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Where are the positions of Windows desktop shortcuts stored?
I am asking about the screen positions of the icons not the actual icons themselves. I know the icons themselves are stored in various DLLs, EXEs etc. The positions are clearly stored in some non-volatile store because they persists through re-boots.
My end goal is to write an app to display, and optionally re-arrange icons on my desktop.
I know this is possible because many available apps do this (e.g., "WinTidy").
I find much talk about "Windows Shell Bags". An interesting article about these are in http://williballethin.com.forensics/shellbags, but that only addresses directories not shortcuts. These are in the registry at various places including
`HKEY_CURRENT_USER/Software/Microsoft/Windows/Shell/Bags/1/Desktop`
`HKEY_USERS/.DEFAULT/Software/Microsoft/Windows/Shell/Bags/1/Desktop`
I wrote a program to extract these but the format of the key values is incomprehensible.
Any body know where and how they are stored?
UPDATE 6/3/20
++++++++++++++++++++++++++++++++++++++
I just switched over to a Win10 64-bit machine and find the solution below no longer works. I believe because of a change in the desktop internals. I figured out how to do this. See "WIN10 ADDENDUM" at the end of this answer.
++++++++++++++++++++++++++++++++++++++
I finally figured out how to do what I want (display and re-arrange desktop icons). My original question concerned locating, reading and writing to the file where the icon info is stored, but this is not a useful approach. Here is what I learned:
Explorer.exe displays desktop items in a giant ListView covering the whole desktop with ListView items corresponding to each visible icon. At startup, Explorer reads info from some arcane file and populates the ListView. On exit, it re-writes that file from the ListView. So modifying the file would not help because it would be overwritten on exit.
The right way to manipulate desktop items is to directly manipulate items in the ListView. Any changes are immediately visible on change, and are saved on exit. To access the items, we can use several Windows messages: LVM_GETITEM, LVM_GETITEMCOUNT, LVM_GETITEMPOSITION and LVM_SETITEMPOSITION. These messages are fairly simple to use with one complication: some require pointers to parameter structures. These structures must be in Explorer's address space not my app's, so some trickery is needed. Here's how to do it. I use LVM_GETITEMPOSITION as an example, which requires a pointer to a POINT structure.
Declare a POINT structure in your app.
Allocate a mirror structure in Explorer's address space using API VirtualAllocEx().
Send LVM_GETITEMPOSITION to Explorer specifying a pointer to this structure.
Read back the result into your app's POINT using API ReadProcessMemory(). This function can read memory across different address spaces.
I have prototyped these operations and they work as I wanted. My code is quite long but I will post excerpts as soon as I clean it up.
UPDATE 10/4/2019 ------------------------------------
CODE EXCERPTS
A set of commonly used utility functions was created to make code more compact and readable. These are named "exp*()" and are included at the end. A reference can be found at http://ramrodtechnology.com/explorer. Much of the basic technique herein was shamelessly stolen from https://www.codeproject.com/Articles/5570/Stealing-Program-s-Memory
Setup
// COMMONLY USED VARS
HANDLE hProcess; // explorer process handle
HWND hWndLV; // explorer main window
// SET UP CONVENIENCE VARS
hProcess = expGetProcessHandle(); // get explorer process handle
if( !hProcess ) exit( 1 );
hWndLV = expGetListView(); // get main ListView of Desktop
if( !hWndLV ) exit( 1 );
Function to Print All Item Names
//# Process a list view window and print item names
int
printAllNames()
{
int ok,icount,indx;
LVITEM item; // point in app space
LVITEM *_pitem; // point in exp space
char text[512];
char *_ptext;
int nr,nwrite; // count of bytes read/written
printf( "\n" );
// ALLOC ITEMS IN EXP SPACE
