Re: Captions with files - C / C++ / MFC Discussion Boards

Sorry: I did not mean a preview image. I thought that, if I (say) photographed a diver in a hardhat diving suit, that it might be possible (after I moved the image onto my computer), to attach to the image a text comment that said "Hardhat diver, Albert Dock, Liverpool", and later to retrieve the comment knowing the filename, both within a Visual C++ for Windows program.

Never considered the problem before. After a little digging, I see that there's a .NET class for manipulating this data field (and others)

I suspect you won't find a (fairly easy) way of doing this without the use of .net

Here 'tis anyway: (c# .Net 4) system.windows.media.imaging.bitmapmetadata[^]
(c++ .Net 4) http://msdn.microsoft.com/en-us/library/ms748873.aspx#_metadata[^]

What I meant is: after the usual #include's:-

#include "targetver.h"
pragma once
#pragma comment(lib, "GdiPlus")
#include "targetver.h"

//#define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows
// Windows Header Files:
#include [windows.h]
#include [gdiplus.h]
#include [stdlib.h]
#include [malloc.h]
#include [memory.h]
#include [tchar.h]
#include [direct.h]
#include [stdio.h]
#include [errno.h]
/* the square brackets should be angle brackets */

FILE *F;

if I could wrote something like

setfilecaption(F,"Hardhat diver in Albert Dock, Liverpool");

getfilecaption(F,s,n); /* get file F's caption into string s, allow n bytes for it. */

modified 15-Apr-12 15:29pm.

Yes indeed, I already understood that. Nonetheless, thanks for taking for the effort to ensure you'd been clear. Thumbs Up | :thumbsup:

Edit: Think your keyboard is on the blink - you've got [] where there should be <>, also a } where there should be a )

Hint: You can enter the angle brackets using the html for them - i.e < is "& lt;" (andLessThanSemicolon)
and > = "& gt;" (andGreaterThanSemicolon)
Note: You just need to remove the space after the & character.

modified 15-Apr-12 15:16pm.

I know about angle brackets :: I used angle brackets first, but the editor treated the texts between the angle brackets as HTML codes and dropped them, and I was in a hurry, so I quickly cut-and-pasted it to Wordpad and changed the brackets. Sorry.

Please, after the usual #include's:-

#include .......

FILE *F;

is there something like this that I could write to set and get a file's text caption?

setfilecaption(F,"Hardhat diver in Albert Dock, Liverpool");

