_findfirst and fopen very slow - C / C++ / MFC Discussion Boards

Alexander Kindel6-Feb-19 13:44

6-Feb-19 13:44

I want the clickable area to be exactly the pixels that are part of the glyph, rather than anywhere in a bounding rectangle that contains the glyph. There are situations where music symbols nest together, or where parts of one are visible through the gaps in another. Using single rectangles for each would count one as obscuring parts of the other even though those parts are visible - any part that's visible should be clickable. I could define a set of bounding rectangles for each glyph in order to approximate them more tightly, but that's a lot of work I'd rather not do unless it turns out that the method I describe is too slow.

Re: memory device context coordinates

leon de boer6-Feb-19 15:55

leon de boer

6-Feb-19 15:55

You are dealing with TTF glyphs not a bitmap and you will need to understand how FUnits and the EMSquare work
TrueType fundamentals - Typography | Microsoft Docs[^]
The glyph is rendered to screen it never is a bitmap.

Now what you could do if font style isn't important is select a bitmap font and it will work much as you think.

Now if you want to do what you are doing with a TTF the function you want is called
GetGlyphOutlineA function | Microsoft Docs[^]
The DC will be your window you are drawing the text on so it matches one to one.

Now the problem is you will have an outline with beziers and lines and to be able to decide if you are in or out you need to scanline the contour at the y value and see if the point is between any two runline points of the scanline. Now if you follow all that this is the two scanline functions you need

/*-ScanlineLine2D-----------------------------------------------------------
 Scanline (sy) intersect and the line between the two vertices. The return
 will be 0 for no intersect or 1 and px will contain x intersect value.
 A horizontal line on the scan line will return no points as is consistant
 with scan lining.
 ---------------------------------------------------------------------------*/
short ScanlineLine2D(long x1, long y1,				// Vertex 1 (x1,y1)
					 long x2, long y2,				// Vertex 2 (x2,y2)
                     long sy, 		                // Scan line y value
                     long* px1){					// X interection pt
    long xt;
	double t;

	if (y2 == y1) return (0);										// Trivial fail horizontal line even if coincides with sy
	if (((sy >= y1) && (sy <= y2)) || ((sy >= y2) && (sy <= y1))){	// Check sy within range between y1 and y2
		
		// yt = (y2-y1)*t + y1		where 0 <= t <= 1, 
		// Re-arranging  t = (yt - y1)/(y2-y1)
		// Our yt value will be sy-epsilon so we don't get single corner points
		// t = ((sy-epsilon) - y1)/(y2-y1)
		// Re-arranging for floats   t = ((sy-y1)-epsilon)/(y2-y1)
		t = ((double)(sy-y1)-FLT_EPSILON)/(double)(y2-y1);		// Calculate t value

		if ( (t >= 0.0) && (t <= 1.0)) {				// Check valid 't'  0.0 <= t <= 1.0
			// xt = (x2-x1)*t + x1		where 0 <= t <= 1 
			xt = (long)((double)(x2-x1)*t) + x1;				// Calculate x at 't'
			if (px1) (*px1) = xt;											// Update intersect point x value
			return (1);												// We have 1 interesect point
		} else return (0);											// Invalid t value no intersection
	} else return (0);												// Return zero sy not in y1-y2 range
}


/*-ScanlineQuadBezier2D-----------------------------------------------------
 Scanline (sy) intersect and the quad bezier between the 3 control points.
 The return will be 0 for no intersect, 1 and px1 will contain x intersect 
 value or 2 and px1 and px2 will contain the x interect values.
 ---------------------------------------------------------------------------*/
short ScanlineQuadBezier2D(long x1, long y1,			// Vertex 1 (x1,y1) = On grid start pt
						   long x2, long y2,			// Vertex 2 (x2,y2) = Control Pt
						   long x3, long y3,			// Vertex 3 (x1,y1) = On grid End point
               			   long sy, 							// Scan line y value
                     	   long* px1, long* px2){		// Interection pt(s)

    short rslt;
	long dx0, dy0, dx1, dy1, dx2, dy2, xf;
	long* px;
    double tmf, tdf, tf, ymf;

