fastplotlib · FlynnOConnell · Dec 14, 2025 · Dec 14, 2025 · Dec 14, 2025 · Dec 14, 2025
@@ -14,6 +14,7 @@
 from ._figure import Figure
 from ..ui import EdgeWindow, SubplotToolbar, StandardRightClickMenu, Popup, GUI_EDGES
 from ..ui import ColormapPicker
+from ..ui._base import COLLAPSE_BUTTON_WIDTH
 
 
 class ImguiFigure(Figure):
@@ -213,7 +214,10 @@ def get_pygfx_render_area(self, *args) -> tuple[int, int, int, int]:
 
         for edge in ["right"]:
             if self.guis[edge]:
-                width -= self._guis[edge].size
+                # when collapsed, the expand button floats over plot area
+                if not self._guis[edge].collapsed:
+                    # subtract gui size plus collapse button width
+                    width -= self._guis[edge].size + COLLAPSE_BUTTON_WIDTH
 
         for edge in ["bottom"]:
             if self.guis[edge]:

@@ -2,11 +2,15 @@
 from typing import Literal
 import numpy as np
 
-from imgui_bundle import imgui
+from imgui_bundle import imgui, icons_fontawesome_6 as fa
 
 from ..layouts._figure import Figure
 
 
+# width of the collapse/expand button
+COLLAPSE_BUTTON_WIDTH = 12
+
+
 GUI_EDGES = ["right", "bottom"]
 
 
@@ -111,6 +115,10 @@ def __init__(
         self._title = title
         self._window_flags = window_flags
 
+        # collapse state for right-side GUI panels
+        # TODO: other sides when they're supported
+        self._collapsed = False
+
         self._x, self._y, self._width, self._height = self.get_rect()
 
         self._figure.canvas.add_event_handler(self._set_rect, "resize")
@@ -151,6 +159,20 @@ def height(self) -> int:
         """height of the window"""
         return self._height
 
+    @property
+    def collapsed(self) -> bool:
+        """whether the window is collapsed, only applicable to right-side GUI"""
+        return self._collapsed
+
+    @collapsed.setter
+    def collapsed(self, value: bool):
+        # TODO: support other edges when needed
+        if self._location != "right":
+            return
+
+        self._collapsed = bool(value)
+        self._set_rect()
+
     def _set_rect(self, *args):
         self._x, self._y, self._width, self._height = self.get_rect()
 
@@ -174,6 +196,7 @@ def get_rect(self) -> tuple[int, int, int, int]:
                 width, height = (width_canvas, self.size)
 
             case "right":
+                # GUI panel starts after the collapse button area
                 x_pos, y_pos = (width_canvas - self.size, 0)
                 width, height = (self.size, height_canvas)
 
@@ -184,12 +207,17 @@ def get_rect(self) -> tuple[int, int, int, int]:
 
     def draw_window(self):
         """helps simplify using imgui by managing window creation & position, and pushing/popping the ID"""
+        if self._location == "right" and self._collapsed:
+            self._draw_expand_button()
+            return
+
+        if self._location == "right":
+            self._draw_collapse_button()
+
         # window position & size
         x, y, w, h = self.get_rect()
         imgui.set_next_window_size((self.width, self.height))
         imgui.set_next_window_pos((self.x, self.y))
-        # imgui.set_next_window_pos((x, y))
-        # imgui.set_next_window_size((w, h))
         flags = self._window_flags
 
