On-Canvas Visualization of Metrics

Show the drawing's reference lines when you need to judge position, proportions, or spacing. Font dimension lines, spacing controls, rulers, and the unit grid are separate displays. Turning one on does not necessarily show the others, and hiding them does not remove their underlying values.

Font Dimension Lines

Choose View > Font Dimensions to show the horizontal dimension lines in the Glyph window. They give the current drawing its baseline, design-height, and vertical-metric references.

Use the labels to distinguish the lines. The baseline is y = 0; Caps height and x Height describe design proportions; Ascender and Descender contribute to the line-spacing framework. The View command covers dimensions from both the Family Dimensions and Font Dimensions pages of Font Info.

If the lines are missing:

  1. Make a glyph current in the Glyph window.
  2. Enable View > Font Dimensions.
  3. Check the visible area and zoom out if the reference heights are outside it.
  4. Release Quick Preview if you are holding a preview key.

Tool and view settings can change which details are displayed. If the lines disappear after switching working contexts, check the view setting in that context.

The Font Dimensions entries under View > Snap and View > Lock control different behaviors. Snapping determines whether editing can align to dimensions; locking controls whether dimension lines can be moved on the canvas. Neither is the visibility command. Snapping is taught in Snapping and Suggestions; detailed dimension-lock behavior belongs to the Glyph-window reference. Showing a line alone does not mean it is locked or that drawing objects will snap to it.

Spacing Controls

Choose View > Metrics & Kerning > Spacing Controls to show the current glyph's spacing controls. The View panel also provides View spacing controls. The Toolbar and property bar offer convenient toggles for the same display.

These controls identify the glyph's horizontal metric boundaries and provide spacing information appropriate to the active tool. In upright measurement, the origin-side boundary corresponds to x = 0 and the advance boundary to the glyph's advance width. The drawing can lie inside these boundaries or overhang them.

The lines are useful even before you begin spacing: they distinguish the glyph's advance interval from the width of its visible drawing. Numerical sidebearing displays depend on the mode and spacing preferences. A missing number therefore does not mean that the glyph has no sidebearing.

Spacing controls and horizontal font dimension lines are independent. To restore a full metric reference, enable both. If the spacing lines lean in an italic font, inspect View > Italic Angle; the slanted metric view uses the font's italic parameters.

The Unit Grid

The font unit grid shows individual font-unit intervals at high magnification. It makes the coordinate system visible: with integer outline coordinates, points fall on whole-unit positions; with fractional coordinates, points can lie between them.

To display it:

  1. Open Preferences > Grid.
  2. Enable the unit-grid option in the Font unit grid section.
  3. Set Pixel size, the display threshold for the grid.
  4. Return to the Glyph window, make a glyph current, and zoom in until one font unit is larger than the threshold on screen.

For example, a threshold of 10 requires roughly ten screen pixels per font unit before the grid becomes useful and appears. A higher threshold requires a closer zoom. Zoom out to hide this fine lattice naturally while inspecting the whole letter.

The font unit grid is separate from the configurable design grid, whose pitch can span several font units; see The Design Grid. Showing the design grid does not control the unit grid, and showing the unit grid does not turn on coordinate rounding or snapping. Use Round coordinates in Font Info to choose integer editing; use the unit grid to see its scale.

Choose View > Rulers to read positions along the canvas edges. The rulers are graduated in font units and reflect the current drawing space. Together, the rulers and unit grid let you distinguish a small coordinate difference from a change caused only by canvas magnification.