CS 325

1
CS 325

• Unix Programming Environment
• and
• Windows Programming
• with Microsoft Foundation Classes (MFC)

2
Lecture 31

• Today
• Built in Dialogs
• CFileDialog
• CColorDialog

3
Projects 6 - 7

• P6 WinOthelloGold
• Ten improvements over the basic interface (not
  your basic interface over a conceptual basic
  interface P5 and P6 may be the same)
• Use a dialog (or multiple dialogs) to give the
  user control over 5 of the improvements
  (background color, piece display, etc)
• P7 WinFinalProject After Spring Break.
• Show it to me anytime after break

4
OnPaint

• Call OnPaint indirectly through one of these
  methods
• Invalidate(BOOL eraseTRUE)
• InvalidateRect(CRect paintregion, BOOL erase)
• Calling Invalidate puts an invalidate message in
  the message queue. OnPaint will not be called
  immediately.
• Void SomeMethod()
• code
• InvalidateRect(region1)
• code
• InvalidateRect(region2)
• code
• InvalidateRect(regionN)
• This results in one (1!) call to paint and its
  at some later time. The paint regions are
  magically merged.

5
Two Major Parameter Systems

• X1, Y1, X2, Y2
• (Left, Top, Right, Bottom)
• X1, Y1, W, H
• (Left, Top, Width, Height)
• CRect(l, t, r, b) gt x1,y1,x2,y2
• CRect(x,y, xW,yH)
• CRect(x,y, x100,y100)
• CRect(CPoint CPoint)
• CRect(CPoint(x,y) CPoint(xW,yH))
• CRect(CPoint(x,y) CPoint(x100,y100))
• CRect(CPoint size)
• CRect(const CRect)
• CRect(LPCRECT) gt CRect(CRect)

6
3 CFrameWnd Methods

• To find the size of the window
• GetWindowRect(CRect)
• CRect what
• GetWindowRect(what)
• //after this call, what will contain the
  coordinates for the entire Window, these
  coordinates will be in relation to the edge of
  the entire screen
• To find the size of the Client window (the white
  space)
• GetClientRect(CRect)
• CRect what
• GetClientRect(what) // what is same as above
• To resize the window
• SetWindowPos(pointer, new-left, new-top, width,
  height, flags)
• SetWindowPos(NULL, 10, 10, 300, 200, 0)
• SetWindowPos(CWND, x, y, cx, cy, FLAGS)

7
Dialogs

• Three (at least) ways to create
• Stand alone application
• Refer to our 1st example
• Embedded within application as temp object
• Declared locally to a method
• Refer to our class examples
• Embedded within application as attribute of the
  frame
• MapObjects
• Always DoModal()
• Can return a value
• Communicating with the dialog via DoDataExchange
• Called automatically when either of these
  happens
• DoModal()
• OnOK()
• UpdateData(bool)

8
DoubleBuffering (Why isnt it automatic!)

• afx_msg void CKalahFrameWndOnPaint()
• //step 1 set up a buffer
• CPaintDC paintDC(this) CDC dbufdc
• dbufdc.CreateCompatibleDC(paintDC)
• CRect screen GetClientRect(screen)
• CBitmap bmp
• bmp.CreateCompatibleBitmap(
• paintDC, screen.Width(), screen.Height() )
• dbufdc.SelectObject(bmp)
• //step2 draw on dbbufdc
• dbbuddc.TextOut()
• dbbufdc.FillRect(CRect(x,y,xw, yh), pBrush)
• //step3 copy buffer to screen
• paintDC.BitBlt(0, 0, screen.Width(),
  screen.Height(),
• dbufdc, 0, 0, SRCCOPY )

9
Common Errors What causes?

• Using wrong menu or dialog name
• Program will crash on startup
• Make sure you match the name specified in RC
• Calling create twice -- Assertion error
• CBrush b new CBrush()
• b-gtcreateSolidBrush(RED)
• b-gtcreateSolidBrush(BLUE)
• Calling create twice -- Assertion error
• CBrush b new CBrush(RED)
• b-gtcreateSolidBrush(BLUE)

10
Existing (useful) components

• Common Dialog boxes
• Open file, print file, etc.
• Should be able to easily use existing common
  dialog boxes within your code
• CDialog class has a subclass CCommonDialog
• CCommonDialog contains
• CFileDialog, CColorDialog, CPrintDialog,
• Also have CPageSetupDialog, CFontDialog,
  CFindReplaceDialog (will not look at these)
• These all require include ltafxdlgs.hgt

11
Example using CFileDialog

• Our sample program
• Uses the standard windows open file dialog
• Opens a window, each left mouse click allows the
  user to select a file
• After selection (dialog box closes), pop up a
  MessageBox that displays the selected file

12
Example Header

• include ltafxwin.hgt
• include ltafxdlgs.hgt
• class CFileOpenWin public CFrameWnd
• public
• CFileOpenWin( )
• afx_msg void OnLButtonDown (UINT, CPoint)
• private
• DECLARE_MESSAGE_MAP( )