_pitem = expAlloc( sizeof(LVITEM) );
_ptext = expAlloc( sizeof(text ) );
printf( " NAME\n" );
printf( " ==================================\n" );
icount = expGetItemCount();
for( indx=0; indx<icount; indx++ ) { // for each item in LV
// SETUP ITEM IN EXP SPACE
memset( &item, 0, sizeof(LVITEM) ); // preclear
item.iItem = indx; // index of item to read
item.iSubItem = 0; // sub index (always 0)
item.mask = LVIF_TEXT; // component to read
item.pszText = _ptext; // buffer to recv text
item.cchTextMax = sizeof(text); // size of buffer
// WRITE ITEM REQ TO EXP SPACE
ok = WriteProcessMemory( hProcess, _pitem, &item, sizeof(LVITEM), &nwrite );
// SEND MESSAGE TO GET ITEM INTO EXP SPACE
ok = SendMessage( hWndLV, LVM_GETITEM, indx, (LPARAM)_pitem );
// READ EXP TEXT INTO APP SPACE
memset( &item, 0, sizeof(LVITEM) );
ok = ReadProcessMemory( hProcess, _pitem, &item, sizeof(POINT), &nr );
ok = ReadProcessMemory( hProcess, _ptext, &text, sizeof(text), &nr );
// PRINT RESULT
printf( " %s\n", text );
}
ok = expFree( _pitem );
ok = expFree( _ptext );
return( TRUE );
//r Returns TRUE on success, FALSE on error
}
Function To Print All Item Positions
//# Process a list view window and print position
int
printAllPositions()
{
int ok,icount,indx,nr;
POINT pt; // point in app space
POINT *_ppt; // point in exp space
icount = expGetItemCount();
_ppt = expAlloc( sizeof(POINT) );
if( !_ppt ) return( FALSE );
printf( " X Y\n" );
printf( "---- ----\n" );
for( indx=0; indx<icount; indx++ ) { // for each item in LV
ok = SendMessage( hWndLV, LVM_GETITEMPOSITION, indx, (LPARAM)_ppt );
ok = ReadProcessMemory( hProcess, _ppt, &pt, sizeof(POINT), &nr );
printf( "%4d %4d\n", pt.x, pt.y );
}
ok = expFree( _ppt );
return( TRUE );
//r Returns TRUE on success
}
Function To Move Item
See 'expSetItemPosition' below. UPDATED 10/6/19
Explorer Utility Functions
// EXPLORER UTILITY FUNCTIONS
//# Allocate a block of memory in explorer space
void *
expAlloc(
int size) // size of block
{
void *p;
p = VirtualAllocEx(
hProcess,
NULL,
size,
MEM_COMMIT,
PAGE_READWRITE );
return( p );
//r Returns addr of memory in EXPLORER space or NULL on error
}
//# Free virtual memory in EXPLORER space
int
expFree(
void *p) // pointer to free
{
int ok;
ok = VirtualFreeEx( hProcess, p, 0, MEM_RELEASE );
return( ok );
//r Returns TRUE on success, else FALSE
}
static int aBiggest; // biggest area so far
static HWND hWndBiggest; // hWnd with biggest area
//# Find main list view of explorer
HWND
expGetListView()
{
//n Approach: Enumerate all child windows of desktop and find largest.
//n This will be the main explorer window.
HWND hWndDesktop;
hWndDesktop = GetDesktopWindow();
if( !hWndDesktop ) return( NULL );
aBiggest = -1; // init
hWndBiggest = NULL; // init
EnumChildWindows( hWndDesktop, CallbackDesktopChild, 0 );
return( hWndBiggest );
//r Returns hWnd of largest explorer list view
}
//# Callback for EnumChildWindows
BOOL CALLBACK CallbackDesktopChild(
HWND hWnd,
LPARAM dwUser)
{
//n Get size of child. If biggest, save hWnd.
int i,w,h,a;
char classname[MAXPATH+1];
RECT rect;
i = GetClassName( hWnd, classname, MAXPATH ); // get class
if( stricmp( classname, "SysListView32" ) ) { // not a list view?
return( TRUE ); // skip it
}
// CALC SIZE
i = GetWindowRect( hWnd, &rect );
w = rect.right - rect.left;
h = rect.bottom - rect.top;
// CHECK IF BIGGEST
a = w * h;
if( a > aBiggest ) { // is biggest?
aBiggest = a;
hWndBiggest = hWnd;
}
return( TRUE ); // TRUE to continue enumeration
}
//# Get process handle of explorer.exe
HANDLE
expGetProcessHandle()
{
//n Approach: take process snapshot and loop through to find "explorer.exe"
//n Needs tlhelp32.h and comctl32.lib
int i,stat;
PROCESSENTRY32 pe;
HANDLE hSnapshot;
char *name;
HANDLE h;
// TAKE A SNAPSHOT
hSnapshot = CreateToolhelp32Snapshot( TH32CS_SNAPPROCESS, 0 );
if( !hSnapshot ) return( NULL );
// LOOP THROUGH PROCESSES AND FIND "explorer.exe"
for( i=0;;i++ ) {
pe.dwSize = sizeof( PROCESSENTRY32 );
if( i == 0 ) stat = Process32First( hSnapshot, &pe );
else stat = Process32Next ( hSnapshot, &pe );
if( !stat ) break; // done or error?
