Import code and add info to readme

Signed-off-by: Christopher Arndt <chris@chrisarndt.de>

README.md

@@ -1,2 +1,43 @@
-# nanogui-experiments
+# NanoGUI Experiments
 
+![NanoGUI Knobs example app](nanogui_knobs.png)
+
+## Quickstart
+
+```con
+python3 -m venv venv
+source venv/bin/activate
+(venv) pip install -r requirenments.txt
+(venv) python3 nanogui_helloworld.py
+```
+
+
+## Knobs Example
+
+```con
+(venv) python3 nanogui_knobs.py
+```
+
+### Key and Mouse Bindings
+
+|                                           |                      |                         |
+| ----------------------------------------- | -------------------- |------------------------ |
+| Mouse click-and-drag knob                 | coarse in-/decrement | +/- one 100th / pixel   |
+| Shift + mouse click-and-drag knob         | fine in-/decrement   | +/- 0.1 / pixel         |
+| Mouse wheel scroll over knob              | coarse in-/decrement | one 100th / click * 2.0 |
+| Shift + mouse wheel scroll over knob      | fine in-/decrement   | +/- 0.1 / click         |
+| Mouse wheel scroll over value entry       | fine in-/decrement   | +/- 0.1                 |
+| Ctrl + left click on knob                 | set to default value |                         |
+| Up/down key while mouse over knob         | coarse in-/decrement | +/- one 100th           |
+| Shift + up/down key while mouse over knob | fine in-/decrement   | +/- 0.1                 |
+| Page up/down key while mouse over knob    | fine in-/decrement   | +/- one 10th            |
+| Mouse click on value entry up/down arrow  | fine in-/decrement   | +/- 0.1                 |
+| Return/Enter while editing value entry    | accept & set value   |                         |
+| Escape key                                | quit                 |                         |
+
+
+### Notes
+
+* No support for scaling or re-layouting on window resize yet.
+* Only the knob value gauge color can currently be specified on instantation,
+  the knob gradient and outline colors are currently hard-coded.

