GDI+ Skeletons

[José Roca]

 

GDI+ Skeletons

Most of the posted GDI+ examples use a fixed skeleton for the SDK style programming, DDT and DDT with the use of the graphic control (introduced in PBWIn 8.0).

The SDK and DDT skeletons call the procedure containing the GDI+ code in the %WM_PAINT message:

      CASE %WM_PAINT
         hDC = BeginPaint(hWnd, ps)
         GDIP_DrawLine hDC  ' --> The name of the procedure changes with each example
         EndPaint(hWnd, ps)

Since the PB/WIN DDT graphic control features persistence, the procedure isn't called in %WM_PAINT, but after the control is created:

   ' Add a graphic control
   CONTROL ADD GRAPHIC, hDlg, %IDC_GRAPHIC,"", 0, 0, 420, 250
   ' Select the drawing target
   GRAPHIC ATTACH hDlg, %IDC_GRAPHIC
   ' Set the foreground and background color
   GRAPHIC COLOR %BLACK, %WHITE
   ' Clear the entire selected graphic window
   GRAPHIC CLEAR
   ' Retrieve the handle of the device context
   GRAPHIC GET DC TO hdc
   ' Draw the graphics
   GDIP_DrawLine hdc

Here is the same example using the three different skeletons:

SDK Skeleton:

Code Select Expand


' ========================================================================================
' GdipDrawLine
' ========================================================================================

#COMPILE EXE
#DIM ALL
#INCLUDE "GDIPLUS.INC"

' ========================================================================================
' The following example draws a line.
' ========================================================================================
SUB GDIP_DrawLine (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pPen AS DWORD

   hStatus = GdipCreateFromHDC(hdc, pGraphics)

   ' // Create a Pen
   hStatus = GdipCreatePen1(GDIP_ARGB(255, 255, 0, 0), 1, %UnitPixel, pPen)

   ' // Draw the line
   GdipDrawLineI pGraphics, pPen, 0, 0, 200, 100

   ' // Cleanup
   IF pPen THEN GdipDeletePen(pPen)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB
' ========================================================================================

' ========================================================================================
' Main
' ========================================================================================
FUNCTION WINMAIN (BYVAL hInstance AS DWORD, BYVAL hPrevInstance AS DWORD, BYVAL lpszCmdLine AS ASCIIZ PTR, BYVAL nCmdShow AS LONG) AS LONG

   LOCAL hr AS LONG
   LOCAL hWndMain AS DWORD
   LOCAL hCtl AS DWORD
   LOCAL hFont AS DWORD
   LOCAL wcex AS WndClassEx
   LOCAL szClassName AS ASCIIZ * 80
   LOCAL rc AS RECT
   LOCAL szCaption AS ASCIIZ * 255
   LOCAL nLeft AS LONG
   LOCAL nTop AS LONG
   LOCAL nWidth AS LONG
   LOCAL nHeight AS LONG
   LOCAL token AS DWORD
   LOCAL StartupInput AS GdiplusStartupInput

   ' Initialize GDI+
   StartupInput.GdiplusVersion = 1
   hr = GdiplusStartup(token, StartupInput, BYVAL %NULL)
   IF hr THEN
      MSGBOX "Error initializing GDI+"
      EXIT FUNCTION
   END IF

   hFont = GetStockObject(%ANSI_VAR_FONT)

   ' Register the window class
   szClassName        = "MyClassName"
   wcex.cbSize        = SIZEOF(wcex)
   wcex.style         = %CS_HREDRAW OR %CS_VREDRAW
   wcex.lpfnWndProc   = CODEPTR(WndProc)
   wcex.cbClsExtra    = 0
   wcex.cbWndExtra    = 0
   wcex.hInstance     = hInstance
   wcex.hCursor       = LoadCursor (%NULL, BYVAL %IDC_ARROW)
   wcex.hbrBackground = GetStockObject(%WHITE_BRUSH)
   wcex.lpszMenuName  = %NULL
   wcex.lpszClassName = VARPTR(szClassName)
   wcex.hIcon         = LoadIcon (%NULL, BYVAL %IDI_APPLICATION) ' Sample, if resource icon: LoadIcon(hInst, "APPICON")
   wcex.hIconSm       = LoadIcon (%NULL, BYVAL %IDI_APPLICATION) ' Remember to set small icon too..
   RegisterClassEx wcex

   ' Window caption
   szCaption = "GdipDrawLine"

   ' Retrieve the nSize of the working area
   SystemParametersInfo %SPI_GETWORKAREA, 0, BYVAL VARPTR(rc), 0

