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-rw-r--r--generic/ttk/ttkTrack.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/generic/ttk/ttkTrack.c b/generic/ttk/ttkTrack.c
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+/* $Id: ttkTrack.c,v 1.1 2006/10/31 01:42:26 hobbs Exp $
+ * Copyright (c) 2004, Joe English
+ *
+ * TrackElementState() -- helper routine for widgets
+ * like scrollbars in which individual elements may
+ * be active or pressed instead of the widget as a whole.
+ *
+ * Usage:
+ * TrackElementState(&recordPtr->core);
+ *
+ * Registers an event handler on the widget that tracks pointer
+ * events and updates the state of the element under the
+ * mouse cursor.
+ *
+ * The "active" element is the one under the mouse cursor,
+ * and is normally set to the ACTIVE state unless another element
+ * is currently being pressed.
+ *
+ * The active element becomes "pressed" on <ButtonPress> events,
+ * and remains "active" and "pressed" until the corresponding
+ * <ButtonRelease> event.
+ *
+ * TODO: Handle "chords" properly (e.g., <B1-ButtonPress-2>)
+ * TODO: Deal with grabs -- possible to get a Press event w/no corresponding Release.
+ *
+ */
+
+#include <tk.h>
+#include "ttkTheme.h"
+#include "ttkWidget.h"
+
+typedef struct
+{
+ WidgetCore *corePtr; /* Widget to track */
+ Ttk_LayoutNode *activeElement; /* element under the mouse cursor */
+ Ttk_LayoutNode *pressedElement; /* currently pressed element */
+} ElementStateTracker;
+
+/*
+ * ActivateElement(es, node) --
+ * Make 'node' the active element if non-NULL.
+ * Deactivates the currently active element if different.
+ *
+ * The active element has TTK_STATE_ACTIVE set _unless_
+ * another element is 'pressed'
+ */
+static void ActivateElement(ElementStateTracker *es, Ttk_LayoutNode *node)
+{
+ if (es->activeElement == node) {
+ /* No change */
+ return;
+ }
+
+ if (!es->pressedElement) {
+ if (es->activeElement) {
+ /* Deactivate old element */
+ Ttk_ChangeElementState(es->activeElement, 0,TTK_STATE_ACTIVE);
+ }
+ if (node) {
+ /* Activate new element */
+ Ttk_ChangeElementState(node, TTK_STATE_ACTIVE,0);
+ }
+ TtkRedisplayWidget(es->corePtr);
+ }
+
+ es->activeElement = node;
+}
+
+/* ReleaseElement --
+ * Releases the currently pressed element, if any.
+ */
+static void ReleaseElement(ElementStateTracker *es)
+{
+ if (!es->pressedElement)
+ return;
+
+ Ttk_ChangeElementState(
+ es->pressedElement, 0,TTK_STATE_PRESSED|TTK_STATE_ACTIVE);
+ es->pressedElement = 0;
+
+ /* Reactivate element under the mouse cursor:
+ */
+ if (es->activeElement)
+ Ttk_ChangeElementState(es->activeElement, TTK_STATE_ACTIVE,0);
+
+ TtkRedisplayWidget(es->corePtr);
+}
+
+/* PressElement --
+ * Presses the specified element.
+ */
+static void PressElement(ElementStateTracker *es, Ttk_LayoutNode *node)
+{
+ if (es->pressedElement) {
+ ReleaseElement(es);
+ }
+
+ if (node) {
+ Ttk_ChangeElementState(
+ node, TTK_STATE_PRESSED|TTK_STATE_ACTIVE, 0);
+ }
+
+ es->pressedElement = node;
+ TtkRedisplayWidget(es->corePtr);
+}
+
+/* ElementStateEventProc --
+ * Event handler for tracking element states.
+ */
+
+static const unsigned ElementStateMask =
+ ButtonPressMask
+ | ButtonReleaseMask
+ | PointerMotionMask
+ | LeaveWindowMask
+ | EnterWindowMask
+ | StructureNotifyMask
+ ;
+
+static void
+ElementStateEventProc(ClientData clientData, XEvent *ev)
+{
+ ElementStateTracker *es = (ElementStateTracker *)clientData;
+ Ttk_LayoutNode *node;
+
+ switch (ev->type)
+ {
+ case MotionNotify :
+ node = Ttk_LayoutIdentify(
+ es->corePtr->layout,ev->xmotion.x,ev->xmotion.y);
+ ActivateElement(es, node);
+ break;
+ case LeaveNotify:
+ ActivateElement(es, 0);
+ break;
+ case EnterNotify:
+ node = Ttk_LayoutIdentify(
+ es->corePtr->layout,ev->xcrossing.x,ev->xcrossing.y);
+ ActivateElement(es, node);
+ break;
+ case ButtonPress:
+ node = Ttk_LayoutIdentify(
+ es->corePtr->layout, ev->xbutton.x, ev->xbutton.y);
+ if (node)
+ PressElement(es, node);
+ break;
+ case ButtonRelease:
+ ReleaseElement(es);
+ break;
+ case DestroyNotify:
+ /* Unregister this event handler and free client data.
+ */
+ Tk_DeleteEventHandler(es->corePtr->tkwin,
+ ElementStateMask, ElementStateEventProc, es);
+ ckfree((ClientData)es);
+ break;
+ }
+}
+
+/*
+ * TrackElementState --
+ * Register an event handler to manage the 'pressed'
+ * and 'active' states of individual widget elements.
+ */
+
+void TrackElementState(WidgetCore *corePtr)
+{
+ ElementStateTracker *es = (ElementStateTracker*)ckalloc(sizeof(*es));
+ es->corePtr = corePtr;
+ es->activeElement = es->pressedElement = 0;
+ Tk_CreateEventHandler(corePtr->tkwin,
+ ElementStateMask,ElementStateEventProc,es);
+}
+
+