name = pe.szExeFile;
if( !stricmp( name, "explorer.exe" ) ) { // matches?
h = OpenProcess( PROCESS_ALL_ACCESS, FALSE, pe.th32ProcessID );
return( h );
}
}
return( NULL );
//r Returns explorer process handle or NULL on error
}
//# Get count of items in explorer list view
int
expGetItemCount()
{
int count;
count = SendMessage( hWndLV, LVM_GETITEMCOUNT, 0, 0 );
return( count );
//r Returns count of item
}
//# Get position of list view icon by index
int
expGetItemPosition(
int indx, // index of item
int *x, // ptr to int to recv x
int *y) // ptr to int to recv y
{
int i,ok,icount;
char classname[MAXPATH+1];
POINT pt; // point in app space
POINT *_ppt; // point in exp space
int nr; // count of bytes read
//int w,h;
i = GetClassName( hWndLV, classname, MAXPATH );
// GET COUNT OF ITEMS IN LIST VIEW
icount = expGetItemCount();
if( indx < 0 || indx >= icount ) return( FALSE );
// ALLOC POINT IN EXP SPACE
_ppt = expAlloc( sizeof(POINT) );
if( !_ppt ) return( FALSE );
// SEND MESSAGE TO GET POS INTO EXP SPACE POINT
ok = SendMessage( hWndLV, LVM_GETITEMPOSITION, indx, (LPARAM)_ppt );
if( !ok ) return( FALSE );
// READ EXP SPACE POINT INTO APP SPACE POINT
ok = ReadProcessMemory( hProcess, _ppt, &pt, sizeof(POINT), &nr );
if( !ok ) return( FALSE );
ok = expFree( _ppt );
if( !ok ) return( FALSE );
if( x ) *x = pt.x;
if( y ) *y = pt.y;
//r Returns TRUE on success
return( TRUE );
}
//# Move item
int
expSetItemPosition(
char *name, // icon name
int x, // new x coord
int y) // new y coord
{
int ok,indx;
LPARAM lParam;
indx = expGetItemIndex( name );
if( indx < 0 ) return( FALSE );
lParam = MAKELPARAM( x, y );
ok = SendMessage( hWndLV, LVM_SETITEMPOSITION, indx, lParam );
if( !ok ) return( FALSE );
return( TRUE );
//r Returns TRUE on success
}
WIN10 ADDENDUM
6/19/20
++++++++++++++++++++++++++++++++++
Under Win10, the solution is much more complicated. You must use various COM objects and interfaces, e.g. IShellWindows, etc. (God, I hate COM). I did not create a library but rather offer a complete working program below. I compiled this using MSVC 2019. Error checking has been omitted for clarity (but you should do it).
