I import a picture(.bmp or .jpeg) as the background of a client view in MFC.
When I click Open, function CDrawToolView::OnFileOpen() open a window to choose a picture, then I use ShowBitmap(CDC* pDC,CString strPicPath) and ShowPic(CDC* pDC,CString strPicPath) to load the picture as backgroud and adjust the size of client view to fit the picture.
I want to set the picture translucent, so the background looks softer. Could some one help me or give some suggestion, thanks.
Here is my code:
void CDrawToolView::ShowBitmap(CDC* pDC,CString strPicPath)
{
HBITMAP hBitmap=(HBITMAP)LoadImage(NULL,strPicPath,IMAGE_BITMAP,0,0,LR_CREATEDIBSECTION|LR_DEFAULTSIZE|LR_LOADFROMFILE);
m_bitmap.Detach();
m_bitmap.Attach(hBitmap);
CRect rect;
GetClientRect(&rect);
CDC dcImage;
if (!dcImage.CreateCompatibleDC(pDC))
{
return;
}
BITMAP bm;
m_bitmap.GetBitmap(&bm);
dcImage.SelectObject(&m_bitmap);
pDC->StretchBlt(0,0,rect.right,rect.bottom,&dcImage,0,0,bm.bmWidth,bm.bmHeight,SRCCOPY);
}
void CDrawToolView::ShowPic(CDC* pDC,CString strPicPath)
{
if(!m_MyImage.IsNull())
m_MyImage.Destroy();
HRESULT hResult=m_MyImage.Load(strPicPath);
int iWidth=m_MyImage.GetWidth();
int iHeight=m_MyImage.GetHeight();
m_MyImage.Draw(pDC->m_hDC,0,0,iWidth,iHeight);
CRect client(0, 0, iWidth, iHeight);
client.bottom=client.bottom+::GetSystemMetrics(SM_CYMENU)+::GetSystemMetrics(SM_CYEDGE)*2;
client.right=client.right+::GetSystemMetrics(SM_CXEDGE)*2;
CFrameWnd* pFrame = GetParentFrame();
pFrame->CalcWindowRect(&client);
int width = client.Width();
int height = client.Height();
int y = (::GetSystemMetrics(SM_CYSCREEN) - height) / 2 + 100;
int x = (::GetSystemMetrics(SM_CXSCREEN) - width) / 2;
pFrame->SetWindowPos( NULL, x, y, width, height, SWP_NOACTIVATE | SWP_NOZORDER );
}
Use AlphaBlend instead of StretchBlt
CDC::AlphaBlend
Set SourceConstantAlpha in your BLENDFUNCTION struct to something like 128 (halfway between transparent and opaque), then adjust until it looks good.
AlphaFormat should be zero unless your usa a 32-bit bitmap with an alpha channel.
Related
Here's my objective: a) capture the device context for the entire screen; b) capture a background window device context (including the title bar); c) draw the desktop content on a buffer device context; d) draw the captured window content on the same buffer device context; e) display the drawn device context on a top window, simulating that the desired window is on top.
The issue is that the title bar isn't drawn on the new window, even though the GetWindowRect function seems to be working fine. That's because some other stuff is drawn instead of the title bar (usually the content of windows on the background when the target window is created).
This is my code right now:
case __SourceDC:
{
HDC desktop_dc = GetDC(NULL);
HWND target_hwnd = FindWindowA(NULL, "Everything");
HDC target_dc = GetWindowDC(target_hwnd);
RECT rc{};
GetWindowRect(target_hwnd, &rc);
RECT clrc{};
GetClientRect(target_hwnd, &clrc);
int width = rc.right - rc.left;
int height = rc.bottom - rc.top;
int x_dst = ((double)rc.left / SCREEN_WIDTH) * m_area.width;
int y_dst = ((double)rc.top / SCREEN_HEIGHT) * m_area.height;
int w_dst = ((double)width / SCREEN_WIDTH) * m_area.width;
int h_dst = ((double)height / SCREEN_HEIGHT) * m_area.height;
SetStretchBltMode(hdc, HALFTONE);
StretchBlt(hdc, 0, 0, m_area.width, m_area.height, desktop_dc, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, SRCCOPY);
StretchBlt(hdc, x_dst, y_dst, w_dst, h_dst, target_dc, 0, 0, width, height, SRCCOPY);
ReleaseDC(target_hwnd, target_dc);
ReleaseDC(NULL, desktop_dc);
}
break;
All the desktop content and the window content is correctly drawn, except for the title bar (and apparently the borders as well).
As you can see from the image, the myWnd window shows the desktop content, but the title bar is not displayed for the target window. Also, nothing changes when the target window is the foreground window.
