Review italic corrections for integral-related symbols

[RuixiZhang42]

The current issue is not the same as issue 95.

The default form of all integral symbols is slanted. For integral symbols with extra shape (circle/arrow/square, etc.) in the middle, the italic corrections imply closely attached lower limits—too close to be comfortable. Issue 296 also points out the missing italic corrections for slanted .ssty and .ssty2 variants.

The ss08 form of all integral symbols is upright. Nevertheless, they still need italic corrections for attaching offset upper and lower limits. Many ss08 variants lack italic corrections.

[RuixiZhang42]

To be technically more precise:

• The italic correction controls how the upper and lower limits are positioned horizontally. The upper limit is offset to the right by ½ italic correction, while the lower limit is offset to the left by ½ italic correction. This is always true whether the limits are placed directly on top/on bottom, or the limits are attached to the upper-right/lower-right, of the big operator. In this view, the italic correction should be kept identical for all integral symbols in one single style. For example, all slanted display integrals, all slanted inline integrals, all upright display integrals, all upright inline integrals, etc., get the same italic correction within the group.
• The problem of upper-right/lower-right limits crashing into the integral symbol should be solved by adjusting the horizontal advance of the integral symbol in question.