256 lines
6.7 KiB
C
256 lines
6.7 KiB
C
//---
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// classes: Node classes used for mathematical notations
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//---
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#include <TeX/TeX.h>
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#include <TeX/structure.h>
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#include <TeX/render.h>
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#include <TeX/defs.h>
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#include <string.h>
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/* Some quick macros to access parameters and their size */
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#define args ((node)->args)
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#define w(n) (args[n]->width)
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#define h(n) (args[n]->height)
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#define l(n) (args[n]->line)
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//---
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// Fractions.
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// * args: 2 (<2 invalidate, >2 ignore)
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// * flow: normal
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//
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// Graphical parameters:
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//
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// TEX_LAYOUT_SPACING (inherited):
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// Spacing between bar and operands
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// TEX_FRACTION_BAR_THICKNESS:
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// Thickness (pixels) of fraction bar
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// TEX_FRACTION_BAR_MARGIN:
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// Additional bar length that extends beyond the operands
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//
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// 1
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// ] TEX_LAYOUT_SPACING
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// ####### ] TEX_FRACTION_BAR_THICKNESS
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// ] TEX_LAYOUT_SPACING
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// 2
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// |_| |_|
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// TEX_FRACTION_BAR_MARGIN
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//---
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void frac_size(struct TeX_Node *node)
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{
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/* Drop the fraction if there are less than two arguments */
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if(!args[1]) { node->hidden = 1; return; }
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int margin = TEX_FRACTION_BAR_MARGIN;
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int thickness = TEX_FRACTION_BAR_THICKNESS;
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int spacing = TEX_LAYOUT_SPACING;
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node->width = max(w(0), w(1)) + 2 * margin;
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node->height = h(0) + h(1) + 2 * spacing + thickness;
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node->line = h(0) + spacing + thickness / 2;
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}
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void frac_render(struct TeX_Node const * node, int x, int y, int color)
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{
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/* Fraction bar */
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for(int i = 0; i < TEX_FRACTION_BAR_THICKNESS; i++)
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{
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int y0 = y + h(0) + TEX_LAYOUT_SPACING + i;
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TeX_line(x, y0, x + node->width - 1, y0, color);
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}
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/* First argument */
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render_flow(args[0],
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x + ((node->width - w(0)) >> 1),
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y,
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color);
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/* Second argument */
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render_flow(args[1],
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x + ((node->width - w(1)) >> 1),
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y + h(0) + 2 * TEX_LAYOUT_SPACING + TEX_FRACTION_BAR_THICKNESS,
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color);
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}
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//---
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// Left and right delimiters.
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// * args: 1 (<1 invalidate, >1 ignore)
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// * flow: adapt width and height to contents until matching delimiter
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//
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// Left and right delimiters are resizable bracket-like elements used to
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// parenthesize or decorate terms. They serve a special flow purpose and
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// are matched together by the size_flow() routine.
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//
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// Graphical parameters:
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//
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// TEX_LEFTRIGHT_ALIGNED:
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// Forces the middle of the decoration to be aligned with the baseline
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// TEX_LEFTRIGHT_SYMMETRICAL:
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// Makes the size of the delimiter symmetrical around the baseline
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// TEX_LEFTRIGHT_MAX_ANGLE:
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// Maximum angle allowed for "<" and ">" delimiters, radians (causes
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// these delimiters to grow in width if their content is tall)
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//
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// Default: Aligned: Aligned symmetrical:
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// / x / x / x
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// | - | - | -
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// < y | y | y
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// | --- < --- < ---
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// \ z \ z | z
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// |
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// \.
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//
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// LaTeX's behavior on this is essentially centered symmetrical, but it
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// seems to resize the contents to make it smoother. Not possible here.
