Maintain window position and size when re-created

Eliminates a UI oddity on Windows when cycling through backends.

BUG=skia:

Change-Id: I83f0325054def80bb9b6e5a9886461f8aad215ae
Reviewed-on: https://skia-review.googlesource.com/9453
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

2 files changed, 19 insertions, 2 deletions

diff --git a/tools/viewer/sk_app/win/Window_win.cpp b/tools/viewer/sk_app/win/Window_win.cpp
index d603a1439d..9614d71c21 100644
--- a/tools/viewer/sk_app/win/Window_win.cpp
+++ b/tools/viewer/sk_app/win/Window_win.cpp
@@ -19,6 +19,11 @@
 
 namespace sk_app {
 
+static int gWindowX = CW_USEDEFAULT;
+static int gWindowY = 0;
+static int gWindowWidth = CW_USEDEFAULT;
+static int gWindowHeight = 0;
+
 Window* Window::CreateNativeWindow(void* platformData) {
     HINSTANCE hInstance = (HINSTANCE)platformData;
 
@@ -31,6 +36,17 @@ Window* Window::CreateNativeWindow(void* platformData) {
     return window;
 }
 
+Window_win::~Window_win() {
+    RECT r;
+    if (GetWindowRect(fHWnd, &r)) {
+        gWindowX = r.left;
+        gWindowY = r.top;
+        gWindowWidth = r.right - r.left;
+        gWindowHeight = r.bottom - r.top;
+    }
+    DestroyWindow(fHWnd);
+}
+
 LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
 
 
@@ -85,7 +101,8 @@ bool Window_win::init(HINSTANCE hInstance) {
  //   gIsFullscreen = fullscreen;
 
     fHWnd = CreateWindow(gSZWindowClass, nullptr, WS_OVERLAPPEDWINDOW,
-                         CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, fHInstance, nullptr);
+                         gWindowX, gWindowY, gWindowWidth, gWindowHeight,
+                         nullptr, nullptr, fHInstance, nullptr);
     if (!fHWnd)
     {
         return false;
diff --git a/tools/viewer/sk_app/win/Window_win.h b/tools/viewer/sk_app/win/Window_win.h
index 0c51304a81..6d2279393a 100644
--- a/tools/viewer/sk_app/win/Window_win.h
+++ b/tools/viewer/sk_app/win/Window_win.h
@@ -16,7 +16,7 @@ namespace sk_app {
 class Window_win : public Window {
 public:
     Window_win() : Window() {}
-    ~Window_win() override { DestroyWindow(fHWnd); }
+    ~Window_win() override;
 
     bool init(HINSTANCE instance);