I've created a basic GUI using the windows library and I've come across a problem. The GUI builds and performs great but the issue is the button functions execute before the actual window loads. I wanted the button to execute the desired function on press rather than on load. Below is the code where I think the problem lies.
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
TCHAR greeting[] = _T("T3chSpl01ts Version - 1.0");
switch (message)
{
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
TextOut(hdc,
5, 5,
greeting, _tcslen(greeting));
EndPaint(hWnd, &ps);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
break;
case WM_CREATE:
{
Button = CreateWindow("Button", "Inject",
WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON, 20, 20, 100, 30,
hWnd, (HMENU)ID_INJECT, GetModuleHandle(NULL), NULL);
}
case WM_COMMAND:
{
switch (LOWORD(wParam))
{
case ID_INJECT:
{
::test();
break;
}
}
}
}
return 0;
}
Your WM_CREATE handler is missing a break statement, so code flow "falls through" into your WM_COMMAND handler when the window is created.
Related
We've noticed an issue with ScrollWindowEx on our Windows app. Because there are a lot of child windows, if you hold down the scrollbar and move around, it causes a huge stall in DesktopWindowManager.
This is documented here
Why is my MFC application hanging after interacting with both scroll-bars?
So, I've taken the call to ScrollWindowEx out and now I can move my scrollbar with no issues, however the window and all its children only get drawn at the new position when I let go of the scrollbar.
It seems that my entire program stalls and gets stuck in the message loop when the scroll bar is held down. This isnt a problem if we can force the window that the scrollbar is attached to to update. But how do I do that ?
I've tried this
UpdateWindow(pPane);
RedrawWindow(pPane,NULL,NULL,RDW_ALLCHILDREN|RDW_INVALIDATE|RDW_ERASE | RDW_INTERNALPAINT | RDW_UPDATENOW);
And it does update and redraw - you can see the glitching - BUT it redraws it at the position that it was last left at. Not where the new position of the scroll bar would set it.
Im calling
SetScrollInfo(...)
with the correct parameters, otherwise it wouldn't work normally
How can I get it to redraw the window and its children with the correct parameters, whilst the scroll bar is held down?
This is my scroll message handler
case WM_VSCROLL:
{
int iVScrollPos;
SCROLLINFO vsi;
ZeroMemory(&vsi, sizeof(SCROLLINFO));
vsi.cbSize=sizeof(SCROLLINFO);
vsi.fMask=SIF_ALL;
GetScrollInfo(hWnd,SB_VERT,&vsi);
iVScrollPos=vsi.nPos;
switch(LOWORD(wParam))
{
case SB_LINEUP:
if(vsi.nPos>vsi.nMin)
vsi.nPos=vsi.nPos-10;
break;
case SB_PAGEUP:
vsi.nPos = vsi.nPos - vsi.nPage;
break;
case SB_LINEDOWN:
if(vsi.nPos<vsi.nMax)
vsi.nPos=vsi.nPos+10;
break;
case SB_PAGEDOWN:
vsi.nPos = vsi.nPos + vsi.nPage;
break;
case SB_THUMBTRACK:
vsi.nPos=vsi.nTrackPos;
break;
}
vsi.nMin=0;
vsi.nMax=pOW->dialogysize;
vsi.nPage=sy;
SetScrollInfo(hWnd,SB_VERT,&vsi,TRUE);
GetScrollInfo(hWnd, SB_VERT, &vsi);
if(vsi.nPos != iVScrollPos)
{
RedrawWindow(hWnd,NULL,NULL,RDW_ALLCHILDREN|RDW_INVALIDATE|RDW_ERASE | RDW_INTERNALPAINT | RDW_UPDATENOW);
}
The window redraws as you move the scroll bar, but in the same place it was when you held the mouse down on the scrollbar. It onlyupdates position when you let go of the mouse button.
Thanks
Shaun
EDIT - Ive created a sample that reproduces the behaviour. Note we have a separate window class to hold the multiple edit windows. I havent handled the WM_SIZE and WM_MOVE messages in this demo but the code should work with the window as it is.