         # begin window
@@ -207,6 +235,102 @@ def draw_window(self):
         # end the window
         imgui.end()
 
+    def _draw_collapse_button(self):
+        """draw collapse button in the reserved area between plot and GUI panel"""
+        width_canvas, height_canvas = self._figure.canvas.get_logical_size()
+
+        # account for bottom GUI if present
+        if self._figure.guis["bottom"] is not None:
+            height_canvas -= self._figure.guis["bottom"].size
+
+        x_pos = width_canvas - self._size - COLLAPSE_BUTTON_WIDTH
+        y_pos = 0
+
+        # remove all window padding so position is exact
+        imgui.push_style_var(imgui.StyleVar_.window_padding, (0, 0))
+
+        imgui.set_next_window_pos((x_pos, y_pos))
+        imgui.set_next_window_size((COLLAPSE_BUTTON_WIDTH, height_canvas))
+
+        flags = (
+            imgui.WindowFlags_.no_title_bar
+            | imgui.WindowFlags_.no_resize
+            | imgui.WindowFlags_.no_move
+            | imgui.WindowFlags_.no_scrollbar
+            | imgui.WindowFlags_.no_collapse
+            | imgui.WindowFlags_.no_background
+        )
+
+        imgui.begin(f"collapse-{self._title}", p_open=None, flags=flags)
+        imgui.push_id(self._id_counter + 1000)
+
+        # transparent button, visible on hover
+        imgui.push_style_color(imgui.Col_.button, (0, 0, 0, 0))
+        imgui.push_style_color(imgui.Col_.button_hovered, (0.5, 0.5, 0.5, 0.5))
+        imgui.push_style_color(imgui.Col_.button_active, (0.6, 0.6, 0.6, 0.6))
+
+        if imgui.button(fa.ICON_FA_CARET_RIGHT, (COLLAPSE_BUTTON_WIDTH, height_canvas)):
+            self._collapsed = True
+            self._set_rect()
+            self._figure._fpl_reset_layout()
+
+        imgui.pop_style_color(3)
+
+        if imgui.is_item_hovered(0):
+            imgui.set_tooltip("collapse")
+
+        imgui.pop_id()
+        imgui.end()
+        imgui.pop_style_var(1)  # window_padding
+
+    def _draw_expand_button(self):
+        """draw expand button at right edge when collapsed"""
+        width_canvas, height_canvas = self._figure.canvas.get_logical_size()
+
+        # account for bottom GUI if present
+        if self._figure.guis["bottom"] is not None:
+            height_canvas -= self._figure.guis["bottom"].size
+
+        x_pos = width_canvas - COLLAPSE_BUTTON_WIDTH
+        y_pos = 0
+
+        # remove all window padding so position is exact
+        imgui.push_style_var(imgui.StyleVar_.window_padding, (0, 0))
+
+        imgui.set_next_window_pos((x_pos, y_pos))
+        imgui.set_next_window_size((COLLAPSE_BUTTON_WIDTH, height_canvas))
+
+        flags = (
+            imgui.WindowFlags_.no_title_bar
+            | imgui.WindowFlags_.no_resize
+            | imgui.WindowFlags_.no_move
+            | imgui.WindowFlags_.no_scrollbar
+            | imgui.WindowFlags_.no_collapse
+            | imgui.WindowFlags_.no_background
+        )
+
+        imgui.begin(f"expand-{self._title}", p_open=None, flags=flags)
+        imgui.push_id(self._id_counter)
+
+        # visible button - needs to stand out when panel is collapsed
+        imgui.push_style_color(imgui.Col_.button, (0.4, 0.4, 0.4, 0.9))
+        imgui.push_style_color(imgui.Col_.button_hovered, (0.5, 0.5, 0.5, 1.0))
+        imgui.push_style_color(imgui.Col_.button_active, (0.6, 0.6, 0.6, 1.0))
+
+        if imgui.button(fa.ICON_FA_CARET_LEFT, (COLLAPSE_BUTTON_WIDTH, height_canvas)):
+            self._collapsed = False
+            self._set_rect()
+            self._figure._fpl_reset_layout()
+
+        imgui.pop_style_color(3)
+
+        if imgui.is_item_hovered(0):
+            imgui.set_tooltip("expand")
+
+        imgui.pop_id()
+        imgui.end()
+        imgui.pop_style_var(1)  # window_padding
+
     def update(self):
         """Implement your GUI here and it will be drawn within the window. See the GUI examples"""
         raise NotImplementedError