winapiwindowheightscrollbar
How do I get the exact size of a window's area, including hidden controls?
I need to get the whole window's display area size, including controls that are hidden. In order to do that, I get the value from top from the very first window and the value of bottom from very last control. However, I'm getting a gap/white are in the end of the display area. See what's like in the below image. The display area is supposed to be until the Edit control's borders is seen. What am I missing?
I'm getting this size by:
int scrollHeight(void)
{
int minTop = 0;
int maxBottom = 0;
RECT rt = {0};
if(allControls_indx == 0) {
return 0;
}
#if 0
assert(allControls[0] == hMainWindow);
assert(allControls[allControls_indx - 1] == hEdit1);
#endif
if(!GetWindowRect(allControls[0], &rt)) {
ErrorExit(NAMEOF(scrollHeight), __LINE__, __FILENAME__);
}
minTop = rt.top;
if(!GetWindowRect(allControls[allControls_indx - 1], &rt)) {
ErrorExit(NAMEOF(scrollHeight), __LINE__, __FILENAME__);
}
maxBottom = rt.bottom;
return maxBottom - minTop;
}
set as scrollbar's page size like this:
setUpScrollBar(hwnd, scrollHeight());
where setUpScrollBar is defined as:
void setUpScrollBar(HWND hwnd, int h)
{
RECT rc = { 0 };
GetClientRect(hwnd, &rc);
SCROLLINFO si = { 0 };
si.cbSize = sizeof(SCROLLINFO);
si.fMask = SIF_ALL;
si.nMin = 0;
si.nMax = h;
si.nPage = (rc.bottom - rc.top);
si.nPos = 0;
si.nTrackPos = 0;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
}
full code:
#pragma comment(lib, "user32.lib")
#pragma comment(lib, "Comctl32.lib")
#pragma comment(lib, "Gdi32.lib")
#define WIN32_LEAN_AND_MEAN
#define UNICODE
#define _UNICODE
#include <windows.h>
#include <Commctrl.h>
#include <crtdbg.h>
#include <strsafe.h>
#include <string.h>
#include <assert.h>
#ifdef UNICODE
#define STRSPLIT wcsrchr
#else
#define STRSPLIT strrchr
#endif
#define __FILENAME__ (STRSPLIT(TEXT(__FILE__), '/') ? STRSPLIT(TEXT(__FILE__), '/') + 1 : TEXT(__FILE__))
#define NAMEOF(s) TEXT(#s)
#define COUNTOF(a) (sizeof(a)/sizeof(a[0]))
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK CreateTabProc(HWND, UINT, WPARAM, LPARAM);
void ErrorExit(LPWSTR lpszFunction, int line, LPWSTR filename);
void InitComControls();
void ErrorExit(LPWSTR lpszFunction, int line, LPWSTR filename);
DWORD ShowLastError(LPWSTR lpszFunction, int line, LPWSTR filename);
void InitComControls();
void CreateTab(HWND hwnd);
void InsertTabItem(HWND tabHwnd, UINT id, LPWSTR text);
void CreateButtons(HWND hwnd);
RECT GetLocalCoordinates(HWND hWnd);
int scrollHeight(void);
int getHeight(HWND control);
void setUpScrollBar(HWND hwnd, int);
void pushControl(HWND);
int displayArea(void);
void setScrollBarSize(HWND hwnd, int s);
inline int my_max(int a, int b);
inline int my_min(int a, int b);
void displayText(HWND h);
HINSTANCE ghInstance;
HWND hTab;
HWND hLabel1, hLabel2;
HWND hEdit1;
HWND hRemoveButton;
enum
{
IDBUTTON_REMOVE = 50
};
#define MAX_CONTROLS 8
static const wchar_t *title[] = { L"Button A1", L"Button B2", L"Button C3",
L"Button D4", L"Button E5", L"Button F6",
L"Button G" , L"Button 001", L"Button 002",
