VC自绘按钮的实现（NO MFC）

 使用MFC的CBitmapButton或者CButtonST等类很容易在按钮上画出位图+文字的Button。但是如果不使用MFC该怎么画呢？下面就是纯粹的SDK做的位图+文字的Button：

// OwnerDrawBtn.cpp : Defines the entry point for the application.

//

#include "stdafx.h"

#include "resource.h"

#define ICON_HEIGHT 32

#define ICON_WIDTH 32

static HINSTANCE hInst; // current instance

static HICON hIcon = NULL;

static void InitializeDialog(HWND hwnd);

static void DrawTheIcon(HWND hButtonWnd, HDC* dc, BOOL bHasTitle, RECT* rpItem, RECT* rpTitle, BOOL bIsPressed, BOOL bIsDisabled);

static void PrepareImageRect(HWND hButtonWnd, BOOL bHasTitle, RECT* rpItem, RECT* rpTitle, BOOL bIsPressed, DWORD dwWidth, DWORD dwHeight, RECT* rpImage);

LRESULT CALLBACK DialogFunc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int APIENTRY WinMain(HINSTANCE hInstance,

HINSTANCE hPrevInstance,

LPSTR     lpCmdLine,

int       nCmdShow)

{

static char szAppName[] = "OWNERDRAWBUTTON";

HWND hwnd;

MSG msg;

WNDCLASSEX wndclass;



wndclass.cbSize   = sizeof(WNDCLASSEX);

wndclass.style   = CS_HREDRAW | CS_VREDRAW;

wndclass.lpfnWndProc = DialogFunc;

wndclass.cbClsExtra  = 0;

wndclass.cbWndExtra  = DLGWINDOWEXTRA;

wndclass.hInstance  = hInstance;

wndclass.hIcon   = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));

wndclass.hCursor  = LoadCursor(NULL, IDC_ARROW);

wndclass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);

wndclass.lpszMenuName = (LPCSTR)szAppName;

wndclass.lpszClassName = szAppName;

wndclass.hIconSm  = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));



RegisterClassEx(&wndclass);



hInst = hInstance; // get current instance.



hwnd = CreateDialog(hInstance, MAKEINTRESOURCE(IDD_DIALOG1), GetDesktopWindow(), (DLGPROC)DialogFunc);



ShowWindow(hwnd, nCmdShow);

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

{

if (!IsWindow(hwnd) || !IsDialogMessage(hwnd, &msg))

{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

}



return msg.wParam;

}

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

{

switch(message)

{

case WM_INITDIALOG:

InitializeDialog(hwnd);

break;

case WM_CREATE:

break;

case WM_COMMAND:

switch (LOWORD(wParam))

{

case IDOK:

::EndDialog(hwnd, LOWORD(wParam));

::PostQuitMessage(0);

break;

default:

break;

}

break;



case WM_DRAWITEM:

{

// draw the owner draw button

LPDRAWITEMSTRUCT lpDIS = (LPDRAWITEMSTRUCT) lParam;

if(lpDIS->CtlID != IDC_BMPBTN)

{

return (0);

}

HDC dc = lpDIS->hDC;

// button state

BOOL bIsPressed = (lpDIS->itemState & ODS_SELECTED);

BOOL bIsFocused  = (lpDIS->itemState & ODS_FOCUS);

BOOL bIsDisabled = (lpDIS->itemState & ODS_DISABLED);

RECT itemRect = lpDIS->rcItem;

::SetBkMode(dc, TRANSPARENT);

if (bIsFocused)

{

HBRUSH br = CreateSolidBrush(RGB(0,0,0)); 

::FrameRect(dc, &itemRect, br);

::InflateRect(&itemRect, -1, -1);

::DeleteObject(br);

}

COLORREF crColor = GetSysColor(COLOR_BTNFACE);

HBRUSH brBackground = CreateSolidBrush(crColor);

::FillRect(dc, &itemRect, brBackground);

::DeleteObject(brBackground);

// Draw pressed button

if (bIsPressed)

{

HBRUSH brBtnShadow = CreateSolidBrush(GetSysColor(COLOR_BTNSHADOW));

::FrameRect(dc, &itemRect, brBtnShadow);

::DeleteObject(brBtnShadow);

}

else // ...else draw non pressed button

{

UINT uState = DFCS_BUTTONPUSH | ((bIsPressed) ? DFCS_PUSHED : 0);

::DrawFrameControl(dc, &itemRect, DFC_BUTTON, uState);