// icons.cpp - Display (and optionally move) desktop icons
#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include <ShlObj.h>
#include <atlbase.h>
int
main(int argc,char** argv)
{
CComPtr<IShellWindows> spShellWindows;
CComPtr<IShellBrowser> spBrowser;
CComPtr<IDispatch> spDispatch;
CComPtr<IShellView> spShellView;
CComPtr<IFolderView> spView;
CComPtr<IShellFolder> spFolder;
CComPtr<IEnumIDList> spEnum;
CComHeapPtr<ITEMID_CHILD> spidl;
CComVariant vtLoc(CLSID_ShellWindows);
CComVariant vtEmpty;
STRRET str;
int count=0;
HRESULT hr;
long lhWnd;
// INITIALIZE COM
CoInitialize(NULL);
// GET ShellWindows INTERFACE
hr = spShellWindows.CoCreateInstance(CLSID_ShellWindows);
// FIND WINDOW
hr = spShellWindows->FindWindowSW(
&vtLoc, &vtEmpty, SWC_DESKTOP, &lhWnd, SWFO_NEEDDISPATCH, &spDispatch);
// GET DISPATCH INTERFACE
CComQIPtr<IServiceProvider>(spDispatch)->
QueryService(SID_STopLevelBrowser, IID_PPV_ARGS(&spBrowser));
spBrowser->QueryActiveShellView(&spShellView);
spShellView->QueryInterface(IID_PPV_ARGS(&spView) );
hr = spView->GetFolder(IID_PPV_ARGS(&spFolder));
// GET ENUMERATOR
spView->Items(SVGIO_ALLVIEW, IID_PPV_ARGS(&spEnum)); // get enumerator
// ENUMERATE ALL DESKTOP ITEMS
for (; spEnum->Next(1, &spidl, nullptr) == S_OK; spidl.Free()) {
// GET/PRINT ICON NAME AND POSITION
char* name;
POINT pt;
spFolder->GetDisplayNameOf(spidl, SHGDN_NORMAL, &str);
StrRetToStr(&str, spidl, &name);
spView->GetItemPosition(spidl, &pt);
printf("%5d %5d \"%s\"\n", pt.x, pt.y, name);
#define MOVE_ICON
#ifdef MOVE_ICON
// OPTIONAL: MOVE *SINGLE* SELECTED ITEM
{
if( !_stricmp(name, "ICON_NAME_TO_MOVE") ) {
PCITEMID_CHILD apidl[1] = { spidl };
int numitems = 1;
// SET pt TO NEW POSITION HERE
hr = spView->SelectAndPositionItems(numitems, apidl, &pt, 0);
}
}
#endif
count++;
}
CoUninitialize(); // release COM
fprintf(stderr, "enumerated %d desktop icons\n", count);
fprintf(stderr, "Press any key to exit...\n");
_getch();
exit(0 );
}
I am facing the following problem when I execute the programme. The program crashed abnormally at line no 1 of the main function. the path of the is all correct, nothing is wrong there. All set-up of the lib-include additional libraries are done perfectly. What could be wrong here?
#include <cv.h>
#include <highgui.h>
int main()
{
//load the video file to the memory
** CvCapture *capture = cvCaptureFromAVI("A.avi"); ** // this instruction crashed the file is there in the folder, that not an issue....
if( !capture ) return 1;
//obtain the frames per seconds of that video
int fps = ( int )cvGetCaptureProperty( capture, CV_CAP_PROP_FPS );
//create a window with the title "Video"
cvNamedWindow("Video");
while(true) {
//grab and retrieve each frames of the video sequencially
IplImage* frame = cvQueryFrame( capture );
if( !frame ) break;
//show the retrieved frame in the "Video" window
cvShowImage( "Video", frame );
int c;
if(fps!=0){
//wait for 1000/fps milliseconds
c = cvWaitKey(1000/fps);
}else{
//wait for 40 milliseconds
c = cvWaitKey(40);
}
//exit the loop if user press "Esc" key (ASCII value of "Esc" is 27)
if((char)c==27 ) break;
}
//destroy the opened window
cvDestroyWindow("Video");
//release memory
cvReleaseCapture( &capture );
return 0;
}
As a sanity check, let's see if the VideoCapture stuff from the OpenCV C++ API works. Let's give this a try:
#include <opencv2/opencv.hpp>
#include <cv.h>
using namespace cv;
VideoCapture capture("A.avi");
Mat matFrame;
capture >> matFrame; //each time you do this, the next video frame goes into the 'matFrame' object
IplImage* frame=cvCloneImage(&(IplImage)matFrame); //convert Mat to IplImage to hook in with your code
I'm mixing the C and C++ OpenCV APIs together here, but I just wanted to help you get it running.