• Need one extra include file (afxdlgs.h)
• Standard header
• Handle only one event
• Left mouse click

13
Example body (part 1)

• include "main.h"
• CFileOpenWinCFileOpenWin() Create(NULL, "File
  Open Example", WS_OVERLAPPEDWINDOW,CRect(100,100,
  500,500))
• afx_msg void CFileOpenWinOnLButtonDown (UINT
  flags, CPoint p)
• CFileDialog myFile(TRUE)
• myFile.DoModal( )
• char text32
• strcpy(text, myFile.GetFileName( ) )
• MessageBox(text, "file")

• Nothing different in constructor
• OnLButtonDown
• Declare a CFileDialog object (TRUE implies
  open, FALSE implies save as)
• Invoke the dialog box via DoModal( )
• Can retrieve the filename selected via objects
  GetFileName method

14
Example body (part 2)

• BEGIN_MESSAGE_MAP (CFileOpenWin, CFrameWnd)
• ON_WM_LBUTTONDOWN( )
• END_MESSAGE_MAP( )
• class CFileOpenApp public CWinApp
• public
• BOOL InitInstance()
• m_pMainWnd new CFileOpenWin
• m_pMainWnd-gtShowWindow (m_nCmdShow)
• m_pMainWnd-gtUpdateWindow()
• return TRUE
• fileApp

• Standard message map (just handles left mouse
  clicks)
• Standard main routine
• Nothing unique or different about these routines

15
Comments on CFileDialog

• Constructor Parameters
• 1st open or save as
• 2nd default file extension (NULL unless
  specified)
• 3rd initial filename that appears in the box
  (NULL unless specified)
• 4th flags (default NULL)
• 5th filters (limit displayed files), default
  NULL
• 6th object parent (NULL)

• Data retrieval options
• GetPathName( )
• GetFileName( )
• GetFileExt( )
• GetFileTitle( )
• All return a CString (array of characters). May
  either convert to string or use old strcpy,
  strcmp, etc. routines

16
Class Exercises

• Example from previous slides is on the web
• Zip 9
• Run the program
• Modify the program as follows
• Create a text file that has your name and your
  partners name in it (two lines)
• Have the program prompt for a file to use
• Read from that file, display each of the two
  lines in a message box

17
Example using CColorDialog

• include ltafxwin.hgt
• include ltafxdlgs.hgt
• class CColorWin public CFrameWnd
• public
• CColorWin()
• afx_msg void OnLButtonDown (UINT, CPoint)
• afx_msg void OnPaint()
• private
• COLORREF m_color
• int m_offset
• DECLARE_MESSAGE_MAP( )

• Our example will allow the user to select a
  color, and then fill the window with that color
• Basic class has two methods, handling
  OnLButtonDown and OnPaint
• Two local members, one controls color and one is
  an offset for the rectangle we draw

18
Example body (part 1)

• Standard constructor
• Establishes window
• Sets initial variable values, color is white and
  offset is zero
• On left button click
• Declare dialog box
• Invoke dialog box
• Retrieve color selected
• Invoke OnPaint

• include "main.h"
• CColorWinCColorWin()
• Create(NULL, "Color Example", WS_OVERLAPPEDWINDO
  W, CRect(100,100,510,530))m_color
  RGB(255,255,255)m_offset 0
• afx_msg void CColorWinOnLButtonDown (UINT
  flags, CPoint p) CColorDialog
  myColormyColor.DoModal()m_color
  myColor.GetColor()Invalidate(FALSE)

19
Example body (part 2)

• afx_msg void CColorWinOnPaint() CPaintDC
  dc(this)CBrush pBrush new CBrush(m_color)
  dc.FillRect(CRect(m_offset, m_offset,400,400),
  pBrush)m_offset 20if (m_offset 200)
  m_offset 0
• BEGIN_MESSAGE_MAP (CColorWin, CFrameWnd)ON_WM_
  LBUTTONDOWN( )ON_WM_PAINT( )
• END_MESSAGE_MAP( )
• // Same main driver code

• OnPaint routine draws a new rectangle (slightly
  offset) using the new color
• Message map handles two events
• Left button down
• Repaint events

20
Class Exercises

• Previous example is out on the web
• Zip10
• Fix this program so that
• The size of the rectangle shrinks in all
  directions (not just the top and left)

21
CColorDialog from last time

• It does not really repaint the way we would
  like it to repaint the screen
• Minimize and then Maximize
• It only remembers the last color, and thus only
  repaints it
• Need it to retain a history of all the colors
  that were selected
• We were also bothered by the fact m_offset
  changes in OnPaint
• Need OnPaint to only refresh
• Also, rectangles are boring
• Draw circles