getfilecaption(F,s,n); /* get file F's caption into string s, allow n bytes for it. */

~~~~~~~~~~~~~~~~
Are these captions stored within the file descriptor, like the last-modified date and suchike, or are they stored in the Windows registry?

There's been no problem caused through your use of brackets.

No, there isn't something available with the interface you describe. The provided functions are available in .NET

See here: reading-writing-and-photo-metadata[^]

Furthermore, the data is stored in neither the directory entry (fileDescriptor) nor the Registry. See for yourself!

Got a Hex-Editor? (Nope? Get one - HxD is okay and $free)
I chose a JPG and did the following:

1) Right-click a photo
2) Select Properties, then the Details tab.
3) Add some unique text - I set the Camera Model field to "Canon EOS".
4) Hit apply
5) Now you can see that the photo's last modified date is the current date and time, furthermore, when you open the image in the HexEditor, you can easily find the text you entered.

It should be fairly easy to implement the getfilecaption function yourself, it's likely going to involve searching the file for some kind of marker (don't think you'll have to parse the whole file, including image data yourself) so that you know where the metadata starts.

Obviously, different filetypes have different structures, so you'd have to implement the function for each of the different image-file types you'd like to support.

Unfortunately, it is unlikely that writing the metadata will be so simple.

Here's a few pertinant links:

JFIF metadata[^]
(2nd search result): Does Exif metadata always get stored just after the jfif header?[^]

Thanks.

Hey again,

I was just doing some stuff with GDI+ the other night when I came across the functions available in gdi+ that would do this. Then sometime last night I recalled this thread.

Seems you don't need to be tied to using .NET, you can just use GDI+
It seems a little messy, though these pages should help you:

Reading and Writing Metadata[^]

EDIT:

C++

#include <gdiplus.h>    // needs gdiplus.lib
#include <gdiplus/Gdiplusimaging.h>    // contains tag names and ids

using namespace Gdiplus;

void onTestButton()
{
  GdiplusStartupInput gdiplusStartupInput;
   ULONG_PTR gdiplusToken;
   GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

   UINT count = 0;
   Image* image = new Image(L"test.jpg");

   // How many properties (pieces of metadata) are in the image?
   count = image->GetPropertyCount();
   if(count == 0)
      return;

   // Allocate a buffer to receive an array of PROPIDs.
   PROPID* propIDs = new PROPID[count];

   image->GetPropertyIdList(count, propIDs);

   // List the retrieved IDs.
   for(UINT j = 0; j < count; ++j)
   {
      int size;
      long *longPtr;//, myInt;
      PropertyItem* propertyItem = NULL;
      size = image->GetPropertyItemSize(propIDs[j]);

    // Allocate a buffer to receive the property item.
       propertyItem = (PropertyItem*)malloc(size);

       // Get the property item.
       image->GetPropertyItem(propIDs[j], size, propertyItem);

        //display it's value'
        if(propertyItem->type == PropertyTagTypeASCII)
        {
              printf("prop tag id: 0x%04X, (string) - value is: %s.\n", propIDs[j], propertyItem->value);
        }
        if(propertyItem->type == PropertyTagTypeLong)
        {
            longPtr = (long*) propertyItem->value;
            printf("prop tag id: 0x%04X, (long) - value is: %d.\n", propIDs[j], *longPtr);
        }
       free(propertyItem);
   }
   delete [] propIDs;
   delete image;
   GdiplusShutdown(gdiplusToken);
}

Output:

prop tag id: 0x010E, (string) - value is: Title.
prop tag id: 0x0131, (string) - value is: GIMP 2.6.8.
prop tag id: 0x0132, (string) - value is: 2012:04:15 10:25:45.
prop tag id: 0x013B, (string) - value is: Author.
prop tag id: 0x8298, (string) - value is: Copyright (c).
prop tag id: 0xA002, (long) - value is: 154.
prop tag id: 0xA003, (long) - value is: 205.
prop tag id: 0x0201, (long) - value is: 14382.
prop tag id: 0x0202, (long) - value is: 4631.

modified 4-May-12 15:10pm.

This is my code:

C++

#include "stdafx.h"
#include <windows.h>
#include <glut.h>
#include <glaux.h>
#pragma comment(lib,"opengl32.lib")
#pragma comment(lib,"glaux.lib")

LRESULT CALLBACK WindowProc(HWND,UINT,WPARAM,LPARAM);
void EnableOpenGL(HWND hwnd,HDC* ,HGLRC*);
void DisableOpenGL(HWND,HDC,HGLRC);

int APIENTRY WinMain(
	HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPSTR nCmdLine,
