Documentation

ToScale v1.0 — Complete Reference

Getting Started

ToScale is a browser-based precision print tool. It lets you place images on a virtual sheet of paper at exact real-world sizes, then export a print-ready PDF. When you print that PDF at 100% scale, your image will be exactly the size you set.

The interface has three main sections: the left sidebar for paper and canvas settings, the canvas in the centre for visual editing, and the right sidebar for layer management and properties.

Uploading Images

Drag one or more image files into the upload zone in the left sidebar, or click it to browse your files. Supported formats are PNG, JPG, WEBP, and SVG. You can upload multiple files at once — each becomes its own layer.

Each uploaded image is added to the top of the layer stack and automatically sized to a sensible default within the paper bounds.

Image quality

For print quality, aim for source images with a resolution of at least 300 pixels per inch at your intended print size. The Layer Info panel in the right sidebar shows the effective print DPI of the selected layer — it turns amber below 150 dpi and red below 72 dpi.

Paper Settings

Choose your paper size from the preset grid in the left sidebar. Available presets are:

• A-series: A3 (297×420mm), A4 (210×297mm), A5 (148×210mm), A6 (105×148mm)
• US sizes: Letter (8.5×11"), Legal (8.5×14"), Tabloid (11×17")
• Photo: 4×6" (101.6×152.4mm)
• Custom: Enter any dimensions in your chosen unit

Toggle between Portrait and Landscape orientation using the buttons below the preset grid. This swaps the width and height of the paper.

Unit System

Switch between mm, cm, and in using the unit tabs. All dimension inputs, ruler labels, and status bar readings update to the selected unit immediately.

Layers

Every image you upload becomes a layer. Layers are shown in the right sidebar from top to bottom (topmost layer is drawn last, appearing above others). Click a layer to select it.

Each layer item shows a thumbnail preview and the source image resolution. Layer controls:

• 👁 Eye icon — toggle layer visibility
• ↑ / ↓ — move layer forward or backward in the stack
• × — delete the layer

Click + Add Image at the bottom of the layer list to upload another image.

Position & Size

With a layer selected, the X and Y fields in the Properties panel set the layer's position. X is the distance from the left edge of the paper to the left edge of the image; Y is the distance from the top edge of the paper to the top edge of the image.

W and H set the print width and height. All values are in your chosen unit. You can type any value directly — press Tab to confirm and move to the next field. Enable Lock aspect ratio to maintain proportions when resizing.

You can also drag layers directly on the canvas. With Snap to Grid (🧲) enabled, positions snap to the grid spacing.

Fit Modes

Contain — the image is scaled to fit entirely within the W×H box, maintaining its aspect ratio. Gaps may appear if the image ratio differs from the box ratio.

Cover — the image is scaled to fill the entire W×H box, maintaining aspect ratio. Parts of the image may be cropped.

Stretch — the image is forced to fill the W×H box exactly, ignoring aspect ratio. Use this for templates where the image must be a precise size.

Adjustments

Each layer has per-layer adjustments in the Properties panel. All adjustments are visible live in the canvas preview.

• Opacity — 0% (invisible) to 100% (fully opaque)
• Rotation — −180° to +180°. The layer rotates around its centre point
• Brightness — 0% (black) to 200% (double brightness)
• Contrast — 0% to 200%
• Saturation — 0% (greyscale) to 200%
• Greyscale — toggle to convert to greyscale
• Flip H / Flip V — mirror the image horizontally or vertically

Every adjustment has both a slider and a number input. You can type exact values directly into the number inputs.

Rulers & Grid

The rulers on the top and left edges of the canvas are calibrated to the paper size in your current unit. They update when you change units, zoom, or switch paper size.

The rulers show a green cursor line tracking your mouse position, and an amber band showing the extent of the selected layer on that axis.

The status bar below the toolbar shows your cursor's X and Y coordinates in real-world units in real time, as well as the selected layer's name and size.

The grid can be toggled, its opacity adjusted, and its spacing changed from the left sidebar. With Snap to Grid enabled, dragging snaps to grid intersections.

Sessions

Click 💾 Save Session in the toolbar or export panel to save your entire workspace — all layers, positions, sizes, adjustments, paper settings, and unit preferences — to a .toscale file on your device.

Click 📂 Load Session and select a .toscale file to restore your workspace exactly as it was. All image data is embedded in the session file, so you don't need the original image files.

Session files are plain JSON and can be opened in any text editor, though editing them manually is not recommended.

Exporting

Use the export panel in the right sidebar to download your work.

⬇ Download PDF — generates a PDF at the selected DPI with your images embedded. This is the recommended format for printing.

⬇ Download PNG — exports a flat PNG raster at the selected DPI. Useful for digital use or importing into other tools.

Resolution options: 72 dpi (screen), 150 dpi (draft), 300 dpi (print), 600 dpi (high quality).

Printing

The golden rule: always print at 100% / Actual Size. Never use "Fit to Page", "Shrink to Printable Area", or any auto-scaling option. These will change the size of your image and break the precision you set in ToScale.

See the Download page for step-by-step instructions for Chrome, Edge, Firefox, and Adobe Acrobat.

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