[LyX/master] Document the drawing of logos

[Jean-Marc]

commit 1f36fa6d567834bd67e5612b6c67f81d10c11ef1
Author: Jean-Marc <lasgout...@lyx.org>
Date:   Sun Mar 15 18:21:01 2015 +0100

    Document the drawing of logos
    
    Also fix a couple of spacings.

diff --git a/src/insets/InsetSpecialChar.cpp b/src/insets/InsetSpecialChar.cpp
index e4fd180..1294d17 100644
--- a/src/insets/InsetSpecialChar.cpp
+++ b/src/insets/InsetSpecialChar.cpp
@@ -49,6 +49,7 @@ int logoWidth(FontInfo const & font, InsetSpecialChar::Kind 
kind) {
        frontend::FontMetrics const & fm = theFontMetrics(font);
        double const em = fm.width('M');
        int width = 0;
+       // See drawlogo() below to understand what this does.
        switch (kind) {
        case InsetSpecialChar::PHRASE_LYX:
                width = fm.width(from_ascii("L")) - 0.16667 * em
@@ -64,6 +65,7 @@ int logoWidth(FontInfo const & font, InsetSpecialChar::Kind 
kind) {
 
        case InsetSpecialChar::PHRASE_LATEX2E:
                width = logoWidth(font, InsetSpecialChar::PHRASE_LATEX)
+                       + 0.15 * em
                        + fm.width(from_ascii("2") + char_type(0x03b5));
                break;
        case InsetSpecialChar::PHRASE_LATEX: {
@@ -140,6 +142,9 @@ void drawLogo(PainterInfo & pi, InsetSpecialChar::Kind 
kind, int & x, int & y) {
        double const em = theFontMetrics(font).width('M');
        switch (kind) {
        case InsetSpecialChar::PHRASE_LYX:
+               /** Reference macro:
+                *  
\providecommand{\LyX}{L\kern-.1667em\lower.25em\hbox{Y}\kern-.125emX\\@};
+                */
                x += pi.pain.text(x, y, from_ascii("L"), font);
                x -= 0.16667 * em;
                x += pi.pain.text(x, y + 0.25 * em, from_ascii("Y"), font);
@@ -147,21 +152,43 @@ void drawLogo(PainterInfo & pi, InsetSpecialChar::Kind 
kind, int & x, int & y) {
                x += pi.pain.text(x, y, from_ascii("X"), font);
                break;
 
-       case InsetSpecialChar::PHRASE_TEX:
+       case InsetSpecialChar::PHRASE_TEX: {
+               /** Reference macro:
+                *  \def\TeX{T\kern-.1667em\lower.5ex\hbox{E}\kern-.125emX\@}
+                */
+               double const ex = theFontMetrics(font).ascent('x');
                x += pi.pain.text(x, y, from_ascii("T"), font);
                x -= 0.16667 * em;
-               x += pi.pain.text(x, y + 0.25 * em, from_ascii("E"), font);
+               x += pi.pain.text(x, y + 0.5 * ex, from_ascii("E"), font);
                x -= 0.125 * em;
                x += pi.pain.text(x, y, from_ascii("X"), font);
                break;
-
+       }
        case InsetSpecialChar::PHRASE_LATEX2E:
+               /** Reference macro:
+                *  \DeclareRobustCommand{\LaTeXe}{\mbox{\m@th
+                *    \if b\expandafter\@car\f@series\@nil\boldmath\fi
+                *    \LaTeX\kern.15em2$_{\textstyle\varepsilon}$}}
+                */
                drawLogo(pi, InsetSpecialChar::PHRASE_LATEX, x, y);
+               x += 0.15 * em;
                x += pi.pain.text(x, y, from_ascii("2"), font);
                x += pi.pain.text(x, y + 0.25 * em, char_type(0x03b5), font);
                break;
 
        case InsetSpecialChar::PHRASE_LATEX: {
+               /** Reference macro:
+                * \DeclareRobustCommand{\LaTeX}{L\kern-.36em%
+                *        {\sbox\z@ T%
+                *         \vbox to\ht\z@{\hbox{\check@mathfonts
+                *                              \fontsize\sf@size\z@
+                *                              \math@fontsfalse\selectfont
+                *                              A}%
+                *                        \vss}%
+                *        }%
+                *        \kern-.15em%
+                *        \TeX}
+                */
                x += pi.pain.text(x, y, from_ascii("L"), font);
                x -= 0.36 * em;
                FontInfo smaller = font;