GetWindowRect(hWnd, &wnd);
hdc = BeginPaint(hWnd, &ps);
hdcMem = CreateCompatibleDC(hdc);
for (int i = 0; i < n; ++i)
{
HRGN rgn = CreateRoundRectRgn(0, 0, CARD_WIDTH, CARD_HEIGHT, 7, 7);
SetWindowRgn(cards[info[i].card], rgn, TRUE);
oldBitmap = SelectObject(hdcMem, cards[info[i].card]);
GetObject(cards[info[i].card], sizeof(bitmap), &bitmap);
BitBlt(hdc, info[i].pos.x, info[i].pos.y, bitmap.bmWidth, bitmap.bmHeight, hdcMem, 0, 0, SRCCOPY);
SelectObject(hdcMem, oldBitmap);
}
I have problem with cutting corners for bitmap picture.
GetWindowRect(hWnd, &wnd);
hdc = BeginPaint(hWnd, &ps);
hdcMem = CreateCompatibleDC(hdc);
for (int i = 0; i < n; ++i)
{
HRGN rgn = CreateRoundRectRgn(info[i].pos.x, info[i].pos.y, info[i].pos.x + CARD_WIDTH, info[i].pos.y + CARD_HEIGHT, 7, 7);
SelectClipRgn(hdc, rgn);
oldBitmap = SelectObject(hdcMem, cards[info[i].card]);
GetObject(cards[info[i].card], sizeof(bitmap), &bitmap);
BitBlt(hdc, info[i].pos.x, info[i].pos.y, bitmap.bmWidth, bitmap.bmHeight, hdcMem, 0, 0, SRCCOPY);
SelectObject(hdcMem, oldBitmap);
}
Thanks to Jonathan Potter.
Related
I'm studying WinAPI double buffering, and when I run the code below, the screen flickers too much. I think I did it right, but where is the problem?
Draw memdc1 and memdc2 to memdc, and memdc to hdc.
switch (iMsg)
{
case WM_CREATE:
hdc = GetDC(hwnd);
GetClientRect(hwnd, &clientRt);
PlaceCenterScreen(hwnd);
SetTimer(hwnd, 1, 10, NULL);
hMixBit = CreateCompatibleBitmap(hdc, 819, 614);
hHouseBit = (HBITMAP)LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_HOUSE));
hTigerBit = (HBITMAP)LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_TIGER));
ReleaseDC(hwnd, hdc);
break;
case WM_TIMER:
posX += 3;
InvalidateRgn(hwnd, NULL, true);
break;
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
memdc = CreateCompatibleDC(hdc);
memdc1 = CreateCompatibleDC(memdc);
memdc2 = CreateCompatibleDC(memdc);
oldHouseBit = (HBITMAP)SelectObject(memdc1, hHouseBit);
oldTigerBit = (HBITMAP)SelectObject(memdc2, hTigerBit);
oldMixBit = (HBITMAP)SelectObject(memdc, hMixBit);
BitBlt(memdc, 0, 0, 819, 614, memdc1, 0, 0, SRCCOPY);
BitBlt(memdc, posX, 0, 67, 47, memdc2, 0, 0, SRCCOPY);
BitBlt(hdc, 0, 0, 819, 614, memdc, 0, 0, SRCCOPY);
SelectObject(memdc1, oldHouseBit);
SelectObject(memdc2, oldTigerBit);
SelectObject(memdc, oldMixBit);
I tried to color customize menu items (pure WinAPI). But there is a line in the menu bar which does not draw with MenuInfo.hbrBack color. If the mouse cursor hover above items a part of this line is redrawn. But if I resize the window the line will return. And in the area of menu bar where no items the line drawn constantly. How can I draw over this annoying line?
