From beb524b97fddc04ca7d52d647aab0dcd16d29cdb Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Thu, 7 May 2020 15:53:27 +0200
Subject: [PATCH] fix resize_to_fit scaling

---
 app/src/input_manager.c |  5 +++--
 app/src/screen.c        | 23 +++++++++++++----------
 app/src/screen.h        |  7 +++++++
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/app/src/input_manager.c b/app/src/input_manager.c
index 1bb32920..e8c8d68e 100644
--- a/app/src/input_manager.c
+++ b/app/src/input_manager.c
@@ -527,8 +527,9 @@ input_manager_process_mouse_button(struct input_manager *im,
 
         // double-click on black borders resize to fit the device screen
         if (event->button == SDL_BUTTON_LEFT && event->clicks == 2) {
-            int x = event->x;
-            int y = event->y;
+            int32_t x = event->x;
+            int32_t y = event->y;
+            screen_hidpi_scale_coords(im->screen, &x, &y);
             SDL_Rect *r = &im->screen->rect;
             bool outside = x < r->x || x >= r->x + r->w
                         || y < r->y || y >= r->y + r->h;
diff --git a/app/src/screen.c b/app/src/screen.c
index 51e7a082..efa6c9ff 100644
--- a/app/src/screen.c
+++ b/app/src/screen.c
@@ -611,16 +611,7 @@ screen_convert_to_frame_coords(struct screen *screen, int32_t x, int32_t y) {
     int32_t w = screen->content_size.width;
     int32_t h = screen->content_size.height;
 
-    // take the HiDPI scaling (dw/ww and dh/wh) into account
-    int ww, wh, dw, dh;
-    SDL_GetWindowSize(screen->window, &ww, &wh);
-    SDL_GL_GetDrawableSize(screen->window, &dw, &dh);
-
-    LOGI("window_size = %dx%d, drawable_size = %dx%d", ww, wh, dw, dh);
-
-    // scale for HiDPI (64 bits for intermediate multiplications)
-    x = (int64_t) x * dw / ww;
-    y = (int64_t) y * dh / wh;
+    screen_hidpi_scale_coords(screen, &x, &y);
 
     x = (int64_t) (x - screen->rect.x) * w / screen->rect.w;
     y = (int64_t) (y - screen->rect.y) * h / screen->rect.h;
@@ -653,3 +644,15 @@ screen_convert_to_frame_coords(struct screen *screen, int32_t x, int32_t y) {
     }
     return result;
 }
+
+void
+screen_hidpi_scale_coords(struct screen *screen, int32_t *x, int32_t *y) {
+    // take the HiDPI scaling (dw/ww and dh/wh) into account
+    int ww, wh, dw, dh;
+    SDL_GetWindowSize(screen->window, &ww, &wh);
+    SDL_GL_GetDrawableSize(screen->window, &dw, &dh);
+
+    // scale for HiDPI (64 bits for intermediate multiplications)
+    *x = (int64_t) *x * dw / ww;
+    *y = (int64_t) *y * dh / wh;
+}
diff --git a/app/src/screen.h b/app/src/screen.h
index 89cefd9e..17fd2477 100644
--- a/app/src/screen.h
+++ b/app/src/screen.h
@@ -127,4 +127,11 @@ screen_handle_window_event(struct screen *screen, const SDL_WindowEvent *event);
 struct point
 screen_convert_to_frame_coords(struct screen *screen, int32_t x, int32_t y);
 
+// Convert coordinates from window to drawable.
+// Events are expressed in window coordinates, but content is expressed in
+// drawable coordinates. They are the same if HiDPI scaling is 1, but differ
+// otherwise.
+void
+screen_hidpi_scale_coords(struct screen *screen, int32_t *x, int32_t *y);
+
 #endif