When you select New… or Modify…, you enter the Style Editing Dialogue. The checkerboard screen in the upper right corner of the dialogue gives you an idea of what your current style looks like. There are plenty of parameters that you can define for the style, valid for both fonts in it:
Box Type - defines what kind of box will be applied behind the subtitle text. You may choose from None, Sized (following the text size), and
Fixed (fixed size box). You may select box color and extent from the text size.
Vertical align - defines the vertical alignment in relation to the region vertical position. You may choose from top (subtitles aligned under the vertical region position line), center (subtitles centered at the vertical region position line) and bottom (subtitles aligned over the vertical region position line).
Horizontal align - defines the horizontal alignment in relation to the horizontal position. You may choose from left, centered, right, and none (no horizontal alignment at all).
Text Justify – defines the alignment of subtitle lines in relation of each other. Depending of the option chosen, the shorter line will be aligned to the longer on the left, center, right or none.
Optional Left Justify - defines how speech lines are to be handled. Usually speech lines are left aligned, but you may choose from the following:
Never - No left alignment of the rows in a single subtitle.
Always - All rows in a single subtitle will be aligned by their left border, and then the overall horizontal alignment will be applied.
Any row starts with dash - If there is a row in a single subtitle, starting with dash, all rows will be aligned by their left border, and then the overall horizontal alignment will be applied.
All rows start with dashes - If all the rows in a single subtitle start with dashes, then all rows will be aligned by their left border. At the same time the overall horizontal alignment will be applied.
Each font may have different options, as follows: Font defines the Windows font type face to use. Font Size defines the size of the font itself.
Clicking the B or I button defines whether it is bold, italic , or both .
Edge Size defines how many pixels the edge will be thicker than the text.
Shadow Size defines how many pixels the shadow will be offset from text.
Character Spacing, Slant, and Width refer to additional spacing and optical deformation of the base font. Spacing lets you define the distance between letters, Slant lets you emulate italic or reverse italic fonts, even if no italic typeface is available, Width lets you squeeze letters horizontally.
You may select colors for the edge and shadow by clicking on the respective color boxes. The lower checkerboard area gives you an exact idea of what your font looks like. If a font or style property is changed, it is applied to all the text within the file, which is using the same style.