screen,
+              struct control_msg *to) {
+    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
+
+    if (!convert_touch_action(from->type, &to->inject_touch_event.action)) {
+        return false;
+    }
+
+    struct size frame_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.pointer_id = from->fingerId;
+    to->inject_touch_event.position.screen_size = frame_size;
+    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;
+}
+
 void
-input_manager_process_touch(struct input_manager *input_manager,
+input_manager_process_touch(struct input_manager *im,
                             const SDL_TouchFingerEvent *event) {
     struct control_msg msg;
-    if (convert_touch(event, input_manager->screen->frame_size, &msg)) {
-        if (!controller_push_msg(input_manager->controller, &msg)) {
+    if (convert_touch(event, im->screen, &msg)) {
+        if (!controller_push_msg(im->controller, &msg)) {
             LOGW("Could not request 'inject touch event'");
         }
     }
 }
 
 static bool
-is_outside_device_screen(struct input_manager *input_manager, int x, int y)
+is_outside_device_screen(struct input_manager *im, int x, int y)
 {
-    return x < 0 || x >= input_manager->screen->frame_size.width ||
-           y < 0 || y >= input_manager->screen->frame_size.height;
+    return x < 0 || x >= im->screen->frame_size.width ||
+           y < 0 || y >= im->screen->frame_size.height;
+}
+
+static bool
+convert_mouse_button(const SDL_MouseButtonEvent *from, struct screen *screen,
+                     struct control_msg *to) {
+    to->type = CONTROL_MSG_TYPE_INJECT_TOUCH_EVENT;
+
+    if (!convert_mouse_action(from->type, &to->inject_touch_event.action)) {
+        return false;
+    }
+
+    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 =
+        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));
+
+    return true;
 }
 
 void
-input_manager_process_mouse_button(struct input_manager *input_manager,
+input_manager_process_mouse_button(struct input_manager *im,
                                    const SDL_MouseButtonEvent *event,
                                    bool control) {
     if (event->which == SDL_TOUCH_MOUSEID) {
@@ -429,19 +478,19 @@ input_manager_process_mouse_button(struct input_manager *input_manager,
     }
     if (event->type == SDL_MOUSEBUTTONDOWN) {
         if (control && event->button == SDL_BUTTON_RIGHT) {
-            press_back_or_turn_screen_on(input_manager->controller);
+            press_back_or_turn_screen_on(im->controller);
             return;
         }
         if (control && event->button == SDL_BUTTON_MIDDLE) {
-            action_home(input_manager->controller, ACTION_DOWN | ACTION_UP);
+            action_home(im->controller, ACTION_DOWN | ACTION_UP);
             return;
         }
         // double-click on black borders resize to fit the device screen
         if (event->button == SDL_BUTTON_LEFT && event->clicks == 2) {
             bool outside =
-                is_outside_device_screen(input_manager, event->x, event->y);
+                is_outside_device_screen(im, event->x, event->y);
             if (outside) {
-                screen_resize_to_fit(input_manager->screen);
+                screen_resize_to_fit(im->screen);
                 return;
             }
         }
@@ -453,23 +502,47 @@ input_manager_process_mouse_button(struct input_manager *input_manager,
     }
 
     struct control_msg msg;
-    if (convert_mouse_button(event, &input_manager->screen->rect, input_manager->screen->frame_size, &msg)) {
-        if (!controller_push_msg(input_manager->controller, &msg)) {
+    if (convert_mouse_button(event, im->screen, &msg)) {
+        if (!controller_push_msg(im->controller, &msg)) {
             LOGW("Could not request 'inject mouse button event'");
         }
     }
 }
 
