GDI+: CachedBitmap Examples

[José Roca]

 
The IGdipCachedBitmap interface allows the creation of instances of cached bitmaps. A cached  bitmap stores a bitmap in a format that is optimized for display on a particular device. To display a cached bitmap, call the DrawCachedBitmap method of the IGdipGraphics interface.

Code Select Expand


' ########################################################################################
' Microsoft Windows
' File: CGDIP_CachedBitmap.bas
' Contents: GDI+ example
' This version uses the CWindow and CGdiPlus classes, and the GraphCtx graphic control
' Compilers: PBWIN 10+, PBCC 6+
' Headers: Windows API headers 2.03+
' Copyright (c) 2011 José Roca. Freeware. Use at your own risk.
' Portions Copyright (c) Microsoft Corporation. All Rights Reserved.
' THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
' EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
' MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
' ########################################################################################

#COMPILE EXE
#DIM ALL
%UNICODE = 1
%USEGRAPHCTX = 1

' // Header files for imported files
#INCLUDE ONCE "CWindow.inc"    ' // CWindow class
#INCLUDE ONCE "CGdiPlus.inc"   ' // CGdiPlus class

%IDC_GRCTX = 1001

' ========================================================================================
' The following example creates a CachedBitmap object based on a Bitmap object and a
' Graphics object. The code calls the DrawCachedBitmap method of that Graphics object
' to display the cached bitmap.
' ========================================================================================
SUB Example_CachedBitmap (BYVAL pGdip AS IGdiPlus, BYVAL hdc AS DWORD)

'   Graphics graphics(hdc);
   LOCAL graphics AS IGdipGraphics
   graphics = pGdip.Graphics(hdc)

'   Bitmap bitmap(L"Grapes.jpg");
   LOCAL pBitmap AS IGdipBitmap
   pBitmap = pGdip.Bitmap("Climber.jpg")

'   CachedBitmap cachedBitmap(&bitmap, &graphics);
   LOCAL cachedBitmap AS IGdipCachedBitmap
   cachedBitmap = pGdip.CachedBitmap(pBitmap, graphics)

'   graphics.DrawCachedBitmap(&cachedBitmap, 10, 10);
   graphics.DrawCachedBitmap(cachedBitmap, 10, 10)

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

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

   ' // Create an instance of the CWindow class
   LOCAL pWindow AS IWindow
   pWindow = CLASS "CWindow"
   IF ISNOTHING(pWindow) THEN EXIT FUNCTION

   ' // Create the main window
   LOCAL hwnd AS DWORD
   hwnd = pWindow.CreateWindow(%NULL, "Cached bitmap", 0, 0, 0, 0, 0, 0, CODEPTR(WindowProc))
   pWindow.SetClientSize 400, 250
   ' // Center the window
   pWindow.CenterWindow

   ' // Create an instance of the GdiPlus class
   LOCAL pGdip AS IGdiPlus
   pGdip = NewGdiPlus

   ' // Add a graphic control
   LOCAL hCtrl AS DWORD
   hCtrl = pWindow.AddGraphCtx(hwnd, %IDC_GRCTX, "", 0, 0, pWindow.ClientWidth, pWindow.ClientHeight)
   GraphCtx_Clear(hCtrl, %WHITE)

   ' // Get the memory device context of the graphic control
   LOCAL hdc AS DWORD
   hdc = GraphCtx_GetDc(hCtrl)

   ' // Draw the graphics
   Example_CachedBitmap(pGdip, hdc)

   ' // Default message pump (you can replace it with your own)
   pWindow.DoEvents(nCmdShow)

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

' ========================================================================================
' Main callback function.
' ========================================================================================
FUNCTION WindowProc (BYVAL hwnd AS DWORD, BYVAL uMsg AS DWORD, BYVAL wParam AS DWORD, BYVAL lParam AS LONG) AS LONG

   SELECT CASE uMsg

      CASE %WM_COMMAND
         SELECT CASE LO(WORD, wParam)
            CASE %IDCANCEL
               ' // If the Escape key has been pressed...
               IF HI(WORD, wParam) = %BN_CLICKED THEN
                  ' // ... close the application by sending a WM_CLOSE message
                  SendMessage hwnd, %WM_CLOSE, 0, 0
               END IF
         END SELECT

      CASE %WM_DESTROY
         ' // End the application
         PostQuitMessage 0
         EXIT FUNCTION