	dx0 = x2 - x1;													// X diff between x2 and x1
	dy0 = y2 - y1;													// Y diff between y2 and y1
	dx1 = x3 - x2;													// X diff between x3 and x2
	dy1 = y3 - y2;													// Y diff between y3 and y2
	if ((dx0 == 0) && (dy0 == 0) && (dx1 == 0) && (dy1 == 0))		// All 3 points are one and same
		return (0);													// Drop point even if coincides with sy	
	if ((dx0 == 0) && (dy0 == 0))									// First 2 points are one and same
		return (ScanlineLine2D(x2, y2, x3, y3, sy, px1));			// Scanline as a line from (x2,y2)<->(x3,y3)
	if((dx1 == 0) && (dy1 == 0))									// Last two points are one and same	
		return (ScanlineLine2D(x1, y1, x2, y2, sy, px1));			// Scanline as a line from (x1,y1)<->(x2,y2)
	dx2 = (dx1-dx0);												// Difference between dx1 and dx0
	dy2 = (dy1-dy0);												// Differnece between dy1 and dy0
	if (dy2 != 0){													// y(t) = a*t*t + b*t + c
		// Calculate apex
		tmf = -(double)dy0/(double)dy2;								// 't' at apex point
		ymf = (double)y1 + FLT_EPSILON + tmf*(double)dy0;		// y at apex point
		tdf = ((double)sy - ymf)/(double)dy2;						// ''t' value at scanline
		if (tdf < 0.0) {									// If t value is invalid
			return (0);												// No intersect
		} else if (tdf != 0.0) tdf = sqrt(tdf);				// Take sqrt of t value
		rslt = 0;													// Preset intersect return count to zero
		px = px1;													// Preset intersect x ptr to px1
		tf = tmf - tdf;												// Calculate first test t value
		if ((tf >= 0.0) && (tf <= 1.0)){				// Valid 't'  0.0 <= t <= 1.0
			xf = (long)(((double)dx2*tf + (double)(dx0*2))*tf) + x1;// Calculate x point of intersec
			(*px) = xf;												// Transfer that result to *px
			rslt++;													// Increment intersect count
			px = px2;												// Advance point to px2
		};
		tf = tmf + tdf;												// Calculate second test t value
		if ((tf >= 0.0) && (tf <= 1.0)){				// Valid 't'  0.0 <= t <= 1.0
			xf = (long)(((double)dx2*tf + (double)(dx0*2))*tf) + x1;// Calculate x point of intersect
			(*px) = xf;												// Transfer that result to *px
			rslt++;													// Increment intersect count
			px = px2;												// Advance ptr to px2
		};		
		return (rslt);												// We can have one or two points returned
	} else if (dy0 != 0) {											// y(t) = b*t + c
		tf = ((double)(sy - y1) - FLT_EPSILON)/(double)(dy0*2);	// Calculate t of intersect
		if  ((tf >= 0.0) && (tf <= 1.0)){			// Valid 't'  0.0 <= t <= 1.0
			xf = (long)(((double)dx2*tf + (double)(dx0*2))*tf) + x1;// Calculate x point of intersect		
			(*px1) = xf;											// Transfer that result to px1
			return (1);												// Return 1 as intersect count
		} else return (0);											// Intersect is outside line segment
	} else return (0);												// Drop horizontal line even if coincides with sy
}

In vino veritas

Re: memory device context coordinates

Alexander Kindel7-Feb-19 23:23

Alexander Kindel

7-Feb-19 23:23

I was actually able to make what I originally had in mind work - I know the glyphs aren't *defined* as bitmaps, but rendering a glyph into a device context with a bitmap selected effectively makes it into it into a bitmap, and that's what I did - but analyzing the glyph outlines directly as you suggest is surely more efficient, so I'll probably try it too.

Re: memory device context coordinates

leon de boer8-Feb-19 21:43

leon de boer

8-Feb-19 21:43

Throw me an email to my personal account if you need a help. I have a pile of code for this stuff from CNC programs I have worked on for filling and inline/outlining the TTF fonts.

In vino veritas

Re: memory device context coordinates

Alexander Kindel8-Feb-19 9:22

Alexander Kindel

8-Feb-19 9:22

The reason the location of the glyph in the memory device context bitmap wasn't what I had expected was that I had long ago set the text alignment of the window device context to TA_BASELINE, but that of the newly-created memory device context was set to something else.

Menu bar on title bar of application

jung-kreidler6-Feb-19 2:23

jung-kreidler

6-Feb-19 2:23

Hi all,

I've had some preview on VS2019. They implemented a new feature, which places the application menu onto the title bar. Any thaughts on how to get this in an MFC application, too?

