core: add products and integrals

Also adding a new font to try out in the SDL2 backend.

README.md

@@ -28,8 +28,7 @@ List of currently supported elements:
 
 Features that are partially implemented (and what is left to finish them):
 
-* Support for inline style and display style (compute display-style subscript
-  and superscript layout, and expose a parameter)
+* Support for inline style and display style (expose a parameter)
 * API functions to build TeX objects without a TeX formula (expose functions
   which are currently in the parser)
 * Full fx-CG 50 support (suitable parenthesis styles)

TODO.md

@@ -5,9 +5,7 @@
 *  Support character-level spacing
 *  Be more generic in what nodes have display mode by default
 
-*  Add products
 *  Add square roots, and honor TEX_SQRT_SLANTED and TEX_SQRT_BAR_LENGTH
 *  Add vectors
 *  Add limits
-*  Add integrals, and honor TEX_INT_DISPLAY
 *  Add matrices

src/classes.c

@@ -241,7 +241,7 @@ void supsubscript_render(struct TeX_Node const * node, int x, int y,
 }
 
 //---
-//	Summation symbols.
+//	Summation symbol.
 //	* args: 0 (ignored)
 //	* flow: default
 //
@@ -268,6 +268,55 @@ void sum_render(__attribute__((unused)) struct TeX_Node const * node, int x,
 	TeX_pixel(x + 8, y + 7, color);
 }
 
+//---
+//	Product symbol.
+//	* args: 0 (ignored)
+//	* flow: default
+//
+//	Just like summation symbols, uses display mode by default.
+//---
+
+void prod_size(struct TeX_Node *node)
+{
+	node->width = 9;
+	node->height = 9;
+	node->line = 4;
+}
+
+void prod_render(__attribute__((unused)) struct TeX_Node const * node, int x,
+	int y, int color)
+{
+	TeX_line(x, y, x + 8, y, color);
+	TeX_line(x + 1, y, x + 1, y + 8, color);
+	TeX_line(x + 0, y + 8, x + 2, y + 8, color);
+	TeX_line(x + 7, y, x + 7, y + 8, color);
+	TeX_line(x + 6, y + 8, x + 8, y + 8, color);
+}
+
+//---
+//	Integral symbol
+//	* args: 0 (ignored)
+//	* flow: default
+//---
+
+void int_size(struct TeX_Node *node)
+{
+	node->width = 5;
+	node->height = 19;
+	node->line = 9;
+}
+
+void int_render(struct TeX_Node const * node, int x, int y, int color)
+{
+	int h = node->height;
+
+	TeX_pixel(x + 3, y, color);
+	TeX_pixel(x + 4, y + 1, color);
+	TeX_line(x + 2, y + 1, x + 2, y + h - 2, color);
+	TeX_pixel(x, y + h - 2, color);
+	TeX_pixel(x + 1, y + h - 1, color);
+}
+
 //---
 //	The class table and lookup functions
 //---
@@ -276,19 +325,25 @@ struct TeX_Class TeX_table[] = {
 	/* Text is omitted from the table and has ID 0 */
 
 	/* Fractions */
-	{ "frac", frac_size, frac_render },
+	{ "frac",  frac_size, frac_render },
+
 	/* Size-aware opening and closing elements */
 	{ "left",  leftright_size, leftright_render },
 	{ "right", leftright_size, leftright_render },
+
 	/* Superscripts and subscripts */
 	{ "\\sup", supsubscript_size, supsubscript_render },
 	{ "\\sub", supsubscript_size, supsubscript_render },
-	/* Sum symbol */
-	{ "sum", sum_size, sum_render },
+
+	/* Large operator symbols */
+	{ "sum",   sum_size, sum_render },
+	{ "prod",  prod_size, prod_render },
+
 	/* Integral */
-	{ "int",     NULL,                   NULL          },
+	{ "int",   int_size, int_render },
+
 	/* NULL terminator */
-	{ NULL,	     NULL,                   NULL          },
+	{ NULL },
 };
 
 /* class_find() - Find a class using a command name */

src/flow.c

@@ -321,7 +321,11 @@ void size_flow(struct TeX_Flow *flow)
 		update(&c, &x, &above, &below);
 
 		int mode = TEX_CHUNK_INLINE;
-		if(!strcmp(class, "sum"))
+		if(!strcmp(class, "sum") || !strcmp(class, "prod")
+		#if TEX_INT_DISPLAY
+			|| !strcmp(class, "int")
+		#endif
+			)
 		{
 			mode = TEX_CHUNK_DISPLAY;
 		}

src/platform/sdl2.c

@@ -17,26 +17,34 @@ static SDL_Renderer *r = NULL;
 static SDL_Texture *font = NULL;
 
 /* Font configuration */
+#define FONT_SIZE 1
 
-#ifndef LARGE_FONT /* Small font */
-
+#if FONT_SIZE==1
 #define FONT_FILE    "font5x7.bmp"
 #define FONT_WIDTH   5
 #define FONT_HEIGHT  7
 #define FONT_OUTER   1
 #define FONT_INNER   2
 #define FONT_OFFSET  0
+#endif
 
-#else /* Large font */
+#if FONT_SIZE==2
+#define FONT_FILE    "font8x9.bmp"
+#define FONT_WIDTH   8
+#define FONT_HEIGHT  9
+#define FONT_OUTER   2
+#define FONT_INNER   2
+#define FONT_OFFSET  32
+#endif
 
+#if FONT_SIZE==3
 #define FONT_FILE    "font10x12.bmp"
 #define FONT_WIDTH   10
 #define FONT_HEIGHT  12
 #define FONT_OUTER   3
 #define FONT_INNER   3
 #define FONT_OFFSET  32
-
-#endif /* Font size */
+#endif
 
 //---
 //	Interface functions
@@ -161,9 +169,10 @@ static void fini(void)
 int main(void)
 {
 	char const * formula =
-	"\\frac{x^7\\left[X,Y\\right]+3\\left|\\frac{A}{B}\\right>}{"
-		"\\left\\{\\frac{a_k+b_k}{5!}\\right\\}^n"
-	"} + \\sum_{k=1}^nk(-1)^k";
+	"\\frac{x^7\\left[X,Y\\right]+3\\left|\\frac{A}{B}\\right>}"
+	      "{\\prod_{k=1}^n\\left\\{\\frac{a_k+b_k}{k!}\\right\\}^5}"
+	" + \\sum_{k=1}^n\\frac{(b-a)^k}{k!}"
+	"+\\int_a^b\\frac{(b-t)^{n+1}}{n!}dt";
 
 	struct TeX_Flow *flow = TeX_parse(formula);
 	if(!flow) { puts("parsing error!"); return 1; }