Import of the watch repository from Pebble

src/fw/applib/ui/window_stack_animation.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "window.h"
+
+#include "applib/ui/animation.h"
+#include "applib/ui/layer.h"
+#include "applib/ui/property_animation_private.h"
+
+typedef struct WindowTransitioningContext WindowTransitioningContext;
+
+typedef Animation *(*WindowTransitionImplementationCreateAnimationFunc)(
+  WindowTransitioningContext *context);
+typedef void (*WindowTransitionImplementationRenderFunc)(WindowTransitioningContext *context,
+                                                         GContext *ctx);
+
+// NOTE: container layer not yet implemented - once there:
+// can assume
+//   context.window_from.layer.parent == context.container_layer &&
+//   context.window_from.layer.parent == context.container_layer
+// needs to
+//   create an animation that drives the visible transition
+//   (e.g. by moving context.window_to.layer.frame)
+//   call context.window_from.handlers.disappear and context.window_to.handers.appear et al.
+// doesn't need to
+//   restore context.window_from.layer.frame (framework will do that)
+// if no animation is returned by .create_animation, the windows will be replaced immediately
+typedef struct {
+  WindowTransitionImplementationCreateAnimationFunc create_animation;
+  WindowTransitionImplementationRenderFunc render;
+} WindowTransitionImplementation;
+
+typedef struct WindowTransitioningContext {
+  Layer *container_layer;
+  Window *window_from;
+  Window *window_to;
+  //! helper vars to patch dirty pixels in the framebuffer
+  int16_t window_from_last_x;
+  int16_t window_to_last_x;
+  //! provide backwards compatibility for 2.x apps that take window.frame during a transition
+  //! to position their UI elements
+  GPoint window_to_displacement;
+  //! Animation attached to the transitioning context
+  Animation *animation;
+  //! Window transition implementation
+  const WindowTransitionImplementation *implementation;
+} WindowTransitioningContext;
+
+const WindowTransitionImplementation *window_transition_get_default_push_implementation(void);
+const WindowTransitionImplementation *window_transition_get_default_pop_implementation(void);
+extern const WindowTransitionImplementation g_window_transition_none_implementation;
+
+void window_transition_context_appearance_call_all(WindowTransitioningContext *ctx);