   ' Calculate the position and nSize of the window
   nWidth  = (((rc.nRight - rc.nLeft)) + 2) * 0.55   ' 55% of the client screen width
   nHeight = (((rc.nBottom - rc.nTop)) + 2) * 0.50   ' 50% of the client screen height
   nLeft   = ((rc.nRight - rc.nLeft) \ 2) - nWidth \ 2
   nTop    = ((rc.nBottom - rc.nTop) \ 2) - (nHeight \ 2)

   ' Create a window using the registered class
   hWndMain = CreateWindowEx(%WS_EX_CONTROLPARENT, _           ' extended style
                             szClassName, _                    ' window class name
                             szCaption, _                      ' window caption
                             %WS_OVERLAPPEDWINDOW OR _
                             %WS_CLIPCHILDREN, _               ' window style
                             nLeft, _                          ' initial x position
                             nTop, _                           ' initial y position
                             nWidth, _                         ' initial x nSize
                             nHeight, _                        ' initial y nSize
                             %NULL, _                          ' parent window handle
                             0, _                              ' window menu handle
                             hInstance, _                      ' program instance handle
                             BYVAL %NULL)                      ' creation parameters

   ' Show the window
   ShowWindow hWndMain, nCmdShow
   UpdateWindow hWndMain

   ' Message handler loop
   LOCAL Msg AS tagMsg
   WHILE GetMessage(Msg, %NULL, 0, 0)
      IF ISFALSE IsDialogMessage(hWndMain, Msg) THEN
         TranslateMessage Msg
         DispatchMessage Msg
      END IF
   WEND

   ' Shutdown GDI+
   GdiplusShutdown token

   FUNCTION = msg.wParam

END FUNCTION
' ========================================================================================

' ========================================================================================
' Main Window procedure
' ========================================================================================
FUNCTION WndProc (BYVAL hWnd AS DWORD, BYVAL wMsg AS DWORD, BYVAL wParam AS DWORD, BYVAL lParam AS LONG) AS LONG

   LOCAL hDC AS DWORD
   LOCAL ps AS PAINTSTRUCT

   SELECT CASE wMsg

      CASE %WM_COMMAND
         SELECT CASE LOWRD(wParam)
            CASE %IDCANCEL
               IF HIWRD(wParam) = %BN_CLICKED THEN
                  SendMessage hWnd, %WM_CLOSE, 0, 0
                  FUNCTION = 0
                  EXIT FUNCTION
               END IF
         END SELECT

      CASE %WM_SYSCOMMAND
         ' Capture this message and send a WM_CLOSE message
         IF (wParam AND &HFFF0) = %SC_CLOSE THEN
            SendMessage hWnd, %WM_CLOSE, 0, 0
            EXIT FUNCTION
         END IF

      CASE %WM_PAINT
         hDC = BeginPaint(hWnd, ps)
         GDIP_DrawLine hDC
         EndPaint(hWnd, ps)

      CASE %WM_DESTROY
         PostQuitMessage 0
         EXIT FUNCTION

   END SELECT

   FUNCTION = DefWindowProc(hWnd, wMsg, wParam, lParam)

END FUNCTION
' ========================================================================================


DDT Skeleton:

Code Select Expand


' ========================================================================================
' GdipDrawLine
' ========================================================================================

#COMPILE EXE
#DIM ALL
#INCLUDE "GDIPLUS.INC"

' ========================================================================================
' The following example draws a line.
' ========================================================================================
SUB GDIP_DrawLine (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pPen AS DWORD

   hStatus = GdipCreateFromHDC(hdc, pGraphics)

   ' // Create a Pen
   hStatus = GdipCreatePen1(GDIP_ARGB(255, 255, 0, 0), 1, %UnitPixel, pPen)

   ' // Draw the line
   GdipDrawLineI pGraphics, pPen, 0, 0, 200, 100

   ' // Cleanup
   IF pPen THEN GdipDeletePen(pPen)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB
' ========================================================================================

' ========================================================================================
' Main
' ========================================================================================
FUNCTION WINMAIN (BYVAL hInstance AS DWORD, BYVAL hPrevInstance AS DWORD, BYVAL lpszCmdLine AS ASCIIZ PTR, BYVAL nCmdShow AS LONG) AS LONG

   LOCAL hr AS LONG
   LOCAL hDlg AS DWORD
   LOCAL token AS DWORD
   LOCAL StartupInput AS GdiplusStartupInput

