§ 简介

为了解卷动列和静态子视窗的一些用法－也为了深入了解颜色－我们将使用COLORS1程式，如程式9-3所示。COLORS1在显示区域的左半部显示三种卷动列，并分别标以「Red」、「 Green」和「Blue」。当您挪动卷动列时，显示区域的右半部将变为三种原色混合而成的合成色，三种原色的数值显示在三个卷动列的下面。

§ 程序

程式9-3　COLORS1

COLORS1.C

/*------------------------------------------------------------------------

COLORS1.C -- Colors Using Scroll Bars

(c) Charles Petzold, 1998

-------------------------------------------------------------------------*/

#include <windows.h>

LRESULT CALLBACK WndProc                 (HWND, UINT, WPARAM, LPARAM) ;

LRESULT CALLBACK ScrollProc        (HWND, UINT, WPARAM, LPARAM) ;

int  　 idFocus ;

WNDPROC OldScroll【3】 ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,

PSTR szCmdLine, int iCmdShow)

{

static TCHAR         szAppName【】 = TEXT ("Colors1") ;

HWND  　 　 　                               hwnd ;

MSG  　 　                                   msg ;

WNDCLASS  　　                       wndclass ;

wndclass.style  　 　 　                       = CS_HREDRAW | CS_VREDRAW ;

wndclass.lpfnWndProc  　                       = WndProc ;

wndclass.cbClsExtra                            = 0 ;

wndclass.cbWndExtra                            = 0 ;

wndclass.hInstance  　　                       = hInstance ;

wndclass.hIcon  　 　 　                       = LoadIcon (NULL, IDI_APPLICATION) ;

wndclass.hCursor  　                           = LoadCursor (NULL, IDC_ARROW) ;

wndclass.hbrBackground                 = CreateSolidBrush (0) ;

wndclass.lpszMenuName　                = NULL ;

wndclass.lpszClassName                 = szAppName ;

if (!RegisterClass (&wndclass))

{

MessageBox (        NULL, TEXT ("This program requires Windows NT!"),

szAppName, MB_ICONERROR) ;

return 0 ;

}

hwnd = CreateWindow (        szAppName, TEXT ("Color Scroll"),

WS_OVERLAPPEDWINDOW,

CW_USEDEFAULT, CW_USEDEFAULT,

CW_USEDEFAULT, CW_USEDEFAULT,

NULL, NULL, hInstance, NULL) ;

ShowWindow (hwnd, iCmdShow) ;

UpdateWindow (hwnd) ;

while (GetMessage (&msg, NULL, 0, 0))

{

TranslateMessage (&msg) ;

DispatchMessage　(&msg) ;

}

return msg.wParam ;

}

LRESULT CALLBACK WndProc (        HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam)

{

static COLORREF crPrim【3】 = {         RGB (255, 0, 0), RGB (0, 255, 0),

RGB (0, 0, 255) } ;

static HBRUSH　                hBrush【3】, hBrushStatic ;

static HWND  　               hwndScroll【3】, hwndLabel【3】, hwndValue【3】, hwndRect ;

static int                         color【3】, cyChar ;

static RECT                 rcColor ;

static TCHAR *        szColorLabel【】 = {         TEXT ("Red"), TEXT ("Green"),

TEXT ("Blue") } ;

HINSTANCE  　 　                       hInstance ;

int  　 　 　 　                       i, cxClient, cyClient ;

TCHAR  　 　                           szBuffer【10】 ;

switch (message)

{

case         WM_CREATE :

hInstance = (HINSTANCE) GetWindowLong (hwnd, GWL_HINSTANCE) ;

// Create the white-rectangle window against which the

// scroll bars will be positioned. The child window ID is 9.

hwndRect = CreateWindow (TEXT ("static"), NULL,

WS_CHILD | WS_VISIBLE | SS_WHITERECT,

0, 0, 0, 0,

hwnd, (HMENU) 9, hInstance, NULL) ;

for (i = 0 ; i < 3 ; i++)

{

// The three scroll bars have IDs 0, 1, and 2, with

// scroll bar ranges from 0 through 255.

hwndScroll = CreateWindow (TEXT ("scrollbar"), NULL,

WS_CHILD | WS_VISIBLE |

WS_TABSTOP | SBS_VERT,

0, 0, 0, 0,

hwnd, (HMENU) i, hInstance, NULL) ;

SetScrollRange (hwndScroll, SB_CTL, 0, 255, FALSE) ;

SetScrollPos   (hwndScroll, SB_CTL, 0, FALSE) ;

// The three color-name labels have IDs 3, 4, and 5,

// and text strings "Red", "Green", and "Blue".

hwndLabel = CreateWindow (TEXT ("static"), zColorLabel,

WS_CHILD | WS_VISIBLE | SS_CENTER,

0, 0, 0, 0,

hwnd, (HMENU) (i + 3),

hInstance, NULL) ;

// The three color-value text fields have IDs 6, 7,

// and 8, and initial text strings of "0".

