Fix re locating window after a guiscale change

src/app/ini_file.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2021  Igara Studio S.A.
+// Copyright (C) 2018-2023  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -259,6 +259,30 @@ void set_config_rect(const char* section, const char* name, const Rect& rect)
   set_config_string(section, name, buf);
 }
 
+RectT<float> get_config_rectf(const char* section, const char* name, const RectT<float>& rect)
+{
+  RectT<float> rect2(rect);
+  const char* value = get_config_string(section, name, "");
+  if (value) {
+    std::vector<std::string> parts;
+    base::split_string(value, parts, " ");
+    if (parts.size() == 4) {
+      rect2.x = strtof(parts[0].c_str(), NULL);
+      rect2.y = strtof(parts[1].c_str(), NULL);
+      rect2.w = strtof(parts[2].c_str(), NULL);
+      rect2.h = strtof(parts[3].c_str(), NULL);
+    }
+  }
+  return rect2;
+}
+
+void set_config_rectf(const char* section, const char* name, const RectT<float>& rect)
+{
+  char buf[128];
+  sprintf(buf, "%f %f %f %f", rect.x, rect.y, rect.w, rect.h);
+  set_config_string(section, name, buf);
+}
+
 app::Color get_config_color(const char* section, const char* name, const app::Color& value)
 {
   return app::Color::fromString(get_config_string(section, name, value.toString().c_str()));

src/app/ini_file.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2019  Igara Studio S.A.
+// Copyright (C) 2018-2023  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -54,6 +54,9 @@ namespace app {
   gfx::Rect get_config_rect(const char* section, const char* name, const gfx::Rect& rect);
   void set_config_rect(const char* section, const char* name, const gfx::Rect& rect);
 
+  gfx::RectT<float> get_config_rectf(const char* section, const char* name, const gfx::RectT<float>& rect);
+  void set_config_rectf(const char* section, const char* name, const gfx::RectT<float>& rect);
+
   app::Color get_config_color(const char* section, const char* name, const app::Color& value);
   void set_config_color(const char* section, const char* name, const app::Color& value);
 

src/app/modules/gui.cpp

@@ -432,21 +432,31 @@ void load_window_pos(Window* window, const char* section,
   window->setBounds(pos);
 
   if (get_multiple_displays()) {
-    // First try to read the new "WindowFrameUnscaled" field (which is unscaled)
-    Rect frame = get_config_rect(section, "WindowFrameUnscaled", gfx::Rect());
+    // First try to read the "WindowFrameNormalized" field
+    // Meaning =
+    //   x: per unit X center position on screen of the window (0.0 -> 1.0).
+    //   y: per unit Y position on screen of the window (0.0 -> 1.0).
+    //   w: unscaled window width in pixels.
+    //   x: unscaled window height in pixels.
+    const os::Window* mainNativeWindow = manager->display()->nativeWindow();
+    int scale = mainNativeWindow->scale() * guiscale();
+    RectT<float> frame = get_config_rectf(section, "WindowFrameNormalized", gfx::RectT<float>());
     if (!frame.isEmpty()) {
-      // Scale the window size with the UI scaling factor.
-      frame.w *= guiscale();
-      frame.h *= guiscale();
+      // De-normalization of the position and size of the window frame.
+      frame.x = float(workarea.w) * frame.x - frame.w * scale / 2;
+      frame.y = float(workarea.h) * frame.y - frame.h * scale / 2;
+      frame.w *= scale;
+      frame.h *= scale;
     }
     // If it's empty read the backward compatible "WindowFrame" field (which is
     // already scaled with UI scaling)
     else {
       frame = get_config_rect(section, "WindowFrame", gfx::Rect());
     }
     if (!frame.isEmpty()) {
-      limit_with_workarea(parentDisplay, frame);
-      window->loadNativeFrame(frame);
+      Rect rect(frame);
+      limit_with_workarea(parentDisplay, rect);
+      window->loadNativeFrame(rect);
     }
   }
   else {
@@ -456,25 +466,39 @@ void load_window_pos(Window* window, const char* section,
 
 void save_window_pos(Window* window, const char* section)
 {
-  gfx::Rect rc;
+  gfx::RectT<float> rc;
 
-  if (!window->lastNativeFrame().isEmpty()) {
-    const os::Window* mainNativeWindow = manager->display()->nativeWindow();
+  if (get_multiple_displays() &&
+      !window->lastNativeFrame().isEmpty()) {
     rc = window->lastNativeFrame();
     set_config_rect(section, "WindowFrame", rc);
+
+    Display* parentDisplay =
+      (window->display() ? window->display():
+                           window->manager()->display());
+    Rect workarea =
+      (get_multiple_displays() ?
+       parentDisplay->nativeWindow()->screen()->workarea():
+       parentDisplay->bounds());
+    const os::Window* mainNativeWindow = manager->display()->nativeWindow();
+    int scale = mainNativeWindow->scale() * guiscale();
+    // Meaning of 'rcNormalized':
+    //   x: per unit X center position on screen of the window (0.0 -> 1.0).
+    //   y: per unit Y position on screen of the window (0.0 -> 1.0).
+    //   w: unscaled window width in pixels.
+    //   x: unscaled window height in pixels.
+    RectT<float> rcNormalized((rc.x + rc.w/2 ) / float(workarea.w),
+                              (rc.y + rc.h/2 ) / float(workarea.h),
+                              rc.w / scale,
+                              rc.h / scale);
     // De-scale the window size to save it normalized.
-    rc.w /= guiscale();
-    rc.h /= guiscale();
-    set_config_rect(section, "WindowFrameUnscaled", rc);
+    set_config_rectf(section, "WindowFrameNormalized", rcNormalized);
     rc.offset(-mainNativeWindow->frame().origin());
-    rc /= mainNativeWindow->scale();
+    rc /= scale;
   }
   else {
     del_config_value(section, "WindowFrame");
     rc = window->bounds();
-    // De-scale the window size to save it normalized.
-    rc.w /= guiscale();
-    rc.h /= guiscale();
   }
 
   set_config_rect(section, "WindowPos", rc);