#include <windows.h>
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
struct
{
COLORREF text = RGB(200, 200, 250);
COLORREF clientBorder = RGB(120, 0, 0);
COLORREF clientBackground = RGB(100, 100, 100);
COLORREF itemBorder = RGB(0, 0, 255);
COLORREF itemBackground = RGB(0, 120, 0);
COLORREF pink = RGB(255, 0, 255);
} colorTheme;
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow)
{
MSG msg;
WNDCLASSEX wc;
wc.cbSize = sizeof(wc);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WndProc;
wc.lpszMenuName = NULL;
wc.lpszClassName = "MainWindow";
wc.cbWndExtra = NULL;
wc.cbClsExtra = NULL;
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);
wc.hIconSm = LoadIcon(NULL, IDI_WINLOGO);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = CreateSolidBrush(colorTheme.clientBackground);
wc.hInstance = hInst;
RegisterClassEx(&wc);
HWND hMainWnd = CreateWindow(
"MainWindow",
"MainWindow",
WS_OVERLAPPEDWINDOW,
100, 100, 450, 120,
(HWND)NULL, NULL, HINSTANCE(hInst), NULL);
HMENU hMenu = CreateMenu();
HMENU hMenuSub1 = CreatePopupMenu();
HMENU hMenuSub2 = CreatePopupMenu();
HMENU hMenuSub3 = CreatePopupMenu();
AppendMenu(hMenu, MF_OWNERDRAW | MF_POPUP, (UINT)hMenuSub1, "SubMenu1");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item01");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item02");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item03");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item04");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item05");
AppendMenu(hMenu, MF_OWNERDRAW | MF_POPUP, (UINT)hMenuSub2, "SubMenu2");
AppendMenu(hMenu, MF_OWNERDRAW | MF_POPUP, (UINT)hMenuSub3, "SubMenu3");
MENUINFO menuInfo;
menuInfo.cbSize = sizeof(menuInfo);
menuInfo.fMask = MIM_BACKGROUND;
menuInfo.hbrBack = CreateSolidBrush(colorTheme.pink);
SetMenuInfo(hMenu, &menuInfo);
SetMenu(hMainWnd, hMenu);
ShowWindow(hMainWnd, nCmdShow);
while (GetMessage(&msg, NULL, NULL, NULL)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg) {
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hDC = BeginPaint(hWnd, &ps);
HFONT hApplicationFont;
LOGFONT applicationFont;
applicationFont.lfHeight = 16;
applicationFont.lfWidth = 6;
applicationFont.lfEscapement = 0;
applicationFont.lfOrientation = 0;
applicationFont.lfWeight = FW_NORMAL;
applicationFont.lfItalic = FALSE;
applicationFont.lfUnderline = FALSE;
applicationFont.lfStrikeOut = FALSE;
applicationFont.lfCharSet = DEFAULT_CHARSET;
applicationFont.lfOutPrecision = OUT_DEFAULT_PRECIS;
applicationFont.lfClipPrecision = CLIP_DEFAULT_PRECIS;
applicationFont.lfQuality = ANTIALIASED_QUALITY;
applicationFont.lfPitchAndFamily = DEFAULT_PITCH;
strcpy_s(applicationFont.lfFaceName, "Arial");
hApplicationFont = CreateFontIndirectA(&applicationFont);
SelectObject(hDC, hApplicationFont);
SelectObject(hDC, GetStockObject(DC_PEN));
SetDCPenColor(hDC, colorTheme.clientBorder);
SelectObject(hDC, GetStockObject(DC_BRUSH));
SetDCBrushColor(hDC, colorTheme.clientBackground);
RECT clientRect;
GetClientRect(hWnd, &clientRect);
Rectangle(hDC, 0, 0, clientRect.right, clientRect.bottom);
EndPaint(hWnd, &ps);
break;
}
case WM_MEASUREITEM:
{
LPMEASUREITEMSTRUCT itemStruct = (LPMEASUREITEMSTRUCT)lParam;
const char* str = (const char*)(itemStruct->itemData);
SIZE strSize;
HDC hDC = GetDC(hWnd);
GetTextExtentPoint32(hDC, str, lstrlen(str), &strSize);
itemStruct->itemWidth = strSize.cx;
itemStruct->itemHeight = 30;
ReleaseDC(hWnd, hDC);
return TRUE;
break;
}
case WM_DRAWITEM:
{
LPDRAWITEMSTRUCT itemStruct = (LPDRAWITEMSTRUCT)lParam;
HDC hDC = itemStruct->hDC;
SelectObject(hDC, GetStockObject(DC_PEN));
SetDCPenColor(hDC, colorTheme.itemBorder);
SelectObject(hDC, GetStockObject(DC_BRUSH));
SetDCBrushColor(hDC, colorTheme.itemBackground);
SetTextColor(hDC, colorTheme.text);
SetBkMode(hDC, TRANSPARENT);
Rectangle(hDC, itemStruct->rcItem.left,
itemStruct->rcItem.top,
itemStruct->rcItem.right,
itemStruct->rcItem.bottom + 1);
DrawText(hDC, (const char*)(itemStruct->itemData), -1, &(itemStruct->rcItem), DT_SINGLELINE | DT_CENTER | DT_VCENTER);
break;
}
case WM_DESTROY:
{
PostQuitMessage(NULL);
break;
}
default:
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
return NULL;
}
It seems to be part of the non-client area of the window. If that's the case then to paint there you need to handle WM_NCPAINT.