What am I missing here? Is this behavior expected? Is StretchBlt working as intended by not capturing the content of the title bar?
Thanks in advance.
Here is my code :
void CPictureCtrl::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
if (mBIsPicLoaded) {
RECT rc;
this->GetClientRect(&rc);
INT width = (INT) rc.right - rc.left;
INT height = (INT)(rc.bottom - rc.top);
Graphics graphics(lpDrawItemStruct->hDC);
Image image(mPstream);
graphics.DrawImage(&image, (INT)rc.left, (INT)rc.top, width, height);
}
Is it possible to extract the buffer from graphics because the picture has been scaled and I would like to have it as base64 ?
Thanks
void Initialize_Window(void)
{
RECT rConsole;
GetWindowRect(GetConsoleWindow(), &rConsole);
SetWindowPos(GetConsoleWindow(), NULL, 0, 0, 800, 700, 0);
SetWindowLong(GetConsoleWindow(), GWL_STYLE, GetWindowLong(GetConsoleWindow(), GWL_STYLE) & ~(WS_SIZEBOX | WS_MAXIMIZEBOX));
SetWindowPos(GetConsoleWindow(), NULL, (GetSystemMetrics(SM_CXSCREEN) - rConsole.right - rConsole.left) / 2, (GetSystemMetrics(SM_CYSCREEN) - rConsole.bottom - rConsole.top) / 2, 0, 0, SWP_NOSIZE);
}
I'm trying to center my console window by using the code above, but seems like the window just moved to a random position on my screen every time I execute the program, any idea how to fix it?
You need (GetSystemMetrics(SM_CXSCREEN) - (rConsole.right - rConsole.left))/2 to get center.
Side note: you can use one SetWindowPos instead of two (and do not need to get window Rect)
const int width = 800;
const int height = 700;
//SetWindowLong()...
SetWindowPos(GetConsoleWindow(), NULL,
GetSystemMetrics(SM_CXSCREEN)/2 - width/2,
GetSystemMetrics(SM_CYSCREEN)/2 - height/2,
width, height, SWP_SHOWWINDOW);
Don't use GetSystemMetrics() for this because it only returns the metrics of the primary monitor. Multi monitor setups are quite common these days so users will be rightly upset if you ignore that.
In addition, a window normally should not be aligned to the physical monitor surface, but to the work area which excludes the taskbar(s). Yes, there can be multiple taskbars (called "appbars" in Windows slang) on either side of the screen. An exception where you would actually use the full physical surface are full screen windows.
To cover both aspects we can use MonitorFromWindow() and GetMonitorInfo().
First we get the "nearest" monitor from the window handle. This is the monitor that either shows the window completely or that has the biggest area of the window on it:
HWND hConsoleWnd = ::GetConsoleWindow();
HMONITOR hMonitor = ::MonitorFromWindow( hConsoleWnd, MONITOR_DEFAULTTONEAREST );
Then we get the work area rectangle of that monitor and center the window relative to that:
if( hMonitor )
{
MONITORINFO info{ sizeof(info) }; // set cbSize member and fill the rest with zero
if( ::GetMonitorInfo( hMonitor, &info ) )
{
int width = 800;
int height = 700;
int x = ( info.rcWork.left + info.rcWork.right ) / 2 - width / 2;
int y = ( info.rcWork.top + info.rcWork.bottom ) / 2 - height / 2;
::SetWindowPos( hConsoleWnd, nullptr, x, y, width, height,
SWP_NOZORDER | SWP_NOOWNERZORDER );
}
}
That's it. In a real-world application you should of course not hardcode the window size because it is a user preference. For first launch a default size can be reasonable but even that should not be hardcoded but scaled according to the Windows DPI settings.
I would like to create 32 bit color icons programmatically using C++ and Win API. For this purpose I use the following code which I found here.
HICON CreateSolidColorIcon(COLORREF iconColor, int width, int height)
{
// Obtain a handle to the screen device context.
HDC hdcScreen = GetDC(NULL);
// Create a memory device context, which we will draw into.
HDC hdcMem = CreateCompatibleDC(hdcScreen);
// Create the bitmap, and select it into the device context for drawing.
HBITMAP hbmp = CreateCompatibleBitmap(hdcScreen, width, height);
HBITMAP hbmpOld = (HBITMAP)SelectObject(hdcMem, hbmp);
// Draw your icon.
//
// For this simple example, we're just drawing a solid color rectangle
// in the specified color with the specified dimensions.
HPEN hpen = CreatePen(PS_SOLID, 1, iconColor);
HPEN hpenOld = (HPEN)SelectObject(hdcMem, hpen);
HBRUSH hbrush = CreateSolidBrush(iconColor);
HBRUSH hbrushOld = (HBRUSH)SelectObject(hdcMem, hbrush);
Rectangle(hdcMem, 0, 0, width, height);
SelectObject(hdcMem, hbrushOld);
SelectObject(hdcMem, hpenOld);
DeleteObject(hbrush);
DeleteObject(hpen);
// Create an icon from the bitmap.
