I have the following code that is supposed to paint a small box located on the bottom-left of a window, move 50 pixels to the right every 200 milliseconds, then reappear on the left once it reaches the right side.
Why doesn't my little rectangle move? It is painted in the same location all the time.
case WM_PAINT:
if (hBitmap != NULL)
{
// Paint the bitmap.
PAINTSTRUCT ps;
HDC hdc;
HDC hdcMem;
HGDIOBJ oldBitmap;
//
hdc = BeginPaint(hwnd, &ps);
// Create a dc in memory to paint on.
hdcMem = CreateCompatibleDC(hdc);
// Select the bitmap.
oldBitmap = SelectObject(hdcMem, hBitmap);
// Copy bitmap to splash screen window.
BitBlt(hdc, 0, 0, bmWidth, bmHeight, hdcMem, 0, 0, SRCCOPY);
// Fill rectangle.
HBRUSH hbr = CreateSolidBrush(RGB(42, 59, 87));
SelectObject(hdc, hbr);
FillRect(hdc, &rc, hbr);
// Cleanup.
SelectObject(hdcMem, oldBitmap);
DeleteObject(hbr);
DeleteObject(oldBitmap);
DeleteDC(hdcMem);
EndPaint(hwnd, &ps);
}
break;
case WM_TIMER:
timeCount++;
addLeft += 50;
if (addLeft == 300)
{
addLeft = 0;
}
// Move rectangle.
rc.left += addLeft;
rc.right += addLeft;
// Refresh the window.
UpdateWindow(hwnd);
// Timer and RECT from the top of the code page, and WinMain:
UINT_PTR ptrTimer;
const int TIMER_INTERVAL = 200;
const int MAX_TIME_COUNT = 100;
int timeCount;
// the timer works, but here's the code anyway.
ptrTimer = SetTimer(hwnd, 1, TIMER_INTERVAL, (TIMERPROC)NULL);
RECT rc;
rc.left = 141;
rc.top = 232;
rc.right = rc.left + 15;
rc.bottom = rc.top + 15;
Thanks for any replies,
Matt
Edit: Thanks hf.enigma, for the reply. This is what I ended up doing before I read your post. This works if anyone else wants to do this, but there are a couple more handles and GDI objects to clear. I am new to C++, so if anyone sees a memory leak here, please let me know. Thanks.
case WM_PAINT:
if (hBitmap != NULL)
{
// Paint the bitmap.
PAINTSTRUCT ps;
HDC hdc;
HDC hdcMem;
HGDIOBJ oldBitmap;
//
hdc = BeginPaint(hwnd, &ps);
hdcMem = CreateCompatibleDC(hdc); // a device context (dc) in memory to paint on.
oldBitmap = SelectObject(hdcMem, hBitmap);
// Copy bitmap to splash screen window.
BitBlt(hdc, 0, 0, bmWidth, bmHeight, hdcMem, 0, 0, SRCCOPY);
EndPaint(hwnd, &ps);
// Cleanup.
SelectObject(hdcMem, oldBitmap);
DeleteObject(oldBitmap);
DeleteDC(hdcMem);
HBRUSH hbr ;
// Fill rectangle.
RECT f;
GetClientRect(hwndBox, &f);
hdc = BeginPaint(hwndBox, &ps);
hdcMem = CreateCompatibleDC(hdc);
hbr = CreateSolidBrush(RGB(42, 59, 87));
SelectObject(hdc, hbr);
FillRect(hdc, &f, hbr);
EndPaint(hwnd, &ps);
// Cleanup.
SelectObject(hdcMem, oldBitmap);
DeleteObject(oldBitmap);
DeleteDC(hdcMem);
DeleteObject(hbr);
}
case WM_TIMER:
timeCount++;
if (addLeft == 60)
{
addLeft = 10000;
ival = 2;
}
// 'Hide' the box for 2/3 of timer interval when
// it reaches the right side.
if (addLeft == 10000)
{
addLeft = 0;
ival = 1;
}
//
switch (ival)
{
case 2:
addLeft += 12;
break;
case 3:
ival = 0;
break;
}
ival++;
if (ival == 2)
{
// Move rectangle.
MoveWindow(hwndBox, rcleft + addLeft, rctop, 12, 12, true);
}
if (timeCount == MAX_TIME_COUNT)
{
DestroyWindow(hwnd);
}
break;
This can be painted like hf.enigma has stated, but FillRect() must be called twice for each paint event. Without 'erasing' the previous block, the window ended up having a long rectangle along the bottom, similar to a progress bar.