It is a single pixel line above the window's client area, so for example if I add the following code to your program I can paint it in red.
// ... in the WNDPROC
case WM_NCPAINT:
{
auto result = DefWindowProc(hWnd, WM_NCPAINT, wParam, lParam);
HDC hdc = GetWindowDC(hWnd);
RECT r = GetNonclientMenuBorderRect(hWnd);
HBRUSH red = CreateSolidBrush(RGB(255, 0, 0));
FillRect(hdc, &r, red);
DeleteObject(red);
ReleaseDC(hWnd, hdc);
return result;
}
// ... elsewhere
RECT MapRectFromClientToWndCoords(HWND hwnd, const RECT& r)
{
RECT wnd_coords = r;
// map to screen
MapWindowPoints(hwnd, NULL, reinterpret_cast<POINT*>(&wnd_coords), 2);
RECT scr_coords;
GetWindowRect(hwnd, &scr_coords);
// map to window coords by substracting the window coord origin in
// screen coords.
OffsetRect(&wnd_coords, -scr_coords.left, -scr_coords.top);
return wnd_coords;
}
RECT GetNonclientMenuBorderRect(HWND hwnd)
{
RECT r;
GetClientRect(hwnd, &r);
r = MapRectFromClientToWndCoords(hwnd, r);
int y = r.top - 1;
return {
r.left,
y,
r.right,
y+1
};
}
Now an issue with the above code is that it is over-painting the rectangle after the default non-client painting is done. In theory this could flicker; in practice I don't notice a flicker. If it did flicker, however, a safer way to do this would be to modify the WPARAM you pass to DefWindowProc(hWnd, WM_NCPAINT, ... ) such that it is the handle to a region that is the region passed to WM_NCPAINT minus the rectangle you want to paint. This doesnt seem necessary to me, for whatever reason.
If you are using themes / visual styles, which pretty much everything is nowadays, you can't override a lot of the menu styling without using a workaround like https://github.com/adzm/win32-custom-menubar-aero-theme which also uses the same approach to get rid of the white line. Note that you will need to handle this in WM_NCPAINT and WM_NCACTIVATE.
i'm sorry for what i did. i edited.
i'd like to use Fillrect on 32bit HBITMAP which is Created with CreateDIBSection
but i can't make rect visible in color that i want to.
(i Drawed a fillrect with CreateSolidBrush blue(RGB(0, 0, 255)) on 32bit HBITMAP(hdcbmp), but it doesn't appear blue.)
here is source code
is there anyway to show rect color that i want to?
sorry for my poor english.
void DrawAlphaBitmap(HWND hWnd, ULONG uWidth, ULONG uHeight)
{
BLENDFUNCTION bf;
HBITMAP hbitmap;
HBITMAP hOldBitmap;
BITMAPINFO bmi;
PVOID pvBits;
HDC hdcwnd = GetDC(hWnd);
HDC hdcbmp = CreateCompatibleDC(hdcwnd);
ZeroMemory(&bmi, sizeof(BITMAPINFO));
bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmi.bmiHeader.biWidth = uWidth;
bmi.bmiHeader.biHeight = uHeight;
bmi.bmiHeader.biPlanes = 1;
bmi.bmiHeader.biBitCount = 32;
bmi.bmiHeader.biCompression = BI_RGB;
bmi.bmiHeader.biSizeImage = bmi.bmiHeader.biWidth * bmi.bmiHeader.biHeight * 4;
hbitmap = CreateDIBSection(hdcbmp, &bmi, DIB_RGB_COLORS, &pvBits, NULL, 0x0);
hOldBitmap = (HBITMAP)SelectObject(hdcbmp, hbitmap);
bf.BlendOp = AC_SRC_OVER;
bf.BlendFlags = 0;
bf.SourceConstantAlpha = 0xff;
bf.AlphaFormat = AC_SRC_ALPHA;
RECT rc2 = { 100, 100, 200, 200 };
FillRect(hdcbmp, &rc2, CreateSolidBrush(RGB(0, 0, 255)));
AlphaBlend(hdcwnd, 0, 0, uWidth, uHeight, hdcbmp, 0, 0, uWidth, uHeight, bf);
SelectObject(hdcbmp, hOldBitmap);
DeleteObject(hbitmap);
DeleteDC(hdcbmp);
ReleaseDC(hWnd, hdcwnd);
}
From documentation for BLENDFUNCTION:
AlphaFormat:
This flag is set when the bitmap has an Alpha channel (that is, per-pixel alpha).