I read image using opencv and save it again, but when I read it later the data not be the same, that I mean after I read the image I save it, then copy the saved image and read the data inside this image but the data will not the same as before, I write small code to do the following
1- read image
2- save the image
3- save image data into text file
4- read the saved image fro step 2
5- compare the values of the image to the values of the text file and print them together
my code is
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include <time.h>
#include <stdint.h>
#include "highgui.h"
IplImage *PlainImage=0,*CipherImage=0,*DecPlainImage=0;
void func_printimage()
{
// create a window
cvNamedWindow("Plain Image",CV_WINDOW_AUTOSIZE);
cvMoveWindow("Plain Image", 800, 600);
// show the image
cvShowImage("Plain Image", PlainImage );
// wait for a key
cvNamedWindow("Cipher Image",CV_WINDOW_AUTOSIZE);
cvMoveWindow("Cipher Image", 800, 600);
// show the image
cvShowImage("Cipher Image", CipherImage );
cvSaveImage("CipherImage.jpg",CipherImage,0);
cvWaitKey(0);
}
int main()
{
//i j and k used as counters
int i,j,step,dep,k,ch,L,C,P,sum=0;
uchar *data_byte;
//Define CPU time parameters for each Layer
PlainImage=cvLoadImage("PlainImage.jpg",3);
CipherImage=cvLoadImage("PlainImage.jpg",3);
L = PlainImage->height;
C = PlainImage->width;
P = PlainImage->nChannels;
step = PlainImage->widthStep;
data_byte=CipherImage->imageData;
printf("Image Information are:\nL=%d\n",L);
printf("C=%d\n",C);
printf("P=%d\n",P);
system("pause");
FILE *f1;
f1 = fopen ("cipher1.txt", "wt");
fprintf(f1,"%d\t%d\t%d\t%d\t",L,C,P,CipherImage->depth);
for(k=0;k<L*C*P;k++)
{
fprintf(f1,"%d\t",data_byte[k]);
}
fclose (f1);
func_printimage();
for(k=0;k<L*C*P;k++)
{
data_byte[k]=0;
}
f1 = fopen ("cipher1.txt", "rt");
fscanf (f1,"%d", &L);
fscanf (f1,"%d", &C);
fscanf (f1,"%d", &P);
fscanf (f1,"%d", &dep);
CipherImage=cvLoadImage("CipherImage.jpg",3);
data_byte=CipherImage->imageData;
printf("Image Information are:\nL=%d\n",L);
printf("C=%d\n",C);
printf("P=%d\n",P);
system("pause");
for(k=0;k<L*C*P;k++)
{
fscanf (f1,"%d", &i);
sum+=abs(i-data_byte[k]);
printf("i=%d data=%d\n",i,data_byte[k]);
}
printf("difference=%d\n",sum);
fclose (f1);
system("pause");
return 0;
}
//End of the main Program
jpg images use Lossy Compression.
You should use png images.
Here in this post i will show you that how to Load an image from your chosen directory and then convert it into gray color, and then store the new one(modified) image in a directory C:\Images.
The code is given below:
#include <cv.h>
#include <highgui.h>,
using namespace cv;
int main( )
{
Mat img;
img = imread(“C:\\prado.jpg”, 1 );
if( !img.data )
{
printf( ” No image data \n ” );
return -1;
}
else
prinf(“Your program is working well”);
Mat gray_image;
cvtColor( img, gray_image, CV_RGB2GRAY );
imwrite( “C://images/Gray_Image.jpg”, gray_image);
imshow( “real image”, img);
imshow( “Gray image”, gray_image);
waitKey(0);
return 0;
}
EXPLANATION:
Mat img = imread(“C:\\prado.jpg”, 1 );
this means to get image from my directory and store it in Mat object which is “img” here, actually Mat object store the data of any image.
cvtColor( img, gray_image, CV_RGB2GRAY );
This line convert the originial (RGB) into other color image(GRAY)
imwrite( “C://images/Gray_Image.jpg”, gray_image);
This one store the new modified image which have been store in Mat object “gray_image” in the directory C://images/ you can chose your own directory
I have been playing with OpenCV (I am pretty new to it) to display live camera. What I wanted to do next was to draw lines on it with my mouse. Does anyone know how to do this? So far, what I have is:
#include "stdafx.h"
#include <stdio.h>
#include "cv.h"
#include "highgui.h"
int main( int argc, char **argv )
{
CvCapture *capture = 0;
IplImage *frame = 0;
int key = 0;
/* initialize camera */
capture = cvCaptureFromCAM( 0 );
/* always check */
if ( !capture ) {
fprintf( stderr, "Cannot open initialize webcam!\n" );
return 1;
}
/* create a window for the video */
cvNamedWindow( "Testing", CV_WINDOW_AUTOSIZE );
while( key != 'q' ) {
/* get a frame */
frame = cvQueryFrame( capture );
/* always check */
if( !frame ) break;
/* display current frame */
cvShowImage( "result", frame );
/* exit if user press 'q' */
key = cvWaitKey( 1 );
}
/* free memory */
cvDestroyWindow( "result" );
cvReleaseCapture( &capture );
return 0;
}
If anyone could help me draw lines on the live video, or if anyone knows of any tips, I'd greatly appreciate it! Thanks!