Regards,
Franz

Changed CMDIChildWnd to CMDIChildWndEx: does not show anything inside the frame

Dansveen4-Feb-19 2:02

Dansveen

4-Feb-19 2:02

Hi all

I have an MFC application that works perfectly with the CMDIChildWnd class, the frame is loaded and a splitterwnd is shown. I needed to create a new MFC application that uses the ribbon as the interface, and for that the only change I made was that my classes inherited from CMDIChildWndEx.
The two MFC applications should work with CMDIChildWndEx, but the old application does not show anything in the frames, it does not show errors, exceptions, it does not show inside the window. I already tried changing the style, forcing the frame size, changing the spliterwnd but nothing worked. See the LoadFrame code:
<pre lang="c++">void CMyFrame::ActivateFrame(int nCmdShow)
{
if (m_pMDIFrame && m_pMDIFrame->SendMessage(WM_IS_ENABLE_MDI_TAB))
{
LONG style = ::GetWindowLong(GetSafeHwnd(), GWL_STYLE) | WS_MAXIMIZE;
style &= ~WS_BORDER & ~WS_THICKFRAME & ~WS_DLGFRAME & ~WS_CAPTION;
::SetWindowLong(GetSafeHwnd(), GWL_STYLE, style);
style = ::GetWindowLong(GetSafeHwnd(), GWL_EXSTYLE);
style &= ~WS_EX_CLIENTEDGE;
::SetWindowLong(GetSafeHwnd(), GWL_EXSTYLE, style);
ShowWindow(SW_SHOWMAXIMIZED);
return;
}

if (m_bInsideMDIFrame)
{
CMDIChildWndEx::ActivateFrame(nCmdShow);
return;
}

long style = ::GetWindowLong(GetSafeHwnd(), GWL_STYLE);
style &= ~WS_MINIMIZEBOX & ~WS_MAXIMIZEBOX;
::SetWindowLong(GetSafeHwnd(), GWL_STYLE, style);
style = ::GetWindowLong(GetSafeHwnd(), GWL_EXSTYLE);
style &= ~WS_EX_CLIENTEDGE;
::SetWindowLong(GetSafeHwnd(), GWL_EXSTYLE, style);

SetWindowPos(NULL, 0, 0, 0, 0, SWP_DRAWFRAME | SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOSIZE);

CFrameWnd::ActivateFrame(SW_SHOWNOACTIVATE);
}

BOOL CMyFrame::LoadFrame(UINT nIDResource, DWORD dwDefaultStyle,
CWnd* pParentWnd, CCreateContext* pContext)
{
if (g_globalVariables.GetParentWnd() == NULL)
{
if (m_bInsideMDIFrame)
return CMDIChildWndEx::LoadFrame(nIDResource, dwDefaultStyle, pParentWnd, pContext);

return CFrameWnd::LoadFrame(nIDResource, dwDefaultStyle, pParentWnd, pContext);
}

ASSERT(m_nIDHelp == 0 || m_nIDHelp == nIDResource);

m_bInsideMDIFrame = FALSE;

m_nIDHelp = nIDResource; // ID for help context (+HID_BASE_RESOURCE)

CString strFullString;
if (strFullString.LoadString(nIDResource))
AfxExtractSubString(m_strTitle, strFullString, 0); // first sub-string

VERIFY(AfxDeferRegisterClass(AFX_WNDFRAMEORVIEW_REG));

dwDefaultStyle = WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS;

// attempt to create the window
LPCTSTR lpszClass = GetIconWndClass(dwDefaultStyle, nIDResource);
LPCTSTR lpszTitle = m_strTitle;

if (!CFrameWnd::Create(lpszClass, lpszTitle, dwDefaultStyle, rectDefault, g_globalVariables.GetParentWnd(), 0, 0, pContext))
return FALSE; // will self destruct on failure normally

// save the default menu handle
ASSERT(m_hWnd != NULL);

m_hMenuDefault = ::GetMenu(m_hWnd);

// load accelerator resource
LoadAccelTable(MAKEINTRESOURCE(nIDResource));

if (pContext == NULL) // send initial update
SendMessageToDescendants(WM_INITIALUPDATE, 0, 0, TRUE, TRUE);

return TRUE;
}</pre>

Another difference is if application uses MDI tabs, in my tests everything indicates that CMDIChildWndEx does not work without the ribbon.
Has anyone had the same problem? Please, can anyone help me?
Thank you very much

_findfirst and fopen very slow

cristiapi31-Jan-19 1:13

cristiapi

31-Jan-19 1:13

I have about 1800 text files in a dir and their number is slowly growing (several files in a day). The size of a file is about 40 kB.
I need to enumerate all the file with the ".states" extension, open the file, check to see if there is a line that starts with a particular sequence of 4 chars and if the line exists, I save the line in a std::vector.

I use the following code, but it takes very long time at the first run (the subsequent runs are very fast):

C++

struct _finddata_t fd; long hFile;
if((hFile=_findfirst("*.states", &fd))== -1L) return; // File not found
do {
    FILE *f= fopen(fd.name, "rS");
    while(fgets(buf, sizeof(buf), f)) {
        if(0 == _strnicmp(buf, "ABCD", 4)) {
            Save buf in a std::vector
            break;
        }
    }
    fclose(f);
} while(_findnext(hFile, &fd) == 0);
_findclose(hFile);

Is there any way to speedup the code?

If I merge all the files in a single file, I solve the problem, but I prefer to keep all the original files.