I ended up making a sub-window the size of the block I wanted, and calling the MoveWindow() function. For me, this is the simplest and most maintainable way to accomplish this without having to use MFC or CLI.
If this can help anyone else, Here is all of the code that I am using for this.
//This displays a splash screen, and starts
//another application that takes a long time
//to load.
#pragma once
#include "resource.h"
#include "PathStatus.h"
#include "StartApp.h"
#include "CenterWindow.h"
#include <string>
#include <stdlib.h>
#include <iostream>
using namespace std;
const LPWSTR CLASS_NAME(L"TMS_Logs");
const LPWSTR PATH_SUFFIX (L"\\bin\\tl.exe");
const int LEN_APP_NAME = 12; // length of "TMS_Logs.exe".
bool b;
int ival;
char *appPath;
HWND hwnd; // Main window.
HBITMAP hBitmap = NULL; // Bitmap painted in window.
HWND hwndBox; // Moving box shows app. is loading.
HWND hwndButton; // Close box.
int bmWidth;
int bmHeight;
UINT_PTR ptrTimer;
const int TIMER_INTERVAL = 50;
const int MAX_TIME_COUNT = 650;
int timeCount;
int addLeft;
int rcleft, rctop, rcright, rcbottom;
RECT rcMover;
RECT rcMover2;
bool exitApp = false;
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow)
{
rcleft = 157;
rctop = 220;
rcright = rcleft + 15;
rcbottom = rctop + 15;
//
rcMover.left = rcleft;
rcMover.bottom = rcbottom;
rcMover.top = rctop;
rcMover.right = rcright;
//
rcMover2.bottom = rcbottom;
rcMover2.top = rctop;
rcMover.left + rcleft + 50;
rcMover.right = rcleft + 50 + 15;
// Get the commandline.
const wchar_t *args = GetCommandLineW();
wstring s(args);
// With no external arguments, GetCommandLineW() returns the
// full path with quotes around it, plus one space after the
// end qoute, e.g., '"c:\fullpath.exe" '.
// Remove the starting and ending quote chars, the space at
// the end, and and the exe path.
//
int len = s.length();
s = s.substr(1, len - 3 - LEN_APP_NAME) + PATH_SUFFIX;
// Convert the wide string to a regular char array.
// Convert the wstring to c-string.
const wchar_t *path = s.c_str();
// Convert the WCHAR to char* and store it in the
// 'appPath' variable.
const size_t BUFFER_SIZE = 200;
size_t i;
appPath = (char*)malloc(BUFFER_SIZE);
wcstombs_s(&i, appPath, BUFFER_SIZE, path, BUFFER_SIZE);
// Create window class objects.
WNDCLASSEX wc;
MSG msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc; // Sets callback function.
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, MAKEINTRESOURCE(IDICN_WSDOT));
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = CLASS_NAME;
wc.hIconSm = wc.hIcon;
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, L"Window Registration Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return -1;
}
// Load the resource bitmap.
hBitmap = LoadBitmap(hInstance, MAKEINTRESOURCE(IDBMP_TL7));
// Make a bitmap to hold the returned width and height.
// This bitmap will be deleted when DeleteObject is called
// for the hBitmap handle.
BITMAP bm;
if (hBitmap != NULL && GetObject(hBitmap, sizeof(bm), &bm))
{
bmWidth = bm.bmWidth;
bmHeight = bm.bmHeight;
}
else
{
MessageBox(hwnd, L"Error loading splash screen bitmap.",
L"Error", MB_ICONEXCLAMATION | MB_OK);
return -1;
}
// Center the window on the monitor
// where the mouse is.
RECT rc;
CenterRectToMonitor(&rc, bmWidth, bmHeight);
//
hwnd = CreateWindowEx(WS_EX_PALETTEWINDOW, wc.lpszClassName, // Uses the properties set in Window Class wc.
L"TMS Logs", WS_POPUP, rc.left, rc.top, bmWidth, bmHeight, NULL, NULL, hInstance, NULL);
if (hwnd == NULL)
{
MessageBox(NULL, L"Error creating Window.", L"Error",
MB_ICONEXCLAMATION | MB_OK);
return -1;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
//bool started = true;
bool started = false;
bool ret;
int x, w, y, h;
x = 369;
y = 10;
w = 19;
h = 19;
// Make close box in upper-right corner.
hwndButton = CreateWindow(
L"BUTTON", // Predefined class.
