Appendix C: Spinner for Windows

spinner.c

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
 
#include <jni.h>
#include <windows.h>
#include <commctrl.h>
 
static DWORD tlsIndex = 0;
static jobject javaClass;
static jmethodID mid;
static WNDPROC oldProc;
 
LRESULT CALLBACK WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    JNIEnv *env = TlsGetValue(tlsIndex);
    if (env != NULL) {
        /* If an exception has already occurred,
         * allow the stack to unwind so that the
         * exception will be thrown in Java. */
        if ((*env)->ExceptionOccurred(env)) return 0;
        switch (msg) {
            case WM_VSCROLL:
                if ((wParam & 0xFFFF) == SB_THUMBPOSITION) {
                    ((*env)->CallStaticVoidMethod(env, javaClass, mid, lParam));
                    return (LRESULT) 0;
                }
                break;
        }
    }
    return CallWindowProc(oldProc, hwnd, msg, wParam, lParam); 
}

/*
 * Class:     spinner_Spinner
 * Method:    createControl
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_spinner_Spinner_createControl
    (JNIEnv *env, jclass that, jint hwndParent)
{
    HWND hwndText, hwndUpDown;
    if (tlsIndex == 0) {
        tlsIndex = TlsAlloc();
        if (tlsIndex == -1) return (jint) 0;
        javaClass = (*env)->NewGlobalRef(env, (jobject) that);
        mid = (*env)->GetStaticMethodID(env, (jobject) that, "widgetSelected", "(I)V");
        oldProc = (WNDPROC) GetWindowLong((HWND) hwndParent, GWL_WNDPROC);
    }
    TlsSetValue(tlsIndex, (LPVOID) env);

    hwndText = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        "EDIT",
        NULL,
        WS_CHILD | WS_VISIBLE | WS_TABSTOP,
        0, 0, 0, 0,
        (HWND) hwndParent,
        0,
        GetModuleHandle(NULL),
        NULL);
    if (hwndText == 0) return (jint) 0;
    hwndUpDown = CreateWindowEx(
        0,
        UPDOWN_CLASS,
        NULL,
        WS_CHILD | WS_VISIBLE | UDS_AUTOBUDDY | UDS_SETBUDDYINT | UDS_ALIGNRIGHT | UDS_ARROWKEYS | UDS_NOTHOUSANDS,
        0, 0, 0, 0,
        (HWND) hwndParent,
        0,
        GetModuleHandle(NULL),
        NULL);
    if (hwndUpDown == 0) return (jint) 0;
    SetWindowLong((HWND) hwndParent, GWL_WNDPROC, (long) WindowProc);
    return (jint) hwndUpDown;
}

/*
 * Class:     spinner_Spinner
 * Method:    computeSize
 * Signature: (I[I)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_computeSize
    (JNIEnv *env, jclass that, jint hwndUpDown, jintArray result) {
    int width, height;
    TEXTMETRIC tm;
    RECT rect;
    int comboHeight;
    int max, digits;
    UINT flags;
    char text[64];
    HWND hwndText = (HWND) SendMessage((HWND) hwndUpDown, UDM_GETBUDDY, 0, 0);
    HDC hDC = GetDC(hwndText);
    HFONT oldFont = 0;
    HFONT newFont = (HFONT) SendMessage(hwndText, WM_GETFONT, 0, 0);

    jint *result1 = NULL;
    result1 = (*env)->GetIntArrayElements(env, result, NULL);

    if (newFont != 0) oldFont = SelectObject(hDC, newFont);
    GetTextMetrics(hDC, &tm);
    comboHeight = GetSystemMetrics(SM_CYVSCROLL);
    height = (comboHeight > tm.tmHeight) ? comboHeight : tm.tmHeight;
    max = SendMessage((HWND) hwndUpDown, UDM_GETRANGE, 0, 0) & 0xFFFF;
    if (max > 0) {
        digits = 0;
        while (max > 0) {
            text[digits] = '0';
            max /= 10;
            digits++;
        }
        flags = DT_CALCRECT | DT_EDITCONTROL | DT_NOPREFIX;
        DrawText(hDC, (LPCTSTR) text, digits, (LPRECT) &rect, flags);
        width = rect.right - rect.left + 3;
    } else {
        width = 10;
    }
    if (newFont != 0) SelectObject(hDC, oldFont);
    ReleaseDC(hwndText, hDC);
    width += GetSystemMetrics(SM_CXVSCROLL);
    SendMessage(hwndText, EM_GETRECT, 0, (LPARAM) &rect);
    if (rect.top == 0) rect.top = 1; // windows bug fix
    width += (rect.left + 1) * 2;
    height += (rect.top + 1) * 2;

    result1 [0] = width;
    result1 [1] = height;
    (*env)->ReleaseIntArrayElements(env, result, result1, 0);
}

