Add a "dynamic layout" Chapter into the first steps document

ChangeLog

@@ -1,6 +1,9 @@
+2019-02-07  Markus Gans  <guru.mail@muenster.de>
+	* Add a "dynamic layout" Chapter into the first steps document
+
 2019-01-30  Markus Gans  <guru.mail@muenster.de>
 	* Printing an FColorPair object can change the foreground and 
-	  background colors
+	  background color
 
 2019-01-27  Markus Gans  <guru.mail@muenster.de>
 	* The print command can now have an FPoint object as a parameter 

doc/first-steps.md

@@ -15,6 +15,7 @@ Table of Contents
 - [Callback function](#example-of-a-callback-function)
 - [Callback method](#example-of-a-callback-function)
 - [Custom signals](#send-custom-signals)
+- [Dynamic layout](#dynamic-layout)
 <!-- /TOC -->
 
 
@@ -287,7 +288,7 @@ class dialogWidget : public FDialog
     }
 
   private:
-    virtual void onTimer (FTimerEvent* ev)
+    virtual void onTimer (FTimerEvent* ev) override
     {
       if ( id == ev->getTimerId() && n < 9999999999 )
       {
@@ -666,4 +667,123 @@ the above program with gcc:
 ```cpp
 g++ -O2 -lfinal -std=c++11 emit-signal.cpp -o emit-signal
 ```
-The FINAL CUT widgets emit the following default signals:
+
+
+Dynamic layout
+--------------
+
+A modern terminal emulation like xterm has no fixed resolution. 
+They offer the possibility to change the height and width of the 
+terminal at any time. That triggers a resize-event that calls 
+the `adjustSize()` method. This method allows adapting the widget 
+to a changed terminal size. You can override the `adjustSize()` 
+method to adjust the size and position of the widget. The method 
+`adjustSize()` will also be called indirectly via calling methods 
+`setGeometry()`, `setX()`, `setY()`, `setPos()`, `setWidth()`, 
+`setHeight()`, `setSize()`, `setTopPadding()`, `setLeftPadding()`, 
+`setBottomPadding()`, `setRightPadding()`, or `setDoubleFlatLine()`.
+
+Scalable dialogs derived from FDialog can change the dialog size by 
+clicking on the lower right corner of the window.  You can intercept 
+a scaling action by overriding the `setSize()` method and adjusting 
+the client widgets.
+
+**File:** *size-adjustment.cpp*
+```cpp
+#include <final/final.h>
+
+using namespace finalcut;
+
+class dialogWidget : public FDialog
+{
+  public:
+    explicit dialogWidget (FWidget* parent = nullptr)
+      : FDialog(parent)
+    {
+      setText ("Dialog");
+      setResizeable();
+      btn.setGeometry (FPoint(1, 1), FSize(12, 1), false);
+      line.setGeometry (FPoint(2, 3), FSize(12, 1), false);
+      // Set dialog geometry and calling adjustSize()
+      setGeometry (FPoint(25, 5), FSize(40, 12));
+      setMinimumSize (FSize(25, 9));
+    }
+
+  private:
+    inline void checkMinValue (int& n)
+    {
+      if ( n < 1 )  // Checks and corrects the minimum value
+        n = 1;
+    }
+
+    void centerDialog()
+    {
+      auto x = int((getDesktopWidth() - getWidth()) / 2);
+      auto y = int((getDesktopHeight() - getHeight()) / 2);
+      checkMinValue(x);
+      checkMinValue(y);
+      setPos (FPoint(x, y), false);
+    }
+
+    void adjustWidgets()
+    {
+      auto bx = int(getWidth() - btn.getWidth() - 3);
+      auto by = int(getHeight() - 4);
+      btn.setPos (FPoint(bx, by), false);
+      line.setWidth (getWidth() - 4);
+      auto ly = int(getHeight() / 2) - 1;
+      line.setY (ly, false);
+    }
+
+    virtual void adjustSize() override
+    {
+      // Calling super class method adjustSize()
+      FDialog::adjustSize();
+      // Centers the dialog in the terminal
+      centerDialog();
+    }
+
+    virtual void setSize (const FSize& size, bool) override
+    {
+      // Calling super class methods setSize() + adjustSize()
+      FDialog::setSize (size, false);
+      FDialog::adjustSize();
+    }
+
+    virtual void draw() override
+    {
+      adjustWidgets();  // Adjust widgets before drawing 
+
+      // Calling super class method draw()
+      FDialog::draw();
+
+      print() << FPoint (3, 3)
+              << FColorPair (fc::Black, fc::White)
+              << "Text on "
+              << FColorPair (fc::Blue, fc::Yellow)
+              << "top";
+    }
+
+    FLineEdit line{"Middle", this};
+    FButton btn{"&Bottom", this};
+};
+
+int main (int argc, char* argv[])
+{
+  FApplication app(argc, argv);
+  dialogWidget dialog(&app);
+  app.setMainWidget(&dialog);
+  dialog.show();
+  return app.exec();
+}
+```
+*(Note: You can close the window with the mouse, 
+<kbd>Shift</kbd>+<kbd>F10</kbd> or <kbd>Ctrl</kbd>+<kbd>^</kbd>)*
+
+
+After entering the source code in *size-adjustment.cpp* you can compile
+the above program with gcc:
+```cpp
+g++ -O2 -lfinal -std=c++11 size-adjustment.cpp -o size-adjustment
+```
+

