PreviewItem Class Reference

#include <PreviewItem.h>

Public Member Functions
	PreviewItem (HINSTANCE hInstance)
	~PreviewItem ()
void	UpdatePreviewItemWindow (int x, int y, char *path)
void	Show (int x, int y, char *path)
void	Hide ()
int	GetWidth ()

Public Attributes
HINSTANCE	hPreviewItemInstance
HWND	hBlackboxWnd
HWND	hPreviewItemWnd
HDC	cachedBackground
int	newItemX
int	newItemY
char	newItemPath [MAX_PATH]
int	PreviewItemX
int	PreviewItemY
int	PreviewItemWidth
int	PreviewItemHeight
bool	PreviewItemHidden

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

Constructor & Destructor Documentation

PreviewItem()

PreviewItem::PreviewItem

(

HINSTANCE

hInstance

)

{
    hPreviewItemWnd = NULL;
    hBlackboxWnd = GetBBWnd();
    hPreviewItemInstance = hInstance;
    cachedBackground = CreateCompatibleDC(NULL);
    PreviewItemX = PreviewItemY = PreviewItemHeight = newItemX = newItemY = 0;
    PreviewItemWidth = 150 * pSettings->scalingFactorHiDPI;
    PreviewItemHidden = true;
 
    // Start GDI+...
//  GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
 
    //====================
 
    // Register window class...
    WNDCLASS wc;
    ZeroMemory(&wc, sizeof(wc));
    wc.hInstance = hPreviewItemInstance;        // hInstance
    wc.lpfnWndProc = PreviewItemWindowProc;        // Window procedure
    wc.lpszClassName = szPreviewItemName;      // Window class name
    wc.hbrBackground = NULL;                    // No class background brush
    wc.style = NULL;                            // Class styles
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);   // Always display the regular arrow cursor
 
    if (!RegisterClass(&wc))
    {
        MessageBox(0, "Error registering preview item window class!", szPreviewItemName, MB_OK | MB_ICONERROR | MB_TOPMOST);
        Log("PreviewItem: Error registering window class!", NULL);
        return;
    }
 
    // Create preview item window...
    hPreviewItemWnd = CreateWindowEx(
        WS_EX_TOOLWINDOW | WS_EX_NOACTIVATE | WS_EX_LAYERED,   // window style
        szPreviewItemName,                                     // window class
        NULL,                                                   // window name
        WS_POPUP | WS_CLIPCHILDREN | WS_CLIPSIBLINGS,           // window parameters
        PreviewItemX,                                           // x position
        PreviewItemY,                                           // y position
        PreviewItemWidth,                                       // window width
        PreviewItemHeight,                                     // window height
        NULL, //pDesktop->hDesktopWnd,                          // owner window
        NULL,                                                   // no menu
        hPreviewItemInstance,                                   // hInstance
        NULL                                                    // no window creation data
    );
 
    if (!hPreviewItemWnd)
    {
        UnregisterClass(szPreviewItemName, hPreviewItemInstance); // Unregister window class
        MessageBox(0, "Error creating preview item window!", szPreviewItemName, MB_OK | MB_ICONERROR | MB_TOPMOST);
        Log("PreviewItem: Error creating window!", NULL);
        return;
    }
 
    ShowWindow(hPreviewItemWnd, SW_HIDE);
    SetWindowPos(hPreviewItemWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOMOVE);
    MakeSticky(hPreviewItemWnd); // Make the preview item window sticky... (i.e. shown regardless of the current workspace)
 
    //====================
 
    // Subscribe to Blackbox messages applicable to menu preview items...
    SendMessage(hBlackboxWnd, BB_REGISTERMESSAGE, (WPARAM)hPreviewItemWnd, (LPARAM)previewItemMessageSubscription);
}

~PreviewItem()

PreviewItem::~PreviewItem

(

)

{
    // Unsubscribe to previously subscribed Blackbox messages...
    SendMessage(hBlackboxWnd, BB_UNREGISTERMESSAGE, (WPARAM)hPreviewItemWnd, (LPARAM)previewItemMessageSubscription);
 
    if (hPreviewItemWnd) DestroyWindow(hPreviewItemWnd); // Destroy window....
    UnregisterClass(szPreviewItemName, hPreviewItemInstance); // Unregister window class...
    if (cachedBackground) DeleteDC(cachedBackground); // Delete the cached gradient...
 