knob.py

@@ -0,0 +1,247 @@
+#!/usr/bin/env python3
+
+import math
+
+from nanogui import Color, Cursor, FloatBox, Vector2f, Vector2i, Widget, glfw
+from nanogui.nanovg import BUTT, RGB, RGBA, RGBAf, LerpRGBA, NVGwinding, RGBAf
+
+
+class Knob(Widget):
+    def __init__(
+        self,
+        parent,
+        label,
+        default=0.0,
+        min_val=0.0,
+        max_val=127.0,
+        unit="%",
+        increment=0.1,
+        size=80,
+        color=RGBA(192, 192, 192, 255),
+    ):
+        super().__init__(parent)
+        self.label = label
+
+        # sizes
+        self._size = size
+        # value gauge width as ratio of knob radius
+        self.gauge_width = 0.125
+        # value indicator line length as ratio of knob radius
+        self.indicator_size = 0.35
+
+        # value and range
+        self.value = default
+        self.min_val = min_val
+        self.max_val = max_val
+        self.default = default
+        self.unit = unit
+        self.increment = increment
+
+        # behaviour
+        self.fine_mode = False
+        self.scroll_speed = 2.0
+        self.scroll_increment = (self.max_val - self.min_val) / 100.0 * self.scroll_speed
+        self.drag_increment = (self.max_val - self.min_val) / 100.0
+        self.callback = None
+        self.set_cursor(Cursor.Hand)
+
+        # colors
+        self.color = color
+        self.knob_color_1 = RGB(86, 92, 95)
+        self.knob_color_2 = RGB(39, 42, 43)
+        self.outline_color_1 = RGBA(190, 190, 190, 0.0)
+        self.outline_color_2 = RGB(23, 23, 23)
+
+    @property
+    def color(self):
+        return self._color
+
+    @color.setter
+    def color(self, col):
+        if isinstance(col, Color):
+            col = RGBAf(col.r, col.g, col.b, col.w)
+
+        self._color = col
+        self.gauge_color = LerpRGBA(RGB(40, 40, 40), col, 0.3)
+
+    def preferred_size(self, ctx):
+        return Vector2i(self._size, self._size)
+
+    def _adjust_value(self, val, inc):
+        if self.fine_mode:
+            inc = self.increment
+
+        new_val = self.value + val * inc
+        new_val = max(self.min_val, min(self.max_val, new_val))
+
+        if new_val != self.value:
+            self.value = new_val
+
+            if self.callback:
+                self.callback(new_val)
+
+            return True
+
+        return False
+
+    def mouse_enter_event(self, pos: Vector2i, enter: bool):
+        if enter:
+            self.request_focus()
+
+        self.set_focused(enter)
+        return True
+
+    def mouse_button_event(self, pos: Vector2i, button: int, down: bool, modifiers: int):
+        if button == glfw.MOUSE_BUTTON_1 and modifiers == glfw.MOD_CONTROL and down:
+            if self.value != self.default:
+                self.value = self.default
+
+                if self.callback:
+                    self.callback(self.value)
+
+        return True
+
+    def mouse_drag_event(self, p: Vector2i, rel: Vector2i, button: int, modifiers: int):
+        self._adjust_value(-rel[1], self.drag_increment)
+        return True
+
+    def scroll_event(self, p: Vector2i, rel: Vector2f):
+        self._adjust_value(rel[1], self.scroll_increment)
+        return True
+
+    def keyboard_event(self, key, scancode, action, modifiers):
+        if key in (glfw.KEY_LEFT_SHIFT, glfw.KEY_RIGHT_SHIFT):
+            if action == glfw.PRESS:
+                self.fine_mode = True
+            elif action == glfw.RELEASE:
+                self.fine_mode = False
+            return True
+        elif action in (glfw.PRESS, glfw.REPEAT):
+            if key == glfw.KEY_UP:
+                self._adjust_value(1, self.drag_increment)
+                return True
+            elif key == glfw.KEY_DOWN:
+                self._adjust_value(-1, self.drag_increment)
+                return True
+            elif key == glfw.KEY_PAGE_UP:
+                self._adjust_value(10, self.drag_increment)
+                return True
+            elif key == glfw.KEY_PAGE_DOWN:
+                self._adjust_value(-10, self.drag_increment)
+                return True
+
+        return False
+
+    def set_callback(self, callback):
+        if callable(callback):
+            self.callback = callback
+        else:
+            raise TypeError("Not a callable.")
+
+    def set_value(self, value, trigger_callback=False):
+        new_val = max(self.min_val, min(self.max_val, value))
+        if new_val != self.value:
+            self.value = new_val
+
+            if trigger_callback and self.callback:
+                self.callback(value)
+
+    def create_value_entry(self, parent, editable=True, font_size=20, widget=FloatBox, **kwargs):
+        entry = widget(parent, **kwargs)
+        entry.set_size((int(self._size * 1.1), int(font_size * 1.2)))
+        entry.set_font_size(font_size)
+        entry.set_editable(editable)
+        entry.set_spinnable(True)
+        entry.set_value(self.value)
+        # entry.number_format("%02.2f")  # method missing in Python bindings
+        entry.set_min_value(self.min_val)
+        entry.set_max_value(self.max_val)
+        entry.set_value_increment(self.increment)
+
+        if self.unit:
+            entry.set_units(self.unit)
+
+        self.set_callback(entry.set_value)
+        entry.set_callback(self.set_value)
+
+        return entry
+
+    def draw(self, ctx):
+        pos = self.position()
+        size = self.size()
+        height = float(size[1])
+        radius = height / 2.0
+
+        gauge_width = radius * self.gauge_width
+        margin = gauge_width / 2.0
+        percent_filled = (self.value - self.min_val) / (self.max_val - self.min_val)
+        knob_diameter = (radius - gauge_width) * 2.0 - margin
+        indicator_length = radius * self.indicator_size
+
+        ctx.Save()
+        ctx.Translate(pos[0], pos[1])
+
+        # Gauge (background)
+        ctx.BeginPath()
+
+        ctx.StrokeWidth(gauge_width)
+        ctx.StrokeColor(self.gauge_color)
+        ctx.LineCap(BUTT.ROUND)
+        ctx.Arc(radius, radius, radius - margin, 0.75 * math.pi, 0.25 * math.pi, NVGwinding.CW)
+        ctx.Stroke()
+
+        # Gauge (fill)
+        ctx.BeginPath()
+
+        ctx.StrokeWidth(gauge_width)
+        ctx.StrokeColor(self.color)
+        ctx.LineCap(BUTT.ROUND)
+        ctx.Arc(
+            radius,
+            radius,
+            radius - margin,
+            0.75 * math.pi,
+            (0.75 + 1.5 * percent_filled) * math.pi,
+            NVGwinding.CW,
+        )
+        ctx.Stroke()
+
+        # Knob
+        ctx.BeginPath()
+
+        ctx.StrokeWidth(2.0)
+        outline_paint = ctx.LinearGradient(
+            0,
+            0,
+            0,
+            height - 10,
+            self.outline_color_1,
+            self.outline_color_2,
+        )
+        ctx.StrokePaint(outline_paint)
+
+        knob_paint = ctx.LinearGradient(
+            radius, gauge_width, radius, knob_diameter, self.knob_color_1, self.knob_color_2
+        )
+        ctx.FillPaint(knob_paint)
+
+        ctx.Circle(radius, radius, knob_diameter / 2.0)
+        ctx.Fill()
+        ctx.Stroke()
+
+        # Indicator
+        ctx.BeginPath()
+
+        ctx.Translate(radius, radius)
+        ctx.Rotate((2.0 + ((percent_filled - 0.5) * 1.5)) * math.pi)
+
+        ctx.StrokeColor(self.color)
+        ctx.StrokeWidth(gauge_width)
+        ctx.LineCap(BUTT.ROUND)
+        indicator_start = radius - margin - indicator_length
+        ctx.MoveTo(0, -indicator_start)
+        ctx.LineTo(0, -(indicator_start + indicator_length))
+        ctx.Stroke()
+
+        ctx.Restore()
+        ctx.ClosePath()

