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import type { TimelineTrack } from "@/types/timeline";
import type { MediaFile } from "@/types/media";
import { videoCache } from "./video-cache";
export interface RenderContext {
ctx: CanvasRenderingContext2D;
time: number;
canvasWidth: number;
canvasHeight: number;
tracks: TimelineTrack[];
mediaFiles: MediaFile[];
backgroundColor?: string;
projectCanvasSize?: { width: number; height: number };
}
export async function renderTimelineFrame({
ctx,
time,
canvasWidth,
canvasHeight,
tracks,
mediaFiles,
backgroundColor,
projectCanvasSize,
}: RenderContext): Promise<void> {
// Background
ctx.clearRect(0, 0, canvasWidth, canvasHeight);
if (backgroundColor && backgroundColor !== "transparent") {
ctx.fillStyle = backgroundColor;
ctx.fillRect(0, 0, canvasWidth, canvasHeight);
}
const scaleX = projectCanvasSize ? canvasWidth / projectCanvasSize.width : 1;
const scaleY = projectCanvasSize
? canvasHeight / projectCanvasSize.height
: 1;
const idToMedia = new Map(mediaFiles.map((m) => [m.id, m] as const));
const active: Array<{
track: TimelineTrack;
element: TimelineTrack["elements"][number];
mediaItem: MediaFile | null;
}> = [];
for (let t = tracks.length - 1; t >= 0; t -= 1) {
const track = tracks[t];
for (const element of track.elements) {
if ((element as any).hidden) continue;
const elementStart = element.startTime;
const elementEnd =
element.startTime +
(element.duration - element.trimStart - element.trimEnd);
if (time >= elementStart && time < elementEnd) {
let mediaItem: MediaFile | null = null;
if (element.type === "media") {
mediaItem =
element.mediaId === "test"
? null
: idToMedia.get(element.mediaId) || null;
}
active.push({ track, element, mediaItem });
}
}
}
for (const { element, mediaItem } of active) {
if (element.type === "media" && mediaItem) {
if (mediaItem.type === "video") {
try {
const localTime = time - element.startTime + element.trimStart;
const frame = await videoCache.getFrameAt(
mediaItem.id,
mediaItem.file,
localTime
);
if (!frame) continue;
const mediaW = Math.max(1, mediaItem.width || canvasWidth);
const mediaH = Math.max(1, mediaItem.height || canvasHeight);
const containScale = Math.min(
canvasWidth / mediaW,
canvasHeight / mediaH
);
const drawW = mediaW * containScale;
const drawH = mediaH * containScale;
const drawX = (canvasWidth - drawW) / 2;
const drawY = (canvasHeight - drawH) / 2;
ctx.drawImage(frame.canvas, drawX, drawY, drawW, drawH);
} catch (error) {
console.warn(
`Failed to render video frame for ${mediaItem.name}:`,
error
);
}
}
if (mediaItem.type === "image") {
const img = new Image();
await new Promise<void>((resolve, reject) => {
img.onload = () => resolve();
img.onerror = () => reject(new Error("Image load failed"));
img.src = mediaItem.url || URL.createObjectURL(mediaItem.file);
});
const mediaW = Math.max(
1,
mediaItem.width || img.naturalWidth || canvasWidth
);
const mediaH = Math.max(
1,
mediaItem.height || img.naturalHeight || canvasHeight
);
const containScale = Math.min(
canvasWidth / mediaW,
canvasHeight / mediaH
);
const drawW = mediaW * containScale;
const drawH = mediaH * containScale;
const drawX = (canvasWidth - drawW) / 2;
const drawY = (canvasHeight - drawH) / 2;
ctx.drawImage(img, drawX, drawY, drawW, drawH);
}
}
if (element.type === "text") {
const posX = canvasWidth / 2 + (element as any).x * scaleX;
const posY = canvasHeight / 2 + (element as any).y * scaleY;
ctx.save();
ctx.translate(posX, posY);
ctx.rotate(((element as any).rotation * Math.PI) / 180);
ctx.globalAlpha = Math.max(0, Math.min(1, (element as any).opacity));
const px = (element as any).fontSize * scaleX;
const weight = (element as any).fontWeight === "bold" ? "bold " : "";
const style = (element as any).fontStyle === "italic" ? "italic " : "";
ctx.font = `${style}${weight}${px}px ${(element as any).fontFamily}`;
ctx.fillStyle = (element as any).color;
ctx.textAlign = (element as any).textAlign;
ctx.textBaseline = "middle";
const metrics = ctx.measureText((element as any).content);
const ascent =
(metrics as unknown as { actualBoundingBoxAscent?: number })
.actualBoundingBoxAscent ?? px * 0.8;
const descent =
(metrics as unknown as { actualBoundingBoxDescent?: number })
.actualBoundingBoxDescent ?? px * 0.2;
const textW = metrics.width;
const textH = ascent + descent;
const padX = 8 * scaleX;
const padY = 4 * scaleX;
if ((element as any).backgroundColor) {
ctx.save();
ctx.fillStyle = (element as any).backgroundColor;
let bgLeft = -textW / 2;
if (ctx.textAlign === "left") bgLeft = 0;
if (ctx.textAlign === "right") bgLeft = -textW;
ctx.fillRect(
bgLeft - padX,
-textH / 2 - padY,
textW + padX * 2,
textH + padY * 2
);
ctx.restore();
}
ctx.fillText((element as any).content, 0, 0);
ctx.restore();
}
}
}
|