    // Shutdown GDI+...
//  GdiplusShutdown(gdiplusToken);
}

Member Function Documentation

UpdatePreviewItemWindow()

void PreviewItem::UpdatePreviewItemWindow	(	int	x,
		int	y,
		char *	path )

{
    if (PreviewItemHidden) return;
 
    // Load the image using GDI+ to add support for JPG, PNG etc...
    // (nb. regular GDI LoadImage() only supports BMP images. GDI+ startup/shutdown is performed by MenuCommon.)
    HDC buf = CreateCompatibleDC(cachedBackground);
    HBITMAP image = NULL;
    wchar_t imagePathWC[MAX_PATH];
//  mbstowcs(imagePathWC, path, MAX_PATH);
    MultiByteToWideChar(CP_ACP, 0, path, strlen(path)+1, imagePathWC, MAX_PATH);
    Bitmap* bitmap = new Bitmap(imagePathWC, FALSE);
    int imageWidth = bitmap->GetWidth();
    int imageHeight = bitmap->GetHeight();
    bitmap->GetHBITMAP(0, &image);
    delete bitmap;
 
    //====================
 
    PreviewItemX = x;
 
    if (image == NULL) // Image loading failed...
    {
        PreviewItemHeight = (PreviewItemWidth * 9) / 16;
        PreviewItemY = y - (PreviewItemHeight / 2);
    }
    else // Image loading succeeded...
    {
        PreviewItemHeight = (PreviewItemWidth * imageHeight) / imageWidth;
        PreviewItemY = y - (PreviewItemHeight / 2);
    }
 
    int screenY = GetSystemMetrics(SM_YVIRTUALSCREEN);
    if (PreviewItemY < screenY) PreviewItemY = screenY;
    int screenHeight = GetSystemMetrics(SM_CYVIRTUALSCREEN);
    if ((PreviewItemY + PreviewItemHeight) > screenHeight) PreviewItemY = screenHeight - PreviewItemHeight;
 
    //====================
 
    RECT r;
    SetRect(&r, 0, 0, PreviewItemWidth, PreviewItemHeight);
 
    HDC hdc = GetWindowDC(hPreviewItemWnd);
    HBITMAP bufbmp = CreateCompatibleBitmap(hdc, r.right - r.left, r.bottom - r.top);
    DeleteObject(SelectObject(cachedBackground, bufbmp));
    ReleaseDC(hPreviewItemWnd, hdc);
 
    //====================
 
    // Draw background...
    SetRect(&r, 0, 0, PreviewItemWidth, PreviewItemHeight);
    HBRUSH brush = CreateSolidBrush(0x000000);
    FillRect(cachedBackground, &r, brush);
    DeleteObject(brush);
 
    //====================
 
    int previewBorder = 2 * pSettings->scalingFactorHiDPI;
 
    if (image != NULL)
    {
        // Draw scaled down image...
        DeleteObject(SelectObject(buf, image));
        SetStretchBltMode(cachedBackground, HALFTONE);
        StretchBlt(cachedBackground, previewBorder, previewBorder, PreviewItemWidth-(previewBorder*2), PreviewItemHeight-(previewBorder*2), buf, 0, 0, imageWidth, imageHeight, SRCCOPY);
        // ### Below: While AlphaBlend() can be used to draw 32bpp ARGB images with per pixel alpha transparency, it also scales images down
        // much less smoothly than StretchBlt() as it reverts from HALFTONE (i.e. pixel averaging) to COLORONCOLOR (i.e. pixel deleting) mode;
        // for more information see https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-alphablend ###
//      BLENDFUNCTION bf;
//      ZeroMemory(&bf, sizeof(BLENDFUNCTION));
//      bf.BlendOp = AC_SRC_OVER;
//      bf.SourceConstantAlpha = 255;
//      bf.AlphaFormat = AC_SRC_ALPHA;
//      AlphaBlend(cachedBackground, previewBorder, previewBorder, PreviewItemWidth-(previewBorder*2), PreviewItemHeight-(previewBorder*2), buf, 0, 0, imageWidth, imageHeight, bf);
        DeleteObject(image);
    }
    else
    {
        // Draw the path string only if the image couldn't be loaded...
        HFONT font = CreateFont(10, 0, 0, 0, FW_NORMAL, false, false, false, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY, DEFAULT_PITCH | FF_DONTCARE, "Segoe UI");
        HGDIOBJ oldfont = SelectObject(cachedBackground, font);
        SetBkMode(cachedBackground, TRANSPARENT);
        InflateRect(&r, -previewBorder, -previewBorder);
        DrawTextWithEffects(cachedBackground, r, path, DT_LEFT | DT_VCENTER | DT_NOPREFIX | DT_PATH_ELLIPSIS, 0xffffff, false, 0, false, 0, 0, 0);
        DeleteObject(SelectObject(cachedBackground, oldfont));
    }
 
    DeleteDC(buf);
 
    //====================
 
    if (bufbmp) DeleteObject(bufbmp);
 