nanogui_customwidget.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+
+import nanogui
+from nanogui import glfw
+from nanogui import BoxLayout, Color, Label, Orientation, Screen, Widget, Window, Vector2i
+from nanogui.nanovg import RGBAf, RGB
+
+
+class CustomWidget(Widget):
+    def __init__(self, parent, size=(100, 100), color=Color(192, 0, 0, 255)):
+        super().__init__(parent)
+        self._size = size
+        self._color = RGBAf(color.r, color.g, color.b, color.w)
+
+    def preferred_size(self, ctx):
+        return Vector2i(self._size)
+
+    def draw(self, ctx):
+        pos = self.position()
+        size = self.size()
+
+        ctx.BeginPath()
+        ctx.Rect(pos[0], pos[1], size[0], size[1])
+        ctx.FillColor(RGB(128, 128, 0))
+        ctx.Fill()
+        ctx.BeginPath()
+        ctx.StrokeWidth(5.0)
+        ctx.StrokeColor(self._color)
+        ctx.MoveTo(pos[0], pos[1])
+        ctx.LineTo(pos[0] + size[0], pos[1] + size[1] / 3.0)
+        ctx.Stroke()
+        ctx.ClosePath()
+
+
+class CustomWidgetApp(Screen):
+    def __init__(self, size=(400, 300)):
+        super().__init__(size, "NanoGUI CustomWidget")
+        self.win = Window(self, "Demo Window")
+
+        self.win.set_layout(BoxLayout(Orientation.Vertical, margin=20, spacing=20))
+        self.resize_event(size)
+
+        Label(self.win, "NanoGUI CustomWidget Demo", "sans-bold")
+
+        cw = CustomWidget(self.win, (200, 100))
+
+        self.draw_all()
+        self.set_visible(True)
+        self.perform_layout()
+
+    def resize_event(self, size):
+        self.win.set_fixed_size(size)
+        self.win.set_size(size)
+        self.win.center()
+        self.win.perform_layout(self.nvg_context())
+        super().resize_event(size)
+        return True
+
+    def keyboard_event(self, key, scancode, action, modifiers):
+        if super().keyboard_event(key, scancode, action, modifiers):
+            return True
+
+        if key == glfw.KEY_ESCAPE and action == glfw.PRESS:
+            self.set_visible(False)
+            return True
+
+        return False
+
+
+if __name__ == "__main__":
+    import gc
+
+    nanogui.init()
+    app = CustomWidgetApp()
+    nanogui.mainloop(refresh=1 / 60.0 * 1000)
+    del app
+    gc.collect()
+    nanogui.shutdown()

