Visual C Examples - Displaying a Bitmap

unununy 2010-03-21

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	Displaying Bitmaps

Introduction

This exercise shows how to display and change bitmaps with little effort.

Prerequisites:

Preparing the Picture

First create or load a picture in a graphics application, such as MS Paint or Paint Shop Pro, that can create good pictures. Don't use the Image Editor of MSVC. For example, here is a picture in Microsoft Paint (MS Paint is an application that installs with Microsoft Windows):
Save the picture as a bitmap (with the .bmp extension) and remember where you save it.

Creating the Application

Start Microsoft Visual Studio or Microsoft Visual C++ and, using MFC AppWizard (exe) or MFC Application, create a Dialog-Based project named Bitmaps1
Delete the TODO line on the dialog box
To add the bitmap picture, in the Resource View, right-click any folder and click Import...
In the Import Picture dialog box, change the files of type to All Files
Locate the folder where you saved the picture and display it in the Look In combo box
Click the name of the picture and click Import
You should receive a message box. Read it and click OK.
Right-click the name IDB_BITMAP1 and click Properties. Change its ID to IDB_PICTURE1
From the Controls toolbox, click the Picture control and draw the frame of the picture where you want to display the picture on the dialog box. Here is an example
In the Properties window, change its ID to IDC_PICTURE
Change its Type to Bitmap and, in the Image combo box, select IDB_PICTURE1 and click anywhere on the dialog box:
As you can see, this was done without a single line of code. You can test the application now to see the result.

Changing Bitmaps

Create additional pictures using MS Paint and save the pictures as Windows Bitmap (.bmp)
Besides the above Picture1.bmp, here are the pictures we will use here:

Import the pictures as we did for the above Picture1.bmp
Change their IDs to IDB_PICTURE2, IDB_PICTURE3, IDB_PICTURE4, and IDB_PICTURE5
Add a combo box under the OK button and change its ID to IDC_CHOICE
Using Ctrl + Enter in the Data property page, create a list as follows:
Set its Type to Drop List and the Owner Draw to No
Uncheck the Sort check box

In the header file of the dialog, declare a private CBitmap variable for each picture. Here is an example:

private:
                            CBitmap Bmp1, Bmp2, Bmp3,  Bmp4,  Bmp5;
                            };

Press Ctrl + W to display the MFC ClassWizard dialog box.
From the Member Variables dialog box, Add a Control variable for the IDC_CHOICE identifier and name it m_Choice
Add a Control variable for the IDC_PICTURE identifier and name it m_Picture
Add a CBN_SELCHANGE event handler for the IDC_CHOICE control and click Edit Code

In the OnInitDialog() method, type the following:

BOOL CBitmaps1Dlg::OnInitDialog()
                            {
                            CDialog::OnInitDialog();
                            . . .
                            // TODO: Add extra initialization here
                            // TODO: Add extra initialization here
                            m_Choice.SetCurSel(0);
                            Bmp1.LoadBitmap(IDB_PICTURE1);
                            Bmp2.LoadBitmap(IDB_PICTURE2);
                            Bmp3.LoadBitmap(IDB_PICTURE3);
                            Bmp4.LoadBitmap(IDB_PICTURE4);
                            Bmp5.LoadBitmap(IDB_PICTURE5);
                            
                            return TRUE;  // return TRUE  unless you set the focus to a control
                            }

Implement the OnSelchange event as follows:

void CBitmaps1Dlg::OnSelchangeChoice()
                            {
                            // TODO: Add your control notification handler code here
                            // What is the current selection?
                            int CurSel = m_Choice.GetCurSel();
                            // Change the bitmap according to the selection
                            switch( CurSel )
                            {
                            case 0:
                            m_Picture.SetBitmap(Bmp1);
                            break;
                            case 1:
                            m_Picture.SetBitmap(Bmp2);
                            break;
                            case 2:
                            m_Picture.SetBitmap(Bmp3);
                            break;
                            case 3:
                            m_Picture.SetBitmap(Bmp4);
                            break;
                            case 4:
                            m_Picture.SetBitmap(Bmp5);
                            break;
                            }
                            }