Vertical text

TextOptions.LayoutMode sets the direction of the lines. Horizontal text is the default. The vertical modes lay out text from top to bottom in columns, as Chinese, Japanese and Korean text is often set.

Layout modes

LayoutMode	Lines	Glyphs
HorizontalTopBottom (default)	Horizontal lines, stacked from top to bottom.	Upright.
HorizontalBottomTop	Horizontal lines, stacked from bottom to top.	Upright.
VerticalLeftRight	Vertical columns, from left to right.	Upright.
VerticalRightLeft	Vertical columns, from right to left.	Upright.
VerticalMixedLeftRight	Vertical columns, from left to right.	East Asian glyphs upright. Latin and other horizontal glyphs turned 90° clockwise.
VerticalMixedRightLeft	Vertical columns, from right to left.	As for VerticalMixedLeftRight.

Traditional Chinese and Japanese books use columns from right to left. Use VerticalMixedRightLeft for that, so that Latin words and numbers in the text lie on their side as they do in print.

using PinataLabs.Typography;

TextOptions options = new(japaneseFont)
{
    LayoutMode = LayoutMode.VerticalMixedRightLeft,
    WrappingLength = 400, // The height of a column.
};

FontRectangle size = TextMeasurer.MeasureSize("縦書きのテキストと English の混在", options);

The library decides which glyphs stay upright from the Unicode vertical orientation property (UAX #50). You can read that property with CodePoint.GetVerticalOrientationType.

How the options change in vertical text

The options keep their meaning, but along the other axis:

• WrappingLength is the height of a column.
• TextAlignment places each column from the top (Start), the bottom (End) or the centre.
• LineSpacing sets the distance between columns.
• MeasureAdvance gives the column height in the vertical direction.

Vertical glyph forms

In vertical text the library applies the font's vert feature. It replaces glyphs with their vertical forms, for example brackets and the long vowel mark ー turned for vertical text. Horizontal-only features such as ligatures and kern are not applied to vertical glyphs. The font's vertical kerning feature (vkrn) is not applied by default either. Add it to FeatureTags if you want it.

The font must have vertical metrics (vhea and vmtx tables) for good results. Fonts made for Chinese, Japanese and Korean have them. For other fonts the library makes vertical metrics from the horizontal ones.

Render vertical text

The GlyphRendererParameters.LayoutMode of each glyph tells you how it was placed:

GlyphLayoutMode	Meaning
Horizontal	The glyph is in horizontal text.
Vertical	The glyph is upright in vertical text.
VerticalRotated	The glyph is turned 90° clockwise in vertical text.

The outline points that your renderer gets are already turned. You do not need to rotate them yourself.