//
// Icons require masks to indicate transparent and opaque areas. Since this
// simple example has no transparent areas, we use a fully opaque mask.
HBITMAP hbmpMask = CreateCompatibleBitmap(hdcScreen, width, height);
ICONINFO ii;
ii.fIcon = TRUE;
ii.hbmMask = hbmpMask;
ii.hbmColor = hbmp;
HICON hIcon = CreateIconIndirect(&ii);
DeleteObject(hbmpMask);
// Clean-up.
SelectObject(hdcMem, hbmpOld);
DeleteObject(hbmp);
DeleteDC(hdcMem);
ReleaseDC(NULL, hdcScreen);
// Return the icon.
return hIcon;
}
In principle the code works and I can use it to create colored icons at runtime using the Win API. However, I have some problems and questions about that code (and creating icons in general) which I would like to discuss.
The icons created with this function don't seem to be of 32 bit color depth. If I use a color like RGB(218, 112, 214) I would expect it to be some light purple. However, the actual displayed color is gray. How can I change the code such that the color is really 32 bit RGB?
The icon created is completly filled with the color, I would like to have a thin black boarder around it... how can this be achieved?
In the MSDN documentation (a bit downwards) it is mentioned that "Before closing, your application must use DestroyIcon to destroy any icon it created by using CreateIconIndirect. It is not necessary to destroy icons created by other functions. " However, in the documentation for e.g. CreateIcon in MSDN it is said that "When you are finished using the icon, destroy it using the DestroyIcon function." which is pretty much a contradiction. When do I actually have to destroy the icon?
Do these rules then also apply when I add the icon to an image list and this list to a combobox? I.e. do I have to clean up the image list and each associated icon?
Any help is highly appreciated.
When do I actually have to destroy the icon?
read about DestroyIcon
It is only necessary to call DestroyIcon for icons and cursors
created with the following functions: CreateIconFromResourceEx (if
called without the LR_SHARED flag), CreateIconIndirect, and
CopyIcon. Do not use this function to destroy a shared icon. A
shared icon is valid as long as the module from which it was loaded
remains in memory. The following functions obtain a shared icon.
LoadIcon
LoadImage (if you use the LR_SHARED flag)
CopyImage (if you use the LR_COPYRETURNORG flag and the hImage parameter is a shared icon)
CreateIconFromResource
CreateIconFromResourceEx (if you use the LR_SHARED flag)
so you need call DestroyIcon for not shared icon, when you are finished using it
ComboBoxEx not destroy image list which you assign to it with CBEM_SETIMAGELIST - so this image list must be valid until ComboBoxEx valid and you must destroy it yourself later.
ImageList_AddIcon
Because the system does not save hicon, you can destroy it after the
macro returns
in other words ImageList_AddIcon make copy of your icon, and you can destroy your original icon, after macro return
for create 32 bit color icon try code like this:
HICON CreateGradientColorIcon(COLORREF iconColor, int width, int height)
{
HICON hIcon = 0;
ICONINFO ii = { TRUE };
ULONG n = width * height;
if (PULONG lpBits = new ULONG[n])
{
PULONG p = lpBits;
ULONG x, y = height, t;
do
{
x = width, t = --y << 8;
do
{
*p++ = iconColor | ((t * --x) / n << 24);
} while (x);
} while (y);
if (ii.hbmColor = CreateBitmap(width, height, 1, 32, lpBits))
{
if (ii.hbmMask = CreateBitmap(width, height, 1, 1, 0))
{
hIcon = CreateIconIndirect(&ii);
DeleteObject(ii.hbmMask);
}
DeleteObject(ii.hbmColor);
}
delete [] lpBits;
}
return hIcon;
}
when I draw (DrawIconEx(, DI_IMAGE|DI_MASK)) this icon over green mesh I view next:
To everyone who has stumbled upon this solution, I am simply posting a little bit more of a documented solution to RbMm's answer. This is basically the same as his solution (maybe not as performant, I'm not sure):
static HICON CreateIconFromBytes(HDC DC, int width, int height, uint32* bytes) {
HICON hIcon = NULL;
ICONINFO iconInfo = {
TRUE, // fIcon, set to true if this is an icon, set to false if this is a cursor
NULL, // xHotspot, set to null for icons
NULL, // yHotspot, set to null for icons
