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|
import type { ParamValues } from "@/params";
import { clamp } from "@/utils/math";
import { TICKS_PER_SECOND } from "@/wasm";
import type { Transform } from "./index";
export type TransitionKind =
| "fade"
| "push-left"
| "push-right"
| "zoom"
| "zoom-out"
| "spin";
export interface VisualTransition {
kind: TransitionKind;
inDuration: number;
outDuration: number;
}
export interface TransitionState {
opacityMultiplier: number;
transform: Transform;
}
export const TRANSITION_KIND_OPTIONS: Array<{
value: TransitionKind;
label: string;
}> = [
{ value: "fade", label: "Soft fade" },
{ value: "push-left", label: "Slide left" },
{ value: "push-right", label: "Slide right" },
{ value: "zoom", label: "Zoom in" },
{ value: "zoom-out", label: "Zoom out" },
{ value: "spin", label: "Spin dissolve" },
];
export function isTransitionKind(value: string): value is TransitionKind {
return TRANSITION_KIND_OPTIONS.some((option) => option.value === value);
}
export function withVisualTransitionParams({
params,
transitionKind,
inDuration,
outDuration,
}: {
params: ParamValues;
transitionKind: TransitionKind;
inDuration: number;
outDuration: number;
}): ParamValues {
return {
...params,
"transition.kind": transitionKind,
"transition.inDuration": inDuration,
"transition.outDuration": outDuration,
};
}
export function buildTransitionFromParams({
params,
}: {
params: ParamValues;
}): VisualTransition {
const kindValue = params["transition.kind"];
const inDurationValue = params["transition.inDuration"];
const outDurationValue = params["transition.outDuration"];
return {
kind:
typeof kindValue === "string" && isTransitionKind(kindValue)
? kindValue
: "fade",
inDuration: readDuration({ value: inDurationValue }),
outDuration: readDuration({ value: outDurationValue }),
};
}
export function applyVisualTransition({
baseTransform,
transition,
localTime,
duration,
canvasWidth,
}: {
baseTransform: Transform;
transition?: VisualTransition;
localTime: number;
duration: number;
canvasWidth: number;
}): TransitionState {
if (!transition || duration <= 0) {
return { opacityMultiplier: 1, transform: baseTransform };
}
const inProgress = progressWithin({
elapsed: localTime,
duration: transition.inDuration,
});
const outProgress = progressWithin({
elapsed: duration - localTime,
duration: transition.outDuration,
});
const progress = Math.min(inProgress, outProgress);
const isSlide =
transition.kind === "push-left" || transition.kind === "push-right";
const opacityMultiplier = isSlide ? 1 : ease({ progress });
const transform = applyTransitionTransform({
transform: baseTransform,
transition,
inProgress,
outProgress,
canvasWidth,
});
return { opacityMultiplier, transform };
}
function readDuration({ value }: { value: unknown }): number {
const seconds =
typeof value === "number" && Number.isFinite(value)
? clamp({ value, min: 0, max: 5 })
: 0;
return seconds * TICKS_PER_SECOND;
}
function progressWithin({
elapsed,
duration,
}: {
elapsed: number;
duration: number;
}): number {
if (duration <= 0) {
return 1;
}
return clamp({ value: elapsed / duration, min: 0, max: 1 });
}
function ease({ progress }: { progress: number }): number {
return progress * progress * (3 - 2 * progress);
}
function applyTransitionTransform({
transform,
transition,
inProgress,
outProgress,
canvasWidth,
}: {
transform: Transform;
transition: VisualTransition;
inProgress: number;
outProgress: number;
canvasWidth: number;
}): Transform {
if (transition.kind === "fade") {
return transform;
}
if (transition.kind === "zoom" || transition.kind === "zoom-out") {
const progress = Math.min(inProgress, outProgress);
const eased = ease({ progress });
const scale =
transition.kind === "zoom" ? 0.96 + eased * 0.04 : 1.04 - eased * 0.04;
return {
...transform,
scaleX: transform.scaleX * scale,
scaleY: transform.scaleY * scale,
};
}
if (transition.kind === "spin") {
const progress = Math.min(inProgress, outProgress);
const eased = ease({ progress });
const scale = 0.96 + eased * 0.04;
return {
...transform,
scaleX: transform.scaleX * scale,
scaleY: transform.scaleY * scale,
rotate: transform.rotate - (1 - eased) * 6,
};
}
const direction = transition.kind === "push-right" ? -1 : 1;
const enteringOffset =
(1 - ease({ progress: inProgress })) * canvasWidth * direction;
const leavingOffset =
(ease({ progress: outProgress }) - 1) * canvasWidth * direction;
return {
...transform,
position: {
x: transform.position.x + enteringOffset + leavingOffset,
y: transform.position.y,
},
};
}
|