L"Button 003", L"Button 004",
L"Button 005", L"Button 006" };
HWND hButton[sizeof(title)/sizeof(title[0])] = {0};
HWND allControls[MAX_CONTROLS];
HWND hMainWindow;
int allControls_indx = 0;
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
PWSTR pCmdLine, int nCmdShow)
{
MSG msg = {0};
HWND hwnd;
WNDCLASSW wc = {0};
wc.lpszClassName = L"Window";
wc.hInstance = hInstance;
wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
wc.lpfnWndProc = WndProc;
wc.hCursor = LoadCursor(0, IDC_ARROW);
InitComControls();
if(!RegisterClass(&wc)) {
ErrorExit(NAMEOF(RegisterClass), __LINE__, __FILENAME__);
}
int width = 500;
int height = 350/2; // half than the usual size, so that the scrollbar show up and we can test it
int screenWidth = GetSystemMetrics(SM_CXSCREEN);
int screenHeight = GetSystemMetrics(SM_CYSCREEN);
int cx = (screenWidth - width) / 2;
int cy = (screenHeight - height) / 2;
hwnd = CreateWindowW(wc.lpszClassName, L"main window",
WS_OVERLAPPEDWINDOW | WS_VISIBLE,
cx, cy, width, height, NULL, NULL,
hInstance, NULL);
ghInstance = hInstance;
while (GetMessage(&msg, NULL, 0, 0))
{
if (!IsDialogMessage(hwnd, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return (int) msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
static int g_scrollY;
switch(msg)
{
case WM_CREATE:
hMainWindow = hwnd;
pushControl(hwnd); // push main window too
hLabel1 = CreateWindowW(L"Static", L"This is label 1...",
WS_VISIBLE | WS_CHILD | WS_TABSTOP,
50, 10, 130, 25, hwnd, (HMENU) 18, NULL, NULL);
pushControl(hLabel1);
hLabel2 = CreateWindowW(L"Static", L"This is label 2...",
WS_VISIBLE | WS_CHILD | WS_TABSTOP,
50, 40, 130, 25, hwnd, (HMENU) 19, NULL, NULL);
hRemoveButton = CreateWindow(L"Button", L"Remove",
WS_VISIBLE | WS_CHILD | WS_TABSTOP,
200, 40, 80, 25,
hwnd,
(HMENU) IDBUTTON_REMOVE,
NULL,
NULL);
pushControl(hLabel2);
CreateTab(hwnd);
CreateButtons(hwnd);
setUpScrollBar(hwnd, scrollHeight());
break;
case WM_VSCROLL:
{
int action = LOWORD(wParam);
//HWND hScroll = (HWND)lParam;
int pos = -1;
if (action == SB_THUMBPOSITION || action == SB_THUMBTRACK) {
pos = HIWORD(wParam);
} else if (action == SB_LINEDOWN) {
pos = g_scrollY + 30;
} else if (action == SB_LINEUP) {
pos = g_scrollY - 30;
}
if (pos == -1)
break;
SCROLLINFO si = { 0 };
si.cbSize = sizeof(SCROLLINFO);
si.fMask = SIF_POS;
si.nPos = pos;
si.nTrackPos = 0;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
GetScrollInfo(hwnd, SB_VERT, &si);
pos = si.nPos;
POINT pt;
pt.x = 0;
pt.y = pos - g_scrollY;
HDC hdc = GetDC(hwnd);
LPtoDP(hdc, &pt, 1);
ReleaseDC(hwnd, hdc);
ScrollWindow(hwnd, 0, -pt.y, NULL, NULL);
g_scrollY = pos;
return 0;
}
break;
case WM_COMMAND:
{
switch(LOWORD(wParam))
{
case IDBUTTON_REMOVE:
ShowWindow(hEdit1, SW_HIDE);
SetScrollRange(hwnd, SB_VERT, 0, displayArea(), TRUE);
break;
}
}
break;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, msg, wParam, lParam);
}
// this is like scrollHeight but control that are hidden
// aren't considered part of the display area.
int displayArea(void)
{
int size = scrollHeight();
// start i with 1 so we skip the mainwindow.
