Fix widget metrics.

README.md

@@ -49,13 +49,9 @@ target and a C device driver (unless you can acquire a suitable binary).
 # Project status
 
 Code has been tested on ESP32, Pi Pico and Pyboard. The API shuld be stable.
-Code is new and issues are likely: please report any found. This document is
-under review. I plan to add further demos and to upgrade the performance of
-some display drivers.
-
-An issue under investigation is that a soft reset is required after a GUI
-application is run and before running another. Otherwise the second application
-displays correctly but is unresponsive.
+Code is new and issues are likely: please report any found. The project is
+under development so check for updates. I also plan to upgrade the performance
+of some display drivers.
 
 # 0. Contents
 
@@ -392,6 +388,11 @@ Demos are run by issuing (for example):
 ```python
 >>> import gui.demos.simple
 ```
+If shut down cleanly with the "close" button a demo can be re-run with (e.g.):
+```python
+gui.demos.simple.test()
+```
+Before running a different demo the host should be reset (ctrl-d) to clear RAM.
 
 These will run on screens of 128x128 pixels or above. The initial ones are
 minimal and aim to demonstrate a single technique.  
@@ -2170,7 +2171,10 @@ class TSeq(Screen):
 
 The "tab order" of widgets on a `Screen` is the order with which they acquire
 focus with successive presses of the `Next` button. It is determined by the
-order in which they are instantiated. 
+order in which they are instantiated. Tab order is important for usability but
+instantiating in the best order can conflict with program logic. This happens
+if a widget's callback refers to others not yet instantiated. See demos
+`dropdown.py` and `linked_sliders.py` for one solution.
 
 The obvious layout for the physical buttons is as per a joystick:
 
@@ -2201,13 +2205,12 @@ have the following bound variables, which should be considered read-only:
 
  * `height` As specified. Does not include border.
  * `width` Ditto.
- * `rows` Height including borders.
- * `cols` Width with borders.
+ * `mrow` Maximum absolute row occupied by the widget.
+ * `mcol` Maximum absolute col occupied by the widget.
 
-This support is fairly "micro" and does not take account of labels and legends.
-This means that `rows` and `cols` for `Dial`, `Meter`, `Slider` and
-`HorizSlider` do not necessarily reflect the full amount of space used by the
-control.
+The `mrow` and `mcol` values enable other widgets to be positioned relative to
+the one previously instantiated. In the cases of sliders, `Dial` and `Meter`
+widgets these take account of space ocupied by legends or labels.
 
 The `aclock.py` demo provides a simple example of this approach.
 
@@ -2254,4 +2257,6 @@ Hopefully these are self explanatory. The `Display` methods use the `framebuf`
 convention of `x, y` coordinates rather than the `row, col` system used by
 micro-gui.
 
+The `primitives.py` demo provides a simple example.
+
 ###### [Contents](./README.md#0-contents)

gui/core/ugui.py

@@ -274,10 +274,9 @@ class Screen:
         cs_new._do_open(cs_old) # Clear and redraw
         cs_new.after_open() # Optional subclass method
         if cs_old is None:  # Initialising
-            try:
-                asyncio.run(Screen.monitor())  # Starts and ends uasyncio
-            finally:
-                asyncio.new_event_loop()
+            asyncio.run(Screen.monitor())  # Starts and ends uasyncio
+            # Don't do asyncio.new_event_loop() as it prevents re-running
+            # the same app.
 
     @classmethod
     async def monitor(cls):
@@ -550,8 +549,9 @@ class Widget:
         self.col = col
         self.height = height
         self.width = width
-        self.rows = height + 4  # For metrics. Default: allow for border.
-        self.cols = width + 4
+        # Maximum row and col. Defaults for user metrics. May be overridden
+        self.mrow = row + height + 2  # in subclass. Allow for border.
+        self.mcol = col + width + 2
         self.visible = True # Used by ButtonList class for invisible buttons
         self.draw = True  # Signals that obect must be redrawn
         self._value = value

gui/demos/aclock.py

@@ -25,9 +25,9 @@ from gui.core.colors import *
 async def aclock(dial, lbldate, lbltim):
     # Return a unit vector of phase phi. Multiplying by this will
     # rotate a vector anticlockwise which is mathematically correct.
-    # Alas clocks modelled on sundials were invented in the northern
-    # hemisphere. Otherwise they would have rotated widdershins
-    # in accordance with maths. Hence negative sign when called.
+    # Alas clocks, modelled on sundials, were invented in the northern
+    # hemisphere. Otherwise they would have rotated widdershins like
+    # the maths. Hence negative sign when called.
     def uv(phi):
         return rect(1, phi)
 
