While working in a jupyter notebook with ipycanvas I faced the issue of printing stuff and show a canvas at the same time.
Either printing is working or the display of the canvas, but both won't.
Is there a way to do both in the same cell?
from ipycanvas import Canvas, hold_canvas
canvas = Canvas(width=600, height=600)
canvas.fill_style = '#584f4e'
canvas.fill_rect(0, 0, 600, 600)
objects_to_draw = []
class Square_obj():
def __init__(self, x,y, width=100, height=40):
self.x = x
self.y = y
self.width = width
self.height = height
self.selected = False
objects_to_draw.append(self)
def set_x_y(self,x_in,y_in) :
self.x = x_in
self.y = y_in
def draw(self):
canvas.fill_style = '#38a8a4'
canvas.fill_rect(self.x - (self.width*0.5), self.y - (self.height) , self.width, self.height)
if self.selected:
canvas.fill_style = '#9dcea6'
else:
canvas.fill_style = '#dee7bc'
canvas.fill_rect(self.x - (self.width*0.5), self.y - (self.height*0.5) , self.width, self.height)
def is_selected(self,x_in, y_in):
x_coord = self.x - (self.width*0.5)
y_coord = self.y - (self.height*0.5)
if x_in > x_coord and x_in < (x_coord+ self.width) and y_in > y_coord and y_in < (y_coord + self.height):
self.set_selected(True)
return True
else:
self.set_selected(False)
return False
def set_selected(self,state):
self.selected = state
def canvas_restart():
canvas.clear()
canvas.fill_style = '#584f4e'
canvas.fill_rect(0, 0, 600, 600)
def handle_mouse_down(x, y):
print("Testing")
if [o for o in objects_to_draw if o.selected]:
[o.set_selected(False) for o in objects_to_draw if o.selected]
return False
check_bool_pos = list(set([check_region.is_selected(x,y) for check_region in objects_to_draw]))
if len(check_bool_pos)== 1:
if check_bool_pos[0] == False:
s = Square_obj(x,y)
s.set_selected(False)
s.draw()
else:
canvas_restart()
[o.draw() for o in objects_to_draw]
if len(check_bool_pos)== 0:
s = Square_obj(x,y)
s.set_selected(False)
s.draw()
def handle_mouse_move(x, y):
if [o for o in objects_to_draw if o.selected]:
with hold_canvas(canvas):
[o for o in objects_to_draw if o.selected][-1].set_x_y(x,y)
canvas_restart()
[o.draw() for o in objects_to_draw]
canvas.on_mouse_down(handle_mouse_down)
canvas.on_mouse_move(handle_mouse_move)
canvas
This is basically the example code from here.
Executing the cell this way shows the canvas properly, but the test message is missing.
If I manually call the handle_mouse_down() function it will be printed.
Since I'm currently using a more complicated version of this example notebook, I'd like to see error / debugging messages while using the canvas.
I'm using Ipycanvas + Ipywidgets together in the same project, so I usually use the Ipywidgets Output to debug. You can do something like:
from ipycanvas import Canvas, hold_canvas
from ipywidgets import Output
canvas = Canvas(width=600, height=600)
canvas.fill_style = '#584f4e'
canvas.fill_rect(0, 0, 600, 600)
debug_output = Output(layout={'border': '1px solid black'})
objects_to_draw = []
class Square_obj():
def __init__(self, x,y, width=100, height=40):
self.x = x
self.y = y
self.width = width
self.height = height
self.selected = False
objects_to_draw.append(self)
def set_x_y(self,x_in,y_in) :
self.x = x_in
self.y = y_in
def draw(self):
canvas.fill_style = '#38a8a4'
canvas.fill_rect(self.x - (self.width*0.5), self.y - (self.height) , self.width, self.height)
if self.selected:
canvas.fill_style = '#9dcea6'
else:
canvas.fill_style = '#dee7bc'
canvas.fill_rect(self.x - (self.width*0.5), self.y - (self.height*0.5) , self.width, self.height)
def is_selected(self,x_in, y_in):
x_coord = self.x - (self.width*0.5)
y_coord = self.y - (self.height*0.5)
if x_in > x_coord and x_in < (x_coord+ self.width) and y_in > y_coord and y_in < (y_coord + self.height):
self.set_selected(True)
return True
else:
self.set_selected(False)
return False
def set_selected(self,state):
self.selected = state
def canvas_restart():
canvas.clear()
canvas.fill_style = '#584f4e'
canvas.fill_rect(0, 0, 600, 600)
@debug_output.capture(clear_output=False)
def handle_mouse_down(x, y):
print("Testing")
if [o for o in objects_to_draw if o.selected]:
[o.set_selected(False) for o in objects_to_draw if o.selected]
return False
check_bool_pos = list(set([check_region.is_selected(x,y) for check_region in objects_to_draw]))
if len(check_bool_pos)== 1:
if check_bool_pos[0] == False:
s = Square_obj(x,y)
s.set_selected(False)
s.draw()
else:
canvas_restart()
[o.draw() for o in objects_to_draw]
if len(check_bool_pos)== 0:
s = Square_obj(x,y)
s.set_selected(False)
s.draw()
@debug_output.capture(clear_output=False)
def handle_mouse_move(x, y):
if [o for o in objects_to_draw if o.selected]:
with hold_canvas(canvas):
[o for o in objects_to_draw if o.selected][-1].set_x_y(x,y)
canvas_restart()
[o.draw() for o in objects_to_draw]
canvas.on_mouse_down(handle_mouse_down)
canvas.on_mouse_move(handle_mouse_move)
display(canvas)
debug_output