IF USESCROLL is defined in and you move the scrollbar up and down it casues a lockup in DesktopWindowManager
IF USESCROLL is not commented in, then the trackPos in the structure still gets updated and I call reDrawWindow, but the child edit windows dont move as I scroll the scrollbar.
As I dont want to have the lockup, how can I get them to move please ?
Thanks again
Shaun
#include <windows.h>
#include <stdio.h>
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK PaneProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)
{
// Register the window class.
WNDCLASS wc = { };
wc.lpfnWndProc = WindowProc;
wc.hInstance = hInstance;
wc.lpszClassName = "Class";
RegisterClass(&wc);
wc.lpfnWndProc = PaneProc;
wc.hInstance = hInstance;
wc.lpszClassName = "Pane";
RegisterClass(&wc);
// Create the window.
HWND hwnd = CreateWindowEx(
0, // Optional window styles.
(LPCSTR)"Class", // Window class
(LPCSTR)"Test", // Window text
WS_OVERLAPPEDWINDOW| WS_BORDER | WS_CAPTION | WS_CLIPSIBLINGS | WS_THICKFRAME | WS_SYSMENU, // Window style
200,200,400,400,
NULL,NULL,hInstance,NULL);
if (hwnd == NULL)
{
return 0;
}
HWND hwndPane = CreateWindowEx(
0, // Optional window styles.
(LPCSTR)"Pane", // Window class
(LPCSTR)"Test", // Window text
WS_OVERLAPPEDWINDOW|WS_VISIBLE|WS_VSCROLL, // Window style
220,220,400,400,
hwnd,NULL,hInstance,NULL);
if (hwndPane == NULL)
{
return 0;
}
for(int i=0;i<200;i++)
{
HWND eb = CreateWindowEx(WS_EX_CLIENTEDGE, TEXT("Edit"), NULL,ES_AUTOHSCROLL | WS_CHILD| WS_VISIBLE, 16, 16+24*i, 64, 24, hwndPane, (HMENU)i+10000, hInstance, NULL);
char tmp[64];
sprintf(tmp,"%d",i);
SetWindowText(eb,tmp);
}
ShowWindow(hwnd, nCmdShow);
ShowWindow(hwndPane, nCmdShow);
// Run the message loop.
while(1)
{
MSG msg = { };
while (PeekMessage(&msg, NULL, 0,0,PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
Sleep(10);
}
return 0;
}
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_DESTROY:
PostQuitMessage(0);
return 0;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hwnd, &ps);
FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+1));
EndPaint(hwnd, &ps);
}
return 0;
}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
LRESULT CALLBACK PaneProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_CREATE:
int iVScrollPos;
SCROLLINFO vsi;
ZeroMemory(&vsi, sizeof(SCROLLINFO));
vsi.cbSize=sizeof(SCROLLINFO);
vsi.fMask=SIF_ALL;
GetScrollInfo(hwnd,SB_VERT,&vsi);
iVScrollPos=vsi.nPos;
vsi.nMin=0;
vsi.nMax=16+24*200+40;
vsi.nPage=400;
SetScrollInfo(hwnd,SB_VERT,&vsi,TRUE);
GetScrollInfo(hwnd, SB_VERT, &vsi);
break;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
case WM_VSCROLL:
{
int iVScrollPos;
SCROLLINFO vsi;
ZeroMemory(&vsi, sizeof(SCROLLINFO));
vsi.cbSize=sizeof(SCROLLINFO);
vsi.fMask=SIF_ALL;
GetScrollInfo(hwnd,SB_VERT,&vsi);
iVScrollPos=vsi.nPos;
switch(LOWORD(wParam))
{
case SB_THUMBTRACK:
vsi.nPos=vsi.nTrackPos;
break;
}
vsi.nMin=0;
vsi.nMax=16+24*200+40;
vsi.nPage=400;
SetScrollInfo(hwnd,SB_VERT,&vsi,TRUE);
GetScrollInfo(hwnd, SB_VERT, &vsi);
if(vsi.nPos != iVScrollPos)
{
float ScrollAmtY=-(vsi.nPos - iVScrollPos);
#define USESCROLL
#ifdef USESCROLL
int ok=ScrollWindowEx(hwnd ,0,ScrollAmtY,NULL,NULL,NULL,NULL,SW_INVALIDATE|SW_ERASE|SW_SCROLLCHILDREN);
#else
UpdateWindow(hwnd);
RedrawWindow(hwnd,NULL,NULL,RDW_ALLCHILDREN|RDW_INVALIDATE|RDW_ERASE | RDW_INTERNALPAINT | RDW_UPDATENOW);
#endif
}
return 0;
}
break;
}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
I am using NM_CUSTOMDRAW for changing the color of Tree View item & its child on some conditions.I want to get subitems control individually but dwDrawStage never get this case CDDS_ITEMPREPAINT| CDDS_SUBITEM my code snippet is here:
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc;
int j;
HWND hwndTree;
TVITEM tv;
TVHITTESTINFO hti;
char achBuf[100];
switch (message)
{
case WM_CREATE:
RECT rcClient; // dimensions of client area
// handle to tree-view control
// Ensure that the common control DLL is loaded.