If it helps, here is my code for drawing rectangles on multiple sized video streams
#include "stdafx.h"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#define SSTR( x ) dynamic_cast< std::ostringstream & >(( std::ostringstream() << std::dec << x ) ).str()
using namespace std;
using namespace cv;
Rect box; //global structures needed for drawing
bool drawing_box = false;
struct mousecallbackstruct{
Mat* src;
Mat* overlay;
string windowname;
};
Mat srcoverlay,smallsrcoverlay; //an overlay must be created for each window you want to draw on
void onMouse(int event, int x, int y, int flags, void* param) //it seems the only way to use this is by keeping different globals for different windows - meaning you have to set up all thise ahead of time, and keep track of it and not mix/match windows/frames!! horrible design here.
{
cout << event;
mousecallbackstruct mousestruct;
mousestruct = *((mousecallbackstruct*)param);
Mat* srcp = mousestruct.src;
Mat* overlayp = mousestruct.overlay; // yeah, yeah, i use 7 lines where I could use 3, so sue me
Mat src = *srcp;
Mat overlay = *overlayp;
if(!src.data){
cout << "your void * cast didn't work :(\n";
return;
}
switch( event ){
case CV_EVENT_MOUSEMOVE:
if( drawing_box ){
box.width = x-box.x;
box.height = y-box.y;
}
break;
case CV_EVENT_LBUTTONDOWN: //start drawing
drawing_box = true;
box = cvRect( x, y, 0, 0 );
break;
case CV_EVENT_LBUTTONDBLCLK: //double click to clear
drawing_box = false;
overlay.setTo(cv::Scalar::all(0)); //clear it
break;
case CV_EVENT_LBUTTONUP: //draw what we created with Lbuttondown
drawing_box = false;
if( box.width < 0 ){
box.x += box.width;
box.width *= -1;
}
if( box.height < 0 ){
box.y += box.height;
box.height *= -1;
}
rectangle( overlay, Point(box.x, box.y), Point(box.x+box.width,box.y+box.height),CV_RGB(100,200,100),4); //draw rectangle. You can change this to line or circle or whatever. Maybe with the Right mouse button.
break;
}
}
void iimshow(mousecallbackstruct* mystructp){ //this is where we add the text/drawing created in the mouse handler to the actual image (since mouse handler events do not coincide with the drawing events)
mousecallbackstruct mystruct = *mystructp; //custom struct made for the mouse callback - very handy for other functions too
Mat overlay, src;
Mat* srcp = mystruct.src;
Mat* overlayp = mystruct.overlay;
src = *srcp; // yeah, yeah, i use 9 lines where I could use 3, so sue me
overlay = *overlayp;
string name = mystruct.windowname;
Mat added,imageROI;
try{
//cout << "tch:" << overlay.rows << "," << src.rows << ";" << overlay.cols << "," << src.cols << ";" << src.channels() << "," << overlay.channels() <<"," << src.type() << "," << overlay.type() << "\n";
if(overlay.data && overlay.rows == src.rows && overlay.cols == src.cols && overlay.channels() == src.channels()){ //basic error checking
add(src,overlay,added);
}else{
//try to resize it
imageROI= overlay(Rect(0,0,src.cols,src.rows));
add(src,imageROI,added);
}
imshow(name,added);// the actual draw moment
}catch(...){ //if resize didn't work then this should catch it and you can see what didn't match up
cout << "Error. Mismatch:" << overlay.rows << "," << src.rows << ";" << overlay.cols << "," << src.cols << ";" << src.channels() << "," << overlay.channels() <<"," << src.type() << "," << overlay.type() << "\n";
imshow(name + "overlay",overlay);
imshow(name+"source",src);
}
}
int _tmain(int argc, _TCHAR* argv[]){
VideoCapture cap(0); // open the default camera
if(!cap.isOpened()) { // check if we succeeded
cout << "NO camera found \n";
return -1;
}
Mat src,smallsrc,overlay;
cap >> src; //grab 1 frame to build our preliminary Mats and overlays
srcoverlay.create(src.rows,src.cols,src.type()); //create overlays
smallsrcoverlay.create(src.rows,src.cols,src.type());
