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Midplane Designs

Image Annotator

Drop a PNG/JPG or use File → Open Image. Edits stay in this session; exports are flattened.

Session only
Global Settings

Changes apply immediately. Sizes are image pixels, independent of view zoom.

Instructions

Midplane Image Annotator · v3.1.3 · Open → Annotate → Export

Open and replace an image

Drop one PNG/JPG on the canvas or choose File → Open Image (Ctrl+O). Replacing session edits requires confirmation. Exports are flattened and cannot restore editable annotations.

Dimensions

Choose Dimension, click two fixed image anchors, then click to place the line. Auto chooses horizontal, vertical, aligned or a projected diagonal; Diagonal Auto and fixed orientations remain available. Enter the label manually. Drag the dimension line or its label independently; values are not automatic measurements.

Text and leaders

Choose Text. First click fixes the leader tip; cursor movement previews the text; second click places it and opens Object Settings. Escape cancels incomplete placement. Drag text without moving its tip. Side handles adjust wrapping width. The editor can disable the pointer or explicitly reset its anchor. Multiline content, justification, line spacing and optional backgrounds remain per object.

Ovals

Drag with Oval to create an outline; Shift constrains a circle. Click the outline to select, drag to move, use side/corner handles to resize in local axes, and drag the rotation handle to rotate. Shift snaps rotation15°. Hollow interiors do not select the shape.

Appearance and Object Settings

Click an annotation to edit it. Drag the editor header to move it; switching objects updates the open editor, and deselecting or closing hides it. Global Color and Global Size are on the toolbar. Global Settings holds font family/size, line width, head style/size, outside tail length and White Outline. Use Global restores each applicable inheritance; overrides show Custom. Global Size scales inherited and custom sizes without moving anchors. Ovals inherit twice global line width; custom widths stay independent. Line Opacity controls Oval stroke and halo; text background opacity stays separate. White Outline improves contrast and has global/individual ON/OFF controls.

Crop and expand canvas

Crop → Crop / expand canvas (Ctrl+Alt+C) opens a reversible preview. Drag body, edges or corners; choose a ratio or Freeform. Extending outside the photo adds white canvas. Apply or Enter on the canvas commits once; Cancel or Escape discards. Enter inside an input, menu, button or other interactive control does not trigger the crop shortcut. Reset Crop restores the full original photo and current expanded canvas.

Fit to Contents

Crop → Fit to Contents (Ctrl+Alt+F) proposes independent edges around meaningful visible image pixels and complete annotation footprints, even off-canvas. It can shrink and expand different edges together, adding10 image pixels of margin plus conservative raster/rounding allowance. Adjust the Freeform proposal before Apply. White/transparent margins trim; faint nonwhite pixels are retained, so JPEG noise can keep extra space. Prior photo cropping stays excluded during expansion; Reset Crop restores it. Blank compositions leave the crop unchanged.

Zoom, pan and menus

Wheel zooms at the cursor; middle-drag or Shift + left-drag pans. Zoom Out, Fit and Zoom In affect the view only. Hover File/Edit/Crop/Help to open/switch menus; leave the menu to close. Click/tap and keyboard operation remain available. Use menu arrow keys, Home/End, Enter and Escape. Narrow windows move toolbar groups into More.

Keyboard and history

Ctrl+O opens an image. Ctrl+Alt+C starts Crop / expand canvas. Ctrl+Alt+F starts Fit to Contents. Enter applies an active crop when focus is on the canvas/background; Escape cancels it. Ctrl+Z undoes; Ctrl+Y or Ctrl+Shift+Z redoes. Delete removes the selected object outside editable controls, or use Delete Selected in its editor. Shortcuts respect editable/native controls and open dialogs. View changes cancel active gestures coherently.

Export and session-only editing

File → Export PNG / Export JPG downloads full-resolution flattened pixels of the committed crop. Preview guides, selection handles and editor controls are omitted; view zoom does not affect resolution. JPG uses a white matte. Exports are limited to32767px per side and64MP. Work exists only in this browser session: no project saving, autosave or recovery. Confirm downloads before closing or replacing your image.

About

Original Midplane Designs logo

Midplane Image Annotator

v3.1.3

Midplane Image Annotator is a lightweight image annotation application developed by Midplane Designs. It allows users to add dimensions, text, leaders, and shapes to images, adjust the canvas, and export completed PNG or JPG files.

Midplane Designs · Sacramento, CA

www.midplanedesigns.com

Editing is session-only. Export your image before closing or refreshing this page.

Designed for Desktop

This app is designed for use on a desktop or laptop computer.