   END SELECT

   ' // Pass unprocessed messages to Windows
   FUNCTION = DefWindowProc(hwnd, uMsg, wParam, lParam)

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


Flat API version

Code Select Expand


' ########################################################################################
' Microsoft Windows
' File: GDIP_CachedBitmap.bas
' Contents: GDI+ example
' This version uses the CWindow class, the GraphCtx graphic control and the GDI+ Flat API
' Compilers: PBWIN 10+, PBCC 6+
' Headers: Windows API headers 2.03+
' Copyright (c) 2011 José Roca. Freeware. Use at your own risk.
' Portions Copyright (c) Microsoft Corporation. All Rights Reserved.
' THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
' EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
' MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
' ########################################################################################

#COMPILE EXE
#DIM ALL
%UNICODE = 1
%USEGRAPHCTX = 1

' // Header files for imported files
#INCLUDE ONCE "CWindow.inc"    ' // CWindow class
#INCLUDE ONCE "GdiPlus.inc"    ' // GdipPlus API

%IDC_GRCTX = 1001

' ========================================================================================
' The following example creates a CachedBitmap object based on a Bitmap object and a
' Graphics object. The code calls the GdipDrawCachedBitmap function to display the cached bitmap.
' ========================================================================================
SUB Example_CachedBitmap (BYVAL hdc AS DWORD)

'   Graphics graphics(hdc);
   LOCAL graphics AS DWORD
   GdipCreateFromHDC(hdc, graphics)

'   Bitmap bitmap(L"Grapes.jpg");
   LOCAL pBitmap AS DWORD
   GdipCreateBitmapFromFile("Climber.jpg", pBitmap)

'   CachedBitmap cachedBitmap(&bitmap, &graphics);
   LOCAL cachedBitmap AS DWORD
   GdipCreateCachedBitmap(pBitmap, graphics, cachedBitmap)

'   graphics.DrawCachedBitmap(&cachedBitmap, 10, 10);
   GdipDrawCachedBitmap(graphics, cachedBitmap, 10, 10)

   ' // Cleanup
   GdipDeleteCachedBitmap(cachedBitmap)
   GdipDisposeImage(pBitmap)
   GdipDeleteGraphics(graphics)

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

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

   ' // Create an instance of the CWindow class
   LOCAL pWindow AS IWindow
   pWindow = CLASS "CWindow"
   IF ISNOTHING(pWindow) THEN EXIT FUNCTION

   ' // Create the main window
   LOCAL hwnd AS DWORD
   hwnd = pWindow.CreateWindow(%NULL, "Cached bitmap", 0, 0, 0, 0, 0, 0, CODEPTR(WindowProc))
   pWindow.SetClientSize 400, 250
   ' // Center the window
   pWindow.CenterWindow

   ' // Add a GDI+ aware graphic control
   LOCAL hCtrl AS DWORD
   hCtrl = pWindow.AddGdipGraphCtx(hwnd, %IDC_GRCTX, "", 0, 0, pWindow.ClientWidth, pWindow.ClientHeight)
   GraphCtx_Clear(hCtrl, %WHITE)

   ' // Get the memory device context of the graphic control
   LOCAL hdc AS DWORD
   hdc = GraphCtx_GetDc(hCtrl)

   ' // Draw the graphics
   Example_CachedBitmap(hdc)

   ' // Default message pump (you can replace it with your own)
   pWindow.DoEvents(nCmdShow)

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

' ========================================================================================
' Main callback function.
' ========================================================================================
FUNCTION WindowProc (BYVAL hwnd AS DWORD, BYVAL uMsg AS DWORD, BYVAL wParam AS DWORD, BYVAL lParam AS LONG) AS LONG

   SELECT CASE uMsg

      CASE %WM_COMMAND
         SELECT CASE LO(WORD, wParam)
            CASE %IDCANCEL
               ' // If the Escape key has been pressed...
               IF HI(WORD, wParam) = %BN_CLICKED THEN
                  ' // ... close the application by sending a WM_CLOSE message
                  SendMessage hwnd, %WM_CLOSE, 0, 0
               END IF
         END SELECT

      CASE %WM_DESTROY
         ' // End the application
         PostQuitMessage 0
         EXIT FUNCTION

   END SELECT

   ' // Pass unprocessed messages to Windows
   FUNCTION = DefWindowProc(hwnd, uMsg, wParam, lParam)

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