From 36d8defe3eb7ae05f4426d8ff2098e513fbeefff Mon Sep 17 00:00:00 2001
From: Lephenixnoir <sebastien.mld@numericable.fr>
Date: Wed, 19 Jun 2019 11:38:08 -0400
Subject: [PATCH] handle inline vs display mode in the class table

---
 TODO.md               |  2 +-
 include/TeX/classes.h |  3 +++
 include/TeX/flow.h    | 16 ++++++++++++++++
 src/classes.c         | 33 ++++++++++++++++++++-------------
 src/flow.c            | 11 ++++-------
 src/platform/sdl2.c   |  4 ++--
 6 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/TODO.md b/TODO.md
index b2119a1..a02d4cc 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,6 +1,6 @@
 Pure TeX things:
 *  Add a parameter to resolve as inline style or display style
-*  Be more generic in what nodes have display mode by default
+*  Have a decent reference other than the source code
 
 Things that require help from the font manager:
 *  Parametrize character-level and word-level spacing
diff --git a/include/TeX/classes.h b/include/TeX/classes.h
index 79575fe..107d9da 100644
--- a/include/TeX/classes.h
+++ b/include/TeX/classes.h
@@ -47,6 +47,9 @@ struct TeX_Class
 	   @y      Vertical coordinate of the requested rendering position
 	   @color  Requested rendering color */
 	void (*render)(struct TeX_Node const * node, int x, int y, int color);
+
+	/* Sub- and superscript mode, see <TeX/flow.h> for available modes */
+	int mode;
 };
 
 /* TeX_class_find(): Find a class using a command name
diff --git a/include/TeX/flow.h b/include/TeX/flow.h
index f12952a..0ba3bc4 100644
--- a/include/TeX/flow.h
+++ b/include/TeX/flow.h
@@ -25,6 +25,22 @@ struct TeX_Flow
 
 } __attribute__((packed, aligned(sizeof (void *))));
 
+/* Possible subscript and superscript mode.
+
+   TEX_FLOW_INLINE:
+     Subscripts and superscripts are placed on the right of the base, and
+     displaced vertically. (LaTeX's inline mode)
+   TEX_FLOW_DISPLAY:
+     Subscripts and superscripts are placed under and above the base. (LaTeX's
+     display mode)
+   TEX_FLOW_PREFER_DISPLAY:
+     Use display mode when possible, but fall back to inline mode if the user
+     builds an inline mode. */
+
+#define TEX_FLOW_INLINE 0
+#define TEX_FLOW_DISPLAY 1
+#define TEX_FLOW_PREFER_DISPLAY 2
+
 //---
 //	Flow construction and destruction functions
 //---
diff --git a/src/classes.c b/src/classes.c
index 5771cad..e2beb29 100644
--- a/src/classes.c
+++ b/src/classes.c
@@ -519,33 +519,40 @@ void sqrt_render(struct TeX_Node const * node, int x, int y, int color)
 //	The class table and lookup functions
 //---
 
+/* Default sub- and superscript mode for integrals depends on config */
+#if TEX_INT_DISPLAY
+#define INT_MODE TEX_FLOW_PREFER_DISPLAY
+#else
+#define INT_MODE TEX_FLOW_INLINE
+#endif
+
 static struct TeX_Class const class_table[] = {
 	/* Text and environments */
-	{ "\\text", text_layout, text_render },
-	{ "\\end",  env_layout, env_render },
+	{ "\\text", text_layout, text_render, -1 },
+	{ "\\end",  env_layout, env_render, -1 },
 
 	/* Fractions */
-	{ "frac",   frac_layout, frac_render },
+	{ "frac",   frac_layout, frac_render, TEX_FLOW_INLINE },
 
 	/* Size-aware opening and closing elements */
-	{ "left",   leftright_layout, leftright_render },
-	{ "right",  leftright_layout, leftright_render },
+	{ "left",   leftright_layout, leftright_render, TEX_FLOW_INLINE },
+	{ "right",  leftright_layout, leftright_render, TEX_FLOW_INLINE },
 
 	/* Superscripts and subscripts */
-	{ "\\sup",  supsubscript_layout, supsubscript_render },
-	{ "\\sub",  supsubscript_layout, supsubscript_render },
+	{ "\\sup",  supsubscript_layout, supsubscript_render, -1 },
+	{ "\\sub",  supsubscript_layout, supsubscript_render, -1 },
 
 	/* Large operator symbols, integral */
-	{ "sum",    sum_layout, sum_render },
-	{ "prod",   prod_layout, prod_render },
-	{ "int",    int_layout, int_render },
+	{ "sum",    sum_layout, sum_render, TEX_FLOW_PREFER_DISPLAY },
+	{ "prod",   prod_layout, prod_render, TEX_FLOW_PREFER_DISPLAY },
+	{ "int",    int_layout, int_render, INT_MODE },
 
 	/* Vectors, limits */
-	{ "vec",    vec_layout, vec_render },
-	{ "lim",    lim_layout, lim_render },
+	{ "vec",    vec_layout, vec_render, TEX_FLOW_INLINE },
+	{ "lim",    lim_layout, lim_render, TEX_FLOW_DISPLAY },
 
 	/* Square root */
-	{ "sqrt",   sqrt_layout, sqrt_render },
+	{ "sqrt",   sqrt_layout, sqrt_render, TEX_FLOW_INLINE },
 
 	/* NULL terminator */
 	{ NULL },
diff --git a/src/flow.c b/src/flow.c
index c37b0e4..530c7f2 100644
--- a/src/flow.c
+++ b/src/flow.c
@@ -358,13 +358,10 @@ void TeX_flow_layout(struct TeX_Flow *flow)
 		}
 
 		int mode = TEX_CHUNK_INLINE;
-		if(!strcmp(class, "sum")
-		|| !strcmp(class, "prod")
-		|| !strcmp(class, "lim")
-		#if TEX_INT_DISPLAY
-		|| !strcmp(class, "int")
-		#endif
-			)
+		int pref = TeX_class_of(node)->mode;
+
+		if((pref == TEX_FLOW_PREFER_DISPLAY && 1) ||
+			pref == TEX_FLOW_DISPLAY)
 		{
 			mode = TEX_CHUNK_DISPLAY;
 		}
diff --git a/src/platform/sdl2.c b/src/platform/sdl2.c
index 6969fa1..d3d4a81 100644
--- a/src/platform/sdl2.c
+++ b/src/platform/sdl2.c
@@ -177,11 +177,11 @@ int main(void)
 
 /*	Much harder matrix test.
 	formula = "\\left\\{\\begin{matrix}"
-	  "\\frac{-1}{ab}+7&\\sum_{i=1}^{k+\\int f} \\frac{in}{4!}\\\\"
+	  "\\frac{-1}{ab}+7&\\sum_{i=1}^{k+\\int f} \\frac{in}{\\sqrt{4!}}\\\\"
 	  "\\left(\\begin{matrix}"
 	    "cos(t)&-sin(t)\\\\sin(t)&cos(t)"
 	  "\\end{matrix}\\right)\\\\"
-	  "x&y&\\left[\\begin{matrix}\\end{matrix}\\right]"
+	  "x&\\sqrt{y}&\\left[\\begin{matrix}\\end{matrix}\\right]"
 	"\\end{matrix}\\right\\}"; */
 
 	struct TeX_Env *env = TeX_parse(formula);