22
Solution to our problem

• Keep a list of the colors we have utilized
• Could do this by hand
• Prefer something easier (vector class)
• Add a vector of COLORREF objects to class
• Also modify how we keep track of the number of
  colors we have displayed
• In OnPaint routine
• Cycle through vector and print each rectangle
• Learn how to draw ellipses (circles)
• Wont really have to worry about offset this
  time well determine offset based upon the
  position in the vector

23
Modified Class Header

• include ltafxwin.hgt
• include ltafxdlgs.hgt
• include ltvectorgtusing namespace std
• class CColorWin public CFrameWnd
• publicCColorWin()afx_msg void
  OnLButtonDown (UINT, CPoint)afx_msg void
  OnPaint( )
• privateint m_countvectorltCOLORREFgt
  m_vectorDECLARE_MESSAGE_MAP( )

• Another include file
• For vector class
• using clause
• Replace m_offset with m_count
• No need to keep the individual COLORREF object as
  a data member
• Declare a vector of COLORREF objects
• Holds all the colors we have displayed
• Dont need to worry about sizing vector (done
  automatically)

24
Modified OnLButtonDown

• afx_msg void CColorWinOnLButtonDown (UINT
  flags, CPoint p)
• CColorDialog myColor
• myColor.DoModal( )
• COLORREF color
• color myColor.GetColor( )
• m_vector.push_back(color)
• InvalidateRect(NULL,FALSE)
• m_count
• if (m_count 10) m_count 0

• Each time you add a color, insert it into the
  vector we are maintaining of colors we have used
• Increment the number of colored circles we have
  displayed
• Once we hit ten circles, start over (dont keep
  getting smaller forever)

25
Modified OnPaint routine

• afx_msg voidCColorWinOnPaint() CPaintDC
  dc(this)CBrush pBrushCPen pPenfor (int
  a0 altm_count a) pBrush new
  CBrush(m_vectora) pPen new
  CPen(PS_SOLID, 1, m_vectora)
  dc.SelectObject(pBrush) dc.SelectObject(pPen)
  dc.Ellipse(a20,a20, 380-a20,380-a20)
  delete pBrush delete pPen

• Allocate a Brush and Pen
• Fill with brush color
• Draw with pen color
• For each color in vector
• Assign brush color
• Assign pen type color
• Set the current objects
• Brush color
• Pen color
• Draw the ellipse
• Top-left lower-right bounding box (rectangle)
• Delete current brush/pen

26
Class Exercises

• The code from the last example is on the web
• Zip 11
• Run this program.
• Remember the first color you add
• What happens after you add ten colors and it
  cycles back to the big circle?
• Why does this happen?
• How can you fix it?

27
Creating processes in Windows

• No exact Windows equivalent of fork and exec
• Windows has CreateProcess method
• Creates a new process and loads the specified
  program into that process (one step)
• Requires include ltwindows.hgt
• More parameters than fork exec
• Most can be NULL
• Just need to specify program to run and a few
  flags

28
Example using CreateProcess

• include ltwindows.hgt
• include ltiostream.hgt
• void main( ) STARTUPINFO siPROCESS_INFORMATION
  piZeroMemory( si, sizeof(si) )si.cb
  sizeof(si)if ( ! CreateProcess( NULL,
  ..\\print\\debug\\print.exe 5 10", NULL,
  NULL, TRUE, 0, NULL, NULL, si, pi) ) cerr ltlt
  "CreateProcess failed." ltlt endlWaitForSingleObje
  ct( pi.hProcess, INFINITE )CloseHandle(
  pi.hProcess )CloseHandle( pi.hThread )

• Need two variables to handle basic info must
  initialize correctly
• Specify the location of the new process (our
  print process from last time)
• Wait for it to finish

29
CreateProcess syntax

• BOOL CreateProcess (
• LPCTSTR lpApplicationName, // pointer to
  executable module
• LPTSTR lpCommandLine, // pointer to command line
  string
• LPSECURITY_ATTRIBUTES lpProcessAttrib, // process
  security
• LPSECURITY_ATTRIBUTES lpThreadAttrib, // thread
  security
• BOOL bInheritHandles, // handle inheritance flag
• DWORD dwCreationFlags, // creation flags
• LPVOID lpEnvironment, // pointer to new
  environment block
• LPCTSTR lpCurrentDirectory, // pointer to current
  dir name
• LPSTARTUPINFO lpStartupInfo, // pointer to
  STARTUPINFO
• LPPROCESS_INFORMATION lpProcessInformation //
  pointer to PROCESS_INFORMATION
• )

30
Comments on CreateProcess

• Can specify program in either 1st or 2nd args
• If in first, give location of program to run
• If in second, give the command line to execute
• Creation flags
• If 0, runs in existing window
• Also have other flags (combine with )
• CREATE_NEW_CONSOLE probably most useful
• Specify priority, linkage to parent, etc.
• Structures pi and si used for process
  communication (how to start, basic info)

31
Class Exercises

• Write a program (in the Windows VC environment)
  that starts up a copy of notepad as part of its
  execution
• Notepad is located in (?) directory
• Dont forget to double the \ in string literal