feat: transitions component for slick UI's

Based on Vue's transitions

solara/components/__init__.py

@@ -55,6 +55,7 @@
 from .switch import Switch  # noqa: F401 F403
 from .progress import ProgressLinear  # noqa: F401 F403
 from .component_vue import _component_vue, component_vue  # noqa: F401 F403
+from .transition import Transition  # noqa: F401 F403
 import reacton.core
 
 try:

solara/components/_transitions.py

@@ -0,0 +1,49 @@
+import solara
+
+
+@solara.component
+def TransitionFlip(axis: str, show_first=True, children=[], duration=0.2):
+    uid = solara.use_unique_key()[:6]
+    name = f"rotate-{axis}-{uid}"
+    css_code = f"""
+.{name}-enter-active, .{name}-leave-active {{
+  transition: all {duration}s ease-out;
+  backface-visibility: hidden;
+}}
+
+.{name}-enter, .{name}-leave-to  {{
+  transform: rotate{axis}(90deg);
+}}
+.{name}-enter-to, .{name}-leave {{
+  transform: rotate{axis}(0deg);
+}}
+"""
+    solara.Style(css_code)
+    solara.Transition(show_first=show_first, name=name, duration=duration, children=children, mode="out-in")
+
+
+@solara.component
+def TransitionSlide(axis: str = "X", show_first=True, children=[], duration=0.2, translate_enter="50px", translate_leave="-50px"):
+    uid = solara.use_unique_key()[:6]
+    name = f"slide-{axis}-{uid}"
+    css_code = f"""
+.{name}-enter-active, .{name}-leave-active {{
+  transition: all {duration}s ease-out !important;
+}}
+
+.{name}-enter {{
+  transform: translate{axis}({translate_enter});
+  opacity: 0;
+}}
+
+.{name}-leave-to  {{
+  transform: translate{axis}({translate_leave});
+  opacity: 0;
+}}
+.{name}-enter-to, .{name}-leave {{
+  transform: translate{axis}(0px);
+}}
+"""
+    print("css", css_code)
+    solara.Style(css_code)
+    solara.Transition(show_first=show_first, name=name, duration=duration, children=children, mode="out-in")

solara/components/transition.py

@@ -0,0 +1,21 @@
+import solara
+from .component_vue import component_vue
+
+
+@solara.component
+def Transition(show_first=True, children=[], name="", mode="", duration=0.2):
+    """Transitions between two child elements with an animation.
+
+    These transitions are based on Vue's transition system.
+
+    * https://v2.vuejs.org/v2/guide/transitions
+    * https://vuejs.org/guide/built-ins/transition
+
+    """
+    # in Python land we like to work with seconds
+    return _Transition(show_first=show_first, children=children, name=name, mode=mode, duration=duration * 1000)
+
+
+@component_vue("transition.vue")
+def _Transition(show_first=True, children=[], name="", mode="", duration=200):
+    pass  # just a dummy function

solara/components/transition.vue

@@ -0,0 +1,6 @@
+<template>
+    <Transition :name="name" :mode="mode" :duration="duration">
+        <jupyter-widget v-if="show_first && children.length > 0" :widget="children[0]" key="first-widget"></jupyter-widget>
+        <jupyter-widget v-if="!show_first && children.length > 1" :widget="children[1]" key="second-widget"></jupyter-widget>
+    </Transition>
+</template>

solara/lab/__init__.py

@@ -4,6 +4,7 @@
 from ..lifecycle import on_kernel_start  # noqa: F401
 from ..tasks import task, use_task, Task, TaskResult  # noqa: F401, F403
 from ..toestand import computed  # noqa: F401
+from ..components._transitions import TransitionFlip, TransitionSlide  # noqa: F401
 
 
 def __getattr__(name):

solara/website/pages/documentation/examples/general/transitions.py

@@ -0,0 +1,63 @@
+# check out https://solara.dev/ for documentation
+# or https://github.com/widgetti/solara/
+# And check out https://py.cafe/maartenbreddels for more examples
+
+import solara
+import solara.lab
+
+
+clicks = solara.reactive(0)
+
+
+@solara.component
+def Page():
+    color = "green"
+    if clicks.value >= 5:
+        color = "red"
+
+    def increment():
+        clicks.value += 1
+
+    solara.Button(label=f"Clicked: {clicks}", on_click=increment, color=color)
+
+    with solara.lab.TransitionFlip("X", show_first=(clicks.value % 2) == 0, duration=0.2):
+        with solara.Card("Even") as el1:
+            solara.Text("This number is even")
+        with solara.Card("Odd") as el2:
+            solara.Text("This number is even")
+
+    with solara.Card("List"):
+        TodoItem("Write", True)
+        TodoItem("Read", False)
+
+    RemovableCard()
+    RemovableCard()
+    solara.v.use_event(el1, "click", lambda *_ignore: increment())
+    solara.v.use_event(el2, "click", lambda *_ignore: increment())
+
+
+@solara.component
+def RemovableCard():
+    show = solara.use_reactive(True)
+    with solara.lab.TransitionSlide("X", show_first=show.value, duration=0.5, translate_leave="100px"):
+        with solara.Card("Some report"):
+            with solara.Column():
+                solara.Text(
+                    "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
+                )
+                solara.Markdown("*Close the card to see it animate away*")
+            with solara.CardActions():
+                solara.v.Spacer()
+                solara.Button("Close", on_click=lambda: show.set(False), text=True)
+
+
+@solara.component
+def TodoItem(text, default_value):
+    done = solara.use_reactive(default_value)
+
+    with solara.Row(style={"overflow": "hidden"}):
+        solara.Switch(label=text, value=done)
+        solara.v.Spacer()
+
+        with solara.lab.TransitionSlide("X", show_first=done.value, duration=0.2):
+            solara.v.Icon(children=["mdi-check"], color="success")