square root and jumbo matrix example

README.md

@@ -15,24 +15,24 @@ This library is a customizable 2D math rendering tool for calculators. It can be
 
 * Build formulae from TeX syntax or using the structural API
 * Highly-customizable graphical and layout parameters
-* Drawing is based on a few user-provided primitives (point, line, text size,
-  text)
+* Drawing uses only a few user primitives (point, line, text size, text)
 * Compatible with fxlib and gint
 
 List of currently supported elements:
 
 * Fractions (`\frac`)
 * Subscripts and superscripts (`_` and `^`)
-* Grouping parentheses, brackets and braces (`\left` and `\right`)
+* Grouping parentheses, brackets, and braces (`\left` and `\right`)
 * Grouping angle brackets, vertical lines, and dots (invisible)
 * Sums, products and integrals (`\sum`, `\prod` and `\int`)
 * Vectors (`\vec`) and limits (`\lim`)
+* Square roots (`\sqrt`)
 * Matrices (`\begin{matrix} ... \end{matrix}`)
 
 Features that are partially implemented (and what is left to finish them):
 
 * Support for inline style and display style (expose a parameter)
-* Full fx-CG 50 support (suitable parenthesis styles)
+* Theme that can decently port to fx-CG 50 (suitable parenthesis styles)
 
 See the `TODO.md` file for more features to come.
 

TODO.md

@@ -1,33 +1,8 @@
-*  Support Unicode symbols (probably requires help from the font side, urgh)
-   Available blocks:
-   ->  U+0020 .. U+007F   (128)  ASCII
-   ->  U+00A0 .. U+00FF   (96)   Latin-1 Supplement
-   ->  U+0100 .. U+017F   (128)  Latin Extended-A
-   ->  U+0370 .. U+03FF   (144)  Greek
-   ->  U+0400 .. U+047F   (128)  Cyrillic
-   ->  U+2010 .. U+205F   (80)   General punctuation
-   ->  U+2070 .. U+209F   (48)   Subscripts and superscripts
-   ->  U+2160 .. U+217F   (32)   Roman numerals
-   ->  U+2190 .. U+21FF   (112)  Arrows
-   ->  U+2200 .. U+22FF   (256)  Mathematical operators
-   ->  U+25A0 .. U+25FF   (96)   Geometric shapes
-   ->  U+2800 .. U+28FF   (256)  Braille patterns
-   Other interesting blocks?
-   ->  Finish cyrillic
-   ->  IPA extenstions and Phonetic extensions
-   ->  Currency symbols
-   ->  Hiragana and Katakana
-   Other characters supported in FONTCHARACTER:
-   ->  U+2139  Imaginary number
-   ->  U+231F  Fraction symbol
-   ->  U+3010
-   ->  U+3011
-
+Pure TeX things:
 *  Add a parameter to resolve as inline style or display style
-*  Parametrize character-level and word-level spacing
 *  Be more generic in what nodes have display mode by default
+
+Things that require help from the font manager:
+*  Parametrize character-level and word-level spacing
 *  Reduce horizontal spacing by using a proportional font
 *  Have a decent variable-height font system in gint (argh)
-
-*  Add square roots, and honor TEX_SQRT_SLANTED and TEX_SQRT_BAR_LENGTH
-*  Make more matrix tests

include/TeX/config.h

@@ -75,10 +75,18 @@
 /* Extra height between argument and vector */
 #define TEX_VEC_SPACING TEX_LAYOUT_SPACING
 
-/* Make the vertical part of the square root symbol slanted at low heights */
+/* Make the vertical part of the square root symbol slanted at small heights */
 #define TEX_SQRT_SLANTED 1
+/* Maximum height consider small */
+#define TEX_SQRT_SLANT_MAX 10
+/* Horizontal size occupied by the slanted part */
+#define TEX_SQRT_SLANT_LENGTH 2
 /* Length of the top-right bar of square roots (0 to disable) */
 #define TEX_SQRT_BAR_LENGTH 0
+/* Length of tip starting at the bottom left of the square root */
+#define TEX_SQRT_TIP_LENGTH 2
+/* Margin around argument */
+#define TEX_SQRT_MARGIN TEX_LAYOUT_SPACING
 
 /* Spacing between rows and columns in matrices */
 #define TEX_MATRIX_COL_SPACING 4

src/classes.c

@@ -382,7 +382,7 @@ void int_render(struct TeX_Node const * node, int x, int y, int color)
 //	TEX_VEC_MARGIN:
 //	  Horizontal margin around the argument.
 //
-//	------>  ] related to TEX_VEC_ARROW_LENGTH
+//	------>  ] 2 * TEX_VEC_ARROW_LENGTH + 1
 //	         ] TEX_VEC_SPACING
 //	   1
 //	|_| |_|
@@ -438,6 +438,83 @@ void lim_render(__attribute__((unused)) struct TeX_Node const * node, int x,
 	TeX_text("lim", x, y, color);
 }
 
