tklistbox.c

linux系统下的音频通信

 *
 * Results:
 *	A standard Tcl result.  If all went well, then *indexPtr is
 *	filled in with the index (into listPtr) corresponding to
 *	string.  Otherwise an error message is left in interp->result.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */

static int
GetListboxIndex(interp, listPtr, string, endIsSize, indexPtr)
    Tcl_Interp *interp;		/* For error messages. */
    Listbox *listPtr;		/* Listbox for which the index is being
				 * specified. */
    char *string;		/* Specifies an element in the listbox. */
    int endIsSize;		/* If 1, "end" refers to the number of
				 * entries in the listbox.  If 0, "end"
				 * refers to 1 less than the number of
				 * entries. */
    int *indexPtr;		/* Where to store converted index. */
{
    int c;
    size_t length;

    length = strlen(string);
    c = string[0];
    if ((c == 'a') && (strncmp(string, "active", length) == 0)
	    && (length >= 2)) {
	*indexPtr = listPtr->active;
    } else if ((c == 'a') && (strncmp(string, "anchor", length) == 0)
	    && (length >= 2)) {
	*indexPtr = listPtr->selectAnchor;
    } else if ((c == 'e') && (strncmp(string, "end", length) == 0)) {
	if (endIsSize) {
	    *indexPtr = listPtr->numElements;
	} else {
	    *indexPtr = listPtr->numElements - 1;
	}
    } else if (c == '@') {
	int y;
	char *p, *end;

	p = string+1;
	strtol(p, &end, 0);
	if ((end == p) || (*end != ',')) {
	    goto badIndex;
	}
	p = end+1;
	y = strtol(p, &end, 0);
	if ((end == p) || (*end != 0)) {
	    goto badIndex;
	}
	*indexPtr = NearestListboxElement(listPtr, y);
    } else {
	if (Tcl_GetInt(interp, string, indexPtr) != TCL_OK) {
	    Tcl_ResetResult(interp);
	    goto badIndex;
	}
    }
    return TCL_OK;

    badIndex:
    Tcl_AppendResult(interp, "bad listbox index \"", string,
	    "\": must be active, anchor, end, @x,y, or a number",
	    (char *) NULL);
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * ChangeListboxView --
 *
 *	Change the view on a listbox widget so that a given element
 *	is displayed at the top.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	What's displayed on the screen is changed.  If there is a
 *	scrollbar associated with this widget, then the scrollbar
 *	is instructed to change its display too.
 *
 *----------------------------------------------------------------------
 */

static void
ChangeListboxView(listPtr, index)
    register Listbox *listPtr;		/* Information about widget. */
    int index;				/* Index of element in listPtr
					 * that should now appear at the
					 * top of the listbox. */
{
    if (index >= (listPtr->numElements - listPtr->fullLines)) {
	index = listPtr->numElements - listPtr->fullLines;
    }
    if (index < 0) {
	index = 0;
    }
    if (listPtr->topIndex != index) {
	listPtr->topIndex = index;
	if (!(listPtr->flags & REDRAW_PENDING)) {
	    Tcl_DoWhenIdle(DisplayListbox, (ClientData) listPtr);
	    listPtr->flags |= REDRAW_PENDING;
	}
	listPtr->flags |= UPDATE_V_SCROLLBAR;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ChangListboxOffset --
 *
 *	Change the horizontal offset for a listbox.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The listbox may be redrawn to reflect its new horizontal
 *	offset.
 *
 *----------------------------------------------------------------------
 */

static void
ChangeListboxOffset(listPtr, offset)
    register Listbox *listPtr;		/* Information about widget. */
    int offset;				/* Desired new "xOffset" for
					 * listbox. */
{
    int maxOffset;

