fastplotlib · uutzinger · May 21, 2025 · May 21, 2025 · May 21, 2025 · May 21, 2025
@@ -0,0 +1,319 @@
+"""
+Lineplot Qt
+===========
+
+Complex example for lineplot in PyQt that displays 3 traces.
+The plot is a standard black on white with a legend on the right.
+
+"""
+import sys
+import numpy as np
+import time
+from math import pi, cos, sin, ceil, log10
+
+
+try:
+    from PyQt6.QtWidgets import QApplication, QWidget, QVBoxLayout, QMainWindow
+    from PyQt6.QtCore import QTimer, Qt
+
+except ImportError:
+    from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QMainWindow
+    from PyQt5.QtCore import QTimer, Qt
+
+
+import fastplotlib as fpl
+
+def rotate(angle, axis_x, axis_y, axis_z):
+    """
+    Quaternion representing rotation around the given axis by the given angle.
+    """
+    a2 = angle/2.0
+    c = cos(a2)
+    s = sin(a2)
+    return (axis_x * s, axis_y * s, axis_z * s, c)
+
+class FastPlotMain(QMainWindow):
+
+    MAJOR_TICKS = 5
+    MINOR_TICKS = 4
+    DATAPOINTS  = 50000                   # number of data points per line
+    INTERVAL    = 16                     # display refresh in milliseconds
+    WHITE       = (1.0, 1.0, 1.0, 1.0)
+    BLACK       = (0.0, 0.0, 0.0, 1.0)
+    RED         = (1.0, 0.0, 0.0, 1.0)
+    GREEN       = (0.0, 1.0, 0.0, 1.0)
+    BLUE        = (0.0, 0.0, 1.0, 1.0)
+    DARK_GRAY   = (0.2, 0.2, 0.2, 1.0)
+    LIGHT_GRAY  = (0.9, 0.9, 0.9, 1.0)
+
+    def __init__(self):
+        super().__init__()
+
+        # ─── Window ──────────────────────────────────────────────────────────────
+
+        self.setWindowTitle("fastplotlib Line Plot Test")
+        self.resize(800, 600)
+
+        # ─── Figure & Subplot ────────────────────────────────────────────────────
+
+        self.fig = fpl.Figure(
+            (1, 1),
+            size=(800, 600),
+            names = "Line Plot",
+        )
+
+        # Subplot
+        self.ax = self.fig[0, 0]
+
+        # Turn on axi rulers and option grid
+        self.ax.axes.visible = True
+        self.ax.background_color = self.WHITE
+        if self.ax.axes.grids:
+            self.ax.axes.grids.xy.visible = True
+            self.ax.axes.grids.xy.color   = self.DARK_GRAY
+
+        # ─── Docks: Title & Axis Labels ──────────────────────────────────────────  
+
+        # Title
+        self.ax.docks["top"].size = 30
+        self.ax.docks["top"].add_text(
+            "Line Plots",
+            font_size=16,
+            face_color=(0, 0, 0, 1),
+            anchor="middle-center",
+            offset=(0, 0, 0),
+        )
+        self.ax.docks["top"].background_color = self.WHITE
+
+        # X label
+        self.ax.docks["bottom"].size = 30
+        self.ax.docks["bottom"].add_text(
+            "X",
+            font_size=16,
+            face_color=(0, 0, 0, 1),
+            anchor="middle-center",
+            offset=(0, 0, 0),
+        )
+        self.ax.docks["bottom"].background_color = self.WHITE
+
+        # Y label
+        q = rotate(pi/2.0, 0., 0., 1.)  # rotate 90 deg around z-axis
+        self.ax.docks["left"].size = 30
+        self.ax.docks["left"].add_text(
+            "Y",
+            font_size=16,
+            face_color=(0, 0, 0, 1),
+            anchor="middle-center",
+            offset=(0, 0, 0),
+            rotation=q,
+        )
+        self.ax.docks["left"].background_color = self.WHITE
+
+        # ─── Data & Graphics ─────────────────────────────────────────────────────
+
+        # Prepare your data buffers
+        t = np.linspace(-2*np.pi,2*np.pi,self.DATAPOINTS, dtype = np.float32)
+        self.t = t
+        self.phase1 = 0.0
+        self.phase2 = pi/2.