In this case, alpha channel is not set. CreateDIBSection initializes the alpha values to zero. When AC_SRC_ALPHA is set, AlphaBlend ignores pixels whose alpha value is zero. Modify your code as follows:
//bf.AlphaFormat = AC_SRC_ALPHA; <- remove
bf.AlphaFormat = 0; //replace with 0
Side note, you have resource leak in creation of HBRUSH handle. Change the code to
HBRUSH hbrush = CreateSolidBrush(RGB(0, 0, 255));
RECT rc2 = { 0, 0, w, h };
FillRect(memdc, &rc2, hbrush);
DeleteObject(hbrush);
Ideally, your function prototype should be void DrawAlphaBitmap(HDC hdc, ULONG uWidth, ULONG uHeight); so that HDC can be passed directly, for example from BeginPaint/EndPaint in WM_PAINT message.
I am trying to print a brush pattern like I see on the screen but I get different results depending on the printer DC. I use Microsoft PDF or a printer. Both are printing using 600 DPI. I'm trying to get the same pattern when I'm printing by resizing the bitmap that is being used by CreatePatternBrush. This seems to work fine for Microsoft PDF but not for the printer. The pattern using the printer is way too large. Any clue why?
OnBnClickedButtonprint is where I'm trying to print where ScaleBitmap is done on the pattern bitmap. Here is the code:
#include "stdafx.h"
#include "Printing.h"
#include "PrintingDlg.h"
#include "afxdialogex.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
RECT rcSmall = { 25, 25, 75, 75 };
RECT rcBig = { 55, 55, 255, 255 };
RECT rcWholeArea = { 0, 0, 300, 300 };
COLORREF crRed = RGB(255, 0, 0);
COLORREF crGreen = RGB(0, 255, 0);
COLORREF crBlue = RGB(0, 0, 255);
COLORREF crWhite = RGB(255, 255, 255);
COLORREF crBlack = RGB(0, 0, 0);
CPrintingDlg::CPrintingDlg(CWnd* pParent /*=NULL*/)
: CDialogEx(IDD_PRINTING_DIALOG, pParent)
{
WORD HatchBits[8] = { 0xfe, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe };
m_hBitmap = ::CreateBitmap(8, 8, 1, 1, HatchBits);
}
void CPrintingDlg::DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
}
BEGIN_MESSAGE_MAP(CPrintingDlg, CDialogEx)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_BN_CLICKED(IDC_BUTTONPRINT, &CPrintingDlg::OnBnClickedButtonprint)
END_MESSAGE_MAP()
// CPrintingDlg message handlers
BOOL CPrintingDlg::OnInitDialog()
{
CDialogEx::OnInitDialog();
return TRUE; // return TRUE unless you set the focus to a control
}
HBITMAP CPrintingDlg::ScaleBitmap(HDC hdc, HBITMAP hBitmapSrc)
{
double gDPIScaleX = GetDeviceCaps(hdc, LOGPIXELSX) / 96.0f;
double gDPIScaleY = GetDeviceCaps(hdc, LOGPIXELSY) / 96.0f;
if (gDPIScaleX == 1.0 && gDPIScaleY == 1.0)
return hBitmapSrc;
// Get logical coordinates
BITMAP bm;
::GetObject(hBitmapSrc, sizeof(bm), &bm);
int iWidth = (int)(bm.bmWidth * gDPIScaleX);
int iHeight = (int)(bm.bmHeight * gDPIScaleY);
// Select the source DC
HDC hdcSrc = ::CreateCompatibleDC(hdc);
HBITMAP hBitmapOldSrc = (HBITMAP)::SelectObject(hdcSrc, hBitmapSrc);
// Create the bitmap and select the destination DC
HDC hdcDst = ::CreateCompatibleDC(hdc);
