Mouse and Keyboard¶
Often we need to get input from the user in the programs. Easygrphics provides simple ways to get user’s input from keyboard and mouse.
Pause for input¶
The most used user input function in Easygraphics is pause(). This function pause the program, and wait for user to click on the graphics window, or press any key, then continue the program.
Mouse Clicking¶
We can use get_click() to pause the program and wait for a mouse clicking. This function will return the x,y coordinates of the position clicked, and buttons that are pressed when clicking.
from easygraphics import *
def main():
init_graph(800, 600)
set_render_mode(RenderMode.RENDER_MANUAL)
while is_run():
msg = get_click()
str = "clicked on %d,%d ." % (msg.x, msg.y)
clear_device()
draw_text(0, 600, str)
close_graph()
easy_run(main)
Cursor Positions¶
Sometimes we need to get the position of the cursor. We can use get_cursor_pos() to get this job done.
The following program continuously displays mouse cursor’s position.
from easygraphics import *
def main():
init_graph(800, 600)
set_render_mode(RenderMode.RENDER_MANUAL)
while is_run():
x, y = get_cursor_pos()
clear_device()
draw_text(0, 600, "%d,%d" % (x, y))
delay_fps(30)
close_graph()
easy_run(main)
Mouse Button Press and Release¶
You can use get_mouse_msg() to get mouse button press and release messages.
Non-Blocking mouse processing¶
get_click()/get_mouse_msg() will block the program if there are no mouse press/click in the last 100ms. If you want to check the mouse operation non-blockly, you could use the non-blocking function has_mouse_msg() to see if there are any mouse messages, and then use get_mouse_msg() to get the mouse message.
The following program continuously check display cursor’s postion and mouse button press/release events.
from easygraphics import *
def main():
init_graph(800, 600)
set_render_mode(RenderMode.RENDER_MANUAL)
set_fill_color("white")
while is_run():
x, y = get_cursor_pos()
fill_rect(0, 580, 390, 600)
draw_text(0, 600, "%d,%d" % (x, y))
if has_mouse_msg():
msg = get_mouse_msg()
if msg.type == MouseMessageType.PRESS_MESSAGE:
typestr = "pressed"
elif msg.type == MouseMessageType.RELEASE_MESSAGE:
typestr = "released"
fill_rect(400, 580, 800, 600)
draw_text(400, 600, "button %s at %d,%d" % (typestr, x, y))
delay_fps(30)
close_graph()
easy_run(main)
Mouse Message Demo¶
The following program draws a bezier curve interactively
First click on the window to set the first control point of the curve. Then click on the window to set the second control point of the curve. Then drag from any of the above two control points to set the third and the fourth control point.
from easygraphics import *
from PyQt5 import QtCore
def main():
init_graph(800, 600)
set_render_mode(RenderMode.RENDER_MANUAL)
msg = get_click()
x1=msg.x
y1=msg.y
circle(x1, y1, 3)
msg = get_click()
x2=msg.x
y2=msg.y
circle(x2, y2, 3)
line(x1, y1, x2, y2)
x3, y3 = x1, y1
x4, y4 = x2, y2
reg1 = QtCore.QRect(x1 - 2, y1 - 2, 5, 5)
reg2 = QtCore.QRect(x2 - 2, y2 - 2, 5, 5)
draging_which_point = 0
while is_run():
if draging_which_point == 1:
draw_line(x1, y1, x, y)
draw_bezier(x1, y1, x, y, x4, y4, x2, y2)
elif draging_which_point == 2:
draw_line(x2, y2, x, y)
draw_bezier(x1, y1, x3, y3, x, y, x2, y2)
if has_mouse_msg():
# x, y, type, buttons, modifiers = get_mouse_msg()
msg = get_mouse_msg()
if msg.type == MouseMessageType.PRESS_MESSAGE:
if reg1.contains(msg.x, msg.y):
draging_which_point = 1
set_color(Color.WHITE)
set_composition_mode(CompositionMode.SRC_XOR_DEST)
x, y = x3, y3
elif reg2.contains(msg.x, msg.y):
draging_which_point = 2
set_color(Color.WHITE)
set_composition_mode(CompositionMode.SRC_XOR_DEST)
x, y = x4, y4
else:
draging_which_point = 0
elif msg.type == MouseMessageType.RELEASE_MESSAGE:
if draging_which_point == 1:
x3, y3 = msg.x, msg.y
elif draging_which_point == 2:
x4, y4 = msg.x, msg.y
draging_which_point = 0
set_color(Color.BLACK)
set_composition_mode(CompositionMode.SOURCE)
clear_device()
draw_line(x1, y1, x3, y3)
draw_line(x2, y2, x4, y4)
circle(x1, y1, 3)
circle(x2, y2, 3)
draw_bezier(x1, y1, x3, y3, x4, y4, x2, y2)
else:
if draging_which_point == 1:
x, y = get_cursor_pos()
draw_line(x1, y1, x, y)
draw_bezier(x1, y1, x, y, x4, y4, x2, y2)
elif draging_which_point == 2:
x, y = get_cursor_pos()
draw_line(x2, y2, x, y)
draw_bezier(x1, y1, x3, y3, x, y, x2, y2)
delay_fps(60)
close_graph()
easy_run(main)
Char Input¶
We can use has_kb_hit() to see if there is any ascii char pressed, and use get_char() to get the inputted char. has_kb_hit() is non-blocking, and get_char() is blocking.
The following program is a simple print game.
from easygraphics import *
import random
def show_welcome():
clear_device()
set_color("yellow")
set_font_size(64)
draw_text(160, 110, "Print Game");
set_color("white");
c = 0
set_font_size(20)
while is_run():
if has_kb_hit():
break
set_color(color_rgb(c, c, c))
draw_text(180, 400, "Press any key to continue")
c = (c + 8) % 255;
delay_fps(30)
ch = get_char()
clear_device()
def show_goodbye():
clear_device();
set_color("yellow");
set_font_size(48);
draw_text(104, 180, "Bye!!!");
pause()
def main():
init_graph(640, 480)
set_render_mode(RenderMode.RENDER_MANUAL)
set_background_color("black")
show_welcome()
random.seed()
set_font_size(20)
set_fill_color("black")
while is_run():
target = chr(65 + random.randint(0, 25))
x = random.randint(0, 620)
for y in range(16, 460):
set_color("white")
draw_text(x, y, target)
if has_kb_hit():
key = get_char()
if key.upper() == target:
fill_rect(x - 2, y - 22, x + 22, y + 2) # clear the char and generate next char
break
if key == " ":
show_goodbye()
close_graph()
exit()
delay_fps(60)
fill_rect(x - 2, y - 22, x + 22, y + 2) # clear the char
close_graph()
easy_run(main)
Key Pressed¶
We can use has_kb_msg() to see if there is any key pressed, and use get_key() to get the pressed key. has_kb_msg() is non-blocking, and get_key() is blocking.