/*
 * Class:     spinner_Spinner
 * Method:    resizeControl
 * Signature: (IIIII)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_resizeControl
    (JNIEnv *env, jclass that, jint hwndUpDown, jint x, jint y, jint width, jint height)
{
    HWND hwndText = (HWND) SendMessage((HWND) hwndUpDown, UDM_GETBUDDY, 0, 0);
    UINT flags = SWP_NOZORDER | SWP_DRAWFRAME | SWP_NOACTIVATE;
    int upDownWidth = GetSystemMetrics(SM_CXVSCROLL);
    SetWindowPos(hwndText, (HWND) 0, x, y, width - upDownWidth + 2, height, flags);
    SetWindowPos((HWND) hwndUpDown, (HWND) 0, x + width - upDownWidth, y, upDownWidth, height, flags);               
}

/*
 * Class:     spinner_Spinner
 * Method:    setPosition
 * Signature: (II)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_setPosition
    (JNIEnv *env, jclass that, jint hwnd, jint position)
{
    SendMessage((HWND) hwnd, UDM_SETPOS, 0, position);
}

/*
 * Class:     spinner_Spinner
 * Method:    getPosition
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_spinner_Spinner_getPosition
    (JNIEnv *env, jclass that, jint hwnd)
{
    return (jint) SendMessage((HWND) hwnd, UDM_GETPOS, 0, 0) & 0xFFFF;
}

/*
 * Class:     spinner_Spinner
 * Method:    setMaximum
 * Signature: (II)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_setMaximum
    (JNIEnv *env, jclass that, jint hwnd, jint max)
{
    int min = SendMessage((HWND) hwnd, UDM_GETRANGE, 0, 0) >> 16;
    SendMessage((HWND) hwnd, UDM_SETRANGE, 0, (min << 16) | max);
}

/*
 * Class:     spinner_Spinner
 * Method:    getMaximum
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_spinner_Spinner_getMaximum
    (JNIEnv *env, jclass that, jint hwnd)
{
    return SendMessage((HWND) hwnd, UDM_GETRANGE, 0, 0) & 0xFFFF;
}

/*
 * Class:     spinner_Spinner
 * Method:    setMinimum
 * Signature: (II)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_setMinimum
    (JNIEnv *env, jclass that, jint hwnd, jint min)
{
    int max = SendMessage((HWND) hwnd, UDM_GETRANGE, 0, 0) & 0xFFFF;
    SendMessage((HWND) hwnd, UDM_SETRANGE, 0, (min << 16) | max);
}

/*
 * Class:     spinner_Spinner
 * Method:    getMinimum
 * Signature: (I)I
 */
JNIEXPORT jint JNICALL Java_spinner_Spinner_getMinimum
    (JNIEnv *env, jclass that, jint hwnd)
{
    return SendMessage((HWND) hwnd, UDM_GETRANGE, 0, 0) >> 16;
}

/*
 * Class:     spinner_Spinner
 * Method:    setFont
 * Signature: (II)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_setFont
    (JNIEnv *env, jclass that, jint hwnd, jint hFont)
{
    HWND hwndText = (HWND) SendMessage((HWND) hwnd, UDM_GETBUDDY, 0, 0);
    SendMessage(hwndText, WM_SETFONT, hFont, 1);
}

/*
 * Class:     spinner_Spinner
 * Method:    setFocus
 * Signature: (I)V
 */
JNIEXPORT void JNICALL Java_spinner_Spinner_setFocus
    (JNIEnv *env, jclass that, jint hwnd)
{
    HWND hwndText = (HWND) SendMessage((HWND) hwnd, UDM_GETBUDDY, 0, 0);
    SetFocus(hwndText);
}

build.bat

@echo off
 
IF NOT "%IVE_HOME%"=="" GOTO MAKE
 
set IVE_HOME=j:\teamswt\swt-builddir\ive\bin
set path=%IVE_HOME%;%path%
 
rem NOTE:
rem Initialize MSVC 6.0/MSSDK environment
call k:\dev\products\msvc60\vc98\bin\vcvars32.bat
set Mssdk=j:\teamswt\swt-builddir\mssdk
call %Mssdk%\setenv.bat
 
:MAKE
nmake makefile.mak

makefile.mak

# Makefile for module 'spinner.dll'
# assumes IVE_HOME is set in the environment from which nmake is run

!include <win32.mak>

DLLPREFIX=spinner
DLLNAME=$(DLLPREFIX).dll

CFLAGS=-c -W3 -G6 -GD -O1 -nologo -D_X86_=1 -D_WIN32 -D_WIN95 -D_WIN32_WINDOWS=0x0400 -D_MT -MT -DWIN32 -D_WIN32_DCOM /I$(IVE_HOME)\include /I.
LFLAGS=/INCREMENTAL:NO /PDB:NONE /RELEASE /NOLOGO /BASE:0x10000000 /DLL

LINK_LIBS=comctl32.lib user32.lib gdi32.lib

OBJS=$(DLLPREFIX).obj

all: $(OBJS) $(DLLPREFIX)

$(DLLPREFIX): $(OBJS)
    echo $(LINK_LIBS) >templrf
    echo $(LFLAGS) >>templrf
    echo -machine:IX86 >>templrf
    echo -subsystem:windows >>templrf
    echo -out:$(DLLNAME) >>templrf
    echo $(OBJS) >>templrf
    link @templrf
    del templrf

clean:
    del *.obj
    del *.dll
    del *.exp

.c.obj:
    cl $(CFLAGS) $*.c