srcoverlay.setTo(cv::Scalar::all(0)); //clear it
smallsrcoverlay.setTo(cv::Scalar::all(0)); //clear it
namedWindow( "smallsrc", CV_WINDOW_AUTOSIZE );
namedWindow( "source", CV_WINDOW_AUTOSIZE ); //these must be created early for the setmousecallback, AND you have to know what Mats will be using them and not switch them around :(
moveWindow("smallsrc",1000,100); //create a small original capture off to the side of screen
////////////// for each window/mat that uses a mouse handler, you must create one of these structures for it and pass it into the mouse handler, and add a global mat for overlays (at top of code)
mousecallbackstruct srcmousestruct,smallsrcmousestruct; //these get passed into the mouse callback function. Hopefully they update their contents automatically for the callback? :(
srcmousestruct.overlay = &srcoverlay; //fill our custom struct
srcmousestruct.src = &src;
srcmousestruct.windowname = "source";
smallsrcmousestruct.overlay = &smallsrcoverlay; //the small window
smallsrcmousestruct.src = &smallsrc;
smallsrcmousestruct.windowname = "smallsrc";
setMouseCallback(smallsrcmousestruct.windowname, onMouse, (void*)&smallsrcmousestruct); //the actual 'set mouse callback' call
setMouseCallback(srcmousestruct.windowname, onMouse, (void*)&srcmousestruct);
for(;;){ //main loop
/// Load an image
cap >> src;
if( !src.data )
{ return -1; }
resize(src,smallsrc,Size(),.5,.5); //smaller scale window of original
overlay = *srcmousestruct.overlay;
src = *srcmousestruct.src;
iimshow(&srcmousestruct); //my imshow replacement. uses structs
iimshow(&smallsrcmousestruct);
if(waitKey(30) == 27) cin.get(); //esc pauses
}
cin.get();
return 0;
}
You will have to be more clear as to what you mean by drawing on the video.
One option is to handle the mouse positions, by drawing the lines between them, on a black/blank "mask" image, and "apply" this image to each video frame before it is displayed.
To capture mouse events you need to create a callback. This callback will be tied to a specific named window. The documentation for the call cvSetMouseCallback is pretty good. The callback function will know current position and button click information. From there you can capture points on mouse clicks and use those points with cvLine to draw on your frame.
I need to load sound files to a Cocoa-based OpenAL app.
Progress:
The OpenAL utility function alutLoadWAVFile has been deprecated; the alut header is no longer included in Mac OS X SDKs. According to the TechNotes, the actual code is still there for binary compatibility. However, if I attempt to add a declaration for the function, the code will compile but the linker will abort, complaining that the symbol for alutLoadWAVFile could not be found. (I am linking to the OpenAL.framework).
Yet, Apple OpenAL sample code still uses this symbol. When I Clean the sample code project, it compiles and links just fine. Yet there is no declaration of the function to be found. (Side question: how can it build and link, then?)
So, I found some code by George Warner at Apple, containing replacement functions for alutCreateBufferFromFile and alutLoadMemoryFromFile. Although capable of creating an OpenAL buffer directly from most any kind of audio file, the code appears to support only 8bit mono sound files. 16bit stereo or mono 44khz files result in a nasty hissing sound and clipping. (The files are ok; Quicktime plays them just fine.)
Thus, my question: can someone please point me to some .wav loading code/help for Cocoa/Carbon, suitable for use with an OpenAL Buffer? Thankyou.
I'm sure you've solved this already, but for people who find this via Google, here's some barely tested WAV loading code. It works but you'd better double check for memory leaks and whatnot before using for something real.