nanogui_helloworld.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+
+import nanogui
+from nanogui import glfw
+from nanogui import BoxLayout, Button, Label, Orientation, Screen, Window
+
+
+class HelloWorldApp(Screen):
+    def __init__(self, size=(400, 300)):
+        super().__init__(size, "NanoGUI Hello World")
+        self.win = Window(self, "Demo Window")
+
+        self.win.set_layout(BoxLayout(Orientation.Vertical, margin=20, spacing=20))
+        self.resize_event(size)
+
+        Label(self.win, "NanoGUI Demo", "sans-bold")
+        b = Button(self.win, "Say hello!")
+
+        def cb():
+            print("Well, 'ello there!")
+
+        b.set_callback(cb)
+
+        self.set_visible(True)
+        self.perform_layout()
+
+    def resize_event(self, size):
+        self.win.set_fixed_size(size)
+        self.win.set_size(size)
+        self.win.center()
+        self.win.perform_layout(self.nvg_context())
+        super().resize_event(size)
+        return True
+
+    def keyboard_event(self, key, scancode, action, modifiers):
+        if super().keyboard_event(key, scancode, action, modifiers):
+            return True
+
+        if key == glfw.KEY_ESCAPE and action == glfw.PRESS:
+            self.set_visible(False)
+            return True
+
+        return False
+
+
+if __name__ == "__main__":
+    import gc
+
+    nanogui.init()
+    app = HelloWorldApp()
+    nanogui.mainloop(refresh=1 / 60.0 * 1000)
+    del app
+    gc.collect()
+    nanogui.shutdown()

nanogui_knobs.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+
+from random import randint, shuffle, uniform
+
+import nanogui
+from nanogui import BoxLayout, Color, Label, Orientation, Screen, Widget, Window, glfw
+from nanogui.nanovg import RGB
+
+from knob import Knob
+
+
+class KnobsApp(Screen):
+    def __init__(self, size=(450, 250)):
+        super().__init__(size, "NanoGUI Knobs")
+        self.set_background(Color(96, 96, 96, 255))
+        self.win = Window(self, "Envelope")
+        self.win.set_layout(BoxLayout(Orientation.Horizontal, margin=20, spacing=20))
+        self.resize_event(size)
+
+        knobs = (
+            ("Attack", 0.0, 0.0, 5.0, "s", 0.01),
+            ("Decay", 0.0, 0.0, 5.0, "s", 0.01),
+            ("Sustain", 0.0, 0.0, 100.0, "%", 0.01),
+            ("Release", 0.0, 0.0, 5.0, "s", 0.01),
+        )
+
+        self.knobs = []
+        self.entries = []
+        self.labels = []
+
+        for i, knobspec in enumerate(knobs):
+            box = Widget(self.win)
+            box.set_layout(BoxLayout(Orientation.Vertical, spacing=10))
+
+            rgb = [128 + randint(0, 127), randint(0, 127), 64]
+            shuffle(rgb)
+            knob = Knob(box, *knobspec)
+            knob.color = RGB(*rgb)
+            knob.value = round(uniform(knob.min_val, knob.max_val), 2)
+            self.knobs.append(knob)
+            self.entries.append(knob.create_value_entry(box))
+            self.labels.append(Label(box, knob.label, font="sans", font_size=20))
+
+        self.draw_all()
+        self.set_visible(True)
+        self.perform_layout()
+
+    def resize_event(self, size):
+        self.win.set_fixed_size(size)
+        self.win.set_size(size)
+        self.win.center()
+        self.win.perform_layout(self.nvg_context())
+        super().resize_event(size)
+        return True
+
+    def keyboard_event(self, key, scancode, action, modifiers):
+        if super().keyboard_event(key, scancode, action, modifiers):
+            return True
+
+        if key == glfw.KEY_ESCAPE and action == glfw.PRESS:
+            self.set_visible(False)
+            return True
+
+        return True
+
+    def __del__(self):
+        # callbacks referencing other widgets cause memory leakage at cleanup
+        for entry in self.entries:
+            entry.set_callback(lambda x: True)
+        for entry in self.knobs:
+            entry.set_callback(lambda x: True)
+
+
+if __name__ == "__main__":
+    import gc
+
+    nanogui.init()
+    app = KnobsApp()
+    nanogui.mainloop(refresh=1 / 60.0 * 1000)
+    del app
+    gc.collect()
+    nanogui.shutdown()

requirements.txt

@@ -0,0 +1 @@
+nanogui==0.2.0