    /*
     * Make sure that the new offset is within the allowable range, and
     * round it off to an even multiple of xScrollUnit.
     */

    maxOffset = listPtr->maxWidth - (Tk_Width(listPtr->tkwin) -
	    2*listPtr->inset - 2*listPtr->selBorderWidth)
	    + listPtr->xScrollUnit - 1;
    if (offset > maxOffset) {
	offset = maxOffset;
    }
    if (offset < 0) {
	offset = 0;
    }
    offset -= offset % listPtr->xScrollUnit;
    if (offset != listPtr->xOffset) {
	listPtr->xOffset = offset;
	listPtr->flags |= UPDATE_H_SCROLLBAR;
	ListboxRedrawRange(listPtr, 0, listPtr->numElements);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ListboxScanTo --
 *
 *	Given a point (presumably of the curent mouse location)
 *	drag the view in the window to implement the scan operation.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The view in the window may change.
 *
 *----------------------------------------------------------------------
 */

static void
ListboxScanTo(listPtr, x, y)
    register Listbox *listPtr;		/* Information about widget. */
    int x;				/* X-coordinate to use for scan
					 * operation. */
    int y;				/* Y-coordinate to use for scan
					 * operation. */
{
    int newTopIndex, newOffset, maxIndex, maxOffset;

    maxIndex = listPtr->numElements - listPtr->fullLines;
    maxOffset = listPtr->maxWidth + (listPtr->xScrollUnit - 1)
	    - (Tk_Width(listPtr->tkwin) - 2*listPtr->inset
	    - 2*listPtr->selBorderWidth - listPtr->xScrollUnit);

    /*
     * Compute new top line for screen by amplifying the difference
     * between the current position and the place where the scan
     * started (the "mark" position).  If we run off the top or bottom
     * of the list, then reset the mark point so that the current
     * position continues to correspond to the edge of the window.
     * This means that the picture will start dragging as soon as the
     * mouse reverses direction (without this reset, might have to slide
     * mouse a long ways back before the picture starts moving again).
     */

    newTopIndex = listPtr->scanMarkYIndex
	    - (10*(y - listPtr->scanMarkY))/listPtr->lineHeight;
    if (newTopIndex > maxIndex) {
	newTopIndex = listPtr->scanMarkYIndex = maxIndex;
	listPtr->scanMarkY = y;
    } else if (newTopIndex < 0) {
	newTopIndex = listPtr->scanMarkYIndex = 0;
	listPtr->scanMarkY = y;
    }
    ChangeListboxView(listPtr, newTopIndex);

    /*
     * Compute new left edge for display in a similar fashion by amplifying
     * the difference between the current position and the place where the
     * scan started.
     */

    newOffset = listPtr->scanMarkXOffset - (10*(x - listPtr->scanMarkX));
    if (newOffset > maxOffset) {
	newOffset = listPtr->scanMarkXOffset = maxOffset;
	listPtr->scanMarkX = x;
    } else if (newOffset < 0) {
	newOffset = listPtr->scanMarkXOffset = 0;
	listPtr->scanMarkX = x;
    }
    ChangeListboxOffset(listPtr, newOffset);
}

/*
 *----------------------------------------------------------------------
 *
 * NearestListboxElement --
 *
 *	Given a y-coordinate inside a listbox, compute the index of
 *	the element under that y-coordinate (or closest to that
 *	y-coordinate).
 *
 * Results:
 *	The return value is an index of an element of listPtr.  If
 *	listPtr has no elements, then 0 is always returned.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
NearestListboxElement(listPtr, y)
    register Listbox *listPtr;		/* Information about widget. */
    int y;				/* Y-coordinate in listPtr's window. */
{
    int index;

    index = (y - listPtr->inset)/listPtr->lineHeight;
    if (index >= (listPtr->fullLines + listPtr->partialLine)) {
	index = listPtr->fullLines + listPtr->partialLine - 1;
    }
    if (index < 0) {
	index = 0;
    }
    index += listPtr->topIndex;
    if (index >= listPtr->numElements) {
	index = listPtr->numElements-1;
    }
    return index;
}