-void
-input_manager_process_mouse_wheel(struct input_manager *input_manager,
-                                  const SDL_MouseWheelEvent *event) {
+static bool
+convert_mouse_wheel(const SDL_MouseWheelEvent *from, struct screen *screen,
+                    struct control_msg *to) {
+
+    // mouse_x and mouse_y are expressed in pixels relatice to the window
+    int mouse_x;
+    int mouse_y;
+    SDL_GetMouseState(&mouse_x, &mouse_y);
+
     struct position position = {
-        .screen_size = input_manager->screen->frame_size,
-        .point = get_mouse_point(input_manager->screen),
+        .screen_size = screen->frame_size,
+        .point = screen_convert_to_frame_coords(screen, mouse_x, mouse_y),
     };
+
+    to->type = CONTROL_MSG_TYPE_INJECT_SCROLL_EVENT;
+
+    to->inject_scroll_event.position = position;
+
+    int mul = from->direction == SDL_MOUSEWHEEL_NORMAL ? 1 : -1;
+    // SDL behavior seems inconsistent between horizontal and vertical scrolling
+    // so reverse the horizontal
+    // <https://wiki.libsdl.org/SDL_MouseWheelEvent#Remarks>
+    to->inject_scroll_event.hscroll = -mul * from->x;
+    to->inject_scroll_event.vscroll = mul * from->y;
+
+    return true;
+}
+
+void
+input_manager_process_mouse_wheel(struct input_manager *im,
+                                  const SDL_MouseWheelEvent *event) {
     struct control_msg msg;
-    if (convert_mouse_wheel(event, position, &msg)) {
-        if (!controller_push_msg(input_manager->controller, &msg)) {
+    if (convert_mouse_wheel(event, im->screen, &msg)) {
+        if (!controller_push_msg(im->controller, &msg)) {
             LOGW("Could not request 'inject mouse wheel event'");
         }
     }

app/src/input_manager.h

@@ -17,29 +17,29 @@ struct input_manager {
 };
 
 void
-input_manager_process_text_input(struct input_manager *input_manager,
+input_manager_process_text_input(struct input_manager *im,
                                  const SDL_TextInputEvent *event);
 
 void
-input_manager_process_key(struct input_manager *input_manager,
+input_manager_process_key(struct input_manager *im,
                           const SDL_KeyboardEvent *event,
                           bool control);
 
 void
-input_manager_process_mouse_motion(struct input_manager *input_manager,
+input_manager_process_mouse_motion(struct input_manager *im,
                                    const SDL_MouseMotionEvent *event);
 
 void
-input_manager_process_touch(struct input_manager *input_manager,
+input_manager_process_touch(struct input_manager *im,
                             const SDL_TouchFingerEvent *event);
 
 void
-input_manager_process_mouse_button(struct input_manager *input_manager,
+input_manager_process_mouse_button(struct input_manager *im,
                                    const SDL_MouseButtonEvent *event,
                                    bool control);
 
 void
-input_manager_process_mouse_wheel(struct input_manager *input_manager,
+input_manager_process_mouse_wheel(struct input_manager *im,
                                   const SDL_MouseWheelEvent *event);
 
 #endif

app/src/scrcpy.c

@@ -148,7 +148,7 @@ handle_event(SDL_Event *event, bool control) {
                     screen_render(&screen);
                     break;
                 case SDL_WINDOWEVENT_SIZE_CHANGED:
-                    screen_resized(&screen);
+                    screen_window_resized(&screen);
                     break;
             }
             break;

app/src/screen.c

@@ -16,7 +16,7 @@
 
 // get the window size in a struct size
 static struct size
-get_native_window_size(SDL_Window *window) {
+get_window_size(SDL_Window *window) {
     int width;
     int height;
     SDL_GetWindowSize(window, &width, &height);
@@ -29,11 +29,11 @@ get_native_window_size(SDL_Window *window) {
 
 // get the windowed window size
 static struct size
-get_window_size(const struct screen *screen) {
+get_windowed_window_size(const struct screen *screen) {
     if (screen->fullscreen) {
         return screen->windowed_window_size;
     }
-    return get_native_window_size(screen->window);
+    return get_window_size(screen->window);
 }
 