InitCommonControls();
// Get the dimensions of the parent window's client area, and create
// the tree-view control.
GetClientRect(hWnd, &rcClient);
hwndTV = CreateWindowEx(0,
WC_TREEVIEW,
TEXT("Tree View"),
WS_VISIBLE | WS_CHILD | WS_BORDER | TVS_HASLINES,
0,
0,
rcClient.right,
rcClient.bottom,
hWnd,
(HMENU)ID_TREEVIEW,
hInst,
NULL);
// Initialize the image list, and add items to the control.
// InitTreeViewImageLists and InitTreeViewItems are application-
// defined functions, shown later.
if (!InitTreeViewItems(hwndTV))
{
DestroyWindow(hwndTV);
return FALSE;
}
break;
case WM_COMMAND:
wmId = LOWORD(wParam);
wmEvent = HIWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
case IDC_MAIN_BUTTON:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
//TreeView_EnsureVisible(hwndTV,hti);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
break;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code here...
EndPaint(hWnd, &ps);
break;
case WM_NOTIFY:
{
LPNMTREEVIEW pnm = (LPNMTREEVIEW)lParam;
if (pnm->hdr.code == NM_CUSTOMDRAW)
{
//LPNMLVCUSTOMDRAW lplvcd = (LPNMLVCUSTOMDRAW)lParam;
//TreeView_GetItem(
//pnm->iItem
LPNMTVCUSTOMDRAW lplvcd = (LPNMTVCUSTOMDRAW)lParam;
//pnm->iItem
//TreeView_GetItem(hWnd,pnm->iItem);
switch (lplvcd->nmcd.dwDrawStage)
{
case CDDS_PREPAINT :
return CDRF_NOTIFYITEMDRAW;
break;
case CDDS_ITEMPREPAINT:
if(found_unMatched(lplvcd->nmcd.lItemlParam))
{
hwndTree = GetDlgItem(hWnd,ID_TREEVIEW);
lplvcd->clrText = RGB(0, 255,0);
ZeroMemory(&tv, sizeof(TVITEM));
tv.hItem=(HTREEITEM)lplvcd->nmcd.dwItemSpec;
tv.mask=TVIF_TEXT|TVIF_HANDLE;
tv.cchTextMax=100;
tv.pszText=(LPWSTR)achBuf;
if(TreeView_GetItem(hwndTree,&tv))
{
achBuf;
}
hChild =(HTREEITEM)TreeView_GetChild(hwndTree,(HTREEITEM)lplvcd->nmcd.dwItemSpec);
hSibling=(HTREEITEM)TreeView_GetNextSibling(hwndTree,hChild);
}
return CDRF_NOTIFYSUBITEMDRAW;
break;
case CDDS_POSTPAINT:
return CDRF_DODEFAULT;
break;
case CDDS_ITEMPOSTPAINT| CDDS_SUBITEM :
hwndTree = GetDlgItem(hWnd,ID_TREEVIEW);
ZeroMemory(&tv, sizeof(TVITEM));
tv.hItem=(HTREEITEM)lplvcd->nmcd.dwItemSpec;
tv.mask=TVIF_TEXT|TVIF_HANDLE;
tv.cchTextMax=100;
tv.pszText=(LPWSTR)achBuf;
if(TreeView_GetItem(hwndTree,&tv))
{
achBuf;
}
if((HTREEITEM)lplvcd->nmcd.dwItemSpec==hSibling)
{
lplvcd->clrText = RGB(176, 0,0);
}
return CDRF_NEWFONT;
break;
case CDDS_ITEMPOSTPAINT:
double_click=1;
break;
}
}}break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
this will color my parent node but child nodes(subitem) remained default(black) and return CDRF_NOTIFYSUBITEMDRAW didnt work. Please help!!!