hwndValue = CreateWindow (TEXT ("static"), TEXT ("0"),

WS_CHILD | WS_VISIBLE | SS_CENTER,

0, 0, 0, 0,

hwnd, (HMENU) (i + 6),

hInstance, NULL) ;

OldScroll = (WNDPROC) SetWindowLong (hwndScroll,

GWL_WNDPROC, (LONG) ScrollProc) ;

hBrush = CreateSolidBrush (crPrim) ;

}

hBrushStatic = CreateSolidBrush (

GetSysColor (COLOR_BTNHIGHLIGHT)) ;

cyChar = HIWORD (GetDialogBaseUnits ()) ;

return 0 ;

case         WM_SIZE :

cxClient = LOWORD (lParam) ;

cyClient = HIWORD (lParam) ;

SetRect (&rcColor, cxClient / 2, 0, cxClient, cyClient) ;

MoveWindow (hwndRect, 0, 0, cxClient / 2, cyClient, TRUE) ;

for (i = 0 ; i < 3 ; i++)

{

MoveWindow (hwndScroll,

(2 * i + 1) * cxClient / 14, 2 * cyChar,

cxClient / 14, cyClient - 4 * cyChar, TRUE) ;

MoveWindow (hwndLabel,

(4 * i + 1) * cxClient / 28, cyChar / 2,

cxClient / 7, cyChar, TRUE)

MoveWindow (hwndValue,

(4 * i + 1) * cxClient / 28,

cyClient - 3 * cyChar / 2,

cxClient / 7, cyChar, TRUE) ;

}

SetFocus (hwnd) ;

return 0 ;

case         WM_SETFOCUS :

SetFocus (hwndScroll【idFocus】) ;

return 0 ;

case         WM_VSCROLL :

i = GetWindowLong ((HWND) lParam, GWL_ID) ;

switch (LOWORD (wParam))

{

case         SB_PAGEDOWN :

color += 15 ;

// fall through

case         SB_LINEDOWN :

color = min (255, color + 1) ;

break ;

case         SB_PAGEUP :

color -= 15 ;

// fall through

case         SB_LINEUP :

color = max (0, color - 1) ;

break ;

case         SB_TOP :

color = 0 ;

break ;

case         SB_BOTTOM :

color = 255 ;

break ;

case         SB_THUMBPOSITION :

case        SB_THUMBTRACK :

color = HIWORD (wParam) ;

break ;

default :

break ;

}

SetScrollPos　(hwndScroll, SB_CTL, color, TRUE) ;

wsprintf (szBuffer, TEXT ("%i"), color) ;

SetWindowText (hwndValue, szBuffer) ;

DeleteObject ((HBRUSH)

SetClassLong (hwnd, GCL_HBRBACKGROUND, (LONG)

CreateSolidBrush (RGB (color【0】, color【1】, color【2】)))) ;

InvalidateRect (hwnd, &rcColor, TRUE) ;

return 0 ;

case         WM_CTLCOLORSCROLLBAR :

i = GetWindowLong ((HWND) lParam, GWL_ID) ;

return (LRESULT) hBrush ;

case         WM_CTLCOLORSTATIC :

i = GetWindowLong ((HWND) lParam, GWL_ID) ;

if (i >= 3 && i <= 8)                            // static text controls

{

SetTextColor ((HDC) wParam, crPrim【i % 3】) ;

SetBkColor ((HDC) wParam, GetSysColor (COLOR_BTNHIGHLIGHT));

return (LRESULT) hBrushStatic ;

}

break ;

case         WM_SYSCOLORCHANGE :

DeleteObject (hBrushStatic) ;

hBrushStatic = CreateSolidBrush (GetSysColor(COLOR_BTNHIGHLIGHT)) ;

return 0 ;

case         WM_DESTROY :

DeleteObject ((HBRUSH)

SetClassLong (hwnd, GCL_HBRBACKGROUND, (LONG)

GetStockObject (WHITE_BRUSH))) ;

for (i = 0 ; i < 3 ; i++)

DeleteObject (hBrush) ;

DeleteObject (hBrushStatic) ;

PostQuitMessage (0) ;

return 0 ;

}

return DefWindowProc (hwnd, message, wParam, lParam) ;

}

LRESULT CALLBACK ScrollProc (HWND hwnd, UINT message,

WPARAM wParam, LPARAM lParam)

{

int id = GetWindowLong (hwnd, GWL_ID) ;

switch (message)

{

case WM_KEYDOWN :

if (wParam == VK_TAB)

SetFocus (GetDlgItem (GetParent (hwnd),

(id + (GetKeyState (VK_SHIFT) < 0 ? 2 : 1)) % 3)) ;

break ;

case         WM_SETFOCUS :

idFocus = id ;

break ;

}

return CallWindowProc (OldScroll【id】, hwnd, message, wParam,lParam) ;

}

COLORS1利用子视窗进行工作，该程式使用10个子视窗控制项：3个卷动列、6个静态文字视窗和1个静态矩形框。COLORS1拦截WM_CTLCOLORSCROLLBAR讯息来给红、绿、蓝3个卷动列的内部著色，并拦截WM_CTLCOLORSTATIC讯息来著色静态文字。

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