Tree widget done right.

Tools/idle/TreeWidget.py

@@ -0,0 +1,462 @@
+# XXX TO DO:
+# - popup menu
+# - support partial or total redisplay
+# - key bindings (instead of quick-n-dirty bindings on Canvas):
+#   - up/down arrow keys to move focus around
+#   - ditto for page up/down, home/end
+#   - left/right arrows to expand/collapse & move out/in
+# - more doc strings
+# - add icons for "file", "module", "class", "method"; better "python" icon
+# - callback for selection???
+# - multiple-item selection
+# - tooltips
+# - redo geometry without magic numbers
+# - keep track of object ids to allow more careful cleaning
+# - optimize tree redraw after expand of subnode
+
+import os
+import sys
+import string
+from Tkinter import *
+import imp
+
+import ZoomHeight
+
+ICONDIR = "Icons"
+for _dir in sys.path:
+    _dir = os.path.join(_dir, ICONDIR)
+    if os.path.isdir(_dir):
+        ICONDIR = _dir
+        break
+
+def listicons(icondir=ICONDIR):
+    """Utility to display the available icons."""
+    root = Tk()
+    import glob
+    list = glob.glob(os.path.join(icondir, "*.gif"))
+    list.sort()
+    images = []
+    row = column = 0
+    for file in list:
+        name = os.path.splitext(os.path.basename(file))[0]
+        image = PhotoImage(file=file, master=root)
+        images.append(image)
+        label = Label(root, image=image, bd=1, relief="raised")
+        label.grid(row=row, column=column)
+        label = Label(root, text=name)
+        label.grid(row=row+1, column=column)
+        column = column + 1
+        if column >= 10:
+            row = row+2
+            column = 0
+    root.images = images
+
+
+class TreeNode:
+
+    def __init__(self, canvas, parent, item):
+        self.canvas = canvas
+        self.parent = parent
+        self.item = item
+        self.state = 'collapsed'
+        self.selected = 0
+        self.children = []
+        self.x = self.y = None
+        self.iconimages = {} # cache of PhotoImage instances for icons
+
+    def geticonimage(self, name):
+        try:
+            return self.iconimages[name]
+        except KeyError:
+            pass
+        file, ext = os.path.splitext(name)
+        ext = ext or ".gif"
+        fullname = os.path.join(ICONDIR, file + ext)
+        image = PhotoImage(master=self.canvas, file=fullname)
+        self.iconimages[name] = image
+        return image
+
+    def select(self, event=None):
+        if self.selected:
+            return
+        self.deselectall()
+        self.selected = 1
+        self.canvas.delete(self.image_id)
+        self.drawicon()
+        self.drawtext()
+
+    def deselect(self, event=None):
+        if not self.selected:
+            return
+        self.selected = 0
+        self.canvas.delete(self.image_id)
+        self.drawicon()
+        self.drawtext()
+
+    def deselectall(self):
+        if self.parent:
+            self.parent.deselectall()
+        else:
+            self.deselecttree()
+
+    def deselecttree(self):
+        if self.selected:
+            self.deselect()
+        for child in self.children:
+            child.deselecttree()
+
+    def flip(self, event=None):
+        if self.state == 'expanded':
+            self.collapse()
+        else:
+            self.expand()
+        self.item.OnDoubleClick()
+        return "break"
+
+    def expand(self, event=None):
+        if not self.item._IsExpandable():
+            return
+        if self.state != 'expanded':
+            self.state = 'expanded'
+            self.update()
+            self.view()
+
+    def collapse(self, event=None):
+        if self.state != 'collapsed':
+            self.state = 'collapsed'
+            self.update()
+
+    def view(self):
+        top = self.y - 2
+        bottom = self.lastvisiblechild().y + 17
+        height = bottom - top
+        visible_top = self.canvas.canvasy(0)
+        visible_height = self.canvas.winfo_height()
+        visible_bottom = self.canvas.canvasy(visible_height)
+        if visible_top <= top and bottom <= visible_bottom:
+            return
+        x0, y0, x1, y1 = self.canvas._getints(self.canvas['scrollregion'])
+        if top >= visible_top and height <= visible_height:
+            fraction = top + height - visible_height
+        else:
+            fraction = top
+        fraction = float(fraction) / y1
+        self.canvas.yview_moveto(fraction)
+
+    def lastvisiblechild(self):
+        if self.children and self.state == 'expanded':
+            return self.children[-1].lastvisiblechild()
+        else:
+            return self
+
+    def update(self):
+        if self.parent:
+            self.parent.update()
+        else:
+            oldcursor = self.canvas['cursor']
+            self.canvas['cursor'] = "watch"
+            self.canvas.update()
+            self.canvas.delete(ALL)     # XXX could be more subtle
+            self.draw(7, 2)
+            x0, y0, x1, y1 = self.canvas.bbox(ALL)
+            self.canvas.configure(scrollregion=(0, 0, x1, y1))
+            self.canvas['cursor'] = oldcursor
+
+    def draw(self, x, y):
+        # XXX This hard-codes too many geometry constants!
