📊 可视化日期区间Visualize Date Intervals
把每行“起始 结束”日期区间画成甘特图（按开始日期定位、长度按天数），带日期刻度和图例，可下载 SVG/PNG，最多 200 个。本地处理。Draw date intervals (start end per line) as a Gantt chart positioned by start date with length proportional to days, a date axis and a legend; download as SVG or PNG; up to 200 items. Processed locally.
使用说明与常见问题How-to & FAQ
「可视化日期区间」是什么？What is the Visualize Date Intervals tool?
把每行“起始 结束”日期区间画成甘特图（按开始日期定位、长度按天数），带日期刻度和图例，可下载 SVG/PNG，最多 200 个。本地处理。Draw date intervals (start end per line) as a Gantt chart positioned by start date with length proportional to days, a date axis and a legend; download as SVG or PNG; up to 200 items. Processed locally.
如何使用「可视化日期区间」？How do I use the Visualize Date Intervals tool?
每行输入一个区间“开始日期 结束日期”，下方即显示列表和甘特图；用“下载 SVG”或“下载 PNG”保存图片。Enter one interval per line as start date and end date to get a list and a Gantt chart below; use Download SVG or Download PNG to save the chart.
图是怎么画的？How is the chart drawn?
每个区间一行横条：条的起点对应开始日期，长度与天数成正比（含首尾两天），上方是日期刻度轴，下方有图例；鼠标悬停可看到区间和天数。全部在浏览器内用 SVG 绘制，不使用外部库。One horizontal bar per interval: the bar starts at the start date and its length is proportional to the number of days (both ends included). A date axis with ticks runs along the top and a legend sits below; hover a bar to see its interval and length. Everything is drawn as SVG in your browser without external libraries.
可以下载图片吗？Can I download the chart?
可以，点击“下载 SVG”得到矢量图，点击“下载 PNG”得到 2 倍分辨率的位图。Yes. Download SVG gives a vector file and Download PNG a bitmap at twice the screen resolution.
最多画多少个区间？How many intervals can it draw?
最多 200 个；超过时只画前 200 个并在结果下方提示总数。Up to 200; beyond that the first 200 are drawn and a note below the result gives the total.
某一行格式不对会怎样？What happens when a line is invalid?
其余有效的行照常处理；无效的行（包括末尾多出内容的行，如“2020-01-01 2020-01-05 junk”）不进入结果，并在结果下方用红字列出行号和原因。所有行都无效时显示“未处理任何内容”和前几条错误。The valid lines are processed as usual. Invalid lines, including lines with extra text such as "2020-01-01 2020-01-05 junk", are left out and listed in red below the result with their line numbers and reasons. If no line is valid you get "nothing was processed" with the first errors.
结束日期可以早于开始日期吗？Can the end date be before the start date?
不可以，这样的行会被列为错误。开始和结束可以是同一天（长度 1 天，两端都计入）。No, such a line is listed as an error. Start and end may be the same day (1 day long, both ends count).
用的是哪种历法、支持哪些年份？Which calendar and years are supported?
按外推格里高利历（现行公历规则向前沿用）计算，年份为 0001–9999，输出一律为 4 位年份的 YYYY-MM-DD。1582-10-05 至 1582-10-14 在 1582 年改历的国家并不存在，这里仍按外推格里高利历处理。The proleptic Gregorian calendar (today's rules applied backwards) for years 0001 to 9999, always written as YYYY-MM-DD with a 4-digit year. 1582-10-05 to 1582-10-14 never happened in countries that switched calendars in 1582; they are still handled on the proleptic Gregorian calendar here.
和时区有关吗？Do time zones matter?
无关。「可视化日期区间」只做时长或日期格式的换算，不读取设备时间，时区和夏令时不影响结果。No. The Visualize Date Intervals tool only converts durations or date formats and never reads the device clock, so time zones and daylight saving time do not affect the result.
「可视化日期区间」免费吗？需要注册吗？Is the Visualize Date Intervals tool free? Do I need an account?
「可视化日期区间」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 Visualize Date Intervals tool is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.