NULL, // Monochrome bitmap mask, set to null initially
NULL // Color bitmap mask, set to null initially
};
uint32* rawBitmap = new uint32[width * height];
ULONG uWidth = (ULONG)width;
ULONG uHeight = (ULONG)height;
uint32* bitmapPtr = rawBitmap;
for (ULONG y = 0; y < uHeight; y++) {
for (ULONG x = 0; x < uWidth; x++) {
// Bytes are expected to be in RGB order (8 bits each)
// Swap G and B bytes, so that it is in BGR order for windows
uint32 byte = bytes[x + y * width];
uint8 A = (byte & 0xff000000) >> 24;
uint8 R = (byte & 0xff0000) >> 16;
uint8 G = (byte & 0xff00) >> 8;
uint8 B = (byte & 0xff);
*bitmapPtr = (A << 24) | (R << 16) | (G << 8) | B;
bitmapPtr++;
}
}
iconInfo.hbmColor = CreateBitmap(width, height, 1, 32, rawBitmap);
if (iconInfo.hbmColor) {
iconInfo.hbmMask = CreateCompatibleBitmap(DC, width, height);
if (iconInfo.hbmMask) {
hIcon = CreateIconIndirect(&iconInfo);
if (hIcon == NULL) {
Log::Warning("Failed to create icon.");
}
DeleteObject(iconInfo.hbmMask);
} else {
Log::Warning("Failed to create color mask.");
}
DeleteObject(iconInfo.hbmColor);
} else {
Log::Warning("Failed to create bitmap mask.");
}
delete[] rawBitmap;
return hIcon;
}
This solution will work with STB image library for loading images. So you can literally just load an image with stb, then pass the byte data to this function, and you will get an icon as a result. I had a little bit of trouble setting the icon as well, and eventually did this to get that to work:
HICON icon = CreateIconFromBytes(DC, image.m_Width, image.m_Height, image.m_Pixels);
SendMessage(WND, WM_SETICON, ICON_SMALL, (LPARAM)icon);
SendMessage(WND, WM_SETICON, ICON_BIG, (LPARAM)icon);
SendMessage(WND, WM_SETICON, ICON_SMALL2, (LPARAM)icon);
The only thing you should note about this is that you should probably use 3 different sized icons for the SendMessage() functions, but other than that this worked good for me :)
Edit:
Here's the links to official MSDN documentation as well.
https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-createiconindirect
https://learn.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createbitmap
https://learn.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createcompatiblebitmap
https://learn.microsoft.com/en-us/windows/win32/menurc/using-icons
I have an application that has drawn a grid using CDC (it has text, rectangle, and bitmaps). I want to take a screenshot of that finished grid when it is saved and use that screenshot as a "preview" for the file.
How can I take a screenshot of my application and save it?
Thank you,
Answer is here
void CScreenShotDlg::OnPaint()
{
// device context for painting
CPaintDC dc(this);
// Get the window handle of calculator application.
HWND hWnd = ::FindWindow( 0, _T( "Calculator" ));
// Take screenshot.
PrintWindow( hWnd,
dc.GetSafeHdc(),
0 );
}
Ultimately I ended up doing it this way because I wanted to capture even the hidden parts of the window (since the content extends beyond the screen and requires scrolling):
CDC* WindowToCaptureDC = AfxGetMainWnd()->GetWindowDC();
CDC CaptureDC;
CDC MemDC;
MemDC.CreateCompatibleDC(WindowToCaptureDC);
CaptureDC.CreateCompatibleDC(WindowToCaptureDC);
CBitmap CaptureBmp;
CBitmap ResizeBmp;
int pWidth = grid.tableWidth + grid.marginLeft*2;
int pHeight = grid.tableHeight + grid.marginBottom;
CaptureBmp.CreateCompatibleBitmap( WindowToCaptureDC, pWidth, pHeight);
CaptureDC.SelectObject(&CaptureBmp);
CBrush brush(RGB(255, 255, 255));
CaptureDC.SelectObject(&brush);
CaptureDC.Rectangle(0, 0, pWidth, pHeight);
///Drew items into CaptureDC like I did for OnDraw HERE///
double width = //desired width;
double height = //desired width;
//maintain aspect ratio
if(pWidth!=width || pHeight!=height)
{
double w = width/pWidth;
double h = height/pHeight;
if(w < h)
height = height*w;
else
width = width*h;
}
ResizeBmp.CreateCompatibleBitmap(WindowToCaptureDC, width, height);
MemDC.SelectObject(&ResizeBmp);
MemDC.StretchBlt(0, 0, width, height, &CaptureDC, 0, 0, pWidth, pHeight, SRCCOPY);
CImage TempImageObj;
TempImageObj.Attach((HBITMAP)ResizeBmp.Detach());
CString filePath = _T("LOCATION\\image.bmp");
TempImageObj.Save(filePath);