✏️ 图片描边（贴纸白边 / 轮廓线）Add Stroke to Image (Outline)

使用说明与常见问题How-to & FAQ

「图片描边（贴纸白边 / 轮廓线）」是什么？What is the Add Stroke to Image (Outline) tool?

沿着透明 PNG 中主体的形状加一圈描边：可设宽度、颜色，描在外侧（贴纸白边效果）或内侧，按真实距离计算，转角圆润、边缘抗锯齿；外描边会自动扩大画布，不会被裁掉。适合给抠图、Logo、表情包和贴纸加轮廓，支持批量，图片只在浏览器本地处理。Add a stroke that follows the shape of the subject in a transparent PNG. Set the width and colour and draw it outside (the classic sticker border) or inside. Distances are computed exactly, so corners are smoothly rounded and edges anti-aliased, and an outside stroke enlarges the canvas so nothing is cut off. Great for cut-outs, logos, emoji and stickers. Works in bulk, locally in your browser.

如何使用「图片描边（贴纸白边 / 轮廓线）」？How do I use the Add Stroke to Image (Outline) tool?

在「图片描边（贴纸白边 / 轮廓线）」中，选择或拖入文件，按需设置「描边宽度」、「颜色」、「位置」、「输出格式」等选项，然后点击每个结果旁的「下载」按钮即可；有多个文件时也可以点「全部下载（ZIP）」一次打包下载。In the Add Stroke to Image (Outline): Choose or drop your files, set "Stroke width", "Colour", "Position", "Format", then click the Download button next to each result (with several files, "Download all (ZIP)" saves them together).

描边是怎么计算的？How is the stroke calculated?

先找出图片中不透明的区域（透明度 50% 以上的像素），再用精确的欧几里得距离变换算出每个像素离主体边缘有多远，距离在描边宽度以内的就画上描边颜色，最外一圈按距离做抗锯齿。所以描边宽度处处一致，尖角会变成自然的圆角，和贴纸、表情包常见的白边一样。The opaque part of the image (pixels more than 50% opaque) is found first, then an exact Euclidean distance transform works out how far every pixel is from the subject's edge. Pixels within the stroke width get the stroke colour, and the outermost ring is anti-aliased by distance. That keeps the width even everywhere and turns sharp corners into natural rounded ones, just like the white border on stickers and emoji.

外侧和内侧描边有什么区别？What's the difference between outside and inside?

外侧描边画在主体外面，主体本身不变，画布会自动向四周扩大描边宽度，避免被裁掉（也可以取消勾选保持原尺寸）。内侧描边画在主体边缘以内，覆盖主体最外面一圈，图片尺寸不变，适合不想让图片变大的场合。An outside stroke goes around the subject without covering it, and the canvas grows by the stroke width on every side so nothing is cut off (untick the option to keep the original size). An inside stroke is drawn inside the subject's edge, covering its outermost ring, and the image size stays the same.

为什么我的照片只描了一个方框？Why does my photo only get a rectangle?

描边沿着透明区域和不透明区域的分界线画。普通 JPG 照片没有透明背景，整张图都是“主体”，所以只能沿矩形外框描边，结果旁会提示。请先用抠图工具去掉背景，得到透明背景的 PNG，再来描边。The stroke follows the boundary between transparent and opaque areas. An ordinary JPG photo has no transparent background, so the whole picture counts as the subject and the stroke can only follow its rectangular edge — the result row says so. Remove the background first to get a transparent PNG, then add the stroke.

有哪些选项可以调整？What options can I adjust?

「图片描边（贴纸白边 / 轮廓线）」的设置：「描边宽度」默认 8，范围 1–100；「颜色」默认 #ffffff；「位置」可选 外侧（贴纸效果）、内侧（默认 外侧（贴纸效果））；「输出格式」可选 PNG、WebP（默认 PNG）；「质量」默认 92，范围 40–100；可勾选：「扩大画布以容纳外描边」（默认勾选）；可选文件：常见图片格式（含 HEIC、HEIF、AVIF、WEBP、BMP、JFIF）。改动任一选项后结果会按新设置重新生成。Settings in the Add Stroke to Image (Outline) — "Stroke width" default 8, range 1–100; "Colour" default #ffffff; "Position": Outside, Inside (default Outside); "Format": PNG, WebP (default PNG); "Quality" default 92, range 40–100; tick boxes: "Enlarge canvas for an outside stroke" (on by default); files: common image formats (including HEIC, HEIF, AVIF, WEBP, BMP, JFIF). Changing any option regenerates the result with the new setting.

图片会被上传到服务器吗？Are my images uploaded?

不会。「图片描边（贴纸白边 / 轮廓线）」使用浏览器 Canvas 在本地处理图片，处理后的文件直接从你的浏览器下载。No. The Add Stroke to Image (Outline) processes images locally with the browser Canvas API and the result downloads straight from your browser.

「图片描边（贴纸白边 / 轮廓线）」免费吗？需要注册吗？Is the Add Stroke to Image (Outline) free? Do I need an account?

「图片描边（贴纸白边 / 轮廓线）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Add Stroke to Image (Outline) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.