L"X", // Button text
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON, // Styles
369, // x position
10, // y position
19, // Button width
19, // Button height
hwnd, // Parent window
NULL, // No menu.
(HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
NULL); // Pointer not needed.
// Make a box that moves along the bottom of
// the window while the other app. loads.
x = rcleft;
y = rctop;
w = 10;
h = 10;
hwndBox = CreateWindow(L"static", 0, WS_CHILD | WS_VISIBLE, x, y, w, h, hwnd, NULL,
(HINSTANCE) GetWindowLong (hwnd, GWL_HINSTANCE), NULL);
// Create a timer to close this window after
// several seconds, in case the main app. does
// not send the close window message to this app.
// the WM_TIMER message is handled in the WndProc
// callback function.
ptrTimer = SetTimer(hwnd, 1, TIMER_INTERVAL, (TIMERPROC)NULL);
// Start message Loop.
while ((ret = GetMessage(&msg, NULL, 0, 0)) != 0)
{
if (ret == -1)
{
MessageBox(NULL,
L"Error in Splash screen window message loop, at:\n\n'GetMessage(&msg, NULL, 0, 0))'.\n\nMessage return value was -1.",
L"TMS Logs", MB_ICONEXCLAMATION | MB_OK);
// Exit this app.
return -1;
}
// TranslateMessage(&Msg); // Not needed with what I have here.
DispatchMessage(&msg);
// Check app. path and start the other app.
if (!started)
{
started = true;
if (Path_Accessible(appPath))
{
// Start the main app.
if (!StartApplication(appPath))
{
// The folder or file is missing, or
// the user does not have security
// permissions to the sub-folder.
MessageBox(hwnd, L"Unexpected error at: StartApplication().",
L"Error", MB_ICONEXCLAMATION | MB_OK);
if (appPath)
{
free(appPath);
}
return -1;
}
}
else
{
// Display an error message.
char msg[350];
char* prefix = "Error: Can't find 'tl.exe'.\n\n It's missing from: '";
//char* suffix = " '\ncannot be accessed, or does not exist.";
int count = sizeof(msg);
strncpy(msg, prefix, count);
strncat(msg, appPath, count);
//strncat(msg, suffix, count);
// Convert c-string to wide char. string.
count = strlen(msg) + 1;
wchar_t* wMsg = new wchar_t[count];
size_t returnCount;
int ret = mbstowcs_s(&returnCount, wMsg, count, msg, _TRUNCATE);
if (ret == 0 && returnCount == count)
{
MessageBox(hwnd, wMsg, L"Error", MB_ICONEXCLAMATION | MB_OK);
}
else
{
// Error
MessageBox(hwnd, L"Error: The application path cannot be accessd, or does not exist.", L"Error", MB_ICONEXCLAMATION | MB_OK);
}
delete[] wMsg;
if (appPath)
{
free(appPath);
}
return -1;
}
}
}
if (appPath)
{
free(appPath);
}
return msg.wParam;
}
// Process messages.
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_COMMAND:
// The close button is the only child window,
// so no need to check wparam.
DestroyWindow(hwnd);
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
DestroyWindow(hwndButton);
DestroyWindow(hwndBox);
if (hBitmap != NULL)
{
if (!DeleteObject(hBitmap))
{
MessageBox(hwnd, L"Error at: WndProc(). Failed to delete the application bitmap.",
L"Error", MB_OK);
}
}
if (ptrTimer)
{
if (!KillTimer(hwnd, ptrTimer))
{
MessageBox(hwnd, L"Error at :WndProc(). Failed to free the application timer.",
L"Error", MB_OK);
}
}
PostQuitMessage(0);
break;
case WM_PAINT:
if (hBitmap != NULL)
{
// Paint the bitmap.
PAINTSTRUCT ps;
HDC hdc;
HDC hdcMem;
HGDIOBJ oldBitmap;
//
hdc = BeginPaint(hwnd, &ps);
hdcMem = CreateCompatibleDC(hdc); // a device context (dc) in memory to paint on.
oldBitmap = SelectObject(hdcMem, hBitmap);
// Copy bitmap to splash screen window.
BitBlt(hdc, 0, 0, bmWidth, bmHeight, hdcMem, 0, 0, SRCCOPY);
EndPaint(hwnd, &ps);
// Cleanup.
