Add images, start of per-app README.md files.

README.md

@@ -4,7 +4,7 @@ A collection of 15 small — *minute* — desktop applications written in Python
 using the PyQt framework. These apps are intended as examples from
 which you can poke, hack and prod your way to writing your own tools.
 
-If you find these apps interesting, or want to learn more about
+> If you think this example app is neat and want to learn more about
 PyQt in general, [take a look at my ebook & online course
 "Create Simple GUI Applications"](https://martinfitzpatrick.name/create-simple-gui-applications)
 which covers everything you need to know to start building your own applications with PyQt.

currency/currency.py

@@ -63,7 +63,7 @@ class WorkerSignals(QObject):
 
 class UpdateWorker(QRunnable):
     '''
-    Worker thread for unzipping.
+    Worker thread for updating currency.
     '''
     signals = WorkerSignals()
     is_interrupted = False

notepad/README.md

@@ -0,0 +1,9 @@
+# No2Pads — A Notepad clone in PyQt
+
+A very simple notepad clone using the QTextEdit widget to handle more or less
+everything. Supports file loading, saving and printing.
+
+> If you think this example app is neat and want to learn more about
+PyQt in general, [take a look at my ebook & online course
+"Create Simple GUI Applications"](https://martinfitzpatrick.name/create-simple-gui-applications)
+which covers everything you need to know to start building your own applications with PyQt.

notes/README.md

@@ -0,0 +1,11 @@
+# Brown Note — A desktop Post-it note application in PyQt
+
+Take temporary notes on your desktop, with this floating-note app. Notes
+are stored locally in a SQLite database.
+
+![Brown note](screenshot-notes.png)
+
+> If you think this example app is neat and want to learn more about
+PyQt in general, [take a look at my ebook & online course
+"Create Simple GUI Applications"](https://martinfitzpatrick.name/create-simple-gui-applications)
+which covers everything you need to know to start building your own applications with PyQt.

paint/README.md

@@ -0,0 +1,48 @@
+# Piecasso — A desktop Paint application in PyQt
+
+Express yourself with PieCasso, the only painting programme to feature
+ready made pictures of pie.
+
+Piecasso is a clone of the Paint programme from Windows 95 (ish) with a
+few additions (and subtractions). The programme features standard
+tools including pen, brush, fill, spray can, eraser, text and a number of
+shape drawing widgets. 
+
+![Piecasso](screenshot-paint.png)
+
+You can copy from the image, with a custom shape,
+although pasting + floating is not supported. The canvas is a fixed size
+and loaded images are adjusted to fit. A stamp tool is also included
+which is pre-loaded with pictures of delicious pie.
+
+![Piecasso](screenshot-paint2.png)
+
+> If you think this example app is neat and want to learn more about
+PyQt in general, [take a look at my ebook & online course
+"Create Simple GUI Applications"](https://martinfitzpatrick.name/create-simple-gui-applications)
+which covers everything you need to know to start building your own applications with PyQt.
+
+## Code notes
+
+### Event handling
+
+All tools are implemented with nested event handlers, which forward
+on events as appropriate. This allows for a lot of code re-used between
+tools which have common behaviours (e.g. shape drawing). Adding the select
+region animation requires a timer (to update the crawling ants) which
+added some complexity.
+
+### Flood fill
+
+This was the trickiest part of this app from a performance point of view.
+Checking pixels directly is far too slow (full-canvas fill
+time of approx 10 seconds). Most code to achieve this in Python sensibly
+uses numpy, but I didn't want to introduce a dependency for this alone.
+
+By exporting the image as a bytestring, then down-sampling to a boolean 
+byte-per-pixel (for match/no-match) to simplify the comparison loop, I
+could get it up to a reasonable speed.
+
+The search-to-fill algorithm is still pretty dumb though.
+
+

paint/paint.py

@@ -356,7 +356,8 @@ class Canvas(QLabel):
             self.current_text = ""
             self.timer_event = self.text_timerEvent
 
-        elif e.button() == Qt.RightButton and self.current_pos:
+        elif e.button() == Qt.LeftButton:
+
             self.timer_cleanup()
             # Draw the text to the image
             p = QPainter(self.pixmap())
@@ -370,6 +371,9 @@ class Canvas(QLabel):
 
             self.reset_mode()
 
+        elif e.button() == Qt.RightButton and self.current_pos:
+            self.reset_mode()
+
     def text_timerEvent(self, final=False):
         p = QPainter(self.pixmap())
         p.setCompositionMode(QPainter.RasterOp_SourceXorDestination)
@@ -536,7 +540,7 @@ class Canvas(QLabel):
             self.timer_cleanup()
 
             p = QPainter(self.pixmap())
-            p.setPen(QPen(self.primary_color, 5, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
+            p.setPen(QPen(self.primary_color, self.config['size'], Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
 
             p.drawLine(self.origin_pos, e.pos())
             self.update()
@@ -583,7 +587,7 @@ class Canvas(QLabel):
     def generic_poly_mouseDoubleClickEvent(self, e):
         self.timer_cleanup()
         p = QPainter(self.pixmap())
-        p.setPen(QPen(self.primary_color, 5, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
+        p.setPen(QPen(self.primary_color, self.config['size'], Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
 
         # Note the brush is ignored for polylines.
         if self.secondary_color:

weather/weather.py

@@ -19,6 +19,60 @@ application.
 