@@ -70,13 +70,14 @@ class BaseScreen(Screen):
                   }
 
         wri = CWriter(ssd, font, GREEN, BLACK, verbose=False)
-        gap = 4  # Vertical gap between widgets
         dial = Dial(wri, 2, 2, height = 70, ticks = 12,
                     fgcolor = GREEN, pip = GREEN)
         # Set up clock display: instantiate labels
-        row = dial.rows + gap
+        # Demo of relative positioning.
+        gap = 4  # Vertical gap between widgets
+        row = dial.mrow + gap
         lbldate = Label(wri, row, 2, 100, **labels)
-        row += lbldate.rows + gap
+        row = lbldate.mrow + gap
         lbltim = Label(wri, row, 2, '00.00.00', **labels)
         self.reg_task(aclock(dial, lbldate, lbltim))
         CloseButton(wri)

gui/demos/active.py

@@ -47,12 +47,13 @@ class BaseScreen(Screen):
         self.vslider = Slider(wri, 2, 2, callback=self.slider_cb,
                              bdcolor=RED, slotcolor=BLUE,
                              legends=('0.0', '0.5', '1.0'), value=0.5)
-
+        #Label(wri, 2, self.vslider.mcol, 'FF')
         col = 80
         row = 15
         self.hslider = HorizSlider(wri, row, col, callback=self.slider_cb,
                                    bdcolor=GREEN, slotcolor=BLUE,
                                    legends=('0.0', '0.5', '1.0'), value=0.7)
+        Label(wri, self.hslider.mrow, self.hslider.mcol, 'FF')
         row += 30
         self.scale = Scale(wri, row, col, width = 150, tickcb = tickcb,
                 pointercolor=RED, fontcolor=YELLOW, bdcolor=CYAN,

gui/demos/various.py

@@ -61,8 +61,11 @@ class FooScreen(Screen):
 
         m0 = Meter(wri, 10, 240, divisions = 4, ptcolor=YELLOW, height=80, width=15,
                 label='Meter example', style=Meter.BAR, legends=('0.0', '0.5', '1.0'))
+        #Label(wri, 2, m0.mcol, 'FF')
         # Instantiate displayable objects. bgcolor forces complete redraw.
         dial = Dial(wri, 2, 2, height = 75, ticks = 12, bgcolor=BLACK, bdcolor=None, label=120)  # Border in fg color
+        #Label(wri, dial.mrow, 2, 'FF')
+        #Label(wri, dial.mrow, dial.mcol, 'FF')
         scale = Scale(wri, 2, 100, width = 124, tickcb = tickcb,
                 pointercolor=RED, fontcolor=YELLOW, bdcolor=CYAN)
 

gui/demos/vtest.py

@@ -41,7 +41,10 @@ async def ptr_test(dial):
     ptr = Pointer(dial)
     v = 0j
     steps = 20  # No. of interpolation steps
-    grv = lambda : urandom.getrandbits(16) / 2**15 - 1  # Random: range -1.0 to +1.0
+    # BUG getting a weird visual flicker on occasion, with yellow
+    # being briefly displayed. Where is that coming from?
+    # Does not seem to be affected by max value. TODO
+    grv = lambda : urandom.getrandbits(16) / 2**15 - 1  # Random: range -1.0 to +0.999
     while True:
         v1 = grv() + 1j * grv()  # Random vector
         dv = (v1 - v) / steps  # Interpolation vector

gui/widgets/dial.py

@@ -67,8 +67,9 @@ class Dial(Widget):
         self.pip = self.fgcolor if pip is None else pip
         if label is not None:
             self.label = Label(writer, row + height + 3, col, label)
-            #self.cols = max(self.cols, self.label.cols)
-            #self.rows += 3 + self.label.rows
+            # Adjust metrics
+            self.mrow = self.label.mrow - 2  # Label never has border
+            self.mcol = max(self.mcol, self.label.mcol - 2)
         radius = int(height / 2)
         self.radius = radius
         self.ticks = ticks

gui/widgets/meter.py

@@ -24,6 +24,7 @@ class Meter(Widget):
         self.style = style
         self.ptcolor = ptcolor if ptcolor is not None else self.fgcolor
         if legends is not None:  # Legends are static
+            mcol = 0
             x = col + width + 4
             y = row + height
             dy = 0 if len(legends) <= 1 else height / (len(legends) -1)
@@ -31,6 +32,8 @@ class Meter(Widget):
             for legend in legends:
                 l = Label(writer, round(yl), x, legend)
                 yl -= dy
+                mcol = max(mcol, l.mcol)
+            self.mcol = mcol - 2  # For metrics. Legends never have border.
         self.value(value)
 
     def value(self, n=None, color=None):

gui/widgets/sliders.py

@@ -28,6 +28,9 @@ class Slider(LinearIO):
         super()._set_callbacks(callback, args)
         self.divisions = divisions
         self.legends = legends
+        if legends is not None:  # Adjust column metric
+            ml = max((writer.stringlen(l) for l in legends))
+            self.mcol += ml + 2  # Strings are rendered 2 pixels right of border
         self.fontcolor = self.fgcolor if fontcolor is None else fontcolor
         self.slotcolor = self.bgcolor if slotcolor is None else slotcolor
         # Define slider