+        self.x, self.y = x, y
+        self.drawicon()
+        self.drawtext()
+        if self.state != 'expanded':
+            return y+17
+        # draw children
+        if not self.children:
+            sublist = self.item._GetSubList()
+            if not sublist:
+                # _IsExpandable() was mistaken; that's allowed
+                return y+17
+            for item in sublist:
+                child = TreeNode(self.canvas, self, item)
+                self.children.append(child)
+        cx = x+20
+        cy = y+17
+        cylast = 0
+        for child in self.children:
+            cylast = cy
+            self.canvas.create_line(x+9, cy+7, cx, cy+7, fill="gray50")
+            cy = child.draw(cx, cy)
+            if child.item._IsExpandable():
+                if child.state == 'expanded':
+                    iconname = "minusnode"
+                    callback = child.collapse
+                else:
+                    iconname = "plusnode"
+                    callback = child.expand
+                image = self.geticonimage(iconname)
+                id = self.canvas.create_image(x+9, cylast+7, image=image)
+                # XXX This leaks bindings until canvas is deleted:
+                self.canvas.tag_bind(id, "<1>", callback)
+                self.canvas.tag_bind(id, "<Double-1>", lambda x: None)
+        id = self.canvas.create_line(x+9, y+10, x+9, cylast+7,
+            ##stipple="gray50",     # XXX Seems broken in Tk 8.0.x
+            fill="gray50")
+        self.canvas.tag_lower(id) # XXX .lower(id) before Python 1.5.2
+        return cy
+
+    def drawicon(self):
+        if self.selected:
+            imagename = (self.item.GetSelectedIconName() or
+                         self.item.GetIconName() or
+                         "openfolder")
+        else:
+            imagename = self.item.GetIconName() or "folder"
+        image = self.geticonimage(imagename)
+        id = self.canvas.create_image(self.x, self.y, anchor="nw", image=image)
+        self.image_id = id
+        self.canvas.tag_bind(id, "<1>", self.select)
+        self.canvas.tag_bind(id, "<Double-1>", self.flip)
+
+    def drawtext(self):
+        textx = self.x+20-1
+        texty = self.y-1
+        labeltext = self.item.GetLabelText()
+        if labeltext:
+            id = self.canvas.create_text(textx, texty, anchor="nw",
+                                         text=labeltext)
+            self.canvas.tag_bind(id, "<1>", self.select)
+            self.canvas.tag_bind(id, "<Double-1>", self.flip)
+            x0, y0, x1, y1 = self.canvas.bbox(id)
+            textx = max(x1, 200) + 10
+        text = self.item.GetText() or "<no text>"
+        try:
+            self.entry
+        except AttributeError:
+            pass
+        else:
+            self.edit_finish()
+        try:
+            label = self.label
+        except AttributeError:
+            # padding carefully selected (on Windows) to match Entry widget:
+            self.label = Label(self.canvas, text=text, bd=0, padx=2, pady=2)
+        if self.selected:
+            self.label.configure(fg="white", bg="darkblue")
+        else:
+            self.label.configure(fg="black", bg="white")
+        id = self.canvas.create_window(textx, texty,
+                                       anchor="nw", window=self.label)
+        self.label.bind("<1>", self.select_or_edit)
+        self.label.bind("<Double-1>", self.flip)
+        self.text_id = id
+
+    def select_or_edit(self, event=None):
+        if self.selected and self.item.IsEditable():
+            self.edit(event)
+        else:
+            self.select(event)
+
+    def edit(self, event=None):
+        self.entry = Entry(self.label, bd=0, highlightthickness=1, width=0)
+        self.entry.insert(0, self.label['text'])
+        self.entry.selection_range(0, END)
+        self.entry.pack(ipadx=5)
+        self.entry.focus_set()
+        self.entry.bind("<Return>", self.edit_finish)
+        self.entry.bind("<Escape>", self.edit_cancel)
+
+    def edit_finish(self, event=None):
+        try:
+            entry = self.entry
+            del self.entry
+        except AttributeError:
+            return
+        text = entry.get()
+        entry.destroy()
+        if text and text != self.item.GetText():
+            self.item.SetText(text)
+        text = self.item.GetText()
+        self.label['text'] = text
+        self.drawtext()
+        self.canvas.focus_set()
+
+    def edit_cancel(self, event=None):
+        self.drawtext()
+        self.canvas.focus_set()
+
+
+class TreeItem:
+
+    """Abstract class representing tree items.
+
+    Methods should typically be overridden, otherwise a default action
+    is used.
+
+    """
+
+    def __init__(self):
+        """Constructor.  Do whatever you need to do."""
+
+    def GetText(self):
+        """Return text string to display."""
+
+    def GetLabelText(self):
+        """Return label text string to display in front of text (if any)."""
+
+    expandable = None
+
+    def _IsExpandable(self):
+        """Do not override!  Called by TreeNode."""
+        if self.expandable is None:
+            self.expandable = self.IsExpandable()
+        return self.expandable
+
+    def IsExpandable(self):
+        """Return whether there are subitems."""