SelectObject(hdcMem, oldBitmap);
DeleteObject(oldBitmap);
DeleteDC(hdcMem);
HBRUSH hbr ;
// Fill rectangle.
RECT f;
GetClientRect(hwndBox, &f);
hdc = BeginPaint(hwndBox, &ps);
hdcMem = CreateCompatibleDC(hdc);
hbr = CreateSolidBrush(RGB(42, 59, 87));
SelectObject(hdc, hbr);
FillRect(hdc, &f, hbr);
EndPaint(hwnd, &ps);
// Cleanup.
SelectObject(hdcMem, oldBitmap);
DeleteObject(oldBitmap);
DeleteDC(hdcMem);
DeleteObject(hbr);
}
break;
case WM_TIMER:
timeCount++;
if (addLeft == 60)
{
addLeft = 10000;
ival = 2;
}
// 'Hide' the box for 2/3 of timer interval when
// it reaches the right side.
if (addLeft == 10000)
{
addLeft = 0;
ival = 1;
}
//
switch (ival)
{
case 2:
addLeft += 12;
break;
case 3:
ival = 0;
break;
}
ival++;
if (ival == 2)
{
// Move rectangle.
MoveWindow(hwndBox, rcleft + addLeft, rctop, 12, 12, true);
}
if (timeCount == MAX_TIME_COUNT)
{
DestroyWindow(hwnd);
}
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
Here is the code for referenced H files.
StartApp.H
#pragma once
#define WIN32_LEAN_AND_MEAN // Exclude DDE, RPC, Shell, Sockets, etc.
#define NOCOMM // Exclude serial communication APIs.
#include <Windows.h>
#include <cstdlib>
// Calls the CreateProcess function to start another app.
// ref: https://msdn.microsoft.com/en-us/library/windows/desktop/ms682512(v=vs.85).aspx
bool StartApplication(const char* appPath)
{
// The CreateProcess function requires
// wide char. array, so convert appPath.
size_t count = strlen(appPath) + 1;
wchar_t* path = new wchar_t[count];
size_t returnCount;
int ret = mbstowcs_s(&returnCount, path, count, appPath, _TRUNCATE);
if (ret != 0 || returnCount != count)
{
// Error converting C-string.
delete[] path;
return false;
}
// Required objects.
STARTUPINFO si;
PROCESS_INFORMATION pi;
// Set the size of the objects.
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
// Start the program at 'path'.
bool ok = CreateProcess(
path, // module name/app. path.
NULL, // Command line/path, if null app. path is used.
NULL, // Process handle, use null.
NULL, // Thread handle, use null.
FALSE, // Set handle inheritance to FALSE.
0, // No creation flags.
NULL, // Use parent's environment block.
NULL, // Use parent's starting directory.
&si, // Pointer to STARTUPINFO structure.
&pi); // Pointer to PROCESS_INFORMATION structure.
// Close process and thread handles.
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
delete[] path;
return ok;
}
CenterWindow.H
void CenterRectToMonitor(LPRECT prc, int rcWidth, int rcHeight)
{
POINT pt;
GetCursorPos(&pt);
HMONITOR mon;
mon = MonitorFromPoint(pt, MONITOR_DEFAULTTONEAREST);
MONITORINFO mi;
mi.cbSize = sizeof(mi);
GetMonitorInfo(mon, &mi);
*prc = mi.rcMonitor;
//
// Center the window rectangle to the monitor rectangle.
prc->left = prc->left + (prc->right - prc->left - rcWidth) / 2;
prc->top = prc->top + (prc->bottom - prc->top - rcHeight) / 2;
prc->right = prc->left + rcWidth;
prc->bottom = prc->top + rcHeight;
}
PathStatus.H
#include <sys/stat.h>
const int SUCCESS = 0; // Indicates stat buffer was successfully set.
// Method to check if a file or folder
// exists and is accessible, using the stat
// structure and stat function, ref:
// http://pubs.opengroup.org/onlinepubs/009695399/functions/stat.html
bool Path_Accessible(const char* path)
{
if (path == 0)
{
return false;
}
struct stat path_status;
int result = stat(path, &path_status);
//
// The _S_IFREG flag indicates the path is a
// regular file and not a directory.
//
// To check for a directory, use '_S_IFDIR'.
return result == SUCCESS &&
(path_status.st_mode & _S_IFREG);
}
This is what my splash screen looks like. Note that the small box starts a little to the left of where it is now, moves a little to the right, and this repeats until the other app. this one started sends the WM_CLOSE message to this window.