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//---
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void leftright_size(struct TeX_Node *node)
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{
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int width, height;
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TeX_size("#", &width, &height);
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/* TODO: Not the same on fxcg50 */
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node->width = 3;
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node->height = height;
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node->line = (height+1) >> 1;
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}
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void leftright_render(struct TeX_Node const * node, int x, int y, int color)
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{
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int h = node->height, l = node->line;
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switch(node->subtype)
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{
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case '(':
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TeX_pixel(x + 2, y, color);
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TeX_pixel(x + 1, y + 1, color);
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TeX_line(x, y + 2, x, y + h - 3, color);
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TeX_pixel(x + 1, y + h - 2, color);
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TeX_pixel(x + 2, y + h - 1, color);
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break;
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case ')':
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TeX_pixel(x, y, color);
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TeX_pixel(x + 1, y + 1, color);
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TeX_line(x + 2, y + 2, x + 2, y + h - 3, color);
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TeX_pixel(x + 1, y + h - 2, color);
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TeX_pixel(x, y + h - 1, color);
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break;
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case '[':
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TeX_pixel(x + 1, y, color);
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TeX_pixel(x + 2, y, color);
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TeX_line(x, y, x, y + h - 1, color);
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TeX_pixel(x + 1, y + h - 1, color);
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TeX_pixel(x + 2, y + h - 1, color);
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break;
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case ']':
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TeX_pixel(x, y, color);
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TeX_pixel(x + 1, y, color);
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TeX_line(x + 2, y, x + 2, y + h - 1, color);
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TeX_pixel(x, y + h - 1, color);
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TeX_pixel(x + 1, y + h - 1, color);
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break;
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case '{':
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TeX_pixel(x + 2, y, color);
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TeX_line(x + 1, y + 1, x + 1, y + l - 1, color);
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TeX_pixel(x, y + l, color);
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TeX_line(x + 1, y + l + 1, x + 1, y + h - 2, color);
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TeX_pixel(x + 2, y + h - 1, color);
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break;
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case '}':
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TeX_pixel(x, y, color);
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TeX_line(x + 1, y + 1, x + 1, y + l - 1, color);
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TeX_pixel(x + 2, y + l, color);
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TeX_line(x + 1, y + l + 1, x + 1, y + h - 2, color);
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TeX_pixel(x, y + h - 1, color);
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break;
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}
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}
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//---
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// Superscripts and subscripts.
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// * args: 1 (<1 invalidate, >1 ignore)
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// * flow: elevated or lowered to extend the previous node
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//
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// Superscript and subscripts are very common elements. The class itself
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// does nothing but name them and render its argument. The only special
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// thing about them is their behavior in a flow, which depends on the
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// context and is handled by flow functions in [TeX.c].
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//
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// Graphical parameters:
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//
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// TEX_SUPERSCRIPT_DEPTH:
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// Distance between bottom of superscript and top of base
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// TEX_SUBSCRIPT_ELEVATION:
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// Distance between top of subscript and bottom of base
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//
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// +-----+
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// | |
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// +------+ 1 | --,
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// | Base | | | TEX_SUPERSCRIPT_DEPTH
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// | +-----+ --'
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// +------+
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//
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// +------+
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// | +-----+ --,
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// | Base | | | TEX_SUBSCRIPT_ELEVATION
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// +------| 1 | --'
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// | |
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// +-----+
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//---
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void supsubscript_size(struct TeX_Node *node)
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{
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/* Invalidate node if no argument is provided */
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if(!args[0]) { node->hidden = 1; return; }
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node->width = w(0);
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node->height = h(0);
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node->line = l(0);
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}
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void supsubscript_render(struct TeX_Node const * node, int x, int y,
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int color)
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{
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render_flow(args[0], x, y, color);
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}
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//---
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// The class table and lookup functions
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//---
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struct TeX_Class TeX_table[] = {
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/* Text is omitted from the table and has ID 0 */
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/* Fractions */
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{ "frac", frac_size, frac_render },
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/* Size-aware opening and closing elements */
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{ "left", leftright_size, leftright_render },
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{ "right", leftright_size, leftright_render },
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/* Superscripts and subscripts */
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{ "\\sup", supsubscript_size, supsubscript_render },
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{ "\\sub", supsubscript_size, supsubscript_render },
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/* Integral */
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{ "int", NULL, NULL },
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/* NULL terminator */
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{ NULL, NULL, NULL },
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};
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/* class_find() - Find a class using a command name */
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int class_find(const char *name)
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{
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/* TODO: Do a binary search instead of a linear one */
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for(int i = 0; TeX_table[i].name; i++)
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{
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if(!strcmp(TeX_table[i].name, name)) return i + 1;
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}
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return -1;
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}
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