How can I bring a Canvas to front?-CodePudding

I overlapped 5 Tk.Canvas objects and each will have different images. I want to bring each canvas to front of every other canvases to draw pictures in the most-front canvas.

class window_tk():
def __init__(self,main):
    self.main=main
    self.canvas_org = tk.Canvas(self.main, bg='white')
    self.canvas_layer1 = tk.Canvas(self.main, bg='red')
    self.canvas_layer2 = tk.Canvas(self.main, bg='green')
    self.canvas_layer3 = tk.Canvas(self.main, bg='blue')
    self.canvas_layer4 = tk.Canvas(self.main, bg='black')
    self.btn_load = tk.Button(self.main,text = "Load Image",command = self.load_ct)
    self.btn_layer1 = tk.Button(self.main,text = "Draw in L1",command = self.bring_1)
    self.btn_layer2 = tk.Button(self.main,text = "Draw in L2",command = self.bring_2)
    self.btn_layer3 = tk.Button(self.main,text = "Draw in L3",command = self.bring_3)
    self.btn_layer4 = tk.Button(self.main,text = "Draw in L4",command = self.bring_4)

def bring_1(self):
    self.canvas_layer1.place(x=50,y=00)

def bring_2(self):
    self.canvas_layer2.place(x=50, y=00)

def bring_3(self):
    self.canvas_layer3.place(x=50, y=00)

def bring_4(self):
    self.canvas_layer4.place(x=50, y=00)

I thought the canvas.place() function will bring the canvas front but it was not. Which function can I use ? Or should I unpack all other canvases ?

CodePudding user response：

Since Canvas has override the .tkraise() function, you need to call TCL command directly:

self.canvas.tk.call('raise', self.canvas._w)

CodePudding user response：

You can use the following functions -

canvas.tag_raise(canvas_layer4) -> For bringing to front

canvas.tag_lower(canvas_layer4) -> For pushing back

CodePudding user response：

Please see the answer given by acw1668. The lift function doesn't work for Canvas objects. His answer is correct.

All tkinter objects, Canvas included, support the following method:

w.lift(aboveThis=None) If the argument is None, the window containing w is moved to the top of the window stacking order. To move the window just above some Toplevel window w, pass w as an argument.

This gives you full control over which widget sits on top.

https://anzeljg.github.io/rin2/book2/2405/docs/tkinter/universal.html

Now that I re-read that, I see that its language is slightly incorrect. "w" is any tkinter widget, "above_this" is another tkinter widget. The function places "w" above "above_this" in the stacking order.

CodePudding user response：

You can simply do this on the canvas element you want to bring to front:

canvas { 
    position: absolute;
    z-index: 100;
}

z-index is used to define the stack order of the elements! https://developer.mozilla.org/en-US/docs/Web/CSS/z-index