 // set the window size to be applied when fullscreen is disabled
@@ -112,8 +112,8 @@ get_optimal_size(struct size current_size, struct size frame_size) {
 // same as get_optimal_size(), but read the current size from the window
 static inline struct size
 get_optimal_window_size(const struct screen *screen, struct size frame_size) {
-    struct size current_size = get_window_size(screen);
-    return get_optimal_size(current_size, frame_size);
+    struct size windowed_size = get_windowed_window_size(screen);
+    return get_optimal_size(windowed_size, frame_size);
 }
 
 // initially, there is no current size, so use the frame size as current size
@@ -124,11 +124,11 @@ get_initial_optimal_size(struct size frame_size) {
 
 static void
 update_frame_rect(struct screen *screen) {
-    struct size window_size = get_window_size(screen);
+    int ww;
+    int wh;
+    SDL_GL_GetDrawableSize(screen->window, &ww, &wh);
 
     // 32 bits because we need to multiply two 16 bits values
-    uint32_t ww = window_size.width;
-    uint32_t wh = window_size.height;
     uint32_t fw = screen->frame_size.width;
     uint32_t fh = screen->frame_size.height;
 
@@ -242,11 +242,11 @@ prepare_for_frame(struct screen *screen, struct size new_frame_size) {
         // frame dimension changed, destroy texture
         SDL_DestroyTexture(screen->texture);
 
-        struct size current_size = get_window_size(screen);
+        struct size windowed_size = get_windowed_window_size(screen);
         struct size target_size = {
-            (uint32_t) current_size.width * new_frame_size.width
+            (uint32_t) windowed_size.width * new_frame_size.width
                     / screen->frame_size.width,
-            (uint32_t) current_size.height * new_frame_size.height
+            (uint32_t) windowed_size.height * new_frame_size.height
                     / screen->frame_size.height,
         };
         target_size = get_optimal_size(target_size, new_frame_size);
@@ -293,7 +293,7 @@ screen_update_frame(struct screen *screen, struct video_buffer *vb) {
 }
 
 void
-screen_resized(struct screen *screen) {
+screen_window_resized(struct screen *screen) {
     update_frame_rect(screen);
     screen_render(screen);
 }
@@ -309,7 +309,7 @@ void
 screen_switch_fullscreen(struct screen *screen) {
     if (!screen->fullscreen) {
         // going to fullscreen, store the current windowed window size
-        screen->windowed_window_size = get_native_window_size(screen->window);
+        screen->windowed_window_size = get_window_size(screen->window);
     }
     uint32_t new_mode = screen->fullscreen ? 0 : SDL_WINDOW_FULLSCREEN_DESKTOP;
     if (SDL_SetWindowFullscreen(screen->window, new_mode)) {
@@ -347,3 +347,11 @@ screen_resize_to_pixel_perfect(struct screen *screen) {
         LOGD("Resized to pixel-perfect");
     }
 }
+
+struct point
+screen_convert_to_frame_coords(struct screen *screen, float x, float y) {
+    struct point out;
+    out.x = (x - screen->rect.x) * screen->frame_size.width / screen->rect.w;
+    out.y = (y - screen->rect.y) * screen->frame_size.height / screen->rect.h;
+    return out;
+}

app/src/screen.h

@@ -17,7 +17,7 @@ struct screen {
     struct size frame_size;
     //used only in fullscreen mode to know the windowed window size
     struct size windowed_window_size;
-    struct SDL_Rect rect; // frame location and size inside the window
+    struct SDL_Rect rect;
     bool has_frame;
     bool fullscreen;
     bool no_window;
@@ -67,8 +67,9 @@ screen_destroy(struct screen *screen);
 bool
 screen_update_frame(struct screen *screen, struct video_buffer *vb);
 
+// update content after window resizing
 void
-screen_resized(struct screen *screen);
+screen_window_resized(struct screen *screen);
 
 // render the texture to the renderer
 void
@@ -86,4 +87,9 @@ screen_resize_to_fit(struct screen *screen);
 void
 screen_resize_to_pixel_perfect(struct screen *screen);
 
+// convert point from window coordinates to frame coordinates
+// x and y are expressed in pixels (float to allow partial pixels)
+struct point
+screen_convert_to_frame_coords(struct screen *screen, float x, float y);
+
 #endif