+//---
+//	Square roots
+//	* args: 1 (<1 invalidate, >1 ignore)
+//	* flow: normal
+//
+//	Graphical parameters:
+//
+//	TEX_SQRT_SLANTED:
+//	  Makes the vertical part of the square root slanted when it is small.
+//	TEX_SQRT_SLANT_MAX:
+//	  Maximum height consider small
+//	TEX_SQRT_SLANT_LENGTH:
+//	  Horizontal size occupied by the slanted part.
+//	TEX_SQRT_BAR_LENGTH:
+//	  Length of the top-right bar marking the end of the argument (or 0)
+//	TEX_SQRT_TIP_LENGTH:
+//	  Length of tip starting at the bottom left of the square root
+//	TEX_SQRT_MARGIN:
+//	  Margin around argument
+//
+//	If TEX_SQRT_SLANTED != 0 and height(1) <= TEX_SQRT_SLANT_MAX:
+//
+//	  TEX_SQRT_TIP_LENGTH
+//	   |         _______    v
+//	   |        /       |   |  TEX_SQRT_BAR_LENGTH
+//	   |   v   /    1       ^
+//	   +-->| \/
+//	       ^  <->
+//	   TEX_SQRT_SLANT_LENGTH
+//
+//	All other cases:
+//
+//	  TEX_SQRT_TIP_LENGTH
+//	   |        _______    v
+//	   |       |       |   |  TEX_SQRT_BAR_LENGTH
+//	   |   v   |   1       ^
+//	   +-->|  \|
+//             ^
+//---
+
+void sqrt_layout(struct TeX_Node *node)
+{
+	/* Invalidate the node if no argument is present */
+	if(!args[0]) { node->hidden = 1; return; }
+
+	int slanted = TEX_SQRT_SLANTED && h(0) <= TEX_SQRT_SLANT_MAX;
+
+	node->width = w(0) + 2 * TEX_SQRT_MARGIN + TEX_SQRT_TIP_LENGTH;
+	node->width += (TEX_SQRT_BAR_LENGTH > 0);
+	node->width += (slanted ? TEX_SQRT_SLANT_LENGTH : 1);
+
+	node->height = h(0) + TEX_SQRT_MARGIN + 1;
+	node->line = l(0) + TEX_SQRT_MARGIN + 1;
+}
+
+void sqrt_render(struct TeX_Node const * node, int x, int y, int color)
+{
+	int slanted = TEX_SQRT_SLANTED && h(0) <= TEX_SQRT_SLANT_MAX;
+	int w = node->width;
+	int h = node->height;
+
+	int tip = TEX_SQRT_TIP_LENGTH;
+	TeX_line(x, y + h - tip - 1, x + tip, y + h - 1, color);
+
+	int bar_length = (slanted ? TEX_SQRT_SLANT_LENGTH : 1);
+	TeX_line(x + tip + bar_length - 1, y, x + tip, y + h - 1, color);
+
+	int base = tip + bar_length;
+	TeX_line(x + base, y, x + w - 1, y, color);
+	TeX_line(x + w - 1, y, x + w - 1, y + TEX_SQRT_BAR_LENGTH, color);
+
+	TeX_flow_render(args[0],
+		x + base + TEX_SQRT_MARGIN,
+		y + 1 + TEX_SQRT_MARGIN,
+		color);
+}
+
 //---
 //	The class table and lookup functions
 //---
@@ -467,6 +544,9 @@ static struct TeX_Class const class_table[] = {
 	{ "vec",    vec_layout, vec_render },
 	{ "lim",    lim_layout, lim_render },
 
+	/* Square root */
+	{ "sqrt",   sqrt_layout, sqrt_render },
+
 	/* NULL terminator */
 	{ NULL },
 };

src/env.c

@@ -194,8 +194,8 @@ static void matrix_layout(struct TeX_Env *env)
 		env->width += m->colwidth[j];
 	}
 
-	env->width  += TEX_MATRIX_COL_SPACING * (m->cols - 1);
-	env->height += TEX_MATRIX_ROW_SPACING * (m->rows - 1);
+	env->width  += TEX_MATRIX_COL_SPACING * max(m->cols - 1, 0);
+	env->height += TEX_MATRIX_ROW_SPACING * max(m->rows - 1, 0);
 	env->line = env->height >> 1;
 }
 

src/platform/sdl2.c

@@ -169,12 +169,21 @@ 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}{k!}\\right\\}^5}"
-	" + \\int_a^b\\frac{\\left(b-t\\right)^{n+1}}{n!}dt"
+	" + \\int_a^b\\frac{\\left(b-t\\right)^{n+1}}{n!\\sqrt{n^3}}dt"
 	" + \\left(\\begin{matrix}"
-	   "\\frac{1}{2}&5\\\\"
+	   "\\frac{1}{2}&\\sqrt{5}\\\\"
 	   "-1&a+b"
 	"\\end{matrix}\\right)";
 
+/*	Much harder matrix test.
+	formula = "\\left\\{\\begin{matrix}"
+	  "\\frac{-1}{ab}+7&\\sum_{i=1}^{k+\\int f} \\frac{in}{4!}\\\\"
+	  "\\left(\\begin{matrix}"
+	    "cos(t)&-sin(t)\\\\sin(t)&cos(t)"
+	  "\\end{matrix}\\right)\\\\"
+	  "x&y&\\left[\\begin{matrix}\\end{matrix}\\right]"
+	"\\end{matrix}\\right\\}"; */
+
 	struct TeX_Env *env = TeX_parse(formula);
 	if(!env) { puts("parsing error!"); return 1; }
 	TeX_print_env(env, 0);