remove unnecessary reflows when adding widgets

src/Button.cpp

@@ -12,15 +12,18 @@ namespace Raven {
 void Button::set_text(std::string text) {
     m_text = text;
 
-    if (window()) {
-        fit_text(text);
+    if (!fit_text(text)) {
+        repaint();
     }
 }
 
 void Button::on_init() {
-    set_style(&default_button_style);
-    fit_text(m_text);
+    set_style_pure(&default_button_style);
+
     set_did_init(true);
+    if (!fit_text(m_text)) {
+        reflow();
+    }
 }
 
 void Button::on_paint() {

src/Label.cpp

@@ -9,15 +9,18 @@ namespace Raven {
 void Label::set_text(std::string text) {
     m_text = text;
 
-    if (window()) {
-        fit_text(text);
+    if (!fit_text(text)) {
+        repaint();
     }
 }
 
 void Label::on_init() {
-    set_style(&default_label_style);
-    fit_text(m_text);
+    set_style_pure(&default_label_style);
+
     set_did_init(true);
+    if (!fit_text(m_text)) {
+        reflow();
+    }
 } 
 
 void Label::on_paint() {

src/Widget.cpp

@@ -17,15 +17,12 @@ Point Widget::compute_window_relative() {
     return point;
 }
 
-void Widget::fit_text(std::string &text) {
+bool Widget::fit_text(std::string &text) {
     if (!window())
-        return;
+        return false;
 
     auto size = window()->painter().compute_text_size(rect(), text, style()->font_description());
-    // always repaint, even if resize doesn't reflow
-    if (!resize(size)) {
-        repaint();
-    }
+    return resize(size);
 }
 
 bool Widget::resize(double width, double height) {
@@ -89,10 +86,10 @@ bool Widget::add_child(std::shared_ptr<Widget> child) {
     child->set_parent(this);
 
     // children inherit the window from the parent
-    // TODO?: what happens when the parent changes its window?
+    // NOTE: we're no longer calling reflow() in this function, as we'll rely on the child widget to reflow
+    // after we call set_window() on it.
     child->set_window(m_window);
 
-    reflow();
     return true;
 }
 

src/Widget.hpp

@@ -44,7 +44,7 @@ public:
 
     std::function<void(Event&)> on_event { [](Event&){} };
 
-    void fit_text(std::string &text); 
+    bool fit_text(std::string &text); 
 
     void move_to(double x, double y);
     bool resize(double width, double height);
@@ -57,7 +57,7 @@ public:
 
     Box &rect() { return m_rect; }
     void set_rect(Box rect) { m_rect = rect; reflow(); }
-    void set_rect(Box rect, bool is_pure) { m_rect = rect; if (!is_pure) { reflow(); } }
+    void set_rect_pure(Box rect) { m_rect = rect; }
 
     Point &window_relative() { return m_window_relative; };
 
@@ -72,6 +72,7 @@ public:
 
     GenericStyle *style() { return m_style; }
     void set_style(GenericStyle *style) { m_style = style; reflow(); }
+    void set_style_pure(GenericStyle *style) { m_style = style; }
 
     bool did_init() { return m_did_init; }
     bool is_focused() { return m_is_focused; }
@@ -107,7 +108,7 @@ public:
 protected:
     WidgetType m_type { WidgetType::Widget };
 
-    virtual void on_init() { set_did_init(true); }
+    virtual void on_init() { set_did_init(true); reflow(); }
     virtual void on_mouse_button(MouseButtonEvent &event) {}
     virtual void on_mouse_move(MouseMoveEvent &event) {}
     virtual void on_focus_update(FocusUpdateEvent &event) {}