Live Measurement
Measure the feature you intend to change before editing it. FontLab provides a dragged measurement line, pointer-following Quick Measurement, and automatically placed AutoMeter values. Each answers a different question about the same outline.
The Guides Tool
Select Guides in the Toolbar or press G. Hold G for temporary measuring access from another tool, then release it to return. Use a normal tap when you want to keep the tool active.
Drag from the first point to the second to measure. The property bar reports the origin's x and y coordinates, the horizontal and vertical differences, the angle, and the straight-line length. Delta x and delta y are the coordinate differences; Length is the distance along the measurement vector. Neither is the length of a curved outline between those positions.
Hold Shift for a horizontal or vertical measurement. Hold Control to suppress snap attraction when you need to choose the endpoints freely. On macOS, use Control rather than Command.
For an angle between two directions, begin the first measuring vector, then hold Option/Alt during the drag to establish the second. Read the angle between the vectors. Start with an ordinary measurement drag before adding the modifier: beginning a different Guides-tool gesture with a modifier can create an object instead.
Inspect automatic readouts
Guides mode also exposes useful reference lines and measurements. Hover over nodes and handles to inspect segment and handle lengths, and inspect curve tension where the relevant overlay is enabled. Tension is a proportion of handle extension; it is not a physical distance.
Font guides, glyph guides, and dimension lines are made available for reference in this mode. If you want the same measurement overlays while editing with another tool, use the corresponding View-panel or Glyph Window preference controls.
The Coordinates, Lengths & angles, and Scoreboard displays introduced in Selecting and the Contour Tool are useful companions. The Scoreboard gives a large readout; it does not change which two points a measuring gesture compares.
Quick Measurement
Enable View > Measurements > Quick Measurement, or use the View panel or Measurements-widget button. Move the pointer across the glyph to see distances between nearby paths without drawing a measurement line.
Under Preferences > Glyph Window > Quick measurement, choose when readings appear:
- on fill concentrates on positions inside a filled region.
- on outline concentrates on positions near its edge.
- everywhere also permits readings outside the filled drawing.
FontLab chooses a nearby pair of paths. Check the displayed endpoints so you know what is being measured; a complex counter or overlapping construction can offer more than one plausible pair.
Choose a direction and precision
Hold Shift to favor horizontal or vertical measurement. Shift+Option/Alt requests the horizontal direction; Shift+Control requests the vertical direction. The vertical measurement can follow the current slant setup, so compare it with an upright measurement when diagnosing italic geometry.
Set the displayed precision to integers, one decimal place, or two decimal places as needed. A decimal distance is possible even when all nodes have integer coordinates: distances between curves or along a diagonal need not be whole units. Display precision does not change the font's stored coordinates.
Compare thickness along a stroke
Additional Quick Measurement options include End lines, Center line, and Thickness rainbow.
End lines show distances near both ends of opposing segments. The center line marks their middle. The rainbow visualizes changing thickness, generally moving from blue toward red as the measured distance increases. Uniform blue indicates parallel lines, or a curve-distance relationship matching the contrast used by the Measurements panel.
Quick Measurement and the rainbow can follow curved stems and their centerlines. The rainbow avoids ambiguous sharp corners and stops at intervening contours, so an interrupted display need not mean that a section of the outline is missing. Check the measured edges before interpreting a gap.
Use these as geometric evidence, then inspect the filled letter. A uniform numerical thickness is not always a uniform optical weight, particularly between straight and curved strokes. Do not move a curve only to make every rainbow uniform.
Measure against guides
Hover over a horizontal or vertical guide or dimension line to inspect its distance to nearby contours. Shift or Option/Alt can change the comparison toward nearby guides. For a guide with width, the start edge is the relevant reference for this measurement behavior.
The optional node-offset display shows x and y differences between neighboring nodes when you hover over a segment or node. It is useful for spotting a near-alignment that appears exact at ordinary zoom.
AutoMeter
AutoMeter places measurements where FontLab detects significant geometry: stem widths, counter dimensions, and corner angles. Enable the relevant View-panel controls or the Stem widths, Counters, and Corner angles buttons in the Measurements widget. Preferences > Glyph Window > Auto-meter provides another activation route. Guides mode also exposes these readouts.
Stem widths measure opposing extreme-node segments in the filled area; recall extrema in Structural Soundness. A vertical stem is measured horizontally and a horizontal stroke vertically. Zoom determines whether values fit inside the stem or are placed outside it. Counter readings describe whitespace that is fully or partly enclosed. Corner-angle readings require enough zoom to display clearly.
The detected locations are automatic. In a complex glyph, a reading can describe an incidental interior gap rather than the feature you had in mind. Inspect the indicated edges before using it as a design target.
Edit a measured stem
Editing a stem-width value changes the outlines, not just the label. FontLab moves relevant geometry to achieve the requested width, which can affect nearby curves.
With Preferences > Glyph Window > Coordinates editable enabled, click an editable stem-width value, enter the desired width, and confirm. The field can also offer arrow-key adjustment or a slider. Inspect the result and use Undo if the redistribution was unsuitable. The edit is recorded as a stem-thickness change.
Compare with defined stems
When stem comparison and its tolerance are configured, AutoMeter can distinguish a matching common stem, a nearby deviation, and an unrelated width. Green indicates a match, red a nearby deviation within the tolerance, and gray an unrelated width. A correction control beside an eligible deviating value can move it to a common width.
The comparison uses Font Info > Stems (see Alignment Zones and Standard Stems) and the irregular-stem tolerance described in Font Audit. Those definitions are the reference; a red reading does not prove the design is wrong. Check the proposed width and the affected geometry before accepting a correction.
Use the automatic measurements for consistency checks and the Guides tool for a deliberately chosen distance. Together they help you separate a drawing problem from a misleading choice of measurement.
For editing detected strokes rather than measuring them, see The Stem Tool.
For the Guides tool’s other roles, see Anchors for Positioning for anchors, The Element Model for element guides, Element References for pins, and Previewing, Diagnosing, and Fixing Interpolation for Master Relations. Anchor measurements and cross-element or component measurements are developed in Anchors for Positioning and Element Transformations.