examples/calculator.cpp

@@ -1081,8 +1081,8 @@ void Calc::cb_buttonClicked (finalcut::FWidget*, FDataPtr data)
 //----------------------------------------------------------------------
 void Calc::adjustSize()
 {
-  std::size_t pw = getParentWidget()->getWidth();
+  std::size_t pw = getDesktopWidth();
-  std::size_t ph = getParentWidget()->getHeight();
+  std::size_t ph = getDesktopHeight();
   setX (1 + int(pw - getWidth()) / 2, false);
   setY (1 + int(ph - getHeight()) / 2, false);
   finalcut::FDialog::adjustSize();

examples/mandelbrot.cpp

@@ -142,8 +142,8 @@ void Mandelbrot::onClose (finalcut::FCloseEvent* ev)
 //----------------------------------------------------------------------
 void Mandelbrot::adjustSize()
 {
-  std::size_t h = getParentWidget()->getHeight() - 1;
+  std::size_t h = getDesktopHeight() - 1;
-  std::size_t w = getParentWidget()->getWidth() - 10;
+  std::size_t w = getDesktopWidth() - 10;
   setGeometry(FPoint(6, 1), FSize(w, h), false);
   finalcut::FDialog::adjustSize();
 }

examples/menu.cpp

@@ -291,8 +291,8 @@ void Menu::defaultCallback (finalcut::FMenuList* mb)
 //----------------------------------------------------------------------
 void Menu::adjustSize()
 {
-  int pw = int(getParentWidget()->getWidth());
+  int pw = int(getDesktopWidth());
-  int ph = int(getParentWidget()->getHeight());
+  int ph = int(getDesktopHeight());
   setX (1 + (pw - int(getWidth())) / 2, false);
   setY (1 + (ph - int(getHeight())) / 4, false);
   finalcut::FDialog::adjustSize();

examples/term-attributes.cpp

@@ -173,8 +173,8 @@ void AttribDlg::cb_back (finalcut::FWidget*, FDataPtr)
 //----------------------------------------------------------------------
 void AttribDlg::adjustSize()
 {
-  int x = int((getParentWidget()->getWidth() - getWidth()) / 2);
+  int x = int((getDesktopWidth() - getWidth()) / 2);
-  int y = int((getParentWidget()->getHeight() - getHeight()) / 2) + 1;
+  int y = int((getDesktopHeight() - getHeight()) / 2) + 1;
 
   if ( x < 1 )
     x = 1;

examples/treeview.cpp

@@ -381,9 +381,9 @@ Treeview::~Treeview()  // destructor
 //----------------------------------------------------------------------
 void Treeview::adjustSize()
 {
-  std::size_t h = getParentWidget()->getHeight() - 4;
+  std::size_t h = getDesktopHeight() - 4;
   setHeight (h, false);
-  int X = int((getParentWidget()->getWidth() - getWidth()) / 2);
+  int X = int((getDesktopWidth() - getWidth()) / 2);
 
   if ( X < 1 )
     X = 1;

examples/ui.cpp

@@ -745,7 +745,7 @@ void MyDialog::adjustSize()
 {
   auto h = getParentWidget()->getHeight() - 4;
   setHeight (h, false);
-  auto X = int((getParentWidget()->getWidth() - getWidth()) / 2);
+  auto X = int((getDesktopWidth() - getWidth()) / 2);
 
   if ( X < 1 )
     X = 1;

examples/windows.cpp

@@ -346,8 +346,8 @@ void Window::activateWindow (finalcut::FDialog* win)
 //----------------------------------------------------------------------
 void Window::adjustSize()
 {
-  std::size_t w  = getRootWidget()->getWidth();
+  std::size_t w  = getDesktopWidth();
-  std::size_t h  = getRootWidget()->getHeight();
+  std::size_t h  = getDesktopHeight();
   int X  = int(1 + (w - 40) / 2)
     , Y  = int(1 + (h - 22) / 2)
     , dx = ( w > 80 ) ? int(w - 80) / 2 : 0

src/fwindow.cpp

@@ -388,9 +388,8 @@ void FWindow::setGeometry ( const FPoint& p, const FSize& size, bool adjust)
 
   int old_x = getX();
   int old_y = getY();
-  std::size_t old_width = getWidth();
-  std::size_t old_height = getHeight();
   FPoint pos = p;
+  FSize old_size = getSize();
 
   if ( pos.getY() < 1 )
     pos.setY(1);
@@ -400,7 +399,7 @@ void FWindow::setGeometry ( const FPoint& p, const FSize& size, bool adjust)
   if ( ! isVirtualWindow() )
     return;
 
-  if ( getWidth() != old_width || getHeight() != old_height )
+  if ( getSize() != old_size )
   {
     FRect geometry = getTermGeometry();
     geometry.move(-1, -1);