}

// Read the button's title

char sTitle[100];

::GetWindowText(::GetDlgItem(hwnd, IDC_BMPBTN), sTitle, 100);

RECT captionRect = lpDIS->rcItem;

BOOL bHasTitle = (sTitle[0] != '\0');

DrawTheIcon(::GetDlgItem(hwnd, IDC_BMPBTN), &dc, bHasTitle, &lpDIS->rcItem, &captionRect, bIsPressed, bIsDisabled);

if (bHasTitle)

{// Draw the button's title

// Center text

RECT centerRect = captionRect;

::DrawText(dc, sTitle, -1, &captionRect, DT_WORDBREAK | DT_CENTER | DT_CALCRECT);

LONG captionRectWidth = captionRect.right - captionRect.left;

LONG captionRectHeight = captionRect.bottom - captionRect.top;

LONG centerRectWidth = centerRect.right - centerRect.left;

LONG centerRectHeight = centerRect.bottom - centerRect.top;

::OffsetRect(&captionRect, (centerRectWidth - captionRectWidth)/2, (centerRectHeight - captionRectHeight)/2);

::SetBkMode(dc, TRANSPARENT);

if (bIsDisabled)

{

::OffsetRect(&captionRect, 1, 1);

::SetTextColor(dc, ::GetSysColor(COLOR_3DHILIGHT));

::DrawText(dc, sTitle, -1, &captionRect, DT_WORDBREAK | DT_CENTER);

::OffsetRect(&captionRect, -1, -1);

::SetTextColor(dc, ::GetSysColor(COLOR_3DSHADOW));

::DrawText(dc, sTitle, -1, &captionRect, DT_WORDBREAK | DT_CENTER);

}

else

{

::SetTextColor(dc, ::GetSysColor(COLOR_BTNTEXT));

::SetBkColor(dc, ::GetSysColor(COLOR_BTNFACE));

::DrawText(dc, sTitle, -1, &captionRect, DT_WORDBREAK | DT_CENTER);

}

// Draw the focus rect

if (bIsFocused)

{

RECT focusRect = itemRect;

::InflateRect(&focusRect, -3, -3);

::DrawFocusRect(dc, &focusRect);

}

return (TRUE);

} // End if

break;

}



case WM_DESTROY:

::PostQuitMessage(0);

return FALSE;

}



return FALSE;

}

void InitializeDialog(HWND hwnd)

{

hIcon = ::LoadIcon(hInst, MAKEINTRESOURCE(IDI_ICON1));

::SetFocus(::GetDlgItem(hwnd, IDC_BMPBTN));

}

static void DrawTheIcon(HWND hButtonWnd, HDC* dc, BOOL bHasTitle, RECT* rpItem, RECT* rpTitle, BOOL bIsPressed, BOOL bIsDisabled)

{

RECT rImage;

PrepareImageRect(hButtonWnd, bHasTitle, rpItem, rpTitle, bIsPressed, ICON_WIDTH, ICON_HEIGHT, &rImage);

// Ole'!

::DrawState(*dc,

NULL,

NULL,

(LPARAM)hIcon,

0,

rImage.left,

rImage.top,

(rImage.right - rImage.left),

(rImage.bottom - rImage.top),

(bIsDisabled ? DSS_DISABLED : DSS_NORMAL) | DST_ICON);

}

static void PrepareImageRect(HWND hButtonWnd, BOOL bHasTitle, RECT* rpItem, RECT* rpTitle, BOOL bIsPressed, DWORD dwWidth, DWORD dwHeight, RECT* rpImage)

{

RECT rBtn;

::CopyRect(rpImage, rpItem);

::GetClientRect(hButtonWnd, &rBtn);

if (bHasTitle == FALSE)

{

// Center image horizontally

LONG rpImageWidth = rpImage->right - rpImage->left;

rpImage->left += ((rpImageWidth - (long)dwWidth)/2);

}

else

{

// Image must be placed just inside the focus rect

LONG rpTitleWidth = rpTitle->right - rpTitle->left;

rpTitle->right = rpTitleWidth - dwWidth - 30;

rpTitle->left = 30;

rpImage->left = rBtn.right - dwWidth - 30;

// Center image vertically

LONG rpImageHeight = rpImage->bottom - rpImage->top;

rpImage->top += ((rpImageHeight - (long)dwHeight)/2);

}

}

关键点：必须在BUTTON的属性中设置：Owner draw，这样才会产生WM_DRAWITEM消息

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