1. Python Graphics
N Amanquah
Based on EPROM curriculum

2. Import graphics module
Redraw_callback method of canvas will do that!
Greate a graphics.Image object
Use double buffering to copy it from buffer to screen/canvas
Call canvas.blit(grahicsObject) #eg image
Both image and canvas have blit() fxn
Handle_redraw takes one param –rect of size of area to redraw, pass None to redraw all

3. Primitives Draw_rectangle() Draw_point() Draw_text()
Also methods to draw polygon, ellipse, pieslice etc

4. Example import appuifw, e32, key_codes, graphics WHITE = (255,255,255)
RED = (255,0,0)
BLUE = (0,0,255)
YELLOW = (255,255,0)
def quit():
app_lock.signal()
img = None
#other functions
canvas = appuifw.Canvas(redraw_callback = handle_redraw, event_callback = handle_event)
appuifw.app.body = canvas
appuifw.app.screen = "full"
appuifw.app.exit_key_handler = quit
w, h = canvas.size
img = graphics.Image.new((w, h))
img.clear(BLUE)
app_lock = e32.Ao_lock()
app_lock.wait()

5. The other functions def draw_rectangle():
img.rectangle((50,100,100,150), fill = YELLOW)
def draw_point():
img.point((90,50), outline = RED, width = 30)
def draw_text():
img.text((10,40), u"Hello", fill = WHITE)
def handle_redraw(rect):
if img: #to be sure image has been created b4 being copied to canvas
canvas.blit(img)
def handle_event(event):
ev = event["keycode"]
if event["type"] == appuifw.EEventKeyDown: #others r: keycode, scancode, modifiers and type!
img.clear(BLUE)
if ev == key_codes.EKeyUpArrow:
draw_point()
elif ev == key_codes.EKeyRightArrow:
draw_text()
elif ev == key_codes.EKeyDownArrow:
draw_rectangle()
elif ev == key_codes.EKeyLeftArrow:
handle_redraw(None)

6. The Camera
Program an application that lets you take a picture. The picture shall be stored on the c: drive.
1. from graphics import * and import camera
2. Use the SELECT key to take the picture.
3. Use the LeftSoftKey to to activate the camera mode again.
Example: ex_camera_descr.py
*Check out the python_api.pdf for more parameters! (exposure, white balance, ….) 6

7. camera.stop_finder()
pic = camera.take_photo(size = (640,480))
w,h = canvas.size
canvas.blit(pic,target=(0, 0, w, 0.75 * w), scale = 1)
pic.save('e:\\Images\\picture1.jpg')

8. Image Handling Play with Nokia's Example Scripts: Image Rotation
Example script : image_rotation.py
Image Viewing
Example script : imageviewer.py 8