	int nCmdShow)
{
	WNDCLASSEX wcex;
	HWND hwnd;
	HDC hDC;
	HGLRC hRC;
	MSG msg;
	BOOL bQuit=FALSE;
	float i=0.0f,Angle=0.0f;

	wcex.cbSize=sizeof(WNDCLASSEX);
	wcex.cbClsExtra=0;
	wcex.cbWndExtra=0;
	wcex.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);
	wcex.hCursor=LoadCursor(NULL,IDC_CROSS);
	wcex.hIcon=LoadIcon(NULL,IDI_INFORMATION);
	wcex.hIconSm=NULL;
	wcex.hInstance=hInstance;
	wcex.lpfnWndProc=WindowProc;
	wcex.lpszClassName="OpenGL___Xiang";
	wcex.lpszMenuName=NULL;
	wcex.style=CS_HREDRAW|CS_VREDRAW;
	if (!RegisterClassEx(&wcex))
	{
		MessageBox(NULL,"注册类失败!","Error",MB_ICONERROR);
		return 0;
	}

	hwnd=CreateWindowEx(0,
		"OpenGL___Xiang","OpenGL Sample",WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,
		NULL,NULL,hInstance,0);
	ShowWindow(hwnd,SW_MAXIMIZE);

	EnableOpenGL(hwnd,&hDC,&hRC);
	while (!bQuit)
	{
		if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
		{
			if (msg.message==WM_QUIT)
			{
				bQuit=TRUE;
			}
			else
			{
				TranslateMessage(&msg);
				DispatchMessage(&msg);
			}				
		}
		else
		{
			glClearColor(0.0f,0.0f,0.0f,0.5f);
			glClearDepth(1.0f);
			glEnable(GL_SMOOTH);
			glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);

			glPushMatrix();
			glTranslatef(0.0f,0.0f,0.0f);
			glColor3f(0.0f,1.0f,0.0f);

			for (i=-50;i<=50;i+=1)
			{
                               ///Draw method is here
				glBegin(GL_LINES);
				glVertex3f(	-50,0,i);
				glVertex3f(	50,0,i);

				glVertex3f(	i,0,-50);
				glVertex3f(	i,0,50);
				glEnd();
			}
			glPopMatrix();

			SwapBuffers(hDC);
		}
	}
	DisableOpenGL(hwnd,hDC,hRC);
	DestroyWindow(hwnd);
	return msg.wParam;
}

LRESULT CALLBACK WindowProc(HWND hwnd,UINT msg,WPARAM wparam,LPARAM lparam)
{
	switch (msg)
	{
	case WM_CLOSE:
		PostQuitMessage(0);
		break;
	case WM_KEYDOWN:
		{
			switch (wparam)
			{
			case VK_ESCAPE:
				PostQuitMessage(0);
				break;
			}
		}
		break;
	default:
		return DefWindowProc(hwnd,msg,wparam,lparam);
	}
	return 0;
}

void EnableOpenGL(HWND hwnd,HDC* hDC,HGLRC* hRC)
{
	PIXELFORMATDESCRIPTOR pfd;
	int iFormat;
	*hDC=GetDC(hwnd);
	ZeroMemory(&pfd,sizeof(pfd));
	pfd.nSize=sizeof(pfd);
	pfd.nVersion=1;
	pfd.dwFlags=PFD_DRAW_TO_WINDOW|PFD_SUPPORT_OPENGL|PFD_DOUBLEBUFFER;
	pfd.iPixelType=PFD_TYPE_RGBA;
	pfd.cColorBits=24;
	pfd.cDepthBits=16;
	pfd.iLayerType=PFD_MAIN_PLANE;     //颜色输出单通道？
	iFormat=ChoosePixelFormat(*hDC,&pfd);
	SetPixelFormat(*hDC,iFormat,&pfd);
	*hRC=wglCreateContext(*hDC);
	wglMakeCurrent(*hDC,*hRC);
}

void DisableOpenGL(HWND hwnd,HDC hdc,HGLRC hRC)
{
	wglMakeCurrent(NULL,NULL);
	wglDeleteContext(hRC);
	ReleaseDC(hwnd,hdc);
}
//Just draw a single line,Why? how to draw?

Well, your program is operating in ORTHO mode (No perspective)

Therefore, changing the object's Z position while maintaining the object's X,Y position will not result in a different position on screen.

You are indeed drawing 100 lines(actually, 100 quads - with outline only style), they're all drawn on top of each other!

Try to substitute this for your own loop:

C++

for (i=0;i<50;i++)
        {
                           ///Draw method is here
            glBegin(GL_LINES);
            glVertex3f( -1,(i*0.02)-0.5,1);
            glVertex3f( 1,(i*0.02)-0.5,1);

            glVertex3f( -1,(i*0.02)-0.5,1);
            glVertex3f( 1,(i*0.02)-0.5,1);
            glEnd();
        }

You may wish to search for "OpenGL Viewing Transformation Matrix", for more discussion on the topic. gldPerspective and glvPerspective are functions I've used in the past, though they rely on glut - you've included it, however your code is typical of that wishing to avoid the use of GLUT.

Here's the functions I use for perspective:

C++

void gldPerspective(GLdouble fovx, GLdouble aspect, GLdouble zNear, GLdouble zFar)
{
    // This code is based off the MESA source for gluPerspective
    // *NOTE* This assumes GL_PROJECTION is the current matrix
    GLdouble xmin, xmax, ymin, ymax;
    GLdouble m[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

    xmax = zNear * tan(fovx * M_PI / 360.0);
    xmin = -xmax;

    ymin = xmin / aspect;
    ymax = xmax / aspect;

    // Set up the projection matrix
    m[0] = (2.0 * zNear) / (xmax - xmin);
    m[5] = (2.0 * zNear) / (ymax - ymin);
    m[10] = -(zFar + zNear) / (zFar - zNear);

    m[2] = (xmax + xmin) / (xmax - xmin);
    m[6] = (ymax + ymin) / (ymax - ymin);
    m[11] = -1.0;

    m[14] = -(2.0 * zFar * zNear) / (zFar - zNear);

    glMatrixMode(GL_PROJECTION);