How can I handle individual items being clicked in a MS Windows treeview ?
My windows proc has :
LRESULT CALLBACK WndProcTreeView(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {
PAINTSTRUCT paintStruct;
HDC hDC;
switch (message)
{
case WM_PAINT:
{
hDC = BeginPaint(hwnd, &paintStruct);
EndPaint(hwnd, &paintStruct);
break;
}
case WM_NOTIFY:
{
switch (reinterpret_cast<LPNMHDR>(lParam)->code) {
case NM_CLICK:
MessageBox(nullptr, "click", "click", MB_OK);
}
}
default:
{
return DefWindowProc(hwnd, message, wParam, lParam);
break;
}
}
Which outputs a message box when I click on the treeview control. How can I handle individual elements ?
Example of a treeview item being added to the list :
std::string vTxt = std::string("Vertex count : ") + std::to_string(mesh.v.size());
tvinsert.hInsertAfter = mesh_items[mesh_items.size() - 1];
tvinsert.hParent = mesh_items[mesh_items.size() - 1];
tvinsert.item.mask = TVIF_TEXT;
tvinsert.item.pszText = (LPSTR)vTxt.c_str();
mesh_items_sub.push_back((HTREEITEM)SendMessage(hwnd, TVM_INSERTITEM, 0, (LPARAM)&tvinsert));
I have seen using SendDlgItemMessage instead (which gives an ID as LOWORD(wParam) inside the windows proc) but it requires IDs set in a resource file - which I don't know how to create.
Two things I needed for my code to work : first give each item a lparam value and changing TVIF_TEXT as item's mask to TVIF_TEXT | TVIF_IMAGE | TVIF_SELECTEDIMAGE | TVIF_PARAM (TVIF_PARAM allowing for an lparam to be passed to the window proc thus identifying the controller).
Working code excerpt :
TV_INSERTSTRUCT tvinsert;
// ...
tvinsert.hInsertAfter = Root;
tvinsert.hParent = Root;
tvinsert.item.pszText = std::string("some text...").c_str();
tvinsert.item.lParam = ID_SOME_ID; // << #defined constant or plain int
tvinsert.item.mask = TVIF_TEXT | TVIF_IMAGE | TVIF_SELECTEDIMAGE | TVIF_PARAM;
root_sub.push_back((HTREEITEM)SendMessage(hwnd, TVM_INSERTITEM, 0, (LPARAM)&tvinsert));
// window proc code below
LRESULT CALLBACK WndProcTreeView(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {
PAINTSTRUCT paintStruct;
HDC hDC;
switch (message)
{
case WM_PAINT:
{
hDC = BeginPaint(hwnd, &paintStruct);
EndPaint(hwnd, &paintStruct);
break;
}
case WM_NOTIFY:
{
LPNM_TREEVIEW pntv = (LPNM_TREEVIEW)lParam;
if (pntv->hdr.code == TVN_SELCHANGED) {
switch (pntv->itemNew.lParam) {
case ID_SOME_ID:
std::cout << "ID_SOME_ID selected caught here..." << std::endl;
break;
}
}
}
default:
{
return DefWindowProc(hwnd, message, wParam, lParam);
break;
}
}
return 0;
}
Good explanation/example here (in french) http://chgi.developpez.com/windows/treeview/
I want to change label background color within a function, I tried this code but nothing changed after calling changecolor function
HWND hWndLabel;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
hWndLabel = CreateWindowEx(WS_EX_TRANSPARENT,
L"STATIC", L"", WS_CHILD | WS_VISIBLE | SS_LEFT | WS_SYSMENU,
75, 75, 70, 70, hWnd, (HMENU)labelId, hInst, NULL);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
case WM_COMMAND: // all events are handled here
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
break;
}
return 0;
}
DWORD WINAPI changecolor(){
HDC hdc = GetDC(hWndLabel); // get context
SetBkColor(hdc, RGB(0, 0, 230)); // Code Copied from the above answer by cpx.