static bool LoadWAVFile(const char* filename, ALenum* format, ALvoid** data, ALsizei* size, ALsizei* freq, Float64* estimatedDurationOut)
{
CFStringRef filenameStr = CFStringCreateWithCString( NULL, filename, kCFStringEncodingUTF8 );
CFURLRef url = CFURLCreateWithFileSystemPath( NULL, filenameStr, kCFURLPOSIXPathStyle, false );
CFRelease( filenameStr );
AudioFileID audioFile;
OSStatus error = AudioFileOpenURL( url, kAudioFileReadPermission, kAudioFileWAVEType, &audioFile );
CFRelease( url );
if ( error != noErr )
{
fprintf( stderr, "Error opening audio file. %d\n", error );
return false;
}
AudioStreamBasicDescription basicDescription;
UInt32 propertySize = sizeof(basicDescription);
error = AudioFileGetProperty( audioFile, kAudioFilePropertyDataFormat, &propertySize, &basicDescription );
if ( error != noErr )
{
fprintf( stderr, "Error reading audio file basic description. %d\n", error );
AudioFileClose( audioFile );
return false;
}
if ( basicDescription.mFormatID != kAudioFormatLinearPCM )
{
// Need PCM for Open AL. WAVs are (I believe) by definition PCM, so this check isn't necessary. It's just here
// in case I ever use this with another audio format.
fprintf( stderr, "Audio file is not linear-PCM. %d\n", basicDescription.mFormatID );
AudioFileClose( audioFile );
return false;
}
UInt64 audioDataByteCount = 0;
propertySize = sizeof(audioDataByteCount);
error = AudioFileGetProperty( audioFile, kAudioFilePropertyAudioDataByteCount, &propertySize, &audioDataByteCount );
if ( error != noErr )
{
fprintf( stderr, "Error reading audio file byte count. %d\n", error );
AudioFileClose( audioFile );
return false;
}
Float64 estimatedDuration = 0;
propertySize = sizeof(estimatedDuration);
error = AudioFileGetProperty( audioFile, kAudioFilePropertyEstimatedDuration, &propertySize, &estimatedDuration );
if ( error != noErr )
{
fprintf( stderr, "Error reading estimated duration of audio file. %d\n", error );
AudioFileClose( audioFile );
return false;
}
ALenum alFormat = 0;
if ( basicDescription.mChannelsPerFrame == 1 )
{
if ( basicDescription.mBitsPerChannel == 8 )
alFormat = AL_FORMAT_MONO8;
else if ( basicDescription.mBitsPerChannel == 16 )
alFormat = AL_FORMAT_MONO16;
else
{
fprintf( stderr, "Expected 8 or 16 bits for the mono channel but got %d\n", basicDescription.mBitsPerChannel );
AudioFileClose( audioFile );
return false;
}
}
else if ( basicDescription.mChannelsPerFrame == 2 )
{
if ( basicDescription.mBitsPerChannel == 8 )
alFormat = AL_FORMAT_STEREO8;
else if ( basicDescription.mBitsPerChannel == 16 )
alFormat = AL_FORMAT_STEREO16;
else
{
fprintf( stderr, "Expected 8 or 16 bits per channel but got %d\n", basicDescription.mBitsPerChannel );
AudioFileClose( audioFile );
return false;
}
}
else
{
fprintf( stderr, "Expected 1 or 2 channels in audio file but got %d\n", basicDescription.mChannelsPerFrame );
AudioFileClose( audioFile );
return false;
}
UInt32 numBytesToRead = audioDataByteCount;
void* buffer = malloc( numBytesToRead );
if ( buffer == NULL )
{
fprintf( stderr, "Error allocating buffer for audio data of size %u\n", numBytesToRead );
return false;
}
error = AudioFileReadBytes( audioFile, false, 0, &numBytesToRead, buffer );
AudioFileClose( audioFile );
if ( error != noErr )
{
fprintf( stderr, "Error reading audio bytes. %d\n", error );
free(buffer);
return false;
}
if ( numBytesToRead != audioDataByteCount )
{
fprintf( stderr, "Tried to read %lld bytes from the audio file but only got %d bytes\n", audioDataByteCount, numBytesToRead );
free(buffer);
return false;
}
*freq = basicDescription.mSampleRate;
*size = audioDataByteCount;
*format = alFormat;
*data = buffer;
*estimatedDurationOut = estimatedDuration;
return true;
}
Use the AudioFileReadBytes function from Audio Services. Examples can be found in the Finch sound engine, see the Sound+IO category.
This may be an obvious suggestion, but since you didn't mention it: have you tried the library at http://www.openal.org/ as suggested in Apple's technote?
As for how the sample code links and builds, it's not finding a prototype (if you turn on -Wall, you'll get an implicit function declaration warning), but OpenAL.framework--at least in the SDK they are using in the sample project--does in fact export _alutLoadWAVFile, which you can check with nm. What's the exact link error you get, and what SDK are you using?