    // Add to current matrix
    glMultMatrixd(m);
}



void glvPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar)
{
    // This code is based off the MESA source for gluPerspective
    // *NOTE* This assumes GL_PROJECTION is the current matrix
    GLdouble xmin, xmax, ymin, ymax;
    GLdouble m[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

    xmax = zNear * tan(fovy * M_PI / 360.0);
    xmin = -xmax;

    ymin = xmin / aspect;
    ymax = xmax / aspect;

    // Set up the projection matrix
    m[0] = (2 * zNear) / (xmax - xmin);
    m[5] = (2 * zNear) / (ymax - ymin);
    m[10]= -(zFar + zNear) / (zFar - zNear);

    m[2] = (xmax + xmin) / (xmax - xmin);
    m[6] = (ymax + ymin) / (ymax - ymin);
    m[11] = -aspect;

    m[14] = -(2 * zFar * zNear) / (zFar - zNear);

    glMatrixMode(GL_PROJECTION);
    // Add to current matrix
    glMultMatrixd(m);
}

hi all,

progress bar control not working well with larger than 2147483647 value.

can anybody please assist me how can i use Progress bar with larger values

thanks in advance.

Since the range is an int and that is the max value of an int then you would have to either subclass the progress bar to take a different kind of range or find one that will do what you want.

Why is common sense not common?
Never argue with an idiot. They will drag you down to their level where they are an expert.
Sometimes it takes a lot of work to be lazy
Please stand in front of my pistol, smile and wait for the flash - JSOP 2012

Sure, why not scale your values by 10 first?

Most screens aren't going to be wider than 1920px, if the client area of your control was to occupy the whole width, you still have fewer than 2000 uniquely displayable positions. It therefore follows that the smallest increment possible in such a situation is 0.05%

If you take a maxValue of (say) 3 billion then divide by 10 you get 3 hundred million. You would need your progress to advance by about 150,000 just to make the progress bar 1 pixel wider.

In short - you don't generally have a need for the progress bar range to be larger than about 2000. You just have to make sure that you scale curProgress and maxProgress to be under 214748364.

yes i get the max value for progressbar is 2147483647,

now here how can i calculate from which amount of step i need to stepit the progress bar to reach the end.

thanks.

I've just looked at the VS help for progress bars. I think you missed something in your research.

The max value for a progress bar is actually 65535 - The max value of a word. If you look at the message PBM_SETRANGE, you can see that it is used like this:

C++

PBM_SETRANGE
wParam = 0;
lParam = MAKELPARAM(nMinRange, nMaxRange);

Since a LPARAM is 32 bits wide and it must hold both the min AND the max values, you only have 16 bits per field. It therefore follows that the nMaxRange is 65555.

In the example that comes with VS2010, a progBar is used to indicate the progress of reading a file.

I've include a couple of exceprts:

C++

cb = GetFileSize(hFile, (LPDWORD) NULL);

// Set the range and increment of the progress
// bar.

SendMessage(hwndPB, PBM_SETRANGE, 0, MAKELPARAM(0, cb / 2048));
SendMessage(hwndPB, PBM_SETSTEP, (WPARAM) 1, 0);

C++

do {
    ReadFile(hFile, pchTmp, sizeof(char) * 2048, &cb, (LPOVERLAPPED) NULL);
    // TODO: Write an error handler to check that all the
    // requested data was read.
    // Include here any code that parses the
    // file.
    .
    .
    .
    // Advance the current position of the
    // progress bar by the increment.
    SendMessage(hwndPB, PBM_STEPIT, 0, 0);
} while (cb);

Just use a scaling factor on your values for the slider.

I don't know what usage you will be using the slider, but if it is for a progress (of something) then add additional information about what is going on, because the slider will probably not move that much for large values.

Watched code never compiles.

I made a toolbar in my program, and on the main menubar, made a "View" menu item with a list of toolbars.

So I wrote CreateWindowEx to create the toolbar on program load. When you click the red X on the toolbar, I DestroyWindow, and the toolbar is gone. Then if I go to View, and click the toolbar, I run CreateWindowEx and make the Toolbar again.

Symptom:

When I make the toolbar the 2nd time, the toolbar window is not active. I can load stuff in it, but can't use the red x or the treeview inside the window. I get get focus on the window to use it.

Question:

I'm not sure what I did wrong, or if I'm just missing something in one of the Proc's.

That was a really bad idea there. I went back to hide and show, and figured out how to avoid the WM_DESTROY message when clicking the close button on the window bar.

could you post the CreateWindowEx() code snippet Smile | :)

It turned out to be a big mess. The Bool bRegister was a unsuccessful attempt to unregister the class after it was created. I thought if I could create the class, create the window, that I could destroy the window, and unregister the class to create a clean slate, and start the process again.

On the 2nd time around, the window would paint, but it would not respond. When I took the other toolbar and dragged it across the regenerated toolbar, the regenerated toolbar would not paint again and dissappear. So I added the WS_CLIPSIBLINGS, and upon regeneration, no window at all.

So I went back to show and hide, and added a return 1 to the WM_CLOSE in the Windows Proc, to cancel destroying the window, and to just run ShowWindow and update the checkbox in the main menu.

HWND _project_Explorer_Create( HWND hWndMain, HINSTANCE hInstance, HWND hMDIClientArea, HWND hWndStatusBar )
{
	
	hProjectExplorer_Instance = hInstance;
	LoadString( hInstance, IDM_PROJECT_EXPLORER_CLASS, sz_ProjectExplorer_Class, MAX_LOADSTRING );

	//BOOL bRegister = FALSE;
	//bRegister = UnregisterClass( sz_ProjectExplorer_Class, hInstance );
	//DWORD dwErrorCode = GetLastError();
		
	WNDCLASSEX toolWindow;
	toolWindow.cbSize = sizeof(WNDCLASSEX);

	if ( !GetClassInfoEx( hInstance, sz_ProjectExplorer_Class, &toolWindow ) ) {
	
		toolWindow.style		= CS_HREDRAW | CS_VREDRAW;
		toolWindow.lpfnWndProc		= _project_Explorer_WndProc;
		toolWindow.cbClsExtra		= 0;
		toolWindow.cbWndExtra		= 0;
		toolWindow.hInstance		= hInstance;
		toolWindow.hIcon		= 0;
		toolWindow.hCursor		= 0;
		toolWindow.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
		toolWindow.lpszMenuName		= 0;
		toolWindow.lpszClassName	= sz_ProjectExplorer_Class;
		toolWindow.hIconSm              = 0;

		RegisterClassEx( &toolWindow );

	}
									
	RECT winRect, statusBarRect;
	INT winWidth, winHeight, tbWidth, tbHeight, sbWidth, sbHeight;	
	
	if(GetWindowRect( hMDIClientArea, &winRect)) {
		winWidth = winRect.right - winRect.left;
		winHeight = winRect.bottom - winRect.top;

		GetWindowRect( hWndStatusBar, &statusBarRect );
		sbWidth = statusBarRect.right - statusBarRect.left;
		sbHeight = statusBarRect.bottom - statusBarRect.top;
						
		tbWidth = 250;
		tbHeight = (INT)floor(( (float)winHeight * (float).60 ) - 1 );		
		
		// Create the Project Explorer Window
		hWnd_ProjectExplorer = CreateWindowEx(
			WS_EX_TOOLWINDOW,
			sz_ProjectExplorer_Class,
			TEXT( "Project Explorer" ),
			WS_CHILD | WS_SYSMENU | WS_CAPTION | WS_VISIBLE | WS_CLIPSIBLINGS,
			winWidth - tbWidth - 1, 1,
			tbWidth, tbHeight, 
			hWndMain, 
			NULL, 
			GetModuleHandle(0),
			NULL
		);		

		ShowWindow( hWnd_ProjectExplorer, SW_SHOW);
		UpdateWindow( hWndMain );		
	}	
	return hWnd_ProjectExplorer;
}

thanks for ur reply,

use this code snippet

..........
static bool reg =false;
WNDCLASSEX wcex;

wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));

if( reg )
{
UnregisterClass(szWindowClass, hInstance );
}
if (!RegisterClassEx(&wcex))
{
MessageBox(NULL,
_T("Call to RegisterClassEx failed!"),
_T("Win32 Guided Tour"),
NULL);

return 1;
}
reg = true;
.............

Well thanks, but I'm not going to try that. I don't see the point of it. I'd rather have an explanation as to why I can't destroy a window and it's class and recreate it like an MDI Child Window.

Toolbar with treeview?
What kind of toolbar you are referring to? Are you sure you are creating a toolbar? Maybe it is a tool window?

Could you please post a snippet showing how you create this toolbar.

JohnCz

It's a tool window, I just called it a toolbar so folks got the bigger picture of what I was trying to do.

So far so good, I have my MDI frame, and the 2 sidebars (toolbars) on the left. They size correctly, move and resize upon mid resize. The hide and show works good.

Next phase is to dock them, but I need to tighten up the program first, and do an initial alpha test release. Hopefully this week.

C++

I can do the following:

boost::scoped_ptr<MyClass> class;

class->DoSomething(); // Has not been initialized yet

class.reset(new MyClass);

Doesn't it go against RAII? I keep reading that scoped_ptr is RAII but i can use object before it is initialized.

Thanks