HBITMAP hBitmapDst = ::CreateCompatibleBitmap(hdcDst, iWidth, iHeight);
HBITMAP hBitmapOldDst = (HBITMAP)::SelectObject(hdcDst, hBitmapDst);
// Resize
::StretchBlt(hdcDst, 0, 0, iWidth, iHeight, hdcSrc, 0, 0, bm.bmWidth, bm.bmHeight, SRCCOPY);
// Reselect the old bitmaps
::SelectObject(hdcSrc, hBitmapOldSrc);
::SelectObject(hdcDst, hBitmapOldDst);
// Delete the resources
DeleteDC(hdcSrc);
DeleteDC(hdcDst);
return hBitmapDst;
}
RECT CPrintingDlg::ScaleRect(HDC hdc, RECT rcOriginal)
{
double gDPIScaleX = GetDeviceCaps(hdc, LOGPIXELSX) / 96.0f;
double gDPIScaleY = GetDeviceCaps(hdc, LOGPIXELSY) / 96.0f;
if (gDPIScaleX == 1.0 && gDPIScaleY == 1.0)
return rcOriginal;
RECT rcScaled;
rcScaled.left = (long)(rcOriginal.left * gDPIScaleX);
rcScaled.right = (long)(rcOriginal.right * gDPIScaleX);
rcScaled.top = (long)(rcOriginal.top * gDPIScaleY);
rcScaled.bottom = (long)(rcOriginal.bottom * gDPIScaleY);
return rcScaled;
}
void CPrintingDlg::DrawRectangle(HDC hdc, RECT rect, COLORREF cr)
{
HPEN hPen = ::CreatePen(PS_SOLID, 1, cr);
::SelectObject(hdc, hPen);
HBRUSH hBrush = ::CreateSolidBrush(cr);
::SelectObject(hdc, hBrush);
::Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
}
void CPrintingDlg::DrawPatternRectangle(HDC hdc, HBITMAP hBitmap, RECT rect, COLORREF cr)
{
int oldROP2 = 0;
HPEN hPen = ::CreatePen(PS_SOLID, 1, crBlack);
::SelectObject(hdc, hPen);
HBRUSH hPatternBrush = ::CreatePatternBrush(hBitmap);
::SelectObject(hdc, hPatternBrush);
::SetTextColor(hdc, crBlack);
if (::GetROP2(hdc) == R2_COPYPEN)
{
::SetBkColor(hdc, crWhite);
oldROP2 = ::SetROP2(hdc, R2_MASKNOTPEN);
::Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
::SetBkColor(hdc, cr);
::SetROP2(hdc, R2_MERGEPEN);
::Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
::SetROP2(hdc, oldROP2);
}
else
{
::SetBkColor(hdc, cr);
::Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
}
}
void CPrintingDlg::OnPaint()
{
CPaintDC hdc(this);
DrawRectangle(hdc, rcWholeArea, crWhite);
DrawRectangle(hdc, rcSmall, crGreen);
DrawPatternRectangle(hdc, m_hBitmap, rcBig, crRed);
}
void CPrintingDlg::OnBnClickedButtonprint()
{
CPrintDialog dlgPrint(FALSE, PD_NOSELECTION);
dlgPrint.GetDefaults();
dlgPrint.m_pd.Flags &= ~PD_RETURNDEFAULT;
DEVMODE* dm = (DEVMODE*)GlobalLock(dlgPrint.m_pd.hDevMode);
dm->dmFields |= DM_ORIENTATION;
dm->dmOrientation = DMORIENT_LANDSCAPE;
GlobalUnlock(dlgPrint.m_pd.hDevMode);
dlgPrint.DoModal();
HDC hdc = dlgPrint.GetPrinterDC();
DOCINFO docInfo;
ZeroMemory(&docInfo, sizeof(docInfo));
docInfo.cbSize = sizeof(docInfo);
docInfo.lpszDocName = _T("PrintTest");
StartDoc(hdc, &docInfo);
StartPage(hdc);
DrawRectangle(hdc, ScaleRect(hdc, rcWholeArea), crWhite);
DrawRectangle(hdc, ScaleRect(hdc, rcSmall), crGreen);
DrawPatternRectangle(hdc, ScaleBitmap(hdc, m_hBitmap), ScaleRect(hdc, rcBig), crRed);
EndPage(hdc);
EndDoc(hdc);
DeleteDC(hdc);
}
Here is what I'm trying to print:
I attampted to draw a irregular window with the UpdateLayeredWindow(), in msvc2008, xp sp3.