return 0;
}
I read that Static controls send their parent a WM_CTLCOLORSTATIC message just before they paint themselves. code is implemented within CALLBACK function, but where this code is called (changing color)?, how can I call SetTextColor within a function
code example :
case WM_CTLCOLORSTATIC:
if (the_button_was_clicked) {
HDC hdc = reinterpret_cast<HDC>(wParam);
SetTextColor(hdc, COLORREF(0xFF, 0x00, 0x00));
}
return ::GetSysColorBrush(COLOR_WINDOW); // example color, adjust for your circumstance
Try something more like this:
HWND hWndLabel;
HBRUSH hBrushLabel;
COLORREF clrLabelText;
COLORREF clrLabelBkGnd;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
hWndLabel = CreateWindowEx(0, L"STATIC", L"", WS_CHILD | WS_VISIBLE | SS_LEFT,
75, 75, 70, 70, hWnd, (HMENU)labelId, hInst, NULL);
hBrushLabel = NULL;
clrLabelText = GetSysColor(COLOR_WINDOWTEXT);
clrLabelBkGnd = GetSysColor(COLOR_WINDOW);
break;
case WM_DESTROY:
if (hBrushLabel) DeleteObject(hBrushLabel);
PostQuitMessage(0);
break;
case WM_CTLCOLORSTATIC: {
HDC hdc = reinterpret_cast<HDC>(wParam);
SetTextColor(hdc, clrLabelText);
SetBkColor(hdc, clrLabelBkGnd);
if (!hBrushLabel) hBrushLabel = CreateSolidBrush(clrLabelBkGnd);
return reinterpret_cast<LRESULT>(hBrushLabel);
}
case WM_COMMAND: // all events are handled here
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
break;
}
return 0;
}
DWORD WINAPI changecolor()
{
if (hBrushLabel) {
DeleteObject(hBrushLabel);
hBrushLabel = NULL;
}
clrLabelText = RGB(0xFF, 0x00, 0x00);
clrLabelBkGnd = RGB(0, 0, 230);
InvalidateRect(hWndLabel, NULL, TRUE);
return 0;
}
There is a similar example in the WM_CTLCOLORSTATIC documentation.
The following C++ example shows how to set the text foreground and background colors of a static control in response to the WM_CTLCOLORSTATIC message. The hbrBkgnd variable is a static HBRUSH variable that is initialized to NULL, and stores the background brush between calls to WM_CTLCOLORSTATIC. The brush must be destroyed by a call to the DeleteObject function when it is no longer needed, typically when the associated dialog box is destroyed.
case WM_CTLCOLORSTATIC:
{
HDC hdcStatic = (HDC) wParam;
SetTextColor(hdcStatic, RGB(255,255,255));
SetBkColor(hdcStatic, RGB(0,0,0));
if (hbrBkgnd == NULL)
{
hbrBkgnd = CreateSolidBrush(RGB(0,0,0));
}
return (INT_PTR)hbrBkgnd;
}
A friend of mine is about to release an application and asked me to create a launcher for it. I found it a good excuse to finally study WinAPI and thought that a simple launcher would be easily doable even in a relatively small time window.
I was wrong.
