Recompute property browser viewport on resize.

Before this commit, resizing the property browser would cut off
the rows at the bottom, or else add black space, until next refresh.

This could be perhaps more elegantly done by adding an onResize event
but given that each of them would be followed by onRender anyway, it
seems there's no benefit to adding onResize.

src/textwin.cpp

@@ -563,7 +563,11 @@ void TextWindow::Show() {
         }
     }
 
-    if(window) {
+    if(window) Resize();
+}
+
+void TextWindow::Resize()
+{
     double width, height;
     window->GetContentSize(&width, &height);
 
@@ -578,7 +582,6 @@ void TextWindow::Show() {
     window->SetScrollbarVisible(top[rows - 1] + 1 > halfRows);
     window->Invalidate();
 }
-}
 
 void TextWindow::DrawOrHitTestIcons(UiCanvas *uiCanvas, TextWindow::DrawOrHitHow how,
                                     double mx, double my)
@@ -909,6 +912,8 @@ void TextWindow::Paint() {
 
     double width, height;
     window->GetContentSize(&width, &height);
+    if(halfRows != (int)height / (LINE_HEIGHT/2))
+        Resize();
 
     Camera camera = {};
     camera.width      = width;

src/ui.h

@@ -253,6 +253,7 @@ public:
     void ClearScreen();
 
     void Show();
+    void Resize();
 
     // State for the screen that we are showing in the text window.
     enum class Screen : uint32_t {