Simplifies reactive UI logic.

app.py

@@ -10,6 +10,7 @@ Features:
 - Use of `gr.State()` for better use of progress bars.
 """
 import dataclasses
+import functools
 import json
 import logging
 import os
@@ -171,29 +172,17 @@ def create_app():
         prompts = gr.Textbox(label='Prompts (press Shift-ENTER to add a prompt)')
         with gr.Row():
 
-          values = {}
-
           family = gr.Dropdown(value='lit', choices=list(MODEL_MAP), label='Model family')
-          values['family'] = family.value
-
-          # Unfortunately below reactive UI code is a bit convoluted, because:
-          # 1. When e.g. `family.change()` updates `variant`, then that does not
-          #    trigger a `varaint.change()`.
-          # 2. The widget values like `family.value` are *not* updated when the
-          #    widget is updated. Therefore, we keep a manual copy in `values`.
 
-          def make_variant(family_value):
+          def make_variant(family_value, value=None):
             choices = list(MODEL_MAP[family_value])
-            values['variant'] = choices[0]
-            return gr.Dropdown(value=values['variant'], choices=choices, label='Variant')
-          variant = make_variant(family.value)
+            if value is None:
+              value = choices
+          make_variant = functools.partial(gr.Dropdown, label='Variant')
+          variant = make_variant(list(MODEL_MAP['lit']), value='B/16')
 
-          def make_res(family, variant):
-            choices = list(MODEL_MAP[family][variant])
-            values['res'] = choices[0]
-            return gr.Dropdown(value=values['res'], choices=choices, label='Resolution')
-          res = make_res(family.value, variant.value)
-          values['res'] = res.value
+          make_res = functools.partial(gr.Dropdown, label='Resolution')
+          res = make_res(list(MODEL_MAP['lit']['B/16']), value=224)
 
           def make_bias(family, variant, res):
             visible = family == 'siglip'
@@ -205,37 +194,28 @@ def create_app():
             }.get((family, variant, res), -10.0)
             return gr.Slider(value=value, minimum=-20, maximum=0, step=0.05, label='Bias', visible=visible)
           bias = make_bias(family.value, variant.value, res.value)
-          values['bias'] = bias.value
-
-          def family_changed(family):
-            variant = list(MODEL_MAP[family])[0]
-            res = list(MODEL_MAP[family][variant])[0]
-            values['family'] = family
-            values['variant'] = variant
-            values['res'] = res
-            return [
-                make_variant(family),
-                make_res(family, variant),
-                make_bias(family, variant, res),
-            ]
 
-          def variant_changed(variant):
-            res = list(MODEL_MAP[values['family']][variant])[0]
-            values['variant'] = variant
-            values['res'] = res
+          def update_inputs(family, variant, res):
+            d = MODEL_MAP[family]
+            variants = list(d)
+            variant = variant if variant in variants else variants[0]
+            d = d[variant]
+            ress = list(d)
+            res = res if res in ress else ress[0]
             return [
-                make_res(values['family'], variant),
-                make_bias(values['family'], variant, res),
+                make_variant(variants, value=variant),
+                make_res(ress, value=res),
+                make_bias(family, variant, res),
             ]
 
-          def res_changed(res):
-            return make_bias(values['family'], values['variant'], res)
-
-          family.change(family_changed, family, [variant, res, bias])
-          variant.change(variant_changed, variant, [res, bias])
-          res.change(res_changed, res, bias)
+          gr.on(
+            [family.change, variant.change, res.change],
+            update_inputs,
+            [family, variant, res],
+            [variant, res, bias],
+          )
 
-          # (end of code for reactive UI code)
+          # (end of code for reactive UI)
 
         run = gr.Button('Run')
         answers = [