+        return 1
+
+    def _GetSubList(self):
+        """Do not override!  Called by TreeNode."""
+        if not self.IsExpandable():
+            return []
+        sublist = self.GetSubList()
+        if not sublist:
+            self.expandable = 0
+        return sublist
+
+    def IsEditable(self):
+        """Return whether the item's text may be edited."""
+
+    def SetText(self, text):
+        """Change the item's text (if it is editable)."""
+
+    def GetIconName(self):
+        """Return name of icon to be displayed normally."""
+
+    def GetSelectedIconName(self):
+        """Return name of icon to be displayed when selected."""
+
+    def GetSubList(self):
+        """Return list of items forming sublist."""
+
+    def OnDoubleClick(self):
+        """Called on a double-click on the item."""
+
+
+# Example application
+
+class FileTreeItem(TreeItem):
+
+    """Example TreeItem subclass -- browse the file system."""
+
+    def __init__(self, path):
+        self.path = path
+
+    def GetText(self):
+        return os.path.basename(self.path) or self.path
+
+    def IsEditable(self):
+        return os.path.basename(self.path) != ""
+
+    def SetText(self, text):
+        newpath = os.path.dirname(self.path)
+        newpath = os.path.join(newpath, text)
+        if os.path.dirname(newpath) != os.path.dirname(self.path):
+            return
+        try:
+            os.rename(self.path, newpath)
+            self.path = newpath
+        except os.error:
+            pass
+
+    def GetIconName(self):
+        if not self.IsExpandable():
+            return "python" # XXX wish there was a "file" icon
+
+    def IsExpandable(self):
+        return os.path.isdir(self.path)
+
+    def GetSubList(self):
+        try:
+            names = os.listdir(self.path)
+        except os.error:
+            return []
+        names.sort(lambda a, b: cmp(os.path.normcase(a), os.path.normcase(b)))
+        sublist = []
+        for name in names:
+            item = FileTreeItem(os.path.join(self.path, name))
+            sublist.append(item)
+        return sublist
+
+
+# A canvas widget with scroll bars and some useful bindings
+
+class ScrolledCanvas:
+    def __init__(self, master, **opts):
+        if not opts.has_key('yscrollincrement'):
+            opts['yscrollincrement'] = 17
+        self.master = master
+        self.frame = Frame(master)
+        self.frame.rowconfigure(0, weight=1)
+        self.frame.columnconfigure(0, weight=1)
+        self.canvas = apply(Canvas, (self.frame,), opts)
+        self.canvas.grid(row=0, column=0, sticky="nsew")
+        self.vbar = Scrollbar(self.frame, name="vbar")
+        self.vbar.grid(row=0, column=1, sticky="nse")
+        self.hbar = Scrollbar(self.frame, name="hbar", orient="horizontal")
+        self.hbar.grid(row=1, column=0, sticky="ews")
+        self.canvas['yscrollcommand'] = self.vbar.set
+        self.vbar['command'] = self.canvas.yview
+        self.canvas['xscrollcommand'] = self.hbar.set
+        self.hbar['command'] = self.canvas.xview
+        self.canvas.bind("<Key-Prior>", self.page_up)
+        self.canvas.bind("<Key-Next>", self.page_down)
+        self.canvas.bind("<Key-Up>", self.unit_up)
+        self.canvas.bind("<Key-Down>", self.unit_down)
+        if isinstance(master, Toplevel) or isinstance(master, Tk):
+            self.canvas.bind("<Alt-F2>", self.zoom_height)
+        self.canvas.focus_set()
+    def page_up(self, event):
+        self.canvas.yview_scroll(-1, "page")
+        return "break"
+    def page_down(self, event):
+        self.canvas.yview_scroll(1, "page")
+        return "break"
+    def unit_up(self, event):
+        self.canvas.yview_scroll(-1, "unit")
+        return "break"
+    def unit_down(self, event):
+        self.canvas.yview_scroll(1, "unit")
+        return "break"
+    def zoom_height(self, event):
+        ZoomHeight.zoom_height(self.master)
+        return "break"
+
+
+# Testing functions
+
+def test():
+    import PyShell
+    import pyclbr
+    pyclbr._modules.clear()
+    root = Toplevel(PyShell.root)
+    root.configure(bd=0, bg="yellow")
+    root.focus_set()
+    sc = ScrolledCanvas(root, bg="white", highlightthickness=0, takefocus=1)
+    sc.frame.pack(expand=1, fill="both")
+    item = FileTreeItem("C:/windows/desktop")
+    node = TreeNode(sc.canvas, None, item)
+    node.expand()
+
+def test2():
+    # test w/o scrolling canvas
+    root = Tk()
+    root.configure(bd=0)
+    canvas = Canvas(root, bg="white", highlightthickness=0)
+    canvas.pack(expand=1, fill="both")
+    item = FileTreeItem(os.curdir)
+    node = TreeNode(canvas, None, item)
+    node.update()
+    canvas.focus_set()
+
+if __name__ == '__main__':
+    test()