 """
 
+
+def from_ts_to_time_of_day(ts):
+    dt = datetime.fromtimestamp(ts)
+    return dt.strftime("%I%p").lstrip("0")
+
+
+class WorkerSignals(QObject):
+    '''
+    Defines the signals available from a running worker thread.
+    '''
+    finished = pyqtSignal()
+    error = pyqtSignal(str)
+    result = pyqtSignal(dict, dict)
+
+class WeatherWorker(QRunnable):
+    '''
+    Worker thread for weather updates.
+    '''
+    signals = WorkerSignals()
+    is_interrupted = False
+
+    def __init__(self, location):
+        super(WeatherWorker, self).__init__()
+        self.location = location
+
+    @pyqtSlot()
+    def run(self):
+        try:
+            params = dict(
+                q=self.location,
+                appid=OPENWEATHERMAP_API_KEY
+            )
+
+            url = 'http://api.openweathermap.org/data/2.5/weather?%s&units=metric' % urlencode(params)
+            r = requests.get(url)
+            weather = json.loads(r.text)
+
+            # Check if we had a failure (the forecast will fail in the same way).
+            if weather['cod'] != 200:
+                raise Exception(weather['message'])
+
+            url = 'http://api.openweathermap.org/data/2.5/forecast?%s&units=metric' % urlencode(params)
+            r = requests.get(url)
+            forecast = json.loads(r.text)
+
+            self.signals.result.emit(weather, forecast)
+
+        except Exception as e:
+            self.signals.error.emit(str(e))
+
+        self.signals.finished.emit()
+
+
+
 class MainWindow(QMainWindow, Ui_MainWindow):
 
     def __init__(self, *args, **kwargs):
@@ -26,42 +80,45 @@ class MainWindow(QMainWindow, Ui_MainWindow):
         self.setupUi(self)
 
         self.pushButton.pressed.connect(self.update_weather)
-        self.pushButton.pressed.connect(self.update_forecast)
+
+        self.threadpool = QThreadPool()
 
         self.show()
 
-    def from_ts_to_time_of_day(self, ts):
-        dt = datetime.fromtimestamp(ts)
-        return dt.strftime("%I%p").lstrip("0")
+
+    def alert(self, message):
+        alert = QMessageBox.warning(self, "Warning", message)
 
     def update_weather(self):
-        params = dict(
-            q=self.lineEdit.text(),
-            appid=OPENWEATHERMAP_API_KEY
-        )
+        worker = WeatherWorker(self.lineEdit.text())
+        worker.signals.result.connect(self.weather_result)
+        worker.signals.error.connect(self.alert)
+        self.threadpool.start(worker)
 
-        url = 'http://api.openweathermap.org/data/2.5/weather?%s&units=metric' % urlencode(params)
-        r = requests.get(url)
-        data = json.loads(r.text)
+    def weather_result(self, weather, forecasts):
+        self.latitudeLabel.setText("%.2f °" % weather['coord']['lat'])
+        self.longitudeLabel.setText("%.2f °" % weather['coord']['lon'])
 
-        self.latitudeLabel.setText("%.2f °" % data['coord']['lat'])
-        self.longitudeLabel.setText("%.2f °" % data['coord']['lon'])
+        self.windLabel.setText("%.2f m/s" % weather['wind']['speed'])
 
-        self.windLabel.setText("%.2f m/s" % data['wind']['speed'])
+        self.temperatureLabel.setText("%.1f °C" % weather['main']['temp'])
+        self.pressureLabel.setText("%d" % weather['main']['pressure'])
+        self.humidityLabel.setText("%d" % weather['main']['humidity'])
 
-        self.temperatureLabel.setText("%.1f °C" % data['main']['temp'])
-        self.pressureLabel.setText("%d" % data['main']['pressure'])
-        self.humidityLabel.setText("%d" % data['main']['humidity'])
-
-        self.sunriseLabel.setText(self.from_ts_to_time_of_day(data['sys']['sunrise']))
+        self.sunriseLabel.setText(from_ts_to_time_of_day(weather['sys']['sunrise']))
 
         self.weatherLabel.setText("%s (%s)" % (
-            data['weather'][0]['main'],
-            data['weather'][0]['description']
-        )
+            weather['weather'][0]['main'],
+            weather['weather'][0]['description']
         )
+                                  )
 
-        self.set_weather_icon(self.weatherIcon, data['weather'])
+        self.set_weather_icon(self.weatherIcon, weather['weather'])
+
+        for n, forecast in enumerate(forecasts['list'][:5], 1):
+            getattr(self, 'forecastTime%d' % n).setText(from_ts_to_time_of_day(forecast['dt']))
+            self.set_weather_icon(getattr(self, 'forecastIcon%d' % n), forecast['weather'])
+            getattr(self, 'forecastTemp%d' % n).setText("%.1f °C" % forecast['main']['temp'])
 
     def set_weather_icon(self, label, weather):
         label.setPixmap(
@@ -72,20 +129,6 @@ class MainWindow(QMainWindow, Ui_MainWindow):
 
         )
 
-    def update_forecast(self):
-        params = dict(
-            q=self.lineEdit.text(),
-            appid=OPENWEATHERMAP_API_KEY
-        )
-
-        url = 'http://api.openweathermap.org/data/2.5/forecast?%s&units=metric' % urlencode(params)
-        r = requests.get(url)
-        data = json.loads(r.text)
-
-        for n, forecast in enumerate(data['list'][:5], 1):
-            getattr(self, 'forecastTime%d' % n).setText(self.from_ts_to_time_of_day(forecast['dt']))
-            self.set_weather_icon(getattr(self, 'forecastIcon%d' % n), forecast['weather'])
-            getattr(self, 'forecastTemp%d' % n).setText("%.1f °C" % forecast['main']['temp'])
 
 if __name__ == '__main__':