/*
 *----------------------------------------------------------------------
 *
 * ListboxSelect --
 *
 *	Select or deselect one or more elements in a listbox..
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	All of the elements in the range between first and last are
 *	marked as either selected or deselected, depending on the
 *	"select" argument.  Any items whose state changes are redisplayed.
 *	The selection is claimed from X when the number of selected
 *	elements changes from zero to non-zero.
 *
 *----------------------------------------------------------------------
 */

static void
ListboxSelect(listPtr, first, last, select)
    register Listbox *listPtr;		/* Information about widget. */
    int first;				/* Index of first element to
					 * select or deselect. */
    int last;				/* Index of last element to
					 * select or deselect. */
    int select;				/* 1 means select items, 0 means
					 * deselect them. */
{
    int i, firstRedisplay, increment, oldCount;
    Element *elPtr;

    if (last < first) {
	i = first;
	first = last;
	last = i;
    }
    if ((last < 0) || (first >= listPtr->numElements)) {
	return;
    }
    if (first < 0) {
	first = 0;
    }
    if (last >= listPtr->numElements) {
	last = listPtr->numElements - 1;
    }
    oldCount = listPtr->numSelected;
    firstRedisplay = -1;
    increment = select ? 1 : -1;
    for (i = 0, elPtr = listPtr->firstPtr; i < first;
	    i++, elPtr = elPtr->nextPtr) {
	/* Empty loop body. */
    }
    for ( ; i <= last; i++, elPtr = elPtr->nextPtr) {
	if (elPtr->selected == select) {
	    continue;
	}
	listPtr->numSelected += increment;
	elPtr->selected = select;
	if (firstRedisplay < 0) {
	    firstRedisplay = i;
	}
    }
    if (firstRedisplay >= 0) {
	ListboxRedrawRange(listPtr, first, last);
    }
    if ((oldCount == 0) && (listPtr->numSelected > 0)
	    && (listPtr->exportSelection)) {
	Tk_OwnSelection(listPtr->tkwin, XA_PRIMARY, ListboxLostSelection,
		(ClientData) listPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ListboxFetchSelection --
 *
 *	This procedure is called back by Tk when the selection is
 *	requested by someone.  It returns part or all of the selection
 *	in a buffer provided by the caller.
 *
 * Results:
 *	The return value is the number of non-NULL bytes stored
 *	at buffer.  Buffer is filled (or partially filled) with a
 *	NULL-terminated string containing part or all of the selection,
 *	as given by offset and maxBytes.  The selection is returned
 *	as a Tcl list with one list element for each element in the
 *	listbox.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
ListboxFetchSelection(clientData, offset, buffer, maxBytes)
    ClientData clientData;		/* Information about listbox widget. */
    int offset;				/* Offset within selection of first
					 * byte to be returned. */
    char *buffer;			/* Location in which to place
					 * selection. */
    int maxBytes;			/* Maximum number of bytes to place
					 * at buffer, not including terminating
					 * NULL character. */
{
    register Listbox *listPtr = (Listbox *) clientData;
    register Element *elPtr;
    Tcl_DString selection;
    int length, count, needNewline;

    if (!listPtr->exportSelection) {
	return -1;
    }

    /*
     * Use a dynamic string to accumulate the contents of the selection.
     */

    needNewline = 0;
    Tcl_DStringInit(&selection);
    for (elPtr = listPtr->firstPtr; elPtr != NULL; elPtr = elPtr->nextPtr) {
	if (elPtr->selected) {
	    if (needNewline) {
		Tcl_DStringAppend(&selection, "\n", 1);
	    }
	    Tcl_DStringAppend(&selection, elPtr->text, elPtr->textLength);
	    needNewline = 1;
	}
    }

    length = Tcl_DStringLength(&selection);
    if (length == 0) {
	return -1;
    }

    /*
     * Copy the requested portion of the selection to the buffer.
     */

    count = length - offset;
    if (count <= 0) {
	count = 0;
    } else {
	if (count > maxBytes) {
	    count = maxBytes;
	}
	memcpy((VOID *) buffer,
		(VOID *) (Tcl_DStringValue(&selection) + offset),
		(size_t) count);
    }
    buffer[count] = '\0';
    Tcl_DStringFree(&selection);
    return count