   ' Initialize GDI+
   StartupInput.GdiplusVersion = 1
   hr = GdiplusStartup(token, StartupInput, BYVAL %NULL)
   IF hr THEN
      MSGBOX "Error initializing GDI+"
      EXIT FUNCTION
   END IF

   DIALOG NEW 0, "GdipDrawLine", , , 280, 170, %WS_OVERLAPPED OR %WS_THICKFRAME OR %WS_SYSMENU OR _
   %WS_MINIMIZEBOX OR %WS_MAXIMIZEBOX OR %WS_VISIBLE OR %DS_CENTER TO hDlg
   DIALOG SET COLOR hDlg, %BLACK, %WHITE
   DIALOG SHOW MODAL hDlg, CALL DlgProc

   ' Shutdown GDI+
   GdiplusShutdown token

END FUNCTION
' ========================================================================================

' ========================================================================================
' Main Dialog procedure
' ========================================================================================
CALLBACK FUNCTION DlgProc() AS LONG

   LOCAL hDC AS DWORD
   LOCAL ps AS PAINTSTRUCT

   SELECT CASE CBMSG

      CASE %WM_COMMAND
         SELECT CASE CBCTL
            CASE %IDCANCEL
               IF CBCTLMSG = %BN_CLICKED THEN DIALOG END CBHNDL, 0
         END SELECT

      CASE %WM_PAINT
         hDC = BeginPaint(CBHNDL, ps)
         GDIP_DrawLine hDC
         EndPaint(CBHNDL, ps)

   END SELECT

END FUNCTION
' ========================================================================================


DDT Skeleton using the graphic control:

Code Select Expand


' ========================================================================================
' GdipDrawLine
' ========================================================================================

#COMPILE EXE
#DIM ALL
#INCLUDE "GDIPLUS.INC"

%IDC_GRAPHIC = 101

' ========================================================================================
' The following example draws a line.
' ========================================================================================
SUB GDIP_DrawLine (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pPen AS DWORD

   hStatus = GdipCreateFromHDC(hdc, pGraphics)

   ' // Create a Pen
   hStatus = GdipCreatePen1(GDIP_ARGB(255, 255, 0, 0), 1, %UnitPixel, pPen)

   ' // Draw the line
   GdipDrawLineI pGraphics, pPen, 0, 0, 200, 100

   ' // Cleanup
   IF pPen THEN GdipDeletePen(pPen)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB
' ========================================================================================

' ========================================================================================
' Main
' ========================================================================================
FUNCTION WINMAIN (BYVAL hInstance AS DWORD, BYVAL hPrevInstance AS DWORD, BYVAL lpszCmdLine AS ASCIIZ PTR, BYVAL nCmdShow AS LONG) AS LONG

   LOCAL hr AS LONG
   LOCAL hDlg AS DWORD
   LOCAL hdc AS DWORD
   LOCAL token AS DWORD
   LOCAL StartupInput AS GdiplusStartupInput

   ' Initialize GDI+
   StartupInput.GdiplusVersion = 1
   hr = GdiplusStartup(token, StartupInput, BYVAL %NULL)
   IF hr THEN
      MSGBOX "Error initializing GDI+"
      EXIT FUNCTION
   END IF

   ' Create a new dialog
   DIALOG NEW PIXELS, 0, "GdipDrawLine", , , 420, 250, %WS_SYSMENU TO hDlg

   ' Add a graphic control
   CONTROL ADD GRAPHIC, hDlg, %IDC_GRAPHIC,"", 0, 0, 420, 250
   ' Select the drawing target
   GRAPHIC ATTACH hDlg, %IDC_GRAPHIC
   ' Set the foreground and background color
   GRAPHIC COLOR %BLACK, %WHITE
   ' Clear the entire selected graphic window
   GRAPHIC CLEAR
   ' Retrieve the handle of the device context
   GRAPHIC GET DC TO hdc
   ' Draw the graphics
   GDIP_DrawLine hdc

   DIALOG SHOW MODAL hDlg, CALL DlgProc

   ' Shutdown GDI+
   GdiplusShutdown token

END FUNCTION
' ========================================================================================

' ========================================================================================
' Main Dialog procedure
' ========================================================================================
CALLBACK FUNCTION DlgProc() AS LONG

   SELECT CASE CBMSG

      CASE %WM_COMMAND
         SELECT CASE CBCTL
            CASE %IDCANCEL
               IF CBCTLMSG = %BN_CLICKED THEN DIALOG END CBHNDL, 0
         END SELECT

   END SELECT

END FUNCTION
' ========================================================================================