C言語／C++/ScrollTest - Sample is best!

開発環境	Microsoft Visual C++ 2010 Express (SP1)
実行環境	Microsoft Windows XP Home Edition (SP3)
プロジェクトの種類	Win32 プロジェクト
プロジェクト名	ScrollTest
アプリケーションの種類	Windows アプリケーション
追加のオプション	空のプロジェクト
文字セット	Unicode

ScrollTest.c

#include <tchar.h>
#include <Windows.h>
 
#define	WIDTH	800
#define HEIGHT	600
 
// グローバル変数
static const TCHAR	g_atcClassName[] = _T("ScrollTest");
static const TCHAR	g_atcWindowName[] = _T("Scroll Test");
static SCROLLINFO	g_siHorz;
 
// 関数プロトタイプ宣言
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
void OnCreate(HWND hWnd);
void OnSize(HWND hWnd);
void OnHScroll(HWND hWnd, WPARAM wParam, LPARAM lParam);
void OnPaint(HWND hWnd);
 
int APIENTRY _tWinMain(
	HINSTANCE	hInstance,
	HINSTANCE	hPrevInstance,
	LPTSTR		lpCmdLine,
	int		nCmdShow)
{
	WNDCLASSEX	wcex;
	HWND		hWnd;
	MSG		msg;
 
	// ウィンドウクラスの登録
	wcex.cbSize		= sizeof wcex;
	wcex.style		= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon		= LoadIcon(NULL, IDI_APPLICATION);
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW + 1);
	wcex.lpszMenuName	= NULL;
	wcex.lpszClassName	= g_atcClassName;
	wcex.hIconSm		= LoadIcon(NULL, IDI_APPLICATION);
	if (RegisterClassEx(&wcex) == 0) {
		return 0;
	}
 
	// ウィンドウの作成
	hWnd = CreateWindow(
		g_atcClassName,		// ClassName
		g_atcWindowName,	// WindowName
		WS_OVERLAPPEDWINDOW | WS_HSCROLL,	// Style
		CW_USEDEFAULT,		// x
		0,			// y
		CW_USEDEFAULT,		// Width
		0,			// Height
		NULL,			// WndParent
		NULL,			// Menu
		hInstance,
		NULL);
	if (hWnd == NULL) {
		return 0;
	}
 
	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);
 
	while (GetMessage(&msg, NULL, 0, 0)) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return (int)msg.wParam;
}
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	switch (uMsg) {
	case WM_PAINT:
		OnPaint(hWnd);
		break;
	case WM_HSCROLL:
		OnHScroll(hWnd, wParam, lParam);
		break;
	case WM_SIZE:
		OnSize(hWnd);
		break;
	case WM_CREATE:
		OnCreate(hWnd);
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	default:
		return DefWindowProc(hWnd, uMsg, wParam, lParam);
	}
	return 0;
}
 
void OnCreate(HWND hWnd)
{
	RECT	rcClient;
 
	GetClientRect(hWnd, &rcClient);
	g_siHorz.cbSize	= sizeof g_siHorz;
	g_siHorz.fMask	= SIF_RANGE | SIF_PAGE | SIF_POS | SIF_DISABLENOSCROLL;
	g_siHorz.nMin	= 0;
	g_siHorz.nMax	= WIDTH - 1;
	g_siHorz.nPage	= rcClient.right;
	g_siHorz.nPos	= 0;
	SetScrollInfo(hWnd, SB_HORZ, &g_siHorz, FALSE);
}
 
void OnSize(HWND hWnd)
{
	RECT	rcClient;
	int	iPosMax;
 
	GetClientRect(hWnd, &rcClient);
	g_siHorz.nPage	= rcClient.right;
	iPosMax		= g_siHorz.nMax - g_siHorz.nPage + 1;
	iPosMax		= max(iPosMax, 0);
	g_siHorz.nPos	= min(g_siHorz.nPos, iPosMax);
	SetScrollInfo(hWnd, SB_HORZ, &g_siHorz, TRUE);
}
 
void OnHScroll(HWND hWnd, WPARAM wParam, LPARAM lParam)
{
	SCROLLINFO	si;
	int		iPos;
	int		iPosMax;
 
	iPos = g_siHorz.nPos;
	switch (LOWORD(wParam)) {
	case SB_LINEUP:
		iPos -= 10;
		break;
	case SB_LINEDOWN:
		iPos += 10;
		break;
	case SB_PAGEUP:
		iPos -= g_siHorz.nPage;
		break;
	case SB_PAGEDOWN:
		iPos += g_siHorz.nPage;
		break;
	case SB_THUMBTRACK:
		si.cbSize	= sizeof si;
		si.fMask	= SIF_TRACKPOS;
		if (GetScrollInfo(hWnd, SB_HORZ, &si) != 0) {
			iPos = si.nTrackPos;
		}
		break;
	}
	iPosMax = g_siHorz.nMax - g_siHorz.nPage + 1;
	iPos = min(iPos, iPosMax);
	iPos = max(iPos, 0);
	if (iPos == g_siHorz.nPos) {
		return;
	}
	ScrollWindowEx(hWnd, g_siHorz.nPos - iPos, 0,
		NULL, NULL, NULL, NULL, SW_INVALIDATE | SW_ERASE);
	g_siHorz.nPos = iPos;
	SetScrollInfo(hWnd, SB_HORZ, &g_siHorz, TRUE);
	UpdateWindow(hWnd);
}
 
void OnPaint(HWND hWnd)
{
	HDC		hDC;
	PAINTSTRUCT	ps;
	RECT		rcClient;
	TCHAR		atcString[64];
 
	hDC = BeginPaint(hWnd, &ps);
	GetClientRect(hWnd, &rcClient);
 
	Ellipse(hDC, 0 - g_siHorz.nPos, 0, WIDTH - g_siHorz.nPos, HEIGHT);
 
	_stprintf_s(atcString, _countof(atcString), _T("W=%d H=%d"),
		rcClient.right, rcClient.bottom);
	TextOut(hDC, 0 - g_siHorz.nPos, 0, atcString, _tcslen(atcString));
	EndPaint(hWnd, &ps);
}