Gantt charts: todayMarker

简介 / Introduction

Gantt charts are a staple of project management, visualizing task schedules and progress. todayMarker draws a vertical line at the current date, making it immediately clear how each task lines up against “now”. This article covers both PlantUML and Mermaid implementations.

PlantUML 版

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@startgantt
scale 2
Project starts 2026-09-01

[Requirements] lasts 3 days
[System Design] lasts 2 days
[Implementation] lasts 5 days
[Testing] lasts 2 days

then [Deploy]

-- Launch Prep --
[Operations Docs] lasts 2 days
[User Training] lasts 1 days

yellow lasts 1 days
then [Launch Review]

today 42
@enduml

Notes:

• today 42 draws a red vertical line at the “today” position (day 42 from project start).
• PlantUML Gantt uses [Task] lasts N days to define duration.
• then chains tasks sequentially (starts after the previous one finishes).
• -- text -- creates a named separator between task groups.

Mermaid 版

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gantt
    title Project Milestones
    dateFormat YYYY-MM-DD
    axisFormat  %m-%d

    section Design
    Requirements Analysis :done,    des1, 2026-09-01, 3d
    System Design         :active,  des2, after des1, 2d

    section Development
    Implementation        :         dev1, after des2, 5d
    Testing               :         test1, after dev1, 2d

    section Launch
    Deployment            :         launch, after test1, 1d

    todayMarker

Notes:

• Mermaid’s todayMarker keyword draws a blue dashed line at “today” (relative to the current system date when rendered).
• dateFormat defines input parsing; axisFormat controls the tick labels on the X axis.
• done / active keywords indicate task state (completed / in-progress).
• section groups tasks into named phases.

对比 / Side-by-side

小结 / Wrap-up

PlantUML’s today N marker is customizable in color and position, ideal when you need a prominent “today” callout. Mermaid’s todayMarker is a zero-config keyword that works out of the box, perfect for docs embedded in GitHub READMEs or wikis. Both let the team see at a glance where the project stands relative to the current moment — pick the one that fits your toolchain.