+        N = self.t.size
+        self.z = np.zeros_like(self.t, dtype=np.float32)
+
+        # Pre-allocate three (N×3) float32 buffers:
+        self.buf1 = np.empty((N, 3), dtype=np.float32)
+        self.buf2 = np.empty((N, 3), dtype=np.float32)
+        self.buf3 = np.empty((N, 3), dtype=np.float32)
+
+        # Copy the constant x and z columns once:
+        self.buf1[:, 0] = self.t;  self.buf1[:, 2] = self.z
+        self.buf2[:, 0] = self.t;  self.buf2[:, 2] = self.z
+        self.buf3[:, 0] = self.t;  self.buf3[:, 2] = self.z
+
+        # Colors (uniform for all points in a line)
+        rgba1 = np.tile(np.array(self.RED,   dtype=np.float32), (self.DATAPOINTS, 1)) # RED
+        rgba2 = np.tile(np.array(self.BLACK, dtype=np.float32), (self.DATAPOINTS, 1)) # BLACK
+        rgba3 = np.tile(np.array(self.BLUE,  dtype=np.float32), (self.DATAPOINTS, 1)) # BLUE
+
+        # Add the lines to the plot axis
+        self.line1 = self.ax.add_line(self.buf1, colors=rgba1)
+        self.line2 = self.ax.add_line(self.buf2, colors=rgba2)
+        self.line3 = self.ax.add_line(self.buf3, colors=rgba3)
+
+        # ─── View & Axes Ticks ────────────────────────────────────────────────────────   
+
+        self.ax.axes.update_using_camera()
+        self.ax.auto_scale(maintain_aspect=True)
+        # Zoom
+        self.ax.camera.local.scale_x *= 1.0
+        self.ax.camera.local.scale_y *= 1.0
+        # Draw the axes with ticks
+        self.updateAxesTicks(self.ax, self.MAJOR_TICKS, self.MINOR_TICKS)
+
+        # ─── Legend ─────────────────────────────────────────────────────────────
+
+        from fastplotlib.legends import Legend
+        legend_dock = self.ax.docks["right"]  # options are right, left, top, bottom
+        legend_dock.background_color = self.WHITE
+        # legend_dock = self.ax  # not working yet, no floating legend on top of plot
+        legend_dock.size = 200                # if top/bottom dock that is the height of dock in pixels, 
+                                              # if left/right dock that is the width of the dock in pixels,
+        self.legend = Legend(
+            plot_area=legend_dock,            # the plot area to attach the legend to
+            background_color=self.LIGHT_GRAY, # optional: the background color of the legend
+            max_rows = 5                      # how many items per column before wrapping
+        )
+        self.lines = [self.line1, self.line2, self.line3]
+        self.labels = ["sin(x)", "rand + 1", "sin(x + θ) - 1"]
+        for lg, label in zip(self.lines, self.labels):
+            self.legend.add_graphic(lg, label)
+
+        self.legend.update_using_camera()
+
+        # ─── Finalize and Show ────────────────────────────────────────────────────
+
+        canvas = self.fig.show(autoscale=True, maintain_aspect=True) # show the figure
+        self.setCentralWidget(canvas)
+        self.fig.canvas.request_draw()
+
+        # ─── Animation Timer ───────────────────────────────────────────────────
+
+        timer = QTimer(self)
+        timer.timeout.connect(self.animate)
+        timer.start(self.INTERVAL)
+
+        # ─── One Time Scaling ────────────────────────────────────────────────────────
+        # This is to ensure that the plot is at least once autoscaled, otherwise user 
+        # sees no plot area
+
+        QTimer.singleShot(
+            100,                         # 0 ms → next Qt loop
+            self.autoScale               # the slot to call
+        )        
+
+        # ─── Benchmark ──────────────────────────────────────────────────────────
+
+        self.last_time = time.perf_counter()
+        self.num_segments = 0
+
+
+    def autoScale(self):
+        """Run once, right after the first frame is ready."""
+        ax = getattr(self, "ax", None)
+        if ax is None:
+            return  # nothing to autoscale
+
+        self.ax.auto_scale(maintain_aspect=True, zoom=0.9)
+        self.updateAxesTicks(self.ax, self.MAJOR_TICKS, self.MINOR_TICKS)
+        self.fig.canvas.request_draw()
+
+    def updateAxesTicks(self, subplot, n_major, n_minor):
+        """
+        Update the tick marks of the x and y axis.
