Example 2: Rounding Limitations

The following example illustrates the limitations of rounding by itself. Assume that the 12-point Times New Roman “m” shown earlier in this chapter has hints telling the rasterizer to position certain control points on the nearest grid line and to let the other points follow accordingly. A short bar marks each hinted point that controls vertical strokes:

Rounding indicators for vertical control points

Short bars show rounding methods on vertical control points.

For the horizontal strokes, a short bar marks each hinted control point:

Rounding indicators for vertical control points

Short bars show rounding methods on horizontal control points.

After Visual TrueType compiles the hints, the resulting glyph looks better. Even so, the left stem is still twice as wide as the other two, and the serifs are now missing altogether:

Bitmap of 12-point Times New Roman m after rounding

The bitmap of a 12-point Times New Roman “m” after rounding.

Hinting just the control points improved the appearance of the font, but the outline needs more hints to look good. Visual TrueType encourages you to go beyond this basic approach by making rounding part of the links that you create and interpolate to hint control points. For more information, see “Controlling Distances,” and “Controlling Proportions.”