    POINT pt;
    pt.x = PreviewItemX, pt.y = PreviewItemY;
    POINT ptSrc;
    ptSrc.x = 0, ptSrc.y = 0;
 
    BLENDFUNCTION bf;
    bf.BlendOp = AC_SRC_OVER;
    bf.BlendFlags = 0;
    bf.AlphaFormat = AC_SRC_ALPHA;
    bf.SourceConstantAlpha = (unsigned char)255;
 
    SIZE windowSize = { PreviewItemWidth, PreviewItemHeight };
    BOOL result = UpdateLayeredWindow(hPreviewItemWnd, NULL, &pt, &windowSize, cachedBackground, &ptSrc, 0, &bf, ULW_OPAQUE);
/*
    if (!cachedBackground) SendMessage(GetBBWnd(), BB_CONSOLEMESSAGE, (WPARAM)CONSOLE_INFORMATION_MESSAGE, (LPARAM)"xoblite -> PreviewItem -> Invalid cachedBackground!");
 
    if (result == 0)
    {
        int error = GetLastError();
        char msg[255];
        sprintf(msg, "xoblite -> PreviewItem -> UpdateLayeredWindow failed! [error code %d]", error);
        SendMessage(GetBBWnd(), BB_CONSOLEMESSAGE, (WPARAM)CONSOLE_ERROR_MESSAGE, (LPARAM)msg);
    }
*/
}

Show()

void PreviewItem::Show	(	int	x,
		int	y,
		char *	path )

{
    if (!strlen(path)) return;
 
    KillTimer(pPreviewItem->hPreviewItemWnd, PREVIEW_ITEM_TIMER);
 
    // Save the new preview item parameters...
    newItemX = x;
    newItemY = y;
    strcpy(newItemPath, path);
 
    // ... and display it after a short delay...
    // (nb. we do this to get smoother fast scrolling through parent menus,
    //  i.e. no loading of images on every single entry while scrolling)
    SetTimer(pPreviewItem->hPreviewItemWnd, PREVIEW_ITEM_TIMER, 200, (TIMERPROC)NULL);
}

Hide()

void PreviewItem::Hide

(

)

{
    if (!PreviewItemHidden)
    {
        KillTimer(pPreviewItem->hPreviewItemWnd, PREVIEW_ITEM_TIMER);
        PreviewItemHidden = true;
        ShowWindow(hPreviewItemWnd, SW_HIDE);
    }
}

GetWidth()

int PreviewItem::GetWidth

(

)

{
    return PreviewItemWidth;
}

Friends And Related Symbol Documentation

PreviewItemWindowProc

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

friend

{
 
    switch (message)
    {
        case WM_TIMER:
        {
            if (wParam == PREVIEW_ITEM_TIMER)
            {
                KillTimer(pPreviewItem->hPreviewItemWnd, PREVIEW_ITEM_TIMER);
                pPreviewItem->PreviewItemHidden = false;
                pPreviewItem->UpdatePreviewItemWindow(pPreviewItem->newItemX, pPreviewItem->newItemY, pPreviewItem->newItemPath);
                ShowWindow(pPreviewItem->hPreviewItemWnd, SW_SHOWNOACTIVATE);
                SetWindowPos(pPreviewItem->hPreviewItemWnd, HWND_TOP, 0, 0, 0, 0, SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOMOVE | SWP_NOOWNERZORDER);
            }
 
            return 0;
        }
        break;
 
        //====================
 
        case BB_RECONFIGURE:
        {
            pPreviewItem->Hide();
        }
        break;
 
        //====================
 
        case WM_CLOSE:
            return 0;
 
        //====================
 
        case WM_NCHITTEST:
            return HTCLIENT;
 
        //====================
 
        default:
            return DefWindowProc(hwnd, message, wParam, lParam);
 
            //====================
    }
    return 0;
}

Member Data Documentation

hPreviewItemInstance

HINSTANCE PreviewItem::hPreviewItemInstance

hBlackboxWnd

HWND PreviewItem::hBlackboxWnd

hPreviewItemWnd

HWND PreviewItem::hPreviewItemWnd

cachedBackground

HDC PreviewItem::cachedBackground

newItemX

int PreviewItem::newItemX

newItemY

int PreviewItem::newItemY

newItemPath

char PreviewItem::newItemPath[MAX_PATH]

PreviewItemX

int PreviewItem::PreviewItemX

PreviewItemY

int PreviewItem::PreviewItemY

PreviewItemWidth

int PreviewItem::PreviewItemWidth

PreviewItemHeight

int PreviewItem::PreviewItemHeight

PreviewItemHidden

bool PreviewItem::PreviewItemHidden