I'm trying to create a launcher window with 5 buttons that start different things. The goal is to have transparent buttons (not done yet) that have a smaller image inside them. The image should only be displayed when the user hovers over the larger button area.
The images are in .png format. I'm using GDI+ and loading PNG files from resources with http://www.codeproject.com/Articles/3537/Loading-JPG-PNG-resources-using-GDI.
I'm using MouseTrackEvents to keep track of the mouse and I've also subclassed a button. The problem is that I don't know how I should handle the WM_MOUSELEAVE message. I don't know how to erase the image I've drawn. If I have to save the ht_img as a variable and refer to it later, I don't know how.
Here's what I have so far. This example loads the .png from resource IDB_Website2. Displaying the image works (although it keeps being rendered over and over again currently):
WndProc:
LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc;
GDI gdi;
switch (Msg)
{
case WM_CREATE:
{
HWND hwndButton = CreateWindow(TEXT("button"), NULL,
WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON,
80, 10, 100, 50,
hWnd, (HMENU) HT_BUTTON1, NULL, NULL);
HTButton = (WNDPROC) SetWindowLong(hwndButton, GWL_WNDPROC, (LONG) ButtonProc);
}
...
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
gdi.InitList(hInst, hdc);
EndPaint(hWnd, &ps);
break;
Buttonproc (subclassed button):
LRESULT CALLBACK ButtonProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
MouseTrackEvents MouseTrack;
GDI gdi;
HDC odc = GetDC(GetParent(hWnd));
switch(Msg)
{
case WM_MOUSEMOVE:
MouseTrack.OnMouseMove(hWnd);
break;
case WM_MOUSEHOVER:
gdi.Create(IDB_Website2, _T("PNG"), hInst, odc, 62, 347, 200, 40, true);
MouseTrack.Reset(hWnd);
break;
case WM_MOUSELEAVE:
MouseTrack.Reset(hWnd);
break;
}
return CallWindowProc (HTButton, hWnd, Msg, wParam, lParam);
}
class GDI's Create graphic method:
void Create(UINT menuid, LPCTSTR pType, HMODULE hInst, HDC hdc, int x, int y, int w, int h)
{
Graphics grpx(hdc);
ht_img = new CGdiPlusBitmapResource();
ht_img -> Load(menuid, pType, hInst);
grpx.DrawImage(*ht_img, x, y, w, h);
delete ht_img;
}
This has been quite a challenge so far! It's been fun although a bit tear-my-hair-out inducing at times. :-) I'd be grateful for any advice on how I should proceed.
EDIT: Answering Adrian
I tried changing my Buttonproc, but the image doesn't seem to be rendered. Here's what I did:
LRESULT CALLBACK ButtonProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
MouseTrackEvents MouseTrack;
GDI gdi;
HDC odc = GetDC(GetParent(hWnd));
PAINTSTRUCT ps;
int result;
switch(Msg)
{
case WM_MOUSEMOVE:
MouseTrack.OnMouseMove(hWnd);
break;
case WM_MOUSEHOVER:
hovering = true;
break;
case WM_MOUSELEAVE:
hovering = false;
MouseTrack.Reset(hWnd);
break;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
result = CallWindowProc(HTButton, hWnd, Msg, wParam, lParam);
if (hovering == true) {
gdi.Create(IDB_Play2, _T("PNG"), hInst, hdc, 62, 100, 200, 40);
}
EndPaint(hWnd, &ps);
return result;
}
return CallWindowProc (HTButton, hWnd, Msg, wParam, lParam);
}
You probably don't want to do the painting directly in the handling of the mouse events. You probably want to handle WM_PAINT in the button proc by calling the underlying implementation and then augmenting it based on the hover state. Then your mouse handling corresponds to flipping a state variable and invalidating the button (which will cause it to repaint).
case WM_PAINT:
// start with the standard rendering
int result = CallWindowProc (HTButton, hWnd, Msg, wParam, lParam);
// then overdraw our embellishments
if (my_state_variable == hovering) {
DrawOverlayImage();
}
return result; // don't just break here, or you'll call CallWindowProc again