diff options
Diffstat (limited to 'generic/ttk/ttkScroll.c')
| -rw-r--r-- | generic/ttk/ttkScroll.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/generic/ttk/ttkScroll.c b/generic/ttk/ttkScroll.c new file mode 100644 index 0000000..defe05a --- /dev/null +++ b/generic/ttk/ttkScroll.c @@ -0,0 +1,252 @@ +/* + * Copyright 2004, Joe English + * + * Support routines for scrollable widgets. + * + * (This is sort of half-baked; needs some work) + * + * Scrollable interface: + * + * + 'first' is controlled by [xy]view widget command + * and other scrolling commands like 'see'; + * + 'total' depends on widget contents; + * + 'last' depends on first, total, and widget size. + * + * Choreography (typical usage): + * + * 1. User adjusts scrollbar, scrollbar widget calls its -command + * 2. Scrollbar -command invokes the scrollee [xy]view widget method + * 3. TtkScrollviewCommand calls TtkScrollTo(), which updates + * 'first' and schedules a redisplay. + * 4. Once the scrollee knows 'total' and 'last' (typically in + * the LayoutProc), call TtkScrolled(h,first,last,total) to + * synchronize the scrollbar. + * 5. The scrollee -[xy]scrollcommand is called (in an idle callback) + * 6. Which calls the scrollbar 'set' method and redisplays the scrollbar. + * + * If the scrollee has internal scrolling (e.g., a 'see' method), + * it should TtkScrollTo() directly (step 2). + * + * If the widget value changes, it should call TtkScrolled() (step 4). + * (This usually happens automatically when the widget is redisplayed). + * + * If the scrollee's -[xy]scrollcommand changes, it should call + * TtkScrollbarUpdateRequired, which will invoke step (5) (@@@ Fix this) + */ + +#include <tk.h> +#include "ttkTheme.h" +#include "ttkWidget.h" + +/* Private data: + */ +#define SCROLL_UPDATE_PENDING (0x1) +#define SCROLL_UPDATE_REQUIRED (0x2) + +struct ScrollHandleRec +{ + unsigned flags; + WidgetCore *corePtr; + Scrollable *scrollPtr; +}; + +/* TtkCreateScrollHandle -- + * Initialize scroll handle. + */ +ScrollHandle TtkCreateScrollHandle(WidgetCore *corePtr, Scrollable *scrollPtr) +{ + ScrollHandle h = (ScrollHandle)ckalloc(sizeof(*h)); + + h->flags = 0; + h->corePtr = corePtr; + h->scrollPtr = scrollPtr; + + scrollPtr->first = 0; + scrollPtr->last = 1; + scrollPtr->total = 1; + return h; +} + +/* UpdateScrollbar -- + * Call the -scrollcommand callback to sync the scrollbar. + * Returns: Whatever the -scrollcommand does. + */ +static int UpdateScrollbar(Tcl_Interp *interp, ScrollHandle h) +{ + Scrollable *s = h->scrollPtr; + WidgetCore *corePtr = h->corePtr; + char arg1[TCL_DOUBLE_SPACE + 2]; + char arg2[TCL_DOUBLE_SPACE + 2]; + int code; + + h->flags &= ~SCROLL_UPDATE_REQUIRED; + + if (s->scrollCmd == NULL) { + return TCL_OK; + } + + arg1[0] = arg2[0] = ' '; + Tcl_PrintDouble(interp, (double)s->first / s->total, arg1+1); + Tcl_PrintDouble(interp, (double)s->last / s->total, arg2+1); + + Tcl_Preserve(corePtr); + code = Tcl_VarEval(interp, s->scrollCmd, arg1, arg2, NULL); + if (WidgetDestroyed(corePtr)) { + Tcl_Release(corePtr); + return TCL_ERROR; + } + Tcl_Release(corePtr); + + if (code != TCL_OK && !Tcl_InterpDeleted(interp)) { + /* Disable the -scrollcommand, add to stack trace: + */ + ckfree(s->scrollCmd); + s->scrollCmd = 0; + + Tcl_AddErrorInfo(interp, /* @@@ "horizontal" / "vertical" */ + "\n (scrolling command executed by "); + Tcl_AddErrorInfo(interp, Tk_PathName(h->corePtr->tkwin)); + Tcl_AddErrorInfo(interp, ")"); + } + return code; +} + +/* UpdateScrollbarBG -- + * Idle handler to update the scrollbar. + */ +static void UpdateScrollbarBG(ClientData clientData) +{ + ScrollHandle h = (ScrollHandle)clientData; + Tcl_Interp *interp = h->corePtr->interp; + int code; + + h->flags &= ~SCROLL_UPDATE_PENDING; + Tcl_Preserve((ClientData) interp); + code = UpdateScrollbar(interp, h); + if (code == TCL_ERROR && !Tcl_InterpDeleted(interp)) { + Tcl_BackgroundError(interp); + } + Tcl_Release((ClientData) interp); +} + +/* TtkScrolled -- + * Update scroll info, schedule scrollbar update. + */ +void TtkScrolled(ScrollHandle h, int first, int last, int total) +{ + Scrollable *s = h->scrollPtr; + + /* Sanity-check inputs: + */ + if (total <= 0) { + first = 0; + last = 1; + total = 1; + } + + if (last > total) { + first -= (last - total); + if (first < 0) first = 0; + last = total; + } + + if (s->first != first || s->last != last || s->total != total + || (h->flags & SCROLL_UPDATE_REQUIRED)) + { + s->first = first; + s->last = last; + s->total = total; + + if (!(h->flags & SCROLL_UPDATE_PENDING)) { + Tcl_DoWhenIdle(UpdateScrollbarBG, (ClientData)h); + h->flags |= SCROLL_UPDATE_PENDING; + } + } +} + +/* TtkScrollbarUpdateRequired -- + * Force a scrollbar update at the next call to TtkScrolled(), + * even if scroll parameters haven't changed (e.g., if + * -yscrollcommand has changed). + */ + +void TtkScrollbarUpdateRequired(ScrollHandle h) +{ + h->flags |= SCROLL_UPDATE_REQUIRED; +} + +/* TtkScrollviewCommand -- + * Widget [xy]view command implementation. + * + * $w [xy]view -- return current view region + * $w [xy]view $index -- set topmost item + * $w [xy]view moveto $fraction + * $w [xy]view scroll $number $what -- scrollbar interface + */ +int TtkScrollviewCommand( + Tcl_Interp *interp, int objc, Tcl_Obj *const objv[], ScrollHandle h) +{ + Scrollable *s = h->scrollPtr; + int newFirst = s->first; + + if (objc == 2) { + Tcl_Obj *result[2]; + result[0] = Tcl_NewDoubleObj((double)s->first / s->total); + result[1] = Tcl_NewDoubleObj((double)s->last / s->total); + Tcl_SetObjResult(interp, Tcl_NewListObj(2, result)); + return TCL_OK; + } else if (objc == 3) { + if (Tcl_GetIntFromObj(interp, objv[2], &newFirst) != TCL_OK) { + return TCL_ERROR; + } + } else { + double fraction; + int count; + + switch (Tk_GetScrollInfoObj(interp, objc, objv, &fraction, &count)) { + case TK_SCROLL_ERROR: + return TCL_ERROR; + case TK_SCROLL_MOVETO: + newFirst = (int) ((fraction * s->total) + 0.5); + break; + case TK_SCROLL_UNITS: + newFirst = s->first + count; + break; + case TK_SCROLL_PAGES: { + int perPage = s->last - s->first; /* @@@ */ + newFirst = s->first + count * perPage; + break; + } + } + } + + TtkScrollTo(h, newFirst); + + return TCL_OK; +} + +void TtkScrollTo(ScrollHandle h, int newFirst) +{ + Scrollable *s = h->scrollPtr; + + if (newFirst >= s->total) + newFirst = s->total - 1; + if (newFirst > s->first && s->last >= s->total) /* don't scroll past end */ + newFirst = s->first; + if (newFirst < 0) + newFirst = 0; + + if (newFirst != s->first) { + s->first = newFirst; + TtkRedisplayWidget(h->corePtr); + } +} + +void TtkFreeScrollHandle(ScrollHandle h) +{ + if (h->flags & SCROLL_UPDATE_PENDING) { + Tcl_CancelIdleCall(UpdateScrollbarBG, (ClientData)h); + } + ckfree((ClientData)h); +} + |