Here is part of my code:
//Add something(CreateWindowEx()):
hwndCyauWnd = CreateWindowEx(
/*WS_EX_TOOLWINDOW |*/ WS_EX_LEFT | WS_EX_LTRREADING | WS_EX_LAYERED,
lpwsCyauClassName,
lpwsCyauWndName,
WS_CLIPSIBLINGS | WS_POPUP,
GetSystemMetrics(SM_CXSCREEN)-320,
GetSystemMetrics(SM_CYSCREEN)-232,
320, 200,
NULL,
NULL,
hInstance,
NULL);
//Skip Lines
HDC hdcCyauWnd = GetDC(hwndCyauWnd);
HDC hdcBuffer = CreateCompatibleDC(hdcCyauWnd);
//HBITMAP hbmCyau = CreateCompatibleBitmap(hdcBuffer,120, 93);
//SelectObject(hdcBuffer, hbmCyau);
POINT ptZero = {0, 0};
POINT ptDrawPos = {0, 0};
RECT rctCyauWnd;
GetWindowRect(hwndCyauWnd, &rctCyauWnd);
SIZE szCyauWnd={rctCyauWnd.right - rctCyauWnd.left, rctCyauWnd.bottom - rctCyauWnd.top};
BLENDFUNCTION blendPixelFunction = { AC_SRC_OVER, 0, 100, AC_SRC_ALPHA};
Graphics gphCyauWnd(hdcBuffer);
Image imgCyau(L"surface0000.png");
gphCyauWnd.DrawImage(&imgCyau, 0, 0, 125, 93);
UpdateLayeredWindow(hwndCyauWnd,
hdcCyauWnd, &ptZero,
&szCyauWnd,
hdcBuffer, &ptZero,
0, //RGB(255, 255, 255),
&blendPixelFunction,
ULW_ALPHA);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
I have tried several method to use this function, but all failed, NOTHING APPEAR on the screen.
Could anybody tell me what happens and how to slove it?
Add:
Whole source file have been upload to my skydrive, anyone can edit, much appreciation! (I have become a poor underdog now...)
You mixed up GDI and GDI+, which is not a good idea. Here is a working example:
hWnd = CreateWindowEx(WS_EX_LAYERED, szWindowClass, szTitle, 0,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
// Load PNG
CImage img;
img.Load("BACKGR.png");
// Get image sizes
int nWidth = img.GetWidth();
int nHeight = img.GetHeight();
// Create memory DC
HDC hdcScreen = GetDC(NULL);
HDC hDC = CreateCompatibleDC(hdcScreen);
// Create memory bitmap
HBITMAP hBmp = CreateCompatibleBitmap(hdcScreen, nWidth, nHeight);
HBITMAP hBmpOld = (HBITMAP)SelectObject(hDC, hBmp);
// Draw image to memory bitmap (currently selected in memory DC)
img.Draw(hDC, 0, 0, nWidth, nHeight, 0, 0, nWidth, nHeight);
// Call UpdateLayeredWindow
BLENDFUNCTION blend = {0};
blend.BlendOp = AC_SRC_OVER;
blend.SourceConstantAlpha = 128;// half transparent
blend.AlphaFormat = AC_SRC_ALPHA;
POINT ptLocation = {0, 0};
SIZE szWnd = {nWidth, nHeight};
POINT ptSrc = {0, 0};
UpdateLayeredWindow(hWnd, hdcScreen, &ptLocation, &szWnd, hDC, &ptSrc, 0, &blend, ULW_ALPHA);
ShowWindow(hWnd, SW_SHOW);
SelectObject(hDC, hBmpOld);
DeleteObject(hBmp);
DeleteDC(hDC);
ReleaseDC(NULL, hdcScreen);
If you want GDI+ to draw to an image with an alpha channel, you have to draw to a Bitmap, not an HDC, and you have to specify that the Bitmap's format has alpha. To do that with an HBITMAP, you have to also point GDI+ to the bitmap bits.
Something like this:
BITMAPINFOHEADER bih;
HBITMAP hbmp;
HDC hdc;
void *bits;
bih.biSize = sizeof(bih);
bih.biWidth = width;
bih.biHeight = -height;
bih.biPlanes = 1;
bih.biBitCount = 32;
bih.biCompression = BI_RGB;
bih.biSizeImage = 0;
bih.biXPelsPerMeter = 0;
bih.biYPelsPerMeter = 0;
bih.biClrUsed = 0;
bih.biClrImportant = 0;
hdc = CreateCompatibleDC(NULL);
hbmp = CreateDIBSection(hdc, (BITMAPINFO*)&bih, DIB_RGB_COLORS, &bits, NULL, 0);
Bitmap bitmap(width, height, 0, PixelFormat32bppPARGB, bits);
Graphics graphics(bitmap);
graphics->DrawWhatever(...);
graphics->Flush();
SelectObject(hdc, hbitmap);
UpdateLayeredWindow(hwnd, hdc, ...