// we are interested in the "children controls"
for(int i = 1; i < MAX_CONTROLS && allControls[i]; i++)
{
HWND h = allControls[i];
// if it not visible, remove it from display area
if(!IsWindowVisible(h)) {
size -= getHeight(h);
}
}
return size;
}
void pushControl(HWND hwnd)
{
if(allControls_indx > MAX_CONTROLS) {
assert(!"no room for extra controls");
}
allControls[allControls_indx++] = hwnd;
}
void CreateTab(HWND hwnd)
{
hTab =
CreateWindow(WC_TABCONTROLW, NULL,
WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_TABSTOP,
100, 80, 400, 250,
hwnd,
(HMENU) 1,
NULL,
NULL);
InsertTabItem(hTab, 2, L"Tab 1");
InsertTabItem(hTab, 3, L"Tab b");
pushControl(hTab);
}
void CreateButtons(HWND hwnd)
{
RECT rt = GetLocalCoordinates(hTab);
TabCtrl_AdjustRect(hTab, FALSE, &rt);
RECT rt2 = {0};
GetWindowRect(hTab, &rt2);
int tab_width = rt2.right - rt2.left;
int tab_height = rt2.bottom - rt2.top;
int id = 4;
const int cy_breakSize = 25;
int cx_initPos = rt.left;
int cy_initPos = rt.top;
int cx = cx_initPos;
int cy = cy_initPos;
const int button_width = 80;
const int button_height = 25;
const int cx_margin = 10;
int nMaxButtonPerRow = tab_width / (button_width + cx_margin);
for(int i = 0; i < sizeof(title)/sizeof(title[0]); ++i)
{
if(i != 0 && (i % nMaxButtonPerRow) == 0) {
cy += cy_breakSize;
cx = cx_initPos;
}
hButton[i] =
CreateWindow(L"button", title[i],
WS_VISIBLE | WS_CHILD | WS_TABSTOP,
cx,
cy,
button_width,
button_height,
hwnd, (HMENU) id++, NULL, NULL);
cx += button_width;
}
const int edit_width = 180;
const int edit_height = 25;
hEdit1 = CreateWindow(L"Edit", L"Hello, world!",
WS_VISIBLE | WS_CHILD | WS_BORDER,
cx,
// put below tab control's display area
getHeight(hTab) + cx,
edit_width,
edit_height,
hwnd,
(HMENU) id++,
NULL, NULL);
pushControl(hEdit1);
cx += edit_width;
}
void setUpScrollBar(HWND hwnd, int h)
{
RECT rc = { 0 };
GetClientRect(hwnd, &rc);
SCROLLINFO si = { 0 };
si.cbSize = sizeof(SCROLLINFO);
si.fMask = SIF_ALL;
si.nMin = 0;
si.nMax = h;
si.nPage = (rc.bottom - rc.top);
si.nPos = 0;
si.nTrackPos = 0;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
}
void setScrollBarSize(HWND hwnd, int s)
{
SCROLLINFO si = { 0 };
si.cbSize = sizeof(SCROLLINFO);
si.fMask = SIF_RANGE;
si.nMin = 0;
si.nMax = s;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
}
int getHeight(HWND control)
{
RECT rt;
if(!GetWindowRect(control, &rt)) {
ErrorExit(NAMEOF(getHeight), __LINE__, __FILENAME__);
}
return rt.bottom - rt.top;
}
void displayText(HWND h)
{
int len = GetWindowTextLength(h);
if(len == 0) {
return;
}
wchar_t buffer[len + 1];
memset(buffer, 0, sizeof(buffer));
GetWindowText(h, buffer, len+1);
MessageBox(NULL, buffer, L"control text = ", MB_OK);
}
int scrollHeight(void)
{
int minTop = 0;
int maxBottom = 0;
RECT rt = {0};
if(allControls_indx == 0) {
return 0;
}
#if 0
assert(allControls[0] == hMainWindow);
assert(allControls[allControls_indx - 1] == hEdit1);
#endif
if(!GetWindowRect(allControls[0], &rt)) {
ErrorExit(NAMEOF(scrollHeight), __LINE__, __FILENAME__);
}
minTop = rt.top;
if(!GetWindowRect(allControls[allControls_indx - 1], &rt)) {
ErrorExit(NAMEOF(scrollHeight), __LINE__, __FILENAME__);
}
maxBottom = rt.bottom;
return maxBottom - minTop;
}
RECT GetLocalCoordinates(HWND hWnd)
{
RECT Rect;
GetWindowRect(hWnd, &Rect);
MapWindowPoints(HWND_DESKTOP, GetParent(hWnd), (LPPOINT) &Rect, 2);
return Rect;
}
void InsertTabItem(HWND tabHwnd, UINT id, LPWSTR text)
{
TCITEMW tci = {0};
tci.mask = TCIF_TEXT;
tci.pszText = text;
tci.cchTextMax = lstrlenW(text);
SendMessage(tabHwnd, TCM_INSERTITEM, id, (LPARAM) &tci);
}
void InitComControls()
{
INITCOMMONCONTROLSEX icex;
/* initialize this component is required to use tab control,
it seems.