+        """
+
+        # Helper to pick a "nice" power‐of‐10 step and decimal precision
+        def nice_step(lo, hi, n):
+            rng = (hi - lo) / n
+            exp = 0 if rng <= 0 else ceil(log10(rng))
+            return 10 ** exp, max(0, -exp)
+
+        # Grab world‐space extent from the rulers
+        xr, yr = subplot.axes.x, subplot.axes.y
+
+        xmin, _, _ = xr.start_pos
+        xmax, _, _ = xr.end_pos
+        _, ymin, _ = yr.start_pos
+        _, ymax, _ = yr.end_pos
+
+        # Compute the steps
+        maj_x, dec_x = nice_step(xmin, xmax, n_major)
+        maj_y, dec_y = nice_step(ymin, ymax, n_major)
+
+
+        # Apply to each ruler
+        for r, maj, dec in (
+            (xr, maj_x, dec_x), 
+            (yr, maj_y, dec_y),
+        ):
+
+            r.line.material.color = self.BLACK # Ruler color
+
+            r.major_step = maj                  # Major step
+            r.minor_step = maj / n_minor        # Minor step
+
+            r.tick_side = "left" if r is yr else "right" # Tick side
+            r.tick_format = f".{dec}f"          # Label format, TODO this is invalid
+
+            if r.ticks is not None:
+                r.ticks.material.color = self.BLACK # Major ticks color
+
+            if r.points is not None:
+                r.points.material.color = self.BLACK # Major ticks color
+
+            if r.text is not None:
+                r.text.material.color = self.BLACK
+
+        if subplot.axes.grids:
+            gxy = subplot.axes.grids.xy
+            gxy.visible = True                  # Show the grid
+            gxy.axis_color = self.BLACK         # Axis color
+            gxy.major_color = self.BLACK        # Major grid color
+            gxy.minor_color = self.DARK_GRAY    # Minor grid color
+            gxy.major_thickness = 1.0           # Major grid thickness
+            gxy.minor_thickness = 0.5                # Minor grid thickness
+
+        subplot.axes.update_using_camera() # Update the axes with the new ticks
+
+    def animate(self):
+
+        # Increment phases (animate plots)
+        self.phase1 += 0.01  * self.INTERVAL
+        self.phase2 += 0.0101 * self.INTERVAL
+
+        # Generate the data
+
+        #   Line 1: sin(t+phase1) in-place
+        np.sin(self.t + self.phase1, out=self.buf1[:, 1])
+
+        #   Line 2: rand+1; since rand() has no `out` kwarg, write into buf2[:,1] by slicing:
+        self.buf2[:, 1] = np.random.rand(self.t.size).astype(np.float32) + 1.0
+
+        #   Line 3: sin(t+phase2)-1 in-place
+        np.sin(self.t + self.phase2, out=self.buf3[:, 1])
+        self.buf3[:, 1] -= 1.0
+
+        # Update the data in the plot lines
+        self.line1.data = self.buf1
+        self.line2.data = self.buf2
+        self.line3.data = self.buf3
+
+        # Update the axes
+        #self.updateAxesTicks(self.ax, self.MAJOR_TICKS, self.MINOR_TICKS)
+
+        # Redraw the figure
+        self.fig.canvas.request_draw()
+
+        # Benchmark number of segments per second
+        self.num_segments += 3 * self.t.size 
+
+        current_time = time.perf_counter()
+        if current_time - self.last_time >= 1.0:
+            print(f"Segments/s: {self.num_segments}, Segments/Frame: {3*self.t.size}, Frames/s: {1000/(self.INTERVAL):.2f}")
+            self.last_time = current_time
+            self.num_segments = 0
+
+    def closeEvent(self, ev):
+        fpl.loop.stop()
+        super().closeEvent(ev)
+
+
+if __name__ == "__main__":
+    app = QApplication(sys.argv)
+    # app.setStyle("Fusion")
+    # app.setStyleSheet("QWidget { background-color: white; }")
+    fpl.loop._app = app
+
+    win = FastPlotMain()
+    win.show()
+
+    sys.exit(app.exec())