VC video tutorial notes (Lesson 5)

1. cwnd: createsolidcaret: Create an insert operator. showcaret () displays the insert operator. Gettextmetrics () to obtain information about the current font. Cwnd: createcaret ()
Bitmap. loadbitmap (idb_bitmap1); // here, bitmap is a member variable!
Createcaret (& Bitmap );
Showcaret ();
Textmetric TM; // font Structure
DC. gettextmetrics (& TM );//
M_ptorigin.y + = TM. tmheight; // obtain the font height.
2. cstring: loadstring (ID) in VC, which is convenient.
3. Concept of path layer: There are two ways to create a path layer:
(1)
PDC-> beginpath ();
PDC-> rectangle (50, 50, 50 + Sz. CX, 50 + Sz. Cy );
PDC-> endpath ();
PDC-> selectclippath (rgn_diff );
(2)
Csize SZ = PDC-> gettextextent (STR );
Crgn rn;
Rn. createrectrgn (0, 50, Sz. CX, Sz. Cy );
PDC-> selectcliprgn (& RN, rgn_diff );
What is the role of the path layer? It can protect our previous text or images from being overwritten by subsequent paintings.
4. Enter text on The View.
Cfont font; // create a font object
Font. createpointfont (300, "文 ", null); // set
Cfont * poldfont = Dc. SelectObject (& font); // select the font to DC.
Textmetric TM; // create a font information object
DC. gettextmetrics (& TM); // obtain the current font information
If (0x0d = nchar) // process the return key
{
M_strline.empty ();
M_ptorigin.y + = TM. tmheight;
}
Else if (0x08 = nchar) // process the return key
{
Colorref CLR = Dc. settextcolor (DC. getbkcolor ());
DC. textout (m_ptorigin.x, m_ptorigin.y, m_strline );
M_strline = m_strline.left (m_strline.getlength ()-1 );
DC. settextcolor (CLR );
}
Else
{
M_strline + = nchar;
}
Csize SZ = Dc. gettextextent (m_strline );

Cpoint pt; // process the cursor position
PT. x = m_ptorigin.x + Sz. CX;
PT. Y = m_ptorigin.y;

Setcaretpos (PT );
DC. textout (m_ptorigin.x, m_ptorigin.y, m_strline); // output font

DC. SelectObject (poldfont); // select the original font.
5. simulate the process of changing the color of the karaoke bar.
(1) set the timer
(2) Add the following code to the Timer:
// Del m_nwidth + = 5; // This is the member variable of the view and the initial value is 0.
// Del
// Del
// Del cclientdc DC (this );
// Del textmetric TM;
// Del DC. gettextmetrics (& TM );
// Del crect rect;
// Del rect. Left = 0;
// Del rect. Top = 200;
// Del rect. Right = m_nwidth;
// Del rect. Bottom = rect. Top + TM. tmheight; // the length of this rectangle increases with the timer triggering.
// Del
// Del DC. settextcolor (RGB (255, 0, 0 ));
// Del cstring STR;
// Del Str. loadstring (ids_weixin );
// Del DC. drawtext (STR, rect, dt_left); this function is used to output a string to a rectangle. However, if the length of a string exceeds the length of a rectangle, extra characters are truncated.
// Del
// Del rect. Top = 150;
// Del rect. Bottom = rect. Top + TM. tmheight;
// Del DC. drawtext (STR, rect, dt_right );
// Del
// Del csize SZ = Dc. gettextextent (STR); get the string length
// Del if (m_nwidth> Sz. CX) when the length of a rectangle is greater than the length of a string, return it to 0.
// Del {
// Del m_nwidth = 0;
// Del DC. settextcolor (RGB (0,255, 0 ));
// Del DC. textout (0,200, STR );
// Del}
// Del
// Del cview: ontimer (nidevent );
6. settimer can also be operated using the callback function, but it is not convenient. The procedure is as follows:
(1) In the oncreate message response function of view: settimer (, timer2proc );
(2) Implementation of callback functions:
Void callback export timer2proc (
Hwnd, // handle of cwnd that called settimer
Uint nmsg, // wm_timer
Uint nidevent, // timer Identification
DWORD dwtime // system time
)
{
// MessageBox (cmainframe *) afxgetmainwnd ()-> m_hwnd), "ddfaf", "Weixin", 0 );
;
Cmainframe * pmain = (cmainframe *) afxgetapp ()-> m_pmainwnd; // obtain the mainframe pointer
Ctextview * pview = (ctextview *) pmain-> getactiveview (); // get the view pointer
Cclientdc DC (pview); // construct a DC
DC. textout (333,222, "Hello World ");

} // We can see that the pointer to the window or app needs to be obtained when using the callback function, which brings us trouble in our operations. Not convenient.