*/
icex.dwSize = sizeof(INITCOMMONCONTROLSEX);
icex.dwICC = ICC_TAB_CLASSES;
InitCommonControlsEx(&icex);
}
// display the error message from last error seen then
// exit the application, with that last error code seen.
// to test function, do something like:
// if(!GetProcessId(NULL))
// errorExit(TEXT("GetProcessId"));
// not quite a unittest but yeah.
void ErrorExit(LPWSTR lpszFunction, int line, LPWSTR filename)
{
DWORD dw = ShowLastError(lpszFunction, line, filename);
ExitProcess(dw);
}
DWORD ShowLastError(LPWSTR lpszFunction, int line, LPWSTR filename)
{
#define MAX_DIGITS 16
/*
* NOTE!!: calling GetLastError() must be done before calling
* any other function, that would reset the GetLastError(), making
* this function report error about the wrong function.
*/
DWORD dw = GetLastError();
LPVOID lpMsgBuf;
LPVOID lpDisplayBuf;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
dw,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &lpMsgBuf,
0,
NULL
);
lpDisplayBuf = (LPVOID) LocalAlloc(LMEM_ZEROINIT,
(lstrlen((LPCTSTR)lpMsgBuf) +
lstrlen((LPCTSTR)lpszFunction) + 40 +
(line > 0 ? MAX_DIGITS : 0) +
(filename != NULL ? lstrlen(filename) : 0)) *
sizeof(TCHAR)
);
StringCchPrintf((LPTSTR)lpDisplayBuf,
LocalSize(lpDisplayBuf) / sizeof(TCHAR),
TEXT("%s failed with %d: %s"),
lpszFunction, dw, lpMsgBuf
);
MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK);
LocalFree(lpMsgBuf);
LocalFree(lpDisplayBuf);
return dw;
}
Solution
I think there is no problem with your calculation method. But you added the handle of the main window hwnd for the first time, which leads to the fact that the minTop you get in GetWindowRect(allControls[0], &rt) is the top coordinate of the main window, which caused a gap at the end of the display area.
However, you should actually get the coordinates of minTop from hLabel1 so that you won't attend the question.
In addition, you forgot to add hRemoveButton to the allControls array.
Solution: You can choose not to add the main window to the allControls array, or use GetWindowRect(allControls[1], &rt) to get the coordinates of minTop.
if (!GetWindowRect(allControls[1], &rt)) {
ErrorExit((LPWSTR)NAMEOF(scrollHeight), __LINE__, (LPWSTR)__FILENAME__);
}
minTop = rt.top;
Edit:
The reason why part of the edit box is cropped is that your hLabel1 is set to a height of 10 compared to the top, so when the top of hLabel1 is used as minTop, the length of the bottom is reduced by 10 units.
You need to add the y size of the topmost control:
return maxBottom - minTop + y; //The y size of the topmost control.