ラズパイでコンデジを作る ref: https://qiita.com/akiraak/items/59cde5b162b36fe360ce

camera.desktop

[Desktop Entry]
Type=Application
Name=windowpy
Exec=/usr/bin/python2.7 /home/pi/projects/camera/camera.py
Terminal=false

camera.py

import Tkinter as tk
import RPi.GPIO as GPIO
from datetime import datetime
import picamera
import os.path
import time


camera = picamera.PiCamera()
camera.resolution = (2592, 1944)
camera.rotation = 270

switchGPIO = 4
picturesPath = '/home/pi/projects/camera/output' # 写真の保存先


# フルスクリーンアプリを作るためのクラス
class FullScreenApp(object):
    def __init__(self, master, **kwargs):
        self.master = master
        pad = 3
        self._geom = '200x200+0+0'
        master.geometry("{0}x{1}+0+0".format(
            master.winfo_screenwidth() - pad, master.winfo_screenheight() - pad))
        master.bind('<Escape>', self.toggle_geom)

    def toggle_geom(self, event):
        geom = self.master.winfo_geometry()
        print(geom, self._geom)
        self.master.geometry(self._geom)
        self._geom = geom


window = tk.Tk()
FullScreenApp(window)
window.title("Camera")

shotLabel = tk.Label(text='')
shotLabel.place(x=564, y=20)
shotLabel.config(font=('System', 32))
window.update()


# カメラのプレビュー画面を表示する
def previewCamera():
    scale = 0.85
    w = int(640 * scale)
    h = int(480 * scale)
    camera.start_preview(
        fullscreen = False,
        window = (0, 67, w, h))


def initGPIO():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(switchGPIO, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)


def cleanGPIO():
    GPIO.cleanup()


# 写真撮影
def takePicture():
    filename = datetime.now().strftime('%Y%m%d-%H%M%S.jpg')
    path = os.path.join(picturesPath, filename)
    camera.capture(path)
    checkSaved(path)


# 撮影できたかチェックしテキストを画面に表示する（まれに失敗する）
def checkSaved(path):
    if os.path.exists(path) and os.path.getsize(path) > 0:
        shotLabel['text'] = 'Saved'
    else:
        shotLabel['text'] = 'Error'
    window.update()
    time.sleep(3)
    shotLabel['text'] = ''
    window.update()


def main():
    try:
        initGPIO()
        previewCamera()

        switch = False
        while True:
            switchStatus = GPIO.input(switchGPIO) == GPIO.HIGH
            if not switch:
                if switchStatus:
                    takePicture()
            switch = switchStatus
    except KeyboardInterrupt:
        pass

